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Sample records for inverted polymer solar

  1. Towards high performance inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Gong, Xiong

    2013-03-01

    Bulk heterojunction polymer solar cells that can be fabricated by solution processing techniques are under intense investigation in both academic institutions and industrial companies because of their potential to enable mass production of flexible and cost-effective alternative to silicon-based electronics. Despite the envisioned advantages and recent technology advances, so far the performance of polymer solar cells is still inferior to inorganic counterparts in terms of the efficiency and stability. There are many factors limiting the performance of polymer solar cells. Among them, the optical and electronic properties of materials in the active layer, device architecture and elimination of PEDOT:PSS are the most determining factors in the overall performance of polymer solar cells. In this presentation, I will present how we approach high performance of polymer solar cells. For example, by developing novel materials, fabrication polymer photovoltaic cells with an inverted device structure and elimination of PEDOT:PSS, we were able to observe over 8.4% power conversion efficiency from inverted polymer solar cells.

  2. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  3. Photoconductive Cathode Interlayer for Highly Efficient Inverted Polymer Solar Cells.

    PubMed

    Nian, Li; Zhang, Wenqiang; Zhu, Na; Liu, Linlin; Xie, Zengqi; Wu, Hongbin; Würthner, Frank; Ma, Yuguang

    2015-06-10

    A highly photoconductive cathode interlayer was achieved by doping a 1 wt % light absorber, such as perylene bisimide, into a ZnO thin film, which absorbs a very small amount of light but shows highly increased conductivity of 4.50 × 10(-3) S/m under sunlight. Photovoltaic devices based on this kind of photoactive cathode interlayer exhibit significantly improved device performance, which is rather insensitive to the thickness of the cathode interlayer over a broad range. Moreover, a power conversion efficiency as high as 10.5% was obtained by incorporation of our photoconductive cathode interlayer with the PTB7-Th:PC71BM active layer, which is one of the best results for single-junction polymer solar cells.

  4. Electron-collecting oxide layers in inverted polymer solar cells via oxidation of thermally evaporated titanium

    NASA Astrophysics Data System (ADS)

    Zampetti, A.; Salamandra, L.; Brunetti, F.; Reale, A.; Di Carlo, A.; Brown, T. M.

    2016-10-01

    A simple and intuitive deposition technique is discussed to obtain titanium oxide used as an electron collecting layer in polymer solar cells based on the thermal evaporation of pristine titanium and further thermal treatment to convert the metal in oxide. Since the degradation of indium-doped tin oxide at high temperatures is an issue, we demonstrate that the combination of glass/fluorine tin oxide and high temperatures represents a promising approach in the fabrication of inverted polymer solar cells with such a titanium oxide electron collecting layer.

  5. Protonation process of conjugated polyelectrolytes on enhanced power conversion efficiency in the inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yi, Chao; Hu, Rong; Ren, He; Hu, Xiaowen; Wang, Shu; Gong, Xiong; Cao, Yong

    2014-01-01

    In this study, two conjugated polyelectrolytes, polythiophene derivative (PTP) and poly[(9,9-bis [6‧-N, N, N-trimethylammonium] hexyl)-fluorenylene-phenylene] dibromide (PFP), are utilized to modify the surface properties of ZnO electron extraction layer (EEL) in the inverted polymer solar cells (PSCs). Both higher short-circuit current densities and larger open-circuit voltages were observed from the inverted PSCs with ZnO/PFP or ZnO/PTP as compared with those only with ZnO EEL. The protonation process for PTP and PFP in solution is distinguished. Overall, more than 40% enhanced power conversion efficiency (PCE) from the inverted PSCs with ZnO/PFP, in which the PFP could be fully ionized in deionized water, and more than 30% enhanced PCE from the inverted PSCs with ZnO/PTP, as the case that the PTP could not be fully ionized in deionized water, as compared with the inverted PSCs with ZnO EEL were observed, respectively. These results demonstrate that the conjugated polyelectrolytes play an important role in enhancement of device performance of inverted PSCs and that the protonation process of the conjugated polyelectrolytes is critical to the modification for EEL in PSCs.

  6. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    SciTech Connect

    Li, Jiangsheng; Jiu, Tonggang E-mail: fangjf@nimte.ac.cn; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Fang, Junfeng E-mail: fangjf@nimte.ac.cn; Shu, Jie

    2016-05-02

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  7. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    NASA Astrophysics Data System (ADS)

    Li, Jiangsheng; Jiu, Tonggang; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Shu, Jie; Fang, Junfeng

    2016-05-01

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  8. Inverted polymer solar cells with amorphous indium zinc oxide as the electron-collecting electrode

    SciTech Connect

    Cheun, Hyeunseok; Kim, Jungbae; Zhou, Yinhua; Fang, Yunnan; Dindar, Amir; Shim, Jae Won; Fuentes-Hernandez, Canek; Sandhage, Kenneth H.; Kippelen, Bernard

    2010-09-17

    We report on the fabrication and performance of polymer-based inverted solar cells utilizing amorphous indium zinc oxide (a-IZO) as the electron-collecting electrode. Amorphous IZO films of 200 nm thickness were deposited by room temperature sputtering in a high-purity argon atmosphere. The films possessed a high optical transmittance in the visible region (≥ 80%), a low resistivity (3.3 × 10-4 Ωcm), a low surface roughness (root mean square = 0.68 nm), and a low work function (4.46 ± 0.02 eV). Inverted solar cells with the structure a-IZO/P3HT: PCBM/PEDOT:PSS/Ag exhibited a power conversion efficiency of 3% estimated for AM 1.5G, 100 mW/cm2 illumination.

  9. Blade-coated sol-gel indium-gallium-zinc-oxide for inverted polymer solar cell

    NASA Astrophysics Data System (ADS)

    Lee, Yan-Huei; Tsai, Pei-Ting; Chang, Chia-Ju; Meng, Hsin-Fei; Horng, Sheng-Fu; Zan, Hsiao-Wen; Lin, Hung-Cheng; Liu, Hung-Chuan; Tseng, Mei-Rurng; Yeh, Han-Cheng

    2016-11-01

    The inverted organic solar cell was fabricated by using sol-gel indium-gallium-zinc-oxide (IGZO) as the electron-transport layer. The IGZO precursor solution was deposited by blade coating with simultaneous substrate heating at 120 °C from the bottom and hot wind from above. Uniform IGZO film of around 30 nm was formed after annealing at 400 °C. Using the blend of low band-gap polymer poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b:4,5-b')dithiophene)-2,6-diyl-alt- (4-(2-ethylhexanoyl)-thieno [3,4-b]thiophene-)-2-6-diyl)] (PBDTTT-C-T) and [6,6]-Phenyl C71 butyric acid methyl ester ([70]PCBM) as the active layer for the inverted organic solar cell, an efficiency of 6.2% was achieved with a blade speed of 180 mm/s for the IGZO. The efficiency of the inverted organic solar cells was found to depend on the coating speed of the IGZO films, which was attributed to the change in the concentration of surface OH groups. Compared to organic solar cells of conventional structure using PBDTTT-C-T: [70]PCBM as active layer, the inverted organic solar cells showed significant improvement in thermal stability. In addition, the chemical composition, as well as the work function of the IGZO film at the surface and inside can be tuned by the blade speed, which may find applications in other areas like thin-film transistors.

  10. Biopolymer as an electron selective layer for inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Jin Tan, Mein; Zhong, Shu; Wang, Rui; Zhang, Zhongxing; Chellappan, Vijila; Chen, Wei

    2013-08-01

    In this work, a solution-processable electron selective layer is introduced for inverted polymer solar cells (PSCs). Cationic biopolymer poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) is used as a solution-processable work function modifier of indium-tin-oxide transparent conducting electrode to yield efficient inverted PSCs of 3.3% under AM1.5G illumination, with poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester as the active layer. Devices using PDMAEMA exhibit greater stability in ambient "working conditions" as compared to devices using ZnO, retaining 90% of peak power conversion efficiency after 8 weeks. Therefore, PDMAEMA has great potential as a universal work function modifier material with high robustness.

  11. Effect of electron collecting metal oxide layer in normal and inverted structure polymer solar cells

    SciTech Connect

    Ng, A.; Liu, X.; Sun, Y. C.; Djurišić, A. B.; Ng, A. M. C.; Chan, W. K.

    2013-12-04

    We performed a systematic study of the effect of electron collecting metal oxide layer on the performance of P3HT: PCBM solar cells. Zinc oxide (ZnO) or titanium dioxide (TiO{sub 2}) buffer layers were prepared by either e-beam evaporation or solution processing method. We also compared the photovoltaic performance of inserting the buffer layer between indium tin oxide (ITO) and the polymer layer for the inverted structure (ITO/ ZnO or TiO{sub 2}/P3HT:PCBM/V{sub 2}O{sub 5}/Au) as well as inserting the buffers layers between the polymer and the aluminum electrode for the conventional structure (ITO/V{sub 2}O{sub 5}/P3HT:PCBM/ZnO or TiO{sub 2}/Al). The results are shown in detail.

  12. Al-doping effects on the photovoltaic performance of inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yu, Xuan; Shi, Ya-feng; Yu, Xiao-ming; Zhang, Jian-jun; Ge, Ya-ming; Chen, Li-qiao; Pan, Hong-jun

    2016-03-01

    The properties of Al-doped ZnO (AZO) play an important role in the photovoltaic performance of inverted polymer solar cells (PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor ( FF) simultaneously, and the power conversion efficiency ( PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.

  13. Device, Interface, Process and Electrode Engineering Towards Low Cost and High Efficiency Polymer Solar Cells in Inverted Structure

    NASA Astrophysics Data System (ADS)

    Zou, Jingyu

    As a promising technology for economically viable alternative energy source, polymer solar cells (PSCs) have attracted substantial interests and made significant progress in the past few years, due the advantages of being potentially easily solution processed into large areas, flexible, light weight, and have the versatility of material design. In this dissertation, an integrated approach is taken to improve the overall performance of polymer solar cells by the development of new polymer materials, device architectures, interface engineering of the contacts between layers, and new transparent electrodes. First, several new classes of polymers are explored as potential light harvesting materials for solar cells. Processing has been optimized and efficiency as high as 6.24% has been demonstrated. Then, with the development of inverted device structure, which has better air stability by utilizing more air stable, high work function metals, newly developed high efficiency polymers have been integrated into inverted structure device with integrated engineering approach. A comprehensive characterization and optical modeling based on conventional and inverted devices have been performed to understand the effect of device geometry on photovoltaic performance based on a newly developed high performance polymer poly(indacenodithiophene-co-phananthrene-quinoxaline) (PIDT-PhanQ). By modifying anode with a bilayer combining graphene oxide (GO) and poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonic acid) (PEDOT:PSS) as hole transporter/electron blocker, it further improved device performance of inverted structured to 6.38%. A novel processing method of sequentially bilayer deposition for active layer has been conducted based on a low band-gap polymer poly[2, 6-(4, 4-bis-(2-ethylhexyl)-4 H-cyclopenta [2,1-b;3,4-b‧] dithiophene)- alt-4,7-(2, 1, 3- fluorobenzothiadiazole)] (PCPDT-FBT). Inverted structure devices processed from bilayer deposition shows even higher

  14. Versatile Device Architectures for High-Performing Light-Soaking-Free Inverted Polymer Solar Cells.

    PubMed

    Yan, Yu; Cai, Feilong; Yang, Liyan; Li, Wei; Gong, Yanyan; Cai, Jinlong; Liu, Shuang; Gurney, Robert S; Liu, Dan; Wang, Tao

    2017-09-27

    Metal oxide charge transport layers have been widely employed to prepare inverted polymer solar cells with high efficiency and long lifetime. However, the intrinsic defects in the metal oxide layers, especially those prepared from low-temperature routes, overshadow the high efficiency that can be achieved and also introduce "light-soaking" issues to these devices. In this work, we have employed polyethyleneimine (PEI) and poly(9,9-bis(6'-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis-(3-ethyl(oxetane-3-ethyloxy)-hexyl)-fluorene] (PFN-OX) to modify our low-temperature-processed TiO2 electron transport layer (ETL) and demonstrated that the light-soaking issue can be effectively eliminated by PEI modifications because of the formation of abundant dipole moments, whereas PFN-OX was ineffective as a result of deficient dipole moments at the interface. Excitingly, PEI modifications enable versatile device architectures to obtain light-soaking-free, inverted PTB7-Th:PC71BM solar cells with efficiencies of over 10%, by adding PEI either in the bulk or as an adjacent layer below or above the TiO2 ETL.

  15. ZnO nanorod arrays for various low-bandgap polymers in inverted organic solar cells.

    PubMed

    Ho, Ping-Yi; Thiyagu, Subramani; Kao, Shao-Hsuan; Kao, Chia-Yu; Lin, Ching-Fuh

    2014-01-07

    Due to the limited diffusion length of carriers in polymer solar cells (PSCs), the path of carriers is a crucial factor that determines the device performance. Zinc oxide nanorods (NRs) as the electron transport channel can reduce electron-hole recombination and transport the electron to the electrode efficiently for poly(3-hexylthiophene) (P3HT), but have been seldom demonstrated for low-bandgap polymers. Here we successfully applied ZnO NRs, which were grown via the hydrothermal method, as a platform to enhance PSC efficiency for various low-bandgap polymers. In order to assure that the nanorod morphology functioned properly for PSCs, the growth time, the concentration, and the resulting morphology were systematically investigated in depths. Such ZnO NRs were applied to different organic systems, resulting in the increase of the PCE for PBDTTT-C/PC71BM from 4.76% to 6.07% and PBDTTT-C-T/PC71BM from 5.40% to 7.34%. Through those experiments, we established a potentially universal and efficient ZnO NRs platform for various low-bandgap polymers to achieve high efficiency of inverted PSCs.

  16. High-Performance Inverted Polymer Solar Cells with Zirconium Acetylacetonate Buffer Layers.

    PubMed

    Fan, Haijun; Zhu, Xiaozhang

    2016-12-14

    Inverted polymer solar cells incorporating solution-processed zirconium acetylacetonate (ZrAcac) buffer layers were demonstrated. The optimal device delivered a power conversion efficiency up to 9.2%, displaying ∼20% improvement compared with the device of conventional configuration. The performance improvement by adopting ZrAcac as the cathode buffer layer is attributed to the enhanced light-harvesting, facilitated electron transport, and reduced bimolecular recombination loss. The morphology of ZrAcac buffer layer was found to be critical in achieving high performance, which was tunable through the selection of processing solvents. A flat and uniform ZrAcac film consisting of ∼20 nm nanoscale aggregates deposited from a chloroform solution was proved to be highly effective, which only requires a short light-soaking time.

  17. High performance of inverted polymer solar cells with cobalt oxide as hole-transporting layer

    NASA Astrophysics Data System (ADS)

    Wang, Xiangdong; Peng, Qing; Zhu, Weiguo; Lei, Gangtie

    2015-05-01

    Cobalt oxide (II, III) (CoOx) was inserted as efficient hole-transporting interlayer between the active layer and top electrode in inverted polymer solar cells (PSCs) with titanium (diisopropoxide) bis(2, 4-pentanedionate) (TIPD) as an electron selective layer. The work function of CoOx was measured by Kelvin probe and the device performances with different thicknesses of cobalt oxide were studied. The device with CoOx exhibited a remarkable improvement in power conversion efficiency compared with that without CoOx, which indicated that CoOx efficiently prevented the recombination of charge carriers at the organic/top electrode interface. The performance improvement was attributed to the fact that the CoOx thin film can module the Schottky barrier and form an ohmic contact at the organic/metal interface, which makes it a promising hole-transporting layer.

  18. Self-organization of amine-based cathode interfacial materials in inverted polymer solar cells.

    PubMed

    Ma, Di; Lv, Menglan; Lei, Ming; Zhu, Jin; Wang, Haiqiao; Chen, Xiwen

    2014-02-25

    We present a strategy to fabricate polymer solar cells in inverted geometry by self-organization of alcohol soluble cathode interfacial materials in donor-acceptor bulk heterojunction blends. An amine-based fullerene [6,6]-phenyl-C61-butyric acid 2-((2-(dimethylamino)-ethyl)(methyl)amino)ethyl ester (PCBDAN) is used as an additive in poly(3-hexylthiophene) (P3HT) and 6,6-phenyl C61-butyric acid methyl ester (PCBM) blend to give a power conversion efficiency of 3.7% based on devices ITO/P3HT:PCBM:PCBDAN/MoO3/Ag where the ITO alone is used as the cathode. A vertical phase separation in favor of the inverted device architecture is formed: PCBDAN is rich on buried ITO surface reducing its work function, while P3HT is rich on air interface with the hole-collecting electrode. The driving force of the vertical phase separation is ascribed to the surface energy and its components of the blend compositions and the substrates. Similar results are also found with another typical alcohol soluble cathode interfacial materials, poly[(9,9-bis(3'-(N, N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN), implying that self-organization may be a general phenomenon in ternary blends. This self-organization procedure could eliminate the fabrication of printing thin film of interlayers or printing on such thin interlayers and would have potential application for roll-to-roll processing of polymer solar cells.

  19. Inverted planar heterojunction perovskite solar cells employing polymer as the electron conductor.

    PubMed

    Wang, Weiwei; Yuan, Jianyu; Shi, Guozheng; Zhu, Xiangxiang; Shi, Shaohua; Liu, Zeke; Han, Lu; Wang, Hai-Qiao; Ma, Wanli

    2015-02-25

    Inverted planar heterojunction perovskite solar cells employing different polymers, poly{[N,N'-bis(2-octyldodecyl)-1,4,5,8-naphthalene diimide-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (N2200), poly{[N,N'-bis(alkyl)-1,4,5,8-naphthalene diimide-2,6-diyl-alt-5,5'-di(thiophen-2-yl)-2,2'-(E)-2-(2-(thiophen-2-yl)vinyl)thiophene]} (PNVT-8), and PNDI2OD-TT as electron-transporting material (ETM) have been investigated for the first time. The best device performance was obtained when N2200 was applied as the ETM, with JSC of 14.70 mA/cm2, VOC of 0.84 V, and fill factor (FF) of 66%, corresponding to a decent power conversion efficiency (PCE) of ∼ 8.15%. Which is very competitive to the parameters (JSC 14.65 mA/cm2, VOC 0.83 V, FF 70%, and PCE 8.51%) of the reference device employing conventional PCBM as the ETM. The slightly lower FF could be mainly accounted for by the increased recombination in the polymer contained devices. This work demonstrated that polymeric materials can be used as efficient ETM in perovskite solar cells, and we believe this class of polymeric ETMs will further promote the performance of perovskite photovoltaic cells after extended investigation.

  20. Electron-transporting small molecule/ o-xylene hybrid additives to boost the performance of simplified inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Qin, Dashan; Cao, Huan; Zhang, Jidong

    2017-05-01

    Electron-transporting small molecule bathophenanthroline (Bphen) together with o-xylene has been used as hybrid additives to improve the performance of simplified inverted polymer solar cells employing ITO alone as cathode and photoactive layer based on polymer [[2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b] dithiophene] [3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  1. Flexible inverted polymer solar cells fabricated in air at low temperatures

    NASA Astrophysics Data System (ADS)

    Kuwabara, Takayuki; Wang, Xiaofan; Kusumi, Takuji; Yamaguchi, Takahiro; Taima, Tetsuya; Takahashi, Kohshin

    2016-08-01

    A series of modified indium tin oxide (ITO) materials, including sol-gel zinc-oxide-coated ITO (ITO/ZnO), ZnO nanoparticle-coated ITO (ITO/ZnO-NP), 1,4-bis(3-aminopropyl)piperazine (BAP)-modified ITO, and polyethylenimine ethoxylated (PEIE)-modified ITO, were used for electron-collection electrodes in inverted polymer solar cells (PSCs). The modified ITO electrodes were prepared in air at temperatures below 100 °C, using various ITO films on flexible poly(ethylene terephthalate) substrates (PET-ITO) with sheet resistances ranging from 12 to 60 Ω sq-1. The PET-ITO (12 Ω sq-1)/ZnO-NP PSC exhibited an improved power conversion efficiency (PCE) (2.93%), and this PCE was ˜90% of that observed for a cell using glass-ITO/ZnO-NP (sheet resistance = 10 Ω sq-1 PCE = 3.28%). Additionally, we fabricated a flexible inverted ZnO-NP PSC using an indene-C60 bisadduct (ICBA) as the acceptor material in place of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and obtained a PCE of 4.18%.

  2. High electron mobility ZnO film for high-performance inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Lv, Peiwen; Chen, Shan-Ci; Zheng, Qingdong; Huang, Feng; Ding, Kai

    2015-04-01

    High-quality ZnO films (ZnO-MS) are prepared via magnetron sputtering deposition with a high mobility of about 2 cm2/(V.s) and are used as electron transport layer for inverted polymer solar cells (PSCs) with polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester as the active layer. A significant improvement of JSC, about 20% enhancement in contrast to the devices built on sol-gel derived ZnO film (ZnO-Sol), is found in the ZnO-MS based device. High performance ZnO-MS based PSCs exhibit power conversion efficiency (PCE) up to 8.55%, which is much better than the device based on ZnO-Sol (PCE = 7.78%). Further research on cathode materials is promising to achieve higher performance.

  3. Inverted polymer solar cells with employing of electrochemical-anodizing synthesized TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Mehdi, Ahmadi; Sajjad Rashidi, Dafeh; Hamed, Fatehy

    2016-04-01

    An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester (PCBM) with using thin films of TiO2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO2 thin films with different thickness values are fabricated. Two cells use layers of TiO2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol-gel synthesized TiO2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO2 nanotubes grow in length the series resistance (R s) between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.

  4. High-performance inverted polymer solar cells based on thin copper film

    NASA Astrophysics Data System (ADS)

    Luo, Guoping; Cheng, Xiaoping; He, Zhicai; Wu, Hongbin; Cao, Yong

    2015-01-01

    We report the fabrication of cost-effective indium-free polymer solar cells (PSCs) with an inverted structure that incorporates an ultrathin copper (Cu) film as a bottom cathode via thermal evaporation. The average optical transmittance of the 15-nm Cu coated glass substrate in the visible region of the spectrum was found to be around 80% with a highest value of 84.5%. The Cu electrode was modified by an interfacial layer of an alcohol-/water-soluble conjugated polymer, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) interlayer to ensure a very smooth surface. Upon the use of the PFN interfacial layer, the work function of Cu was decreased from 4.68 to 4.31 eV, which can form an Ohmic contact with photoactive layer and facilitate electrode transport and extraction. As a result, a power conversion efficiency of 3.6% was achieved when poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] and a [6,6]-phenyl C71-butyric acid methyl ester blend were utilized as the photoactive layers, demonstrating that the thermally evaporated Cu thin-film electrode can be a promising candidate to replace indium tin oxide for highly efficient PSCs.

  5. High electron mobility ZnO film for high-performance inverted polymer solar cells

    SciTech Connect

    Lv, Peiwen; Chen, Shan-Ci; Zheng, Qingdong; Huang, Feng Ding, Kai

    2015-04-20

    High-quality ZnO films (ZnO-MS) are prepared via magnetron sputtering deposition with a high mobility of about 2 cm{sup 2}/(V·s) and are used as electron transport layer for inverted polymer solar cells (PSCs) with polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′] dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester as the active layer. A significant improvement of J{sub SC}, about 20% enhancement in contrast to the devices built on sol-gel derived ZnO film (ZnO-Sol), is found in the ZnO-MS based device. High performance ZnO-MS based PSCs exhibit power conversion efficiency (PCE) up to 8.55%, which is much better than the device based on ZnO-Sol (PCE = 7.78%). Further research on cathode materials is promising to achieve higher performance.

  6. Well-defined star-shaped conjugated macroelectrolytes as efficient electron-collecting interlayer for inverted polymer solar cells.

    PubMed

    Xu, Weidong; Kan, Zhipeng; Ye, Tengling; Zhao, Li; Lai, Wen-Yong; Xia, Ruidong; Lanzani, Guglielmo; Keivanidis, Panagiotis E; Huang, Wei

    2015-01-14

    A star-shaped monodisperse conjugated macroelectrolyte grafted with cationic side chains, TrNBr, was designed, synthesized, and utilized as efficient electron-collecting cathode interlayers for inverted polymer solar cells. A neutral one composed of identical star-shaped conjugated backbone, TrOH, was also investigated for comparison. The surface properties and the function as interfacial layers on modulating the work function of bottom electrode (indium tin oxide) were systematically studied. Both interfacial electron-selective materials show strongly thickness-dependent performance for inverted polymer solar cells, and the best performance could be achieved via optimizing the thickness with 2.4 nm of TrNBr and 8.7 nm of TrOH. Parallel investigations of optimized TrNBr and TrOH interlayer in inverted architecture with active blend layer of poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:ICBA) demonstrated a remarkable power conversion efficiency (PCE) enhancement (PCE of 4.88% for TrNBr and 4.74% for TrOH) in comparison with those of conventional noninverted devices using Ca/Al cathodes (3.94%) and inverted devices with sol-gel ZnO buffer layer (4.21%). In addition, the inverted devices using the TrNBr and TrOH interlayer exhibited improved device stability in contrast to conventional noninverted devices using Ca/Al cathodes.

  7. Solution-processed cross-linkable hole selective layer for polymer solar cells in the inverted structure

    NASA Astrophysics Data System (ADS)

    Sun, Yanming; Gong, Xiong; Hsu, Ben B. Y.; Yip, Hin-Lap; Jen, Alex K.-Y.; Heeger, Alan J.

    2010-11-01

    Solution-processed cross-linkable tetraphenyldiamine-containing material (TPD-BVB) as a highly efficient hole selective transport layer was demonstrated. Polymer solar cells (PSCs) with an inverted structure fabricated with a thin cross-linked TPD-BVB film show comparable efficiency and superior long-term air stability when compared to devices fabricated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). Thus, solution-processed TPD-BVB is an attractive alternative to PEDOT:PSS as a hole extraction layer in inverted structure PSCs.

  8. Properties of Vanadium-Doped Indium Oxide Deposited at Room Temperature as Transparent Conductor for Inverted Polymer Solar Cells

    NASA Astrophysics Data System (ADS)

    Choi, Min-Jun; Lim, Keun Yong; Park, Hyun-Woo; Kim, Han-Ki; Hwang, Do Kyung; Lim, Sung-Jin; Shim, Jae Won; Chung, Kwun-Bum

    2017-10-01

    The properties of vanadium-doped indium oxide (IVO) deposited at room temperature as a transparent conductor for inverted polymer solar cells have been investigated as a function of the vanadium doping concentration. IVO film prepared with V doping concentration of 0.03% showed optimal properties for use as a transparent conductor with figure of merit of 4.35 × 10-3 Ohm-1, related to altered band alignment between the Fermi level and conduction-band minimum. In the optimal optoelectrical conditions for the IVO film, performance optimization of PTB7:PC70BM inverted polymer solar cells resulted in maximum power conversion efficiency of 4.7 ± 0.4% under simulated air mass 1.5 global illumination at 100 mW/cm2.

  9. Development of highly transparent seedless ZnO nanorods engineered for inverted polymer solar cells.

    PubMed

    Ambade, Swapnil B; Ambade, Rohan B; Lee, Wonjoo; Mane, Rajaram S; Yoon, Sung Cheol; Lee, Soo-Hyoung

    2014-10-21

    This work reports on inverted polymer solar cells (IPSCs) based on highly transparent (>95%), hydrophobic, seedless ZnO nanorods (NRs) as cathode buffers with extremely enhanced electrical characteristics. The transparent NR suspension with stability for more than a year is achieved by adding a small amount of 2-(2-methoxyethoxy) acetic acid (MEA). The ability of the stable nanorod suspension to easily spin-coat is certainly an advance to the fabrication of films over large areas and to replace the conventional seeding method to grow one-dimensional nanostructures for use in optoelectronic devices. We observe a strong correlation between the photovoltaic performance and the transparency of ZnO NRs. IPSCs using poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C60 butyric acid methyl ester (PCBM) mixtures in the active layer and transparent (MEA-capped) ZnO NRs as cathode buffers exhibit a power conversion efficiency of 3.24% under simulated AM 1.5G, 100 mW cm(-2) illumination.

  10. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Zhiyong; Wang, Ning; Fu, Yan

    2016-12-01

    The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO3/Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO2 as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Tidbnd O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  11. Alcohol-soluble interfacial fluorenes for inverted polymer solar cells: sequence induced spatial conformation dipole moment.

    PubMed

    Chen, Lie; Liu, Xiangfu; Wei, Yingkai; Wu, Feiyan; Chen, Yiwang

    2016-01-21

    Three fluorene-based alcohol-soluble organic small molecule electrolytes (SMEs) with different conjugated backbones, namely, TFTN-Br, FTFN-Br and FTTFN-Br, were designed as cathode interfacial layers for inverted polymer solar cells (i-PSCs). The insertion of SMEs to the ITO/active layer interfaces effectively lowered the energy barrier for electron transport and improved the inherent compatibility between the hydrophilic ITO and hydrophobic active layers. Due to these advantages, the device based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl-C61 butyric acid methyl ester (PC61BM) with TFTN-Br as the cathode interfacial layer achieved an improved power conversion efficiency (PCE) of 3.8%, which is a 26% improvement when compared to the standard device comprising ZnO cathode interfacial layers (PCE = 3.0%). Devices with FTFN-Br and FTTFN-Br also showed an improved PCE of 3.1% and 3.5%, respectively. The variation in device performance enhancement was found to be primarily correlated with the different conformation of their assembly onto the electrode caused by the joint sequence of the polar group of the SMEs, consequently impacting the dipole moment and interface morphology. In addition, introducing SMEs as the cathode interfacial layer also produced devices with long-term stability.

  12. Electrical and Optical Properties of ZnO Processed by Atomic Layer Deposition in Inverted Polymer Solar Cells

    SciTech Connect

    Cheun, Hyeunseok; Fuentes-Hernandez, Canek; Zhou, Yinhua; Potscavage, William J.; Kim, Sung-Jin; Shim, Jae Won; Dindar, Amir; Kippelen, Bernard

    2010-12-09

    We report on the photovoltaic properties of inverted polymer solar cells where the transparent electron-collecting electrode is formed by a ZnO-modified indium-tin oxide (ITO) electrode. The ZnO layers were deposited by atomic layer deposition (ALD) with varying thicknesses from 0.1 to 100 nm. The work function, surface roughness, and morphology of ITO/ZnO were found to be independent of the ZnO thickness. However, the device performance was found to be strongly dependent on a critical ZnO thickness, around 10 nm. Below the critical thickness the device performance was degraded because of the appearance of a “kink” in the current-voltage characteristics. The kink features became less pronounced after ultraviolet (UV) exposure. This was attributed to oxygen desorption, leading to an increased conductivity of the ZnO layer. At and above this critical thickness, the device performance significantly improved and no longer depended strongly on the thickness of the ZnO layer, in agreement with optical simulations. Instead, these optical simulations showed that the thickness of the active layer plays a more important role than the thickness of the ZnO layer in optimizing the photovoltaic properties of inverted solar cells. Inverted polymer solar cells with an increased thickness of the active layer showed a power conversion efficiency (PCE) of 3.06% estimated for AM1.5G, a 100 mW cm-2 illumination.

  13. Alternative alcohol-soluble conjugated small molecule electrolytes for high-efficiency inverted polymer solar cells.

    PubMed

    Shi, Yueqin; Tan, Licheng; Chen, Lie; Chen, Yiwang

    2015-02-07

    New alcohol-soluble conjugated small molecule electrolytes (CSMEs), 3,6-bis-(5-benzoic acid-thiophen-2-yl)-2,5-bis-(2-ethylhexyl)-2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4-dione liquid crystalline (DPP-COOH) and di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II) dye (N719), are developed as interfacial modification in inverted polymer solar cells (PSCs). Further optimization of the device architecture by combining the electrolytes as hole and electron buffer layers can significantly promote the photovoltaic performances of PSCs due to the integrated advantages of excellent alcohol processability, hole and electron mobility, interfacial dipole effect and good energy level alignment with electrodes. Moreover, the PSCs with the CSMEs interlayers based on narrow band-gap PTB7:PC71BM active layers show considerable improvement in power conversion efficiency (PCE), compared with P3HT:PCBM active layer-based devices. Devices with DPP-COOH and N719 modifications after thermal treatment at 120 °C exhibit the PCE of 8.0% and 7.6% under AM 1.5G irradiation, respectively, improving from 6.7% PCE of the pristine device without any interfacial layer. Encouragingly, the simultaneous use of CSMEs as hole and electron modification layers can boost the PCE to 8.2%. These findings demonstrate that the utilization of alcohol-soluble small molecule conjugated electrolytes with lower band gaps as interfacial modification layers is an effective and practical strategy for improving photovoltaic performance in PSCs.

  14. Unraveling the effect of polymer dots doping in inverted low bandgap organic solar cells.

    PubMed

    Zhang, Xinyuan; Liu, Chunyu; Li, Jinfeng; He, Yeyuan; Li, Zhiqi; Li, Hao; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-06-28

    In this study, molecular doping with polymer dots was designed to unravel its effect on the photoconductivity in organic solar cells. The photocurrent in organic solar cells exhibited a considerable increase under optimal doping concentration, leading to an ultimate enhancement of power conversion efficiency from 2.30% to 3.64%. This can be attributed primarily to the improvement of the initial boost in charge carriers due to the background carriers induced by the polymer dots and increased tail absorption by the active layer. Based on single carrier device and impedance measurements, polymer dopant can efficiently decrease charge recombination and improve charge carriers mobilities. The obtained achievements pave an approach of molecular doping in affecting the operation of organic solar cells.

  15. MoO3 Thickness, Thermal Annealing and Solvent Annealing Effects on Inverted and Direct Polymer Photovoltaic Solar Cells

    PubMed Central

    Chambon, Sylvain; Derue, Lionel; Lahaye, Michel; Pavageau, Bertrand; Hirsch, Lionel; Wantz, Guillaume

    2012-01-01

    Several parameters of the fabrication process of inverted polymer bulk heterojunction solar cells based on titanium oxide as an electron selective layer and molybdenum oxide as a hole selective layer were tested in order to achieve efficient organic photovoltaic solar cells. Thermal annealing treatment is a common process to achieve optimum morphology, but it proved to be damageable for the performance of this kind of inverted solar cells. We demonstrate using Auger analysis combined with argon etching that diffusion of species occurs from the MoO3/Ag top layers into the active layer upon thermal annealing. In order to achieve efficient devices, the morphology of the bulk heterojunction was then manipulated using the solvent annealing technique as an alternative to thermal annealing. The influence of the MoO3 thickness was studied on inverted, as well as direct, structure. It appeared that only 1 nm-thick MoO3 is enough to exhibit highly efficient devices (PCE = 3.8%) and that increasing the thickness up to 15 nm does not change the device performance.

  16. Hydrophilic Conjugated Polymers with Large Bandgaps and Deep-Lying HOMO Levels as an Efficient Cathode Interlayer in Inverted Polymer Solar Cells.

    PubMed

    Kan, Yuanyuan; Zhu, Yongxiang; Liu, Zhulin; Zhang, Lianjie; Chen, Junwu; Cao, Yong

    2015-08-01

    Two hydrophilic conjugated polymers, PmP-NOH and PmP36F-NOH, with polar diethanol-amine on the side chains and main chain structures of poly(meta-phenylene) and poly(meta-phenylene-alt-3,6-fluorene), respectively, are successfully synthesized. The films of PmP-NOH and PmP36F-NOH show absorption edges at 340 and 343 nm, respectively. The calculated optical bandgaps of the two polymers are 3.65 and 3.62 eV, respectively, the largest ones so far reported for hydrophilic conjugated polymers. PmP-NOH and PmP36F-NOH also possess deep-lying highest occupied molecular orbital levels of -6.19 and -6.15 eV, respectively. Inserting PmP-NOH and PmP36F-NOH as a cathode interlayer in inverted polymer solar cells with a PTB7/PC71 BM blend as the active layer, high power conversion efficiencies of 8.58% and 8.33%, respectively, are achieved, demonstrating that the two hydrophilic polymers are excellent interlayers for efficient inverted polymer solar cells.

  17. Conductive water/alcohol-soluble neutral fullerene derivative as an interfacial layer for inverted polymer solar cells with high efficiency.

    PubMed

    Yi, Chao; Yue, Kan; Zhang, Wen-Bin; Lu, Xiaocun; Hou, Jianhui; Li, Yongfang; Huang, Lin; Newkome, George R; Cheng, Stephen Z D; Gong, Xiong

    2014-08-27

    Dipole induced vacuum level shift has been demonstrated to be responsible for the enhanced efficiency in polymer solar cells (PSCs).The modified energy level alignment could reduce the energy barrier and facilitate charge transport, thereby increasing the efficiency of PSCs. Herein, we report a new mechanism toward enhanced efficiency by using a nondipolar water/alcohol-soluble neutral fullerene derivative to reengineer the surface of the zinc oxide (ZnO) electron extraction layer (EEL) in inverted PSCs. Because of the neutral property (ion-free) of the fullerene derivatives, no dipole moment was introduced at the EEL/active layer interface. A negligible change in open-circuit voltage was observed from inverted PSCs with the neutral fullerene derivative layer. The neutral fullerene derivative layer greatly increased the surface electronic conductivity of the ZnO EEL, suppressed surface charge recombination, and increased the short-circuit current density and fill factor. An overall power conversion efficiency increase of more than 30% from inverted PSCs was obtained. These results demonstrate that the surface electronic conductivity of the EEL plays an important role in high performance inverted PSCs.

  18. Improving charge transport property and energy transfer with carbon quantum dots in inverted polymer solar cells

    SciTech Connect

    Liu, Chunyu; Chang, Kaiwen; Guo, Wenbin E-mail: chenwy@jlu.edu.cn Li, Hao; Shen, Liang; Chen, Weiyou E-mail: chenwy@jlu.edu.cn; Yan, Dawei E-mail: chenwy@jlu.edu.cn

    2014-08-18

    Carbon quantum dots (Cdots) are synthesized by a simple method and introduced into active layer of polymer solar cells (PSCs). The performance of doped devices was apparently improved, and the highest power conversion efficiency of 7.05% was obtained, corresponding to a 28.2% enhancement compared with that of the contrast device. The charge transport properties, resistance, impedance, and transient absorption spectrum are systematically investigated to explore how the Cdots affect on PSCs performance. This study reveals the importance of Cdots in enhancing the efficiency of PSCs and gives insight into the mechanism of charge transport improvement.

  19. Inverted polymer solar cell using `Ta' doped V2O5 thin film as cathodic buffer layer

    NASA Astrophysics Data System (ADS)

    Kovendhan, M.; Joseph, D. Paul; Babu, K. Sowri; Sendilkumar, A.

    2017-05-01

    `Ta' 8 wt % doped V2O5 thin film was deposited onto ITO substrate by thermal evaporation method. The XRD pattern confirms the film to be polycrystalline with orthorhombic structure. The SEM image show a smooth spongy bush like structure. Transparency of `Ta' 8 wt % doped V2O5 film is around 35% in visible region and it decreased in IR region. Transport properties were studied by Hall effect measurements. Inverted polymer solar cell using `Ta' 8 wt % doped V2O5 thin film as cathodic buffer layer with device structure ITO/`Ta' 8 wt % V2O5/P3HT:PCBM/MoO3/Ag has been fabricated and studied.

  20. Optimized inverted polymer solar cells incorporating Cs2CO3-doped C60 as electron transport layer

    NASA Astrophysics Data System (ADS)

    Barbot, A.; Lucas, B.; Di Bin, C.; Ratier, B.; Aldissi, M.

    2013-05-01

    An efficient charge transfer between co-sublimed cesium carbonate (Cs2CO3) and fullerene C60 provides an n-type material exhibiting an electrical conductivity above 1 S/cm. This type of doped layers can be used in organic optoelectronic devices to reduce ohmic losses at organic-electrode interfaces. We report here an analysis of inverted polymer-based solar cells incorporating Cs2CO3 doped C60 as electron transport layer (ETL). The optimization of both dopant concentration and thickness resulted in a maximum efficiency of 3.79% compared to 3% for similar devices using undoped C60 as ETL and 2.13% for devices without any ETL.

  1. Physically adsorbed fullerene layer on positively charged sites on zinc oxide cathode affords efficiency enhancement in inverted polymer solar cell.

    PubMed

    Cheng, Yu-Shan; Liao, Sih-Hao; Li, Yi-Lun; Chen, Show-An

    2013-07-24

    We present a novel idea for overcoming the drawback of poor contact between the ZnO cathode and active layer interface in an inverted polymer solar cell (i-PSC), simply by incorporating an electron-acceptor self-assembled monolayer (SAM)--tetrafluoroterephthalic acid (TFTPA)--on the ZnO cathode surface to create an electron-poor surface of TFTPA on ZnO. The TFTPA molecules on ZnO are anchored on the ZnO surface by reacting its carboxyl groups with hydroxyl groups on the ZnO surface, such that the tetrafluoroterephthalate moieties lay on the surface with plane-on electron-poor benzene rings acting as positive charge centers. Upon coating a layer of fullerenes on top of it, the fullerene molecules can be physically adsorbed by Coulombic interaction and facilitate a promoted electron collection from the bulk. The active layer is composed of the mid bandgap polymer poly(3-hexylthiophene) (P3HT) or low bandgap polymer, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl

  2. A nano-grid structure made of perovskite SrTiO3 nanowires for efficient electron transport layers in inverted polymer solar cells.

    PubMed

    Kim, Jeong Won; Suh, Yo-han; Lee, Chang-Lyoul; Kim, Yong Seok; Kim, Won Bae

    2015-03-14

    A nano-grid structure of perovskite SrTiO3 NWs is developed for a novel electron transport layer in inverted polymer solar cells. Due to the excellent charge transporting properties of the SrTiO3 nano-grid structure, the device employing this nanostructure showed ∼32% enhanced photovoltaic performance, compared to the solar cell using a TiO2 thin film.

  3. Chemical Modification of n-Type-Material Naphthalene Diimide on ITO for Efficient and Stable Inverted Polymer Solar Cells.

    PubMed

    Li, Zhendong; Liu, Yanfeng; Zhang, Kaicheng; Wang, Zhaowei; Huang, Peng; Li, Dahua; Zhou, Yi; Song, Bo

    2017-09-05

    To provide orthogonal solvent processable surface modification and improve the device stability of bulk-heterojunction polymer solar cells (PSCs), n-type semiconducting material naphthalene diimide (NDI) was chemically introduced onto the ITO surface as a cathode interlayer (CIL) using 3-bromopropyltrimethoxysilane (BrTMS) as a coupling agent. After modification, the work function of ITO can be decreased from 4.70 to 4.23 eV. The modified ITO cathode was applied in inverted PSCs based on PTB7-Th:PC71BM. With the CIL modification, a champion power conversion efficiency (PCE) of 5.87% was achieved, showing a dramatic improvement compared to that of devices (PCE = 3.58%) without CIL. More importantly, with these chemical bonded interlayers, the stability of inverted PSCs was greatly enhanced. The improved PCE and stability can be attributed to the increased open-circuit voltage and the formation of robust chemical bonds in NDI-TMS films, respectively. This study demonstrated that chemical modification of ITO with n-type semiconducting materials provides an avenue for not only solving the solvent orthogonal problem but also improving the device performance in terms of the PCE and the stability.

  4. Efficient inverted polymer solar cells integrated with a compound electron extraction layer

    NASA Astrophysics Data System (ADS)

    Ma, Zhong-Sheng; Wang, Qian-Kun; Li, Chi; Li, Yan-Qing; Zhang, Dan-Dan; Liu, Weimin; Wang, Pengfei; Tang, Jian-Xin

    2015-12-01

    We constructed an effective electron extraction layer (EEL) used for polymer solar cells by integrating one new kind of organic material of 4,4‧-(1,4-phenylene) bis(2-phenyl-6-p-tolylnicotinonitrile) (p-PPtNT) and cesium carbonate (Cs2CO3) used as a compound EEL (CEEL). The CEEL based device exhibits an ideal PCE of 4.15%, corresponding to an enhancement 220% in contrast to that of control device without EEL, which is also comparable to that of ZnO based device. Our analyses indicated that the remarkably improved PCE for CEEL based device is mainly ascribed to the Ohmic contact and the negligible electron extraction barrier at cathode/active layer by inserting CEEL.

  5. Low-Work-Function, ITO-Free Transparent Cathodes for Inverted Polymer Solar Cells.

    PubMed

    Xue, Zhichao; Liu, Xingyuan; Lv, Ying; Zhang, Nan; Guo, Xiaoyang

    2015-09-16

    A low-work-function, indium tin oxide (ITO)-free transparent cathode having a tin oxide (SnOX)/Ag/SnOX/bismuth oxide (Bi2O3) (SASB) structure is developed without using annealing treatment. This represents the first time that Bi2O3 has been introduced to lower the work function of transparent electrodes. The SASB transparent cathode exhibits excellent photoelectric properties with a maximum transmittance of ∼88%, a low sheet resistance of ∼9.0 Ω·sq(-1), and a suitable work function of 4.22 eV that matches the lowest unoccupied molecular orbital level of the acceptor for exacting electrons efficiently. The power conversion efficiency of the polymer solar cell with the SASB electrode is 6.21%, which is comparable to that of ITO-based devices. The results indicate that SASB is a good alternative to ITO as transparent cathodes in optoelectronic devices.

  6. High-efficiency inverted polymer solar cells controlled by the thickness of polyethylenimine ethoxylated (PEIE) interfacial layers.

    PubMed

    Li, Ping; Wang, Gang; Cai, Lun; Ding, Baofu; Zhou, Dachen; Hu, Yi; Zhang, Yujun; Xiang, Jin; Wan, Keming; Chen, Lijia; Alameh, Kamal; Song, Qunliang

    2014-11-21

    In this work, we investigate the effect of the thickness of the polyethylenimine ethoxylated (PEIE) interface layer on the performance of two types of polymer solar cells based on inverted poly(3-hexylthiophene) (P3HT):phenyl C61-butryric acid methyl ester (PCBM) and thieno[3,4-b]thiophene/benzodithiophene (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM). Maximum power conversion efficiencies of 4.18% and 7.40% were achieved at a 5.02 nm thick PEIE interface layer, for the above-mentioned solar cell types, respectively. The optimized PEIE layer provides a strong enough dipole for the best charge collection while maintaining charge tunneling ability. Optical transmittance and atomic force microscopy measurements indicate that all PEIE films have the same high transmittance and smooth surface morphology, ruling out the influence of the PEIE layer on these two parameters. The measured external quantum efficiencies for the devices with thick PEIE layers are quite similar to those of the optimized devices, indicating the poor charge collection ability of thick PEIE layers. The relatively low performance of devices with a PEIE layer of thickness less than 5 nm is the result of a weak dipole and partial coverage of the PEIE layer on ITO.

  7. Enhanced efficiency of inverted polymer solar cells by using solution-processed TiOx/CsOx cathode buffer layer.

    PubMed

    Zhou, Xiaodong; Fan, Xi; Sun, Xianke; Zhang, Yunli; Zhu, Ziqiang

    2015-01-01

    In this work, a double-buffer film of TiOx coated with CsOx (TiOx/CsOx) was solution prepared to be applied in poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:ICBA) and P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) inverted polymer solar cells (PSCs). Compared with TiOx films and CsOx films, the TiOx/CsOx double-buffer film exhibited a favorable energy-level alignment among TiOx, CsOx, and the electron acceptor of PCBM or ICBA a better surface morphology; and an enhanced wetting and adhesion property with a contact angle of 21.0°, leading to a higher electron mobility of 5.52 × 10(-3) cm(2) V(-1)·s(-1). Moreover, the P3HT:ICBA and P3HT:PCBM photovoltaic devices with the double-buffer film showed the best power conversion efficiency up to 5.65% and 3.76%, respectively. Our results not only present that the double-buffer film is superior than the single film of TiOx and CsOx, but also imply that the solution-processed film has a potential to be generally used in roll-to-roll processed organic photovoltaic devices.

  8. Orienting the Microstructure Evolution of Copper Phthalocyanine as an Anode Interlayer in Inverted Polymer Solar Cells for High Performance.

    PubMed

    Li, Zhiqi; Liu, Chunyu; Zhang, Xinyuan; Li, Shujun; Zhang, Xulin; Guo, Jiaxin; Guo, Wenbin; Zhang, Liu; Ruan, Shengping

    2017-09-20

    Recent advances in the interfacial modification of inverted-type polymer solar cells (PSCs) have resulted from controlling the surface energy of the cathode-modified layer (TiO2 or ZnO) to enhance the short-circuit current (Jsc) or optimizing the contact morphology of the cathode (indium tin oxide or fluorine-doped tin oxide) and active layer to increase the fill factor. Herein, we report that the performance enhancement of PSCs is achieved by incorporating a donor macromolecule copper phthalocyanine (CuPc) as an anode modification layer. Using the approach based on orienting the microstructure evolution, uniformly dispersed island-shaped CuPc spot accumulations are built on the top of PTB7:PC71BM blend film, leading to an efficient spectral absorption and photogenerated exciton splitting. The best power conversion efficiency of PSCs is increased up to 9.726%. In addition to the enhanced light absorption, the tailored anode energy level alignment and optimized boundary morphology by incorporating the CuPc interlayer boost charge extraction efficiency and suppress the interfacial molecular recombination. These results demonstrate that surface morphology induction through molecular deposition is an effective method to improve the performance of PSCs, which reveals the potential implications of the interlayer between the organic active layer and the electrode buffer layer.

  9. Dye-sensitized nanoarrays with discotic liquid crystals as interlayer for high-efficiency inverted polymer solar cells.

    PubMed

    Shi, Yueqin; Tan, Licheng; Chen, Yiwang

    2014-10-22

    The well-aligned and highly uniform one-dimensional ZnO with organic dyes core/shell (ZNs) and ZnO with dyes and liquid crystals core/double-shells nanoarrays (ZNLs) with controllable lengths were fabricated as electron transport layers (ETLs) in inverted polymer solar cells (PSCs). Ditetrabutylammonium cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II) dye (N719) was presented to reduce the surface defects of ZnO nanoarrays (NAs). In addition, the shell modification could decrease the electron injection barrier between ZnO and active layer, thereby facilitating electron injection effectively and forming a direct electron transport channel into the cathode. Due to the orientation of nanoarrays and the self-organization of 3,6,7,10,11-pentakis(hexyloxy)-2-hydroxytriphenylene liquid crystals (LCs) in liquid crystalline mesophase and isotropic phase transition, the components of active layer would be driven rearrange and infiltrate among the interspaces of nanoarrays more orderly. The increased interfacial contact between cathode and active layer would benefit charge generation, transportation and collection. On the basis of these advantages, it was found the N719 shell and N719/LCs double-shells modifications of ZnO NAs could boost the photovoltaic performance of PSCs with the best power conversion efficiency (PCE) of 7.3% and 8.0%, respectively.

  10. Doping ZnO with Water/Alcohol-Soluble Small Molecules as Electron Transport Layers for Inverted Polymer Solar Cells.

    PubMed

    Liu, Chang; Zhang, Lin; Xiao, Liangang; Peng, Xiaobin; Cao, Yong

    2016-10-03

    By doping ZnO with porphyrin small molecules (FNEZnP-OE and FNEZnP-T) as cathode electron transport layers (ETLs), the inverted polymer solar cells (i-PSC) with PTB7:PC71BM (PTB7: polythieno[3,4-b]-thiophene-co-benzodithiophene, PC71BM: [6, 6]-phenyl-C71-butyric acid methyl ester) as the active materials exhibit enhanced device performance. While the power conversion efficiency (PCE) of the PSCs with pure ZnO ETL is 7.52%, that of the devices with FNEZnP-T-doped ZnO ETL shows a slightly improved PCE of 8.09%, and that of the PSCs with FNEZnP-OE-doped ZnO ETL is further enhanced up to 9.24% with an over 20% improvement compared to that with pure ZnO ETL. The better performance is contributed by the better interfacial contact and reduced work function induced by 9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorenes and 3,4-bis-(2-(2-methoxy-ethoxy)-ethoxy)-phenyls in the porphyrin small molecules. More importantly, the PCE is still higher than 8% even when the thickness of FNEZnP-OE-doped ZnO ETL is up to 110 nm, which are important criteria for eventually making organic photovoltaic modules with roll-to-roll coat processing.

  11. Light-Soaking-Free Inverted Polymer Solar Cells with an Efficiency of 10.5% by Compositional and Surface Modifications to a Low-Temperature-Processed TiO2 Electron-Transport Layer.

    PubMed

    Yan, Yu; Cai, Feilong; Yang, Liyan; Li, Jinghai; Zhang, Yiwei; Qin, Fei; Xiong, Chuanxi; Zhou, Yinhua; Lidzey, David G; Wang, Tao

    2017-01-01

    Compositional modification and surface treatments of a TiO2 film prepared by a low-temperature route are carried out by a new promising method. Inverted polymer solar cells incorporating the post-treated TiO2 :TOPD electron-transport layer achieve the highest efficiency of 10.5%, and more importantly, eliminate the light-soaking problem that is commonly observed in metal-oxide-based inverted polymer solar cells.

  12. Solution-processed MoO3:PEDOT:PSS hybrid hole transporting layer for inverted polymer solar cells.

    PubMed

    Wang, Yiling; Luo, Qun; Wu, Na; Wang, Qiankun; Zhu, Hongfei; Chen, Liwei; Li, Yan-Qing; Luo, Liqiang; Ma, Chang-Qi

    2015-04-08

    Solution-processed organic-inorganic hybrids composing of MoO3 nanoparticles and PEDOT:PSS were developed for use in inverted organic solar cells as hole transporting layer (HTL). The hybrid MoO3:PEDOT:PSS inks were prepared by simply mixing PEDOT:PSS aqueous and MoO3 ethanol suspension together. A core-shell structure was proposed in the MoO3:PEDOT:PSS hybrid ink, where PEDOT chains act as the core and MoO3 nanoparticles connected with PSS chains act as the composite shell. The mixing with PEDOT:PSS suppressed the aggregation of MoO3 nanoparticles, which led to a smoother surface. In addition, since the hydrophilic PSS chains were passivated through preferentially connection with MoO3, the stronger adhesion between MoO3 nanoparticles and the photoactive layer improved the film forming ability of the MoO3:PEDOT:PSS hybrid ink. The MoO3:PEDOT:PSS hybrid HTL can therefore be feasibly deposited onto the hydrophobic photoactive polymer layer without any surface treatment. The use of the MoO3:PEDOT:PSS hybrid HTL resulted in the optimized P3HT:PC61BM- and PTB7:PC61BM-based inverted organic solar cells reaching highest power conversion efficiencies of 3.29% and 5.92%, respectively, which were comparable with that of the control devices using thermally evaporated MoO3 HTL (3.05% and 6.01%, respectively). Furthermore, less HTL thickness dependence of device performance was found for the hybrid HTL-based devices, which makes it more compatible with roll-to-roll printing process. In the end, influence of the blend ratio of MoO3 to PEDOT:PSS on photovoltaic performance and device stability was studied carefully, results indicated that the device performance would decrease with the increase of MoO3 blended ratio, whereas the long-term stability was improved.

  13. Plasmonic-enhanced performance for polymer solar cells prepared with inverted structures

    NASA Astrophysics Data System (ADS)

    Kao, Chuan-Sheng; Chen, Fang-Chung; Liao, Ching-Wen; Huang, Michael H.; Hsu, Chain-Shu

    2012-11-01

    We incorporated gold nanoparticles (Au NPs) in inverted organic photovoltaic devices to enhance the device performance. The photocurrent and fill factors were improved after the addition of Au NPs into the Cs2CO3 buffer layer. The photoluminescent measurements revealed a significant increase of light absorption of the photoactive layer. We attribute the improvement to local field enhancement induced by the localized surface plasmon resonance. Further, through the study of the morphologies of the cathode interfaces, we found that the rough surfaces might increase the device resistances. This drawback, however, was overwhelmed by the advantageous plasmonic effects.

  14. Inverted hybrid CdSe-polymer solar cells adopting PEDOT:PSS/MoO3 as dual hole transport layers.

    PubMed

    Zhu, Leize; Richardson, Beau J; Yu, Qiuming

    2016-02-07

    Inverted CdSe quantum dots (QDs):poly (3-hexylthiophene) (P3HT) organic/inorganic hybrid solar cells (OIHSCs) with the PSS/MoO3 dual hole transport layers (HTLs) showed superior performance over those with a single HTL of PSS or MoO3. The enhanced electron blocking at the active layer/anode interface as well as the prevention of leakage current accounted for the enhancement in the efficiency of the solar cells with the dual HTLs. By adopting the inverted structure and using the dual HTLs, the resistive losses of the CdSe QDs:P3HT hybrid system at high illumination power were effectively prevented. Further study showed the structure of dual HTLs was applicable to the solar cells with CdSe QDs and nanorods (NRs) blended with poly(thienothiophene-co-benzodithiophenes)7-F20 (PTB7-F20).

  15. Amphiphilic fullerene/ZnO hybrids as cathode buffer layers to improve charge selectivity of inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Hu, Ting; Chen, Lie; Yuan, Kai; Chen, Yiwang

    2015-05-01

    Two types of novel fullerene derivative/ZnO hybrids were prepared by physically blending amphiphilic fullerene-end-capped poly(ethylene glycol) (C60-PEG) with ZnO nanocrystals (ZnO/C60-PEG) and by in situ grown ZnO from C60-PEG (ZnO@C60-PEG) at relatively low temperatures. The C60-PEG could act as n-doping on the ZnO while the PEG side chain of C60-PEG could passivate the defects of the ZnO at the same time, consequently increasing the lowest unoccupied molecular orbital (LUMO) level. Compared with the ZnO/C60-PEG by the physical blend approach, the ZnO@C60-PEG by the growth approach showed a more favorable morphology and higher electron mobility by developing a homogeneous network. As a consequence, the efficiency of the inverted polymer solar cells based on thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) is raised to 8.0% for the ZnO@C60-PEG cathode buffer layer and to 7.5% for the ZnO/C60-PEG cathode buffer layer with improved long-term stability.Two types of novel fullerene derivative/ZnO hybrids were prepared by physically blending amphiphilic fullerene-end-capped poly(ethylene glycol) (C60-PEG) with ZnO nanocrystals (ZnO/C60-PEG) and by in situ grown ZnO from C60-PEG (ZnO@C60-PEG) at relatively low temperatures. The C60-PEG could act as n-doping on the ZnO while the PEG side chain of C60-PEG could passivate the defects of the ZnO at the same time, consequently increasing the lowest unoccupied molecular orbital (LUMO) level. Compared with the ZnO/C60-PEG by the physical blend approach, the ZnO@C60-PEG by the growth approach showed a more favorable morphology and higher electron mobility by developing a homogeneous network. As a consequence, the efficiency of the inverted polymer solar cells based on thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) is raised to 8.0% for the ZnO@C60-PEG cathode buffer layer and to 7.5% for the ZnO/C60-PEG cathode buffer layer

  16. Synthesis of ZnO Nanocrystals and Application in Inverted Polymer Solar Cells

    NASA Astrophysics Data System (ADS)

    Dong, Jing-Jing; Wu, Jian; Hao, Hui-Ying; Xing, Jie; Liu, Hao; Gao, Hua

    2017-09-01

    Controllable synthesis of various ZnO nanocrystals was achieved via a simple and cost-effective hydrothermal process. The morphology evolution of the ZnO nanostructures was well monitored by tuning hydrothermal growth parameters, such as solution concentration, reaction temperature, and surfactant. As-obtained ZnO nanocrystals with different morphologies, e.g., ZnO nanorods, nanotetrapods, nanoflowers, and nanocubes, were further introduced into the organic bulk heterojunction solar cells as the electron transport channel. It was found that the device performance was closely related to the morphology of the ZnO nanocrystals.

  17. Synthesis of ZnO Nanocrystals and Application in Inverted Polymer Solar Cells.

    PubMed

    Dong, Jing-Jing; Wu, Jian; Hao, Hui-Ying; Xing, Jie; Liu, Hao; Gao, Hua

    2017-09-09

    Controllable synthesis of various ZnO nanocrystals was achieved via a simple and cost-effective hydrothermal process. The morphology evolution of the ZnO nanostructures was well monitored by tuning hydrothermal growth parameters, such as solution concentration, reaction temperature, and surfactant. As-obtained ZnO nanocrystals with different morphologies, e.g., ZnO nanorods, nanotetrapods, nanoflowers, and nanocubes, were further introduced into the organic bulk heterojunction solar cells as the electron transport channel. It was found that the device performance was closely related to the morphology of the ZnO nanocrystals.

  18. Optimization of a polymer top electrode for inverted semitransparent organic solar cells

    SciTech Connect

    Zhou, Yinhua; Cheun, Hyeunseok; Choi, Seungkeun; Fuentes-Hernandez, Canek; Kippelen, Bernard

    2011-05-01

    We report on semitransparent organic solar cells using a single-layer blend based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the top electrode. The PEDOT:PSS blend was prepared by mixing a high-conductivity formulation of PEDOT:PSS (H.C. Starck CLEVIOS PH-1000) and another formulation of PEDOT:PSS (H.C. Starck CLEVIOS CPP 105D). The PEDOT:PSS blend yields good wetting properties on the hydrophobic surface of a blend of poly(3-hexylthiophene) (P3HT) with phenyl-C61-butyric acid methyl ester (PC60 BM), and shows a conductivity over 400 S cm-1. Semitransparent organic solar cells using the PEDOT:PSS blend as the top electrode with a structure of glass/ITO/ZnO/P3HT:PC60BM/PEDOT:PSS-blend exhibited an average power conversion efficiency of 2.4% estimated for 100 mW cm-2 AM 1.5G illumination.

  19. A nano-grid structure made of perovskite SrTiO3 nanowires for efficient electron transport layers in inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Jeong Won; Suh, Yo-Han; Lee, Chang-Lyoul; Kim, Yong Seok; Kim, Won Bae

    2015-02-01

    A nano-grid structure of perovskite SrTiO3 NWs is developed for a novel electron transport layer in inverted polymer solar cells. Due to the excellent charge transporting properties of the SrTiO3 nano-grid structure, the device employing this nanostructure showed ~32% enhanced photovoltaic performance, compared to the solar cell using a TiO2 thin film.A nano-grid structure of perovskite SrTiO3 NWs is developed for a novel electron transport layer in inverted polymer solar cells. Due to the excellent charge transporting properties of the SrTiO3 nano-grid structure, the device employing this nanostructure showed ~32% enhanced photovoltaic performance, compared to the solar cell using a TiO2 thin film. Electronic supplementary information (ESI) available: Experimental details, HR-TEM images with EDX atomic ratio analysis, FE-SEM images, transmittance spectra and light absorbance spectra. See DOI: 10.1039/c4nr06720g

  20. Organic/Organic Cathode Bi-Interlayers Based on a Water-Soluble Nonconjugated Polymer and an Alcohol-Soluble Conjugated Polymer for High Efficiency Inverted Polymer Solar Cells.

    PubMed

    Cai, Ping; Jia, Hongfu; Chen, Junwu; Cao, Yong

    2015-12-23

    In this work, organic/organic cathode bi-interlayers based on a water-soluble nonconjugated polymer PDMC and an alcohol-soluble conjugated polymer PFN were introduced to modifythe ITO cathode for inverted polymer solar cells (PSCs). PDMC with ultrahigh molecular weight would facilitate to form strong adsorption on the ITO substrate, while PFN could provide both compatibly interfacial contacts with the bottom PDMC interlayer and the upper organic active layer. The PDMC/PFN cathode bi-interlayers could decrease work function of the ITO cathode to 3.8 eV, supplying the most efficient ohmic interfacial contacts for electron collection at the ITO cathode. With a PTB7:PC71BM blend as the active layer, inverted PSCs based on the PDMC/PFN cathode bi-interlayers showed the highest efficiency of 9.01% and the best air stability within 60 days if compared with devices based on a separate PDMC or PFN cathode interlayer. The results suggest that the PDMC/PFN cathode bi-interlayers would play an important role to achieve high efficiency and stable inverted PSCs.

  1. Enhanced performance in inverted polymer solar cells with D-π-A-type molecular dye incorporated on ZnO buffer layer.

    PubMed

    Song, Chang Eun; Ryu, Ka Yeon; Hong, Seong-Jin; Bathula, Chinna; Lee, Sang Kyu; Shin, Won Suk; Lee, Jong-Cheol; Choi, Si Kyung; Kim, Joo Hyun; Moon, Sang-Jin

    2013-08-01

    We report the superior characteristics of a ZnO buffer layer covered with a phenothiazine-based, π-conjugated donor-acceptor (D-π-A)-type organic dye (called "d-ZnO"). The use of this system for the performance enhancement of inverted bulk heterojunction polymer solar cells (PSCs) with the configuration of indium tin oxide/d-ZnO/polymer:PC71 BM/MoO3 /Ag (PC71 BM=[6,6]-phenyl C71 butyric acid methyl ester) is investigated. The layer of organic dyes anchored on the ZnO surface through carboxylate bonding reduces the shunt path on bare ZnO surface and provides better interfacial contacts and energy level alignments between the ZnO layer and the photoactive layer. This phenomenon consequently leads to highly enhanced photovoltaic parameters (fill factor, open-circuit voltage, and short-circuit current density) and power conversion efficiencies (PCEs). Inverted solar cells containing the d-ZnO layer not only revealed about 34% (PCE: 4.37%) and 18% (PCE: 7.11%) improvement in the PCEs of the representative poly-3(hexylthiophene) (P3HT) and low-band-gap poly{[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-alt-[2-(2'-ethylhexanoyl)-thieno[3,4-b]thiophen-4,6-diyl]} (PBDTTT-C-T) polymer systems, respectively, but also showed 2-4 times longer device lifetimes than their counterparts without the organic dye layer. These results demonstrate that this simple approach used in inverted PSCs with a metal oxide buffer layer could become a promising procedure to fabricate highly efficient and stable PSCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Air-stable efficient inverted polymer solar cells using solution-processed nanocrystalline ZnO interfacial layer.

    PubMed

    Tan, Mein Jin; Zhong, Shu; Li, Jun; Chen, Zhikuan; Chen, Wei

    2013-06-12

    In this work, efficient bulk heterojunction (BHJ) organic solar cells (OSC) in inverted configuration have been demonstrated. Power conversion efficiency (PCE) of 3.7% is reported for OSC employing silver top electrodes, molybdenum trioxide (MoO3) as the hole-transport interlayer (HTL), active layer comprising of poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as well as a nanocrystalline solution-synthesized zinc oxide (ZnO) nanoparticle (NP) film as the electron-transport layer (ETL). By using solution-processable ZnO crystalline NPs as ETL, we can eliminate the typical high temperature processing/annealing step, which is widely adopted in the conventional ZnO ETL fabrication process via the sol-gel method. Such highly crystalline ZnO NP films can enhance charge collection at the electrodes. It is also found that inverted OSCs exhibit greater air stability and lifetime performance compared to the OSC employing the normal structure.

  3. Transfer-printing of active layers to achieve high quality interfaces in sequentially deposited multilayer inverted polymer solar cells fabricated in air

    PubMed Central

    Vohra, Varun; Anzai, Takuya; Inaba, Shusei; Porzio, William; Barba, Luisa

    2016-01-01

    Abstract Polymer solar cells (PSCs) are greatly influenced by both the vertical concentration gradient in the active layer and the quality of the various interfaces. To achieve vertical concentration gradients in inverted PSCs, a sequential deposition approach is necessary. However, a direct approach to sequential deposition by spin-coating results in partial dissolution of the underlying layers which decreases the control over the process and results in not well-defined interfaces. Here, we demonstrate that by using a transfer-printing process based on polydimethylsiloxane (PDMS) stamps we can obtain increased control over the thickness of the various layers while at the same time increasing the quality of the interfaces and the overall concentration gradient within the active layer of PSCs prepared in air. To optimize the process and understand the influence of various interlayers, our approach is based on surface free energy, spreading parameters and work of adhesion calculations. The key parameter presented here is the insertion of high quality hole transporting and electron transporting layers, respectively above and underneath the active layer of the inverted structure PSC which not only facilitates the transfer process but also induces the adequate vertical concentration gradient in the device to facilitate charge extraction. The resulting non-encapsulated devices (active layer prepared in air) demonstrate over 40% increase in power conversion efficiency with respect to the reference spin-coated inverted PSCs. PMID:27877901

  4. Transfer-printing of active layers to achieve high quality interfaces in sequentially deposited multilayer inverted polymer solar cells fabricated in air.

    PubMed

    Vohra, Varun; Anzai, Takuya; Inaba, Shusei; Porzio, William; Barba, Luisa

    2016-01-01

    Polymer solar cells (PSCs) are greatly influenced by both the vertical concentration gradient in the active layer and the quality of the various interfaces. To achieve vertical concentration gradients in inverted PSCs, a sequential deposition approach is necessary. However, a direct approach to sequential deposition by spin-coating results in partial dissolution of the underlying layers which decreases the control over the process and results in not well-defined interfaces. Here, we demonstrate that by using a transfer-printing process based on polydimethylsiloxane (PDMS) stamps we can obtain increased control over the thickness of the various layers while at the same time increasing the quality of the interfaces and the overall concentration gradient within the active layer of PSCs prepared in air. To optimize the process and understand the influence of various interlayers, our approach is based on surface free energy, spreading parameters and work of adhesion calculations. The key parameter presented here is the insertion of high quality hole transporting and electron transporting layers, respectively above and underneath the active layer of the inverted structure PSC which not only facilitates the transfer process but also induces the adequate vertical concentration gradient in the device to facilitate charge extraction. The resulting non-encapsulated devices (active layer prepared in air) demonstrate over 40% increase in power conversion efficiency with respect to the reference spin-coated inverted PSCs.

  5. Inverted polymer fullerene solar cells exceeding 10% efficiency with poly(2-ethyl-2-oxazoline) nanodots on electron-collecting buffer layers.

    PubMed

    Nam, Sungho; Seo, Jooyeok; Woo, Sungho; Kim, Wook Hyun; Kim, Hwajeong; Bradley, Donal D C; Kim, Youngkyoo

    2015-12-14

    Polymer solar cells have been spotlighted due to their potential for low-cost manufacturing but their efficiency is still less than required for commercial application as lightweight/flexible modules. Forming a dipole layer at the electron-collecting interface has been suggested as one of the more attractive approaches for efficiency enhancement. However, only a few dipole layer material types have been reported so far, including only one non-ionic (charge neutral) polymer. Here we show that a further neutral polymer, namely poly(2-ethyl-2-oxazoline) (PEOz) can be successfully used as a dipole layer. Inclusion of a PEOz layer, in particular with a nanodot morphology, increases the effective work function at the electron-collecting interface within inverted solar cells and thermal annealing of PEOz layer leads to a state-of-the-art 10.74% efficiency for single-stack bulk heterojunction blend structures comprising poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-alt-3-fluorothieno[3,4-b]thiophene-2-carboxylate] as donor and [6,6]-phenyl-C71-butyric acid methyl ester as acceptor.

  6. Inverted polymer fullerene solar cells exceeding 10% efficiency with poly(2-ethyl-2-oxazoline) nanodots on electron-collecting buffer layers

    PubMed Central

    Nam, Sungho; Seo, Jooyeok; Woo, Sungho; Kim, Wook Hyun; Kim, Hwajeong; Bradley, Donal D. C.; Kim, Youngkyoo

    2015-01-01

    Polymer solar cells have been spotlighted due to their potential for low-cost manufacturing but their efficiency is still less than required for commercial application as lightweight/flexible modules. Forming a dipole layer at the electron-collecting interface has been suggested as one of the more attractive approaches for efficiency enhancement. However, only a few dipole layer material types have been reported so far, including only one non-ionic (charge neutral) polymer. Here we show that a further neutral polymer, namely poly(2-ethyl-2-oxazoline) (PEOz) can be successfully used as a dipole layer. Inclusion of a PEOz layer, in particular with a nanodot morphology, increases the effective work function at the electron-collecting interface within inverted solar cells and thermal annealing of PEOz layer leads to a state-of-the-art 10.74% efficiency for single-stack bulk heterojunction blend structures comprising poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-alt-3-fluorothieno[3,4-b]thiophene-2-carboxylate] as donor and [6,6]-phenyl-C71-butyric acid methyl ester as acceptor. PMID:26656447

  7. 3-Dimensional ZnO/CdS nanocomposite with high mobility as an efficient electron transport layer for inverted polymer solar cells.

    PubMed

    Wang, Yilin; Fu, Haiyan; Wang, Ying; Tan, Licheng; Chen, Lie; Chen, Yiwang

    2016-04-28

    The inclusions of solution-processed ZnO electron transport layers (ETLs) of inverted polymer solar cells can lead to various surface defects, which can act as interfacial recombination centers for photogenerated charges and thereby can lead to degradation of the device performance. Three-dimensional (3D) CdS with different morphologies, such as flower-like CdS (F-CdS), branched CdS (B-CdS), and spherical CdS (S-CdS), are synthesized to modify ZnO ETLs, by effectively removing the intragap states of the ZnO nanocrystal films by forming ZnO/F-CdS, ZnO/B-CdS, and ZnO/S-CdS composite ETLs, respectively. Moreover, ZnO/CdS possesses higher electron mobility and provides a larger interface between the ETL and active layer, which is beneficial for enhancing the power conversion efficiency (PCE) of the inverted organic solar cells. In particular, a device based on a ZnO/S-CdS ETL and thieno[3,4-b]-thiophene/benzodithiophene (PTB7):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) active layer achieved a PCE of 8.0%, together with better long-term stability.

  8. Morphologic improvement of the PBDTTT-C and PC71BM blend film with mixed solvent for high-performance inverted polymer solar cells.

    PubMed

    Chen, Hsin-Yi; Lin, Shang-Hong; Sun, Jen-Yu; Hsu, Chi-Hsing; Lan, Shiang; Lin, Ching-Fuh

    2013-12-06

    Tracing the evolution of the bulk heterojunction structure, a dramatic promotion in the efficiency of polymer solar cells has been obtained in recent years. The active layer morphology of low-bandgap polymer solar cells is one of the critical factors for high-efficiency performance. In the past, the relationship between morphology improvement and the device's characteristics (such as efficiency, fill factor and short-circuit current) in low-bandgap polymer solar cells has been studied intensively with regards to the conventional structure. Here we demonstrate the morphologic improvement of the poly[(4,8-bis-(2-ethylhexyloxy)-benzo[1,2-b;4,5-b']dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiopene)-2,6-diyl]/[6,6]-phenyl C71 butyric acid methyl ester (PBDTTT-C/PC71BM) blend film for inverted solar cells. By utilizing a mixed solvent of dichlorobenzene/chlorobenzene with (1,8-diiodooctane) additives, the device efficiency can be significantly enhanced, from 0.92% to 4.43%. This enhancement is attributed to active layer morphologic improvement promoting carrier transport. Furthermore, the thickness optimization of the active layer and the electron blocking layer MoO3 further contributes to efficiency. The device performance could be achieved with an efficiency as high as 5.35%, an open-circuit voltage of 0.70 V, a short-circuit current density of 13.5 mA cm(-2), and a fill factor of 57%.

  9. High-efficiency inverted polymer solar cells with transparent and work-function tunable MoO(3)-Al composite film as cathode buffer layer.

    PubMed

    Liu, Jian; Shao, Shuyan; Fang, Gang; Meng, Bin; Xie, Zhiyuan; Wang, Lixiang

    2012-05-22

    High-efficiency inverted polymer solar cells based on PCDTBT:PC(70)BM blend with the MoO(3)-Al composite film as the cathode buffer layer and the MoO(3)/Al as the anode have been demonstrated. A V(OC) of 0.88 V, a J(SC) of 10.88 mA cm(-2), a FF of 70.7% and a PCE of 6.77% are achieved. The MoO(3)-Al composite films are highly transparent with adjustable work functions which can be fine tuned based on the Al content in the composite, thus allowing us to optimize the interfacial property at cathode buffer layer/BHJ interfaces to reduce recombination loss and to improve the photovoltaic performance. This new approach has simplified the device fabrication and will render economizing in large scale applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Development of bifacial inverted polymer solar cells using a conductivity-controlled transparent PEDOT:PSS and a striped Au electrode on the hole collection side

    NASA Astrophysics Data System (ADS)

    Kuwabara, Takayuki; Katori, Shinji; Arima, Kazuhiro; Omura, Yoshihiro; Yamaguchi, Takahiro; Taima, Tetsuya; Takahashi, Kohshin

    2014-02-01

    An inverted bifacial polymer solar cell was developed using a conductivity-controlled transparent poly(3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid) (PEDOT:PSS) as a hole collection layer and a striped Au electrode with a large open aperture ratio (Rap) as a hole collection electrode. We investigated the performance of the device by varying the interelectrode distance of the striped Au electrode and the sheet resistance of the PEDOT:PSS film. The device using untreated Clevios P (PEDOT:PSS) showed a maximum electric output (Pw) in the Rap range of 50 to 65%. When alcohol-treated Clevios P (Clevios P+) with a lower electrical resistance was used, the maximum Pw increased by 40% compared with that of the device using Clevios P. The maximum Pw was obtained in the Rap range of 84% as the hole collection efficiency of the striped Au electrode improved with the decreased sheet resistance of the PEDOT:PSS.

  11. Modification of the Highly Conductive PEDOT:PSS Layer for Use in Silver Nanogrid Electrodes for Flexible Inverted Polymer Solar Cells.

    PubMed

    Wang, Jie; Fei, Fei; Luo, Qun; Nie, Shuhong; Wu, Na; Chen, Xiaolian; Su, Wenming; Li, Yuanjie; Ma, Chang-Qi

    2017-03-01

    Silver nanogrid based flexible transparent electrode is recognized as the most promising alternative to ITO electrode for organic electronics, owing to its low production cost and excellent flexibility. Typically, a highly conductive thin film coating layer, such as highly conductive PEDOT:PSS (HC-PEDOT:PSS) is usually deposited onto the Ag-grid electrode to smooth the surface and to minimize the sheet resistance. In this paper, we found that inverted flexible polymer solar cells with structure of Ag-grid/HC-PEDOT:PSS/ZnO/photoactive layer/MoO3/Al generally exhibits strong S-shaped J-V curves, which could be eliminated by light-soaking treatment. Kelvin probe force microscope (KPFM) measurement proved that a large work function (WF) difference (0.70 eV) between HC-PEDOT:PSS and ZnO is the main reason for the formation of S-shape. White light soaking of the Ag-grid/HC-PEDOT:PSS gradually decreased the WF of HC-PEDOT:PSS from 5.10 to 4.60 eV, leading to a reduced WF difference between HC-PEDOT:PSS and ZnO from 0.70 to 0.38 eV. Such a WF difference decrease was believed to be the working mechanism for the light-soaking effect in this flexible device. Based on this finding, the HC-PEDOT:PSS solution was then modified by doping with polyethylenimine (PEI) and aqueous ammonia. The modified PEDOT:PSS film is characteristic of adjusting WF through varying PEI doping concentrations. By using such a modified PEDOT:PSS layer, light-soaking-free flexible inverted polymer solar cell with a power conversion efficiency of 6.58% was achieved for PTB7-Th:PC71BM cells. The current work provides a useful guideline for interfacial modification for Ag-grid based flexible electrode.

  12. Preparation of anatase TiO2 thin film by low temperature annealing as an electron transport layer in inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Noh, Hongche; Oh, Seong-Geun; Im, Seung Soon

    2015-04-01

    To prepare the anatase TiO2 thin films on ITO glass, amorphous TiO2 colloidal solution was synthesized through the simple sol-gel method by using titanium (IV) isopropoxide as a precursor. This amorphous TiO2 colloidal solution was spread on ITO glass by spin-coating, then treated at 450 °C to obtain anatase TiO2 film (for device A). For other TiO2 films, amorphous TiO2 colloidal solution was treated through solvothermal process at 180 °C to obtain anatase TiO2 colloidal solution. This anatase TiO2 colloidal solution was spread on ITO glass by spin coating, and then annealed at 200 °C (for device B) and 130 °C (for device C), respectively. The average particle size of amorphous TiO2 colloidal solution was about 1.0 nm and that of anatase TiO2 colloidal solution was 10 nm. The thickness of TiO2 films was about 15 nm for all cases. When inverted polymer solar cells were fabricated by using these TiO2 films as an electron transport layer, the device C showed the highest PCE (2.6%) due to the lack of defect, uniformness and high light absorbance of TiO2 films. The result of this study can be applied for the preparation of inverted polymer solar cell using TiO2 films as a buffer layer at low temperature on plastic substrate by roll-to roll process.

  13. Hydroxyl-Terminated CuInS2-Based Quantum Dots: Potential Cathode Interfacial Modifiers for Efficient Inverted Polymer Solar Cells.

    PubMed

    Chen, Hui; Chao, Pengjie; Han, Dengbao; Wang, Huan; Miao, Jingsheng; Zhong, Haizheng; Meng, Hong; He, Feng

    2017-03-01

    The use of interfacial modifiers on cathode or anode layers can effectively reduce the recombination loss and thus have potential to enhance the device performance of polymer solar cells. In this work, we demonstrated that hydroxyl-terminated CuInS2-based quantum dots could be potential cathode interfacial modifiers on ZnO layer for inverted polymer solar cells. By casting of a thin film of CuInS2-based quantum dots onto ZnO layer, the controlled devices show obvious enhancements of open-circuit voltage, short-circuit current, and fill factor. With an optimized interfacial layer with ∼7 nm thickness, an improvement of power conversion efficiency up to 16% is obtained and the optimized power conversion efficiency of PTB7-based (PTB7: poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno[3,4-b] thiophenediyl

  14. Self-Assembly of 1-Pyrenemethanol on ZnO Surface toward Combined Cathode Buffer Layers for Inverted Polymer Solar Cells.

    PubMed

    Cai, Xiang; Yuan, Tao; Liu, Xiangfu; Tu, Guoli

    2017-10-09

    Solid alcohol 1-pyrenemethanol (PyM) was first introduced to modify the zinc oxide (ZnO) layer which is used in the inverted polymer solar cells (PSCs) as a cathode buffer layer (CBL). As a low-cost industrial product, the PyM can modify the surface defects and improve the electron mobility of ZnO CBL, which can be attributed to the self-assembly of PyM on the ZnO surface due to the hydrogen bonds and the conjugated structure in PyM. With a blend of PTB7:PC71BM as active layer, the device with ZnO/PyM CBL exhibited a notable power conversion efficiency (PCE) of 8.26%, which is better than that of control devices based on bare ZnO CBL (7.26%). With the addition of PyM, the device based on PTB7-Th:PC71BM showed a higher PCE of 9.10%, an obvious improvement from the 7.79% of control devices. There was no obvious change in device performance with the increase of PyM solution concentration, indicating that the device fabrications are thickness-insensitive. These results could be particularly useful in solution processing of buffer layer materials to high-efficiency organic solar cells.

  15. Degradation of a thin Ag layer induced by poly(3,4-ethylenedioxythiophene):polystyrene sulfonate in a transmission electron microscopy specimen of an inverted polymer solar cell.

    PubMed

    Suh, Youngjoon; Lu, Ning; Lee, Sang H; Chung, Won-Suk; Kim, Kyungkon; Kim, BongSoo; Ko, Min Jae; Kim, Moon J

    2012-10-24

    It was found that the Ag electrode layer in a transmission electron microscopy (TEM) specimen of an inverted polymer solar cell structure of Ag/PEDOT:PSS/P3HT:PCBM/TiO(2)/ITO/glass (where PEDOT is poly(3,4-ethylenedioxythiophene), PSS is polystyrene sulfonate, and ITO is indium tin oxide) was broken down into particles as time passed. In order to investigate the cause of Ag particle formation and the effect of the degradation on the performance of solar cells, the temporal change of the cross-sectional TEM micrographs was examined together with energy-dispersive X-ray spectroscopy (EDS) analysis and electron tomography. Temporal degradation of Ag/Si and Ag/1 nm-Ti/PEDOT:PSS/ITO/glass structures was also studied. Absorption of water by the PEDOT:PSS layer followed by corrosion of the grain boundaries of the Ag layer by the corrosive water was thought to be the reason of Ag particle formation and fast performance lowering of the device.

  16. Work Station For Inverting Solar Cells

    NASA Technical Reports Server (NTRS)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  17. Low Work Function Lacunary Polyoxometalates as Electron Transport Interlayers for Inverted Polymer Solar Cells of Improved Efficiency and Stability.

    PubMed

    Tountas, Marinos; Topal, Yasemin; Polydorou, Ermioni; Soultati, Anastasia; Verykios, Apostolis; Kaltzoglou, Andreas; Papadopoulos, Theodoros A; Auras, Florian; Seintis, Kostas; Fakis, Mihalis; Palilis, Leonidas C; Tsikritzis, Dimitris; Kennou, Stella; Koutsoureli, Matroni; Papaioannou, George; Ersöz, Mustafa; Kus, Mahmut; Falaras, Polycarpos; Davazoglou, Dimitris; Argitis, Panagiotis; Vasilopoulou, Maria

    2017-07-12

    Effective interface engineering has been shown to play a vital role in facilitating efficient charge-carrier transport, thus boosting the performance of organic photovoltaic devices. Herein, we employ water-soluble lacunary polyoxometalates (POMs) as multifunctional interlayers between the titanium dioxide (TiO2) electron extraction/transport layer and the organic photoactive film to simultaneously enhance the efficiency, lifetime, and photostability of polymer solar cells (PSCs). A significant reduction in the work function (WF) of TiO2 upon POM utilization was observed, with the magnitude being controlled by the negative charge of the anion and the selection of the addenda atom (W or Mo). By inserting a POM interlayer with ∼10 nm thickness into the device structure, a significant improvement in the power conversion efficiency was obtained; the optimized POM-modified poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2- 33 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  18. Interface control of semiconducting metal oxide layers for efficient and stable inverted polymer solar cells with open-circuit voltages over 1.0 volt.

    PubMed

    Yin, Zhigang; Zheng, Qingdong; Chen, Shan-Ci; Cai, Dongdong

    2013-09-25

    Inverted polymer solar cells (PSCs) with high open-circuit voltages of 1.00-1.06 V are fabricated by using an indenofluorene-containing copolymer (PIFTBT8) as an electron donor material and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor material. To improve the photovoltaic performance, interface control of various low-temperature processed ZnO films as cathode buffer layers is systematically investigated for effective electron transportation, while transition metal oxides including MoO3, WO3, NiO, and Cu2O are employed as anode buffer layers for hole-extraction. Incorporation of optimized semiconducting metal oxide interlayers can minimize interfacial power losses, which thus affords large open-circuit voltages (Voc), increased short-circuit current densities (Jsc), and fill factors (FF), eventually contributing to higher power conversion efficiencies (PCEs) as well as better device stability. Due to the improved interfacial contacts and fine-matching energy levels, inverted PSCs with a device configuration of ITO/ZnO/PIFTBT8:PC71BM/MoO3/Ag exhibit a high PCE of 5.05% with a large Voc of 1.04 V, a Jsc of 9.74 mA cm(-2), and an FF of 50.1%. For the single junction inverted PSCs with efficiencies over 5.0%, 1.04 V is the largest Voc ever achieved. By controlling the processing conditions of the active layer, the Voc can further be improved to 1.05 and 1.06 V, with PCEs of 4.70% and 4.18%, respectively. More importantly, the inverted PSCs are ascertained to maintain a PCE of 4.55% (>90% of its initial efficiency) and a Voc of 1.05 V over 180 days, demonstrating good long-term stability, which is much better than that of the conventional devices. The results suggest that the interface engineering of metal oxide interlayers is an important strategy to develop PSCs with good performance.

  19. Roles of thermally-induced vertical phase segregation and crystallization on the photovoltaic performance of bulk heterojunction inverted polymer solar cells

    SciTech Connect

    Cheun, Hyeunseok; Berrigan, John D.; Zhou, Yinhua; Fenoll, Mathieu; Shim, Jaewon; Fuentes-Hernandez, Canek; Sandhage, Kenneth H.; Kippelen, Bernard

    2011-01-01

    Brief 160 °C annealing treatments dramatically enhanced the performance of bulk heterojunction inverted polymer solar cells with an ITO/ZnO/P3HT:PCBM/MoO₃/Ag structure. The influence of such treatments on cell performance has been correlated to vertical phase segregation and crystallization within the photoactive layer of such cells. The photoactive layer, comprised of a mixture of P3HT and PCBM deposited on ZnO, was annealed for 10–30 min at 160 °C. Depth profiling with X-ray photoelectron spectroscopy (XPS) revealed that such annealing resulted in enrichment of the P3HT concentration near the ZnO layer, particularly after 20 and 30 min of annealing. Crystallization of P3HT was detected by X-ray diffraction (XRD) analyses after 10 to 30 min of such annealing, with little difference in the extent of crystallization detected over this time frame. It was found that vertical segregation does not seem to play a role as significant as that of crystallization on cell performance.

  20. Improved photovoltaic performance of inverted polymer solar cells through a sol-gel processed Al-doped ZnO electron extraction layer.

    PubMed

    Kim, Jun Young; Cho, Eunae; Kim, Jaehoon; Shin, Hyeonwoo; Roh, Jeongkyun; Thambidurai, Mariyappan; Kang, Chan-mo; Song, Hyung-Jun; Kim, SeongMin; Kim, Hyeok; Lee, Changhee

    2015-09-21

    We demonstrate that nanocrystalline Al-doped zinc oxide (n-AZO) thin film used as an electron-extraction layer can significantly enhance the performance of inverted polymer solar cells based on the bulk heterojunction of poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) and [6,6]-phenyl C(71)-butyric acid methyl ester (PC(70)BM). A synergistic study with both simulation and experiment on n-AZO was carried out to offer a rational guidance for the efficiency improvement. As a result, An n-AZO film with an average grain size of 13 to 22 nm was prepared by a sol-gel spin-coating method, and a minimum resistivity of 2.1 × 10(-3) Ω·cm was obtained for an Al-doping concentration of 5.83 at.%. When an n-AZO film with a 5.83 at.% Al concentration was inserted between the ITO electrode and the active layer (PCDTBT:PC(70)BM), the power conversion efficiency increased from 3.7 to 5.6%.

  1. Highly Efficient and Air Stable Inverted Polymer Solar Cells Using LiF-Modified ITO Cathode and MoO3/AgAl Alloy Anode.

    PubMed

    Jia, Xiangkun; Jiang, Ziyao; Chen, Xiaohong; Zhou, Jianping; Pan, Likun; Zhu, Furong; Sun, Zhuo; Huang, Sumei

    2016-02-17

    The performance and air stability of inverted polymer solar cells (PSCs) were greatly improved using a combination of LiF-modified ITO cathode and a MoO3/AgAl alloy anode. The power conversion efficiency (PCE) of PSCs with AgAl contact reached 9.4%, which is higher than that of the cells with Ag (8.8%) and Al electrode (7.6%). The PCE of AgAl-based PSCs can further increase up to 10.3% through incorporating an ultrathin LiF-modified ITO. AgAl-based cells also exhibit a superior stability compared to the cells with Ag and Al contacts. PCE of the AgAl-based cells without encapsulation remains 78% of its original value after the cells were aged for 380 days in air. The presence of a LiF-modified ZnO interlayer between ITO and the organic active layer improves the charge collection. The improvement in PCE and stability of the AgAl-based cells is primarily attributed to the formation of AlOx at the MoO3/AgAl interface, preventing Ag diffusion and improving the built-in potential across the active layer in the cells.

  2. Magnetic-field annealing of inverted polymer:fullerene hybrid solar cells with FePt nanowires as additive

    SciTech Connect

    Chen, Chiang-Ting; Chen, Yang-Fang E-mail: yfchen@phys.ntu.edu.tw; Hsu, Fang-Chi E-mail: yfchen@phys.ntu.edu.tw; Li, Cheng-Hung; Chen, Chia-Chun

    2013-12-16

    We demonstrate a facile annealing method to improve the polymer chain ordering of poly(3-hexythiophene) (P3HT):fullerene blend triggered by a small amount of FePt nanowires (FePt NWs). By applying a magnetic field perpendicular to the substrate during the solvent drying process, the resulting P3HT:fullerene:FePt NWs film becomes highly optical anisotropy and exhibits a much stronger X-ray diffraction intensity of P3HT. We hypothesize that the coupling force between the FePt NWs and P3HT can assist the polymer chain alignment leading to an improved device performance. The proposed approach is simple and can be applied to other polymer blend systems as well.

  3. Perylene Bisimide as a Promising Zinc Oxide Surface Modifier: Enhanced Interfacial Combination for Highly Efficient Inverted Polymer Solar Cells.

    PubMed

    Nian, Li; Zhang, Wenqiang; Wu, Siping; Qin, Leiqiang; Liu, Linlin; Xie, Zengqi; Wu, Hongbin; Ma, Yuguang

    2015-11-25

    We report the application of a perylene bisimide (PBI-H) as zinc oxide (ZnO) surface modifier to afford an organic-inorganic co-interlayer for highly efficient inverted organic photovoltaics (i-OPV). By thermal annealing, a N-Zn chemical bond formed between PBI-H and ZnO, inducing close organic-inorganic combination. In addition, this co-interlayer shows decreased work function and increased electron transportation and conductivity, which are benefits for the cathode to enhance charge extraction efficiency and decrease recombination losses. As a result a highly efficient i-OPV was achieved with a power conversion efficiency (PCE) of 9.43% based on this co-interlayer with PTB7:PC71BM as the active layer, which shows over 35% enhancement compared to that of the device without the PBI-H layer. Moreover, this co-interlayer was widely applicable for i-OPVs based on various material systems, such as P3HT:PC61BM and PTB7-Th:PC71BM, resulting in PCE as high as 4.78% and 10.31%, respectively.

  4. Micro-inverter solar panel mounting

    DOEpatents

    Morris, John; Gilchrist, Phillip Charles

    2016-02-02

    Processes, systems, devices, and articles of manufacture are provided. Each may include adapting micro-inverters initially configured for frame-mounting to mounting on a frameless solar panel. This securement may include using an adaptive clamp or several adaptive clamps secured to a micro-inverter or its components, and using compressive forces applied directly to the solar panel to secure the adaptive clamp and the components to the solar panel. The clamps can also include compressive spacers and safeties for managing the compressive forces exerted on the solar panels. Friction zones may also be used for managing slipping between the clamp and the solar panel during or after installation. Adjustments to the clamps may be carried out through various means and by changing the physical size of the clamps themselves.

  5. Inverted flat plate solar collector. Final report

    SciTech Connect

    Brown, M.A.

    1981-08-26

    Construction and testing of an inverted flat plate solar collector are described. Heat transfer and economic analysis were performed to optimize the collector design. The newly designed collector was tested against two other flat plate collectors and the results and comparison of efficiencies are presented. (BCS)

  6. Plasmonic polymer tandem solar cell.

    PubMed

    Yang, Jun; You, Jingbi; Chen, Chun-Chao; Hsu, Wan-Ching; Tan, Hai-ren; Zhang, Xing Wang; Hong, Ziruo; Yang, Yang

    2011-08-23

    We demonstrated plasmonic effects in an inverted tandem polymer solar cell configuration by blending Au nanoparticles (NPs) into the interconnecting layer (ICL) that connects two subcells. Experimental results showed this plasmonic enhanced ICL improves both the top and bottom subcells' efficiency simultaneously by enhancing optical absorption. The presence of Au NPs did not cause electrical characteristics to degrade within the tandem cell. As a result, a 20% improvement of power conversion efficiency has been attained by the light concentration of Au NPs via plasmonic near-field enhancement. The simulated near-field distribution and experimental Raman scattering investigation support our results of plasmonic induced enhancement in solar cell performance. Our finding shows a great potential of incorporating the plasmonic effect with conventional device structure in achieving highly efficient polymer solar cells. © 2011 American Chemical Society

  7. Performance of inverted polymer solar cells with randomly oriented ZnO nanorods coupled with atomic layer deposited ZnO

    NASA Astrophysics Data System (ADS)

    Zafar, Muhammad; Yun, Ju-Young; Kim, Do-Heyoung

    2017-03-01

    Nanostructuring of the electron transport layer (ETL) in organic photovoltaic cells (OPV) is of great interest because it increases the surface area of the cell and electron transport. In this work, hydrothermally grown, randomly oriented, and low areal density ZnO nanorods (NRs) have been adopted as the ETL, and the effect of adding atomic layer deposited (ALD) ZnO on the ZnO NRs on the inverted organic solar cell performance has been investigated. The fabricated inverted organic solar cell with 5-nm-thick ALD-ZnO grown on the ZnO NRs showed the highest power conversion efficiency (PCE) of 3.08%, which is an enhancement of 85% from that of the cell without ALD-ZnO (PCE = 1.67%). The ultrathin ALD-ZnO was found to act as a curing layer of the surface defects on the hydrothermally grown ZnO NRs, resulting in an improvement in photovoltaic performance.

  8. Interlayer for modified cathode in highly efficient inverted ITO-free organic solar cells.

    PubMed

    Tang, Zheng; Andersson, L Mattias; George, Zandra; Vandewal, Koen; Tvingstedt, Kristofer; Heriksson, Patrik; Kroon, Renee; Andersson, Mats R; Inganäs, Olle

    2012-01-24

    Inverted polymer solar cells with a bottom metal cathode modified by a conjugated polymer interlayer show considerable improvement of photocurrent and fill factor, which is due to hole blocking at the interlayer, and a modified surface energy which affects the nanostructure in the TQ1/[70]PCBM blend. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Polymer solar cells

    NASA Astrophysics Data System (ADS)

    Li, Gang; Zhu, Rui; Yang, Yang

    2012-03-01

    Recent progress in the development of polymer solar cells has improved power-conversion efficiencies from 3% to almost 9%. Based on semiconducting polymers, these solar cells are fabricated from solution-processing techniques and have unique prospects for achieving low-cost solar energy harvesting, owing to their material and manufacturing advantages. The potential applications of polymer solar cells are broad, ranging from flexible solar modules and semitransparent solar cells in windows, to building applications and even photon recycling in liquid-crystal displays. This Review covers the scientific origins and basic properties of polymer solar cell technology, material requirements and device operation mechanisms, while also providing a synopsis of major achievements in the field over the past few years. Potential future developments and the applications of this technology are also briefly discussed.

  10. Semi-transparent inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

    2009-08-01

    We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

  11. Roll-to-Roll Processing of Inverted Polymer Solar Cells using Hydrated Vanadium(V)Oxide as a PEDOT:PSS Replacement

    PubMed Central

    Espinosa, Nieves; Dam, Henrik Friis; Tanenbaum, David M.; Andreasen, Jens W.; Jørgensen, Mikkel; Krebs, Frederik C.

    2011-01-01

    The use of hydrated vanadium(V)oxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full roll-to-roll (R2R) processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET) and had the structure PET/ITO/ZnO/P3HT:PCBM/V2O5·(H2O)n/Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(V)oxide layers were processed by slot-die coating. The hydrated vanadium(V)oxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP). Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(V)oxide layer by varying the concentration of the VTIP precursor over two orders of magnitude. Hydrated vanadium(V)oxide layers were characterized by profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and grazing incidence wide angle X-ray scattering. The power conversion efficiency (PCE) for completed modules was up to 0.18%, in contrast to single cells where efficiencies of 0.4% were achieved. Stability tests under indoor and outdoor conditions were accomplished over three weeks on a solar tracker. PMID:28879984

  12. Roll-to-Roll Processing of Inverted Polymer Solar Cells using Hydrated Vanadium(V)Oxide as a PEDOT:PSS Replacement.

    PubMed

    Espinosa, Nieves; Dam, Henrik Friis; Tanenbaum, David M; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-01-11

    The use of hydrated vanadium(V)oxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full roll-to-roll (R2R) processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET) and had the structure PET/ITO/ZnO/P3HT:PCBM/V₂O₅·(H₂O)n/Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(V)oxide layers were processed by slot-die coating. The hydrated vanadium(V)oxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP). Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(V)oxide layer by varying the concentration of the VTIP precursor over two orders of magnitude. Hydrated vanadium(V)oxide layers were characterized by profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and grazing incidence wide angle X-ray scattering. The power conversion efficiency (PCE) for completed modules was up to 0.18%, in contrast to single cells where efficiencies of 0.4% were achieved. Stability tests under indoor and outdoor conditions were accomplished over three weeks on a solar tracker.

  13. Charge-separation enhancement in inverted polymer solar cells by molecular-level triple heterojunction: NiO-np:P3HT:PCBM.

    PubMed

    Pradeep, U W; Villani, M; Calestani, D; Cristofolini, L; Iannotta, S; Zappettini, A; Coppedè, N

    2017-01-20

    Hole collection and transport are crucial physical processes in bulk-heterojunction (BHJ) solar cells, which represent major bottlenecks due to their limitations in power conversion efficiency (PCE). Hence, a more efficient alternative is needed to accept and transport holes to the collection electrode in BHJ solar cells. Here, we bring both electron and hole collection centres close to the point of exciton generation by infiltrating P3HT poly(3-hexylthiophene):PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) blend into a highly porous interconnected p-type NiO-nanoparticle (NiO-np) network, through solvent-assisted grafting. In this study, a hybrid polymer solar cell is demonstrated with a P3HT:PCBM:NiO-np triple-heterojunction active layer which showed greatly improved rectification behaviour, long electron lifetime and generated higher PCE of 4% under AM 1.5 solar illumination with a 75% increase in PCE with respect to the P3HT:PCBM device. The optimum NiO-np amount and active-layer thickness were found to be 2% and 250 nm, respectively.

  14. Charge-separation enhancement in inverted polymer solar cells by molecular-level triple heterojunction: NiO-np:P3HT:PCBM

    NASA Astrophysics Data System (ADS)

    Pradeep, U. W.; Villani, M.; Calestani, D.; Cristofolini, L.; Iannotta, S.; Zappettini, A.; Coppedè, N.

    2017-01-01

    Hole collection and transport are crucial physical processes in bulk-heterojunction (BHJ) solar cells, which represent major bottlenecks due to their limitations in power conversion efficiency (PCE). Hence, a more efficient alternative is needed to accept and transport holes to the collection electrode in BHJ solar cells. Here, we bring both electron and hole collection centres close to the point of exciton generation by infiltrating P3HT poly(3-hexylthiophene):PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) blend into a highly porous interconnected p-type NiO-nanoparticle (NiO-np) network, through solvent-assisted grafting. In this study, a hybrid polymer solar cell is demonstrated with a P3HT:PCBM:NiO-np triple-heterojunction active layer which showed greatly improved rectification behaviour, long electron lifetime and generated higher PCE of 4% under AM 1.5 solar illumination with a 75% increase in PCE with respect to the P3HT:PCBM device. The optimum NiO-np amount and active-layer thickness were found to be 2% and 250 nm, respectively.

  15. Semitransparent inverted polymer solar cells employing a sol-gel-derived TiO2 electron-selective layer on FTO and MoO3/Ag/MoO3 transparent electrode.

    PubMed

    Li, Fumin; Chen, Chong; Tan, Furui; Li, Chunxi; Yue, Gentian; Shen, Liang; Zhang, Weifeng

    2014-01-01

    We report a new semitransparent inverted polymer solar cell (PSC) with a structure of glass/FTO/nc-TiO2/P3HT:PCBM/MoO3/Ag/MoO3. Because high-temperature annealing which decreased the conductivity of indium tin oxide (ITO) must be handled in the process of preparation of nanocrystalline titanium oxide (nc-TiO2), we replace glass/ITO with a glass/fluorine-doped tin oxide (FTO) substrate to improve the device performance. The experimental results show that the replacing FTO substrate enhances light transmittance between 400 and 600 nm and does not change sheet resistance after annealing treatment. The dependence of device performances on resistivity, light transmittance, and thickness of the MoO3/Ag/MoO3 film was investigated. High power conversion efficiency (PCE) was achieved for FTO substrate inverted PSCs, which showed about 75% increase compared to our previously reported ITO substrate device at different thicknesses of the MoO3/Ag/MoO3 transparent electrode films illuminated from the FTO side (bottom side) and about 150% increase illuminated from the MoO3/Ag/MoO3 side (top side).

  16. Semitransparent inverted polymer solar cells employing a sol-gel-derived TiO2 electron-selective layer on FTO and MoO3/Ag/MoO3 transparent electrode

    PubMed Central

    2014-01-01

    We report a new semitransparent inverted polymer solar cell (PSC) with a structure of glass/FTO/nc-TiO2/P3HT:PCBM/MoO3/Ag/MoO3. Because high-temperature annealing which decreased the conductivity of indium tin oxide (ITO) must be handled in the process of preparation of nanocrystalline titanium oxide (nc-TiO2), we replace glass/ITO with a glass/fluorine-doped tin oxide (FTO) substrate to improve the device performance. The experimental results show that the replacing FTO substrate enhances light transmittance between 400 and 600 nm and does not change sheet resistance after annealing treatment. The dependence of device performances on resistivity, light transmittance, and thickness of the MoO3/Ag/MoO3 film was investigated. High power conversion efficiency (PCE) was achieved for FTO substrate inverted PSCs, which showed about 75% increase compared to our previously reported ITO substrate device at different thicknesses of the MoO3/Ag/MoO3 transparent electrode films illuminated from the FTO side (bottom side) and about 150% increase illuminated from the MoO3/Ag/MoO3 side (top side). PMID:25332693

  17. A new method to disperse CdS quantum dot-sensitized TiO2 nanotube arrays into P3HT:PCBM layer for the improvement of efficiency of inverted polymer solar cells

    PubMed Central

    2014-01-01

    We report that the efficiency of ITO/nc-TiO2/P3HT:PCBM/MoO3/Ag inverted polymer solar cells (PSCs) can be improved by dispersing CdS quantum dot (QD)-sensitized TiO2 nanotube arrays (TNTs) in poly (3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) layer. The CdS QDs are deposited on the TNTs by a chemical bath deposition method. The experimental results show that the CdS QD-sensitized TNTs (CdS/TNTs) do not only increase the light absorption of the P3HT:PCBM layer but also reduce the charge recombination in the P3HT:PCBM layer. The dependence of device performances on cycles of CdS deposition on the TNTs was investigated. A high power conversion efficiency (PCE) of 3.52% was achieved for the inverted PSCs with 20 cyclic depositions of CdS on TNTs, which showed a 34% increase compared to the ITO/nc-TiO2/P3HT:PCBM/MoO3/Ag device without the CdS/TNTs. The improved efficiency is attributed to the improved light absorbance and the reduced charge recombination in the active layer. PMID:24936158

  18. EMI from solar panels and inverters

    NASA Astrophysics Data System (ADS)

    1983-01-01

    Results are given of an exploratory investigation to ascertain the potential of electromagnetic interference (EMI) caused by radiation from photovoltaic (PV) systems. This includes a determination of the appropriate parameters to be measured and a review of present standards with emphasis on the FCC docket on incidental radiators. It also includes small residential installations having roof-mounted PV arrays. The results will be used to make recommendations as to what further work, if any, is needed to ensure that EMI from a PV system is negligible. Measured data so far show that the inverters in the solar-panel system tested caused severe EMI problems in the AM broadcast band (0.5 to 1.6 MH2), while FM and television reception was not significantly affected.

  19. Nanoimprinted polymer solar cell.

    PubMed

    Yang, Yi; Mielczarek, Kamil; Aryal, Mukti; Zakhidov, Anvar; Hu, Walter

    2012-04-24

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. A vertically bicontinuous and interdigitized heterojunction between donor and acceptor has been regarded as one of the ideal structures to enable both efficient charge separation and transport. Synergistic control of polymer orientation in the nanostructured heterojunction is also critical to improve the performance of polymer solar cells. Nanoimprint lithography has emerged as a new approach to simultaneously control both the heterojunction morphology and polymer chains in organic photovoltaics. Currently, in the area of nanoimprinted polymer solar cells, much progress has been achieved in the fabrication of nanostructured morphology, control of molecular orientation/crystallinity, deposition of acceptor materials, patterned electrodes, understanding of structure-property correlations, and device performance. This review article summarizes the recent studies on nanoimprinted polymer solar cells and discusses the outstanding challenges and opportunities for future work.

  20. ITO Modification for Efficient Inverted Organic Solar Cells.

    PubMed

    Susarova, Diana K; Akkuratov, Alexander V; Kukharenko, Andrey I; Cholakh, Seif O; Kurmaev, Ernst Z; Troshin, Pavel A

    2017-10-03

    We demonstrate a facile approach to designing transparent electron-collecting electrodes by depositing thin layers of medium and low work function metals on top of transparent conductive metal oxides (TCOs) such as ITO and FTO. The modified electrodes were fairly stable for months under ambient conditions and maintained their electrical characteristics. XPS spectroscopy data strongly suggested integration of the deposited metal in the TCO structure resulting in additional doping of the conducting oxide at the interface. Kelvin probe microscopy measurements revealed a significant decrease in the ITO work function after modification. Organic solar cells based on three different conjugated polymers have demonstrated state of the art performances in inverted device geometry using Mg- or Yb-modified ITO as electron collecting electrode. The simplicity of the proposed approach and the excellent ambient stability of the modified ITO electrodes allows one to expect their wide utilization in research laboratories and electronic industry.

  1. Direct observation of UV-induced charge accumulation in inverted-type polymer solar cells with a TiOx layer: Microscopic elucidation of the light-soaking phenomenon

    NASA Astrophysics Data System (ADS)

    Son, D.; Kuwabara, T.; Takahashi, K.; Marumoto, K.

    2016-09-01

    The mechanism of light-soaking phenomenon in inverted-type organic solar cells (IOSCs) with a structure of indium-tin-oxide/TiOx/P3HT:PCBM/Au was studied by electron spin resonance (ESR) spectroscopy. Charge accumulation in the cell during UV-light irradiation was observed using ESR, which was clearly correlated with the light-soaking phenomenon. The origin of the charge accumulation is clarified as holes that are deeply trapped at p-type P3HT polymer-chain ends with bromine after hole transfer from the band excitation in the TiOx layer. The holes are considered to be electrostatically attracted to trapped electrons in the TiOx layer after the band excitation. These accumulated charges are the origin of the light-soaking phenomenon. Our results strongly suggest that passivation of the residual OH groups in the TiOx layer is needed to avoid the light-soaking phenomenon by preventing electron trappings, a step that is indispensable in the operation of highly stable IOSCs without UV-light irradiation based on a low-cost and low-temperature device fabrication process using flexible plastic substrates.

  2. Role of thin n-type metal-oxide interlayers in inverted organic solar cells.

    PubMed

    Gadisa, Abay; Liu, Yingchi; Samulski, Edward T; Lopez, Rene

    2012-08-01

    We have investigated the photovoltaic properties of inverted solar cells comprising a bulk heterojunction film of poly(3-hexylthiophene) and phenyl-C(61)-butyric acid methyl ester, sandwiched between an indium-tin-oxide/Al-doped zinc oxide (ZnO-Al) front, and tungsten oxide/aluminum back electrodes. The inverted solar cells convert photons to electrons at an external quantum efficiency (EQE) exceeding 70%. This is a 10-15% increase over EQEs of conventional solar cells. The increase in EQE is not fully explained by the difference in the optical transparency of electrodes, interference effects due to an optical spacer effect of the metal-oxide electrode buffer layers, or variation in charge generation profile. We propose that a large additional splitting of excited states at the ZnO-Al/polymer interface leads to the considerably large photocurrent yield in inverted cells. Our finding provides new insights into the benefits of n-type metal-oxide interlayers in bulk heterojunction solar cells, namely the splitting of excited states and conduction of free electrons simultaneously.

  3. Efficient eco-friendly inverted quantum dot sensitized solar cells.

    PubMed

    Park, Jinhyung; Sajjad, Muhammad T; Jouneau, Pierre-Henri; Ruseckas, Arvydas; Faure-Vincent, Jérôme; Samuel, Ifor D W; Reiss, Peter; Aldakov, Dmitry

    2016-01-21

    Recent progress in quantum dot (QD) sensitized solar cells has demonstrated the possibility of low-cost and efficient photovoltaics. However, the standard device structure based on n-type materials often suffers from slow hole injection rate, which may lead to unbalanced charge transport. We have fabricated efficient p-type (inverted) QD sensitized cells, which combine the advantages of conventional QD cells with p-type dye sensitized configurations. Moreover, p-type QD sensitized cells can be used in highly promising tandem configurations with n-type ones. QDs without toxic Cd and Pb elements and with improved absorption and stability were successfully deposited onto mesoporous NiO electrode showing good coverage and penetration according to morphological analysis. Detailed photophysical charge transfer studies showed that high hole injection rates (10(8) s(-1)) observed in such systems are comparable with electron injection in conventional n-type QD assemblies. Inverted solar cells fabricated with various QDs demonstrate excellent power conversion efficiencies of up to 1.25%, which is 4 times higher than the best values for previous inverted QD sensitized cells. Attempts to passivate the surface of the QDs show that traditional methods of reduction of recombination in the QD sensitized cells are not applicable to the inverted architectures.

  4. Stretchable polymer solar cell fibers.

    PubMed

    Zhang, Zhitao; Yang, Zhibin; Deng, Jue; Zhang, Ye; Guan, Guozhen; Peng, Huisheng

    2015-02-11

    Power yourself up: a sweater made from solar cells! Stretchable and wearable fibers are shown to be highly efficient polymer solar cells. Their stable energy conversion efficiency variation is below 10% even after 1000 bending cycles or stretching under a strain of 30%. These fibers can easily be woven into fabric from which any type of clothing can be made.

  5. The research of multilevel transistor inverter for converting energy of solar panels

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  6. Conjugated Polymer Solar Cells

    DTIC Science & Technology

    2006-05-01

    for films was measured in a pumped vacuum cell. The quantum yield was calculated from the integrated PL spectra and measured optical density...At the same time, the known disadvantages of pristine conjugated polymers are: • the quantum yield of free charges is far below than unity under...possibility of improving the photovoltaic properties of conjugated polymers using polymer CTCs. EXPECTED RESULTS We planned to perform a well -directed

  7. Nanostructured Electron-Selective Interlayer for Efficient Inverted Organic Solar Cells.

    PubMed

    Song, Jiyun; Lim, Jaehoon; Lee, Donggu; Thambidurai, M; Kim, Jun Young; Park, Myeongjin; Song, Hyung-Jun; Lee, Seonghoon; Char, Kookheon; Lee, Changhee

    2015-08-26

    We report a unique nanostructured electron-selective interlayer comprising of In-doped ZnO (ZnO:In) and vertically aligned CdSe tetrapods (TPs) for inverted polymer:fullerene bulkheterojunction (BHJ) solar cells. With dimension-controlled CdSe TPs, the direct inorganic electron transport pathway is provided, resulting in the improvement of the short circuit current and fill factor of devices. We demonstrate that the enhancement is attributed to the roles of CdSe TPs that reduce the recombination losses between the active layer and buffer layer, improve the hole-blocking as well as electron-transporting properties, and simultaneously improve charge collection characteristics. As a result, the power conversion efficiency of PTB7:PC70BM based solar cell with nanostructured CdSe TPs increases to 7.55%. We expect this approach can be extended to a general platform for improving charge extraction in organic solar cells.

  8. Performance enhancement in inverted solar cells by interfacial modification of ZnO nanoparticle buffer layer.

    PubMed

    Ambade, Swapnil B; Ambade, Rohan B; Kim, Seojin; Park, Hanok; Yoo, Dong Jin; Leel, Soo-Hyoung

    2014-11-01

    Polymer solar cells (PSCs) have attracted increasing attention in recent years. The rapid progress and mounting interest suggest the feasibility of PSC commercialization. However, critical issues such as stability and the weak nature of their interfaces posses quite a challenge. In the context of improving stability, PSCs with inverted geometry consising of inorganic oxide layer acting as an n-buffer offer quite the panacea. Zinc oxide (ZnO) is one of the most preferred semiconducting wide band gap oxides as an efficient cathode layer that effectively extracts and transports photoelectrons from the acceptor to the conducting indium-doped tin oxide (ITO) due to its high conductivity and transparency. However, the existence of a back charge transfer from metal oxides to electron-donating conjugated polymer and poor contact with the bulk heterojunction (BHJ) active layer results in serious interfacial recombination and leads to relatively low photovoltaic performance. One approach to improving the performance and charge selectivity of these types of inverted devices consists of modifying the interface between the inorganic metal oxide (e.g., ZnO) and organic active layer using a sub-monolayer of interfacial materials (e.g., functional dyes). In this work, we demonstrate that the photovoltaic parameters of inverted solar cells comprising a thin overlayer of functional dyes over ZnO nanoparticle as an n-buffer layer are highly influenced by the anchoring groups they possess. While an inverted PSC containing an n-buffer of only ZnO exhibited an overall power conversion efficiency (PCE) of 2.87%, the devices with an interlayer of dyes containing functional cyano-carboxylic, cyano-cyano, and carboxylic groups exhibited PCE of 3.52%, 3.39%, and 3.21%, respectively, due to increased forward charge collection resulting from enhanced electronic coupling between the ZnO and BHJ active layers.

  9. Advanced Inverter Functions to Support High Levels of Distributed Solar: Policy and Regulatory Considerations (Brochure)

    SciTech Connect

    Not Available

    2014-11-01

    This paper explains how advanced inverter functions (sometimes called 'smart inverters') contribute to the integration of high levels of solar PV generation onto the electrical grid and covers the contributions of advanced functions to maintaining grid stability. Policy and regulatory considerations associated with the deployment of advanced inverter functions are also introduced.

  10. Organic solar cells under the BHJ approach using conventional/inverted architectures

    NASA Astrophysics Data System (ADS)

    Salinas, J. F.; Salto, C.; Maldonado, J. L.; Ramos-Ortíz, G.; Rodríguez, M.; Meneses-Nava, M. A.; Barbosa-García, Oracio; Farfán, N.; Santillan, R.

    2011-08-01

    The search of clean and renewable energy sources is one of the most important challenges that mankind confronts. Recently there has been a notable interest to develop organic photovoltaic (OPV) technology as a mean of renewable energy source since it combines low-cost and easy fabrication. Most of the efforts have been directed to increase the efficiency, leaving aside the durability of the organic materials, however, a new architecture known as inverted solar cell might bring a never seen durability (years) that could make possible large scale applications of this technology. Here are presented the results we achieved using both, the conventional and inverted architectures employing as organic donor (D) the very well known semi-conducting polymer P3HT, in mixtures with the acceptor (A) fullerene PC61BM. The morphology of thin polymer films prepared by using the spin coating technique was analyzed by AFM. For the conventional architecture the cells were fabricated following the structure ITO/PEDOT:PSS/P3HT:PC61BM/Wood´s metal, where the Wood´s metal cathode is an alloy that melts at 75 °C. For the inverted architecture the structure ITO/ZnO/P3HT:PC61BM /PEDOT:PSS/(Ag, Cu or Silver paint) was used, where ITO worked as cathode by switching its work function through the introduction of ZnO nanoparticles. Under tests using Xenon lamp irradiation at 100 mW/cm2, the conventional and the inverted architectures produced efficiencies of 1.75 % and 0.5 %, respectively. For both architectures the chosen back-contact materials (Wood´s metal and silver paint) allowed us to easily make the OPVs cells without the need of vacuum steps.

  11. Surface Plasmon Resonance Effect in Inverted Perovskite Solar Cells.

    PubMed

    Cui, Jin; Chen, Cheng; Han, Junbo; Cao, Kun; Zhang, Wenjun; Shen, Yan; Wang, Mingkui

    2016-03-01

    This work reports on incorporation of spectrally tuned gold/silica (Au/SiO2) core/shell nanospheres and nanorods into the inverted perovskite solar cells (PVSC). The band gap of hybrid lead halide iodide (CH3NH3PbI3) can be gradually increased by replacing iodide with increasing amounts of bromide, which can not only offer an appreciate solar radiation window for the surface plasmon resonance effect utilization, but also potentially result in a large open circuit voltage. The introduction of localized surface plasmons in CH3NH3PbI2.85Br0.15-based photovoltaic system, which occur in response to electromagnetic radiation, has shown dramatic enhancement of exciton dissociation. The synchronized improvement in photovoltage and photocurrent leads to an inverted CH3NH3PbI2.85Br0.15 planar PVSC device with power conversion efficiency of 13.7%. The spectral response characterization, time resolved photoluminescence, and transient photovoltage decay measurements highlight the efficient and simple method for perovskite devices.

  12. Surface Plasmon Resonance Effect in Inverted Perovskite Solar Cells

    PubMed Central

    Cui, Jin; Chen, Cheng; Han, Junbo; Cao, Kun; Zhang, Wenjun; Shen, Yan

    2016-01-01

    This work reports on incorporation of spectrally tuned gold/silica (Au/SiO2) core/shell nanospheres and nanorods into the inverted perovskite solar cells (PVSC). The band gap of hybrid lead halide iodide (CH3NH3PbI3) can be gradually increased by replacing iodide with increasing amounts of bromide, which can not only offer an appreciate solar radiation window for the surface plasmon resonance effect utilization, but also potentially result in a large open circuit voltage. The introduction of localized surface plasmons in CH3NH3PbI2.85Br0.15‐based photovoltaic system, which occur in response to electromagnetic radiation, has shown dramatic enhancement of exciton dissociation. The synchronized improvement in photovoltage and photocurrent leads to an inverted CH3NH3PbI2.85Br0.15 planar PVSC device with power conversion efficiency of 13.7%. The spectral response characterization, time resolved photoluminescence, and transient photovoltage decay measurements highlight the efficient and simple method for perovskite devices. PMID:28174678

  13. Synthetic polymers for solar harvesting.

    PubMed

    Ghiggino, Kenneth P; Bell, Toby D M; Hooley, Emma N

    2012-01-01

    Synthetic polymers incorporating appropriate chromophores can act as light harvesting antennae for artificial photosynthetic systems. The photophysical processes occurring in a polymer based on phenylene vinylene have been investigated at the single chain level and in bulk solution to study energy transfer processes. Most single chains of an alternating copolymer of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and 1,4-phenylene vinylene (alt-co-MEH-PPV) dispersed in a transparent polymer matrix act as single chromophore emitters demonstrating that energy transfer is an efficient process in these polymers. However for individual polymer chains there are fluctuations in emission intensity ('blinking') and shifts in emission spectra, decay lifetimes and emission dipole orientation occurring on a time-scale of tens of seconds. Fluorescence blinking also occurs on a sub-millisecond time-scale and follows exponential kinetics, whereas the longer blinking is better described by a power law. These observations can be interpreted as arising from environmental relaxation processes and/or changes in the emitter and demonstrate the wide distribution of photophysical behaviours that can be observed among the individual molecules of a polymer sample. The relevance of these studies to the application of polymer materials for solar harvesting is highlighted.

  14. Reversible degradation of inverted organic solar cells by concentrated sunlight.

    PubMed

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A; Krebs, Frederik C

    2011-06-03

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5-15 suns at three different stages: for a pristine cell, after 30 min exposure at 5 suns and after 30 min of rest in the dark. High intensity exposure introduced a major performance decrease for all solar intensities, followed by a partial recovery of the lost performance over time: at 1 sun only 6% of the initial performance was conserved after the high intensity exposure, while after rest the performance had recovered to 60% of the initial value. The timescale of the recovery effect was studied by monitoring the cell performance at 1 sun after high intensity exposure. This showed that cell performance was almost completely restored after 180 min. The transient state is believed to be a result of the breakdown of the diode behaviour of the ZnO electron transport layer by O(2) desorption, increasing the hole conductivity. These results imply that accelerated degradation of organic solar cells by concentrated sunlight is not a straightforward process, and care has to be taken to allow for a sound accelerated lifetime assessment based on concentrated sunlight.

  15. Fabrication and characterization of inverted organic solar cells using shuttle cock-type metal phthalocyanine and PCBM:P3HT

    SciTech Connect

    Suzuki, Atsushi Furukawa, Ryo Akiyama, Tsuyoshi Oku, Takeo

    2015-02-27

    Inverted organic solar cells using shuttle cock-type phthalocyanine, semiconducting polymer and fullerenes were fabricated and characterized. Photovoltaic and optical properties of the solar cells with inverted structures were investigated by optical absorption, current density-voltage characteristics. The photovoltaic properties of the tandem organic solar cell using titanyl phthalocyanine, vanadyl phthalocyanine, poly(3-hexylthiophene) (P3HT) and [6, 6]-phenyl C{sub 61}-butyric acid methyl ester (PCBM) were improved. Effect of annealing and solvent treatment on surface morphologies of the active layer was investigated. The photovoltaic mechanisms, energy levels and band gap of active layers were discussed for improvement of the photovoltaic performance.

  16. Enhanced Performance of Inverted Polymer Solar Cells by Combining ZnO Nanoparticles and Poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] as Electron Transport Layer.

    PubMed

    Han, Changfeng; Cheng, Yuanyuan; Chen, Ling; Qian, Lei; Yang, Ziyan; Xue, Wei; Zhang, Ting; Yang, Yixing; Cao, Weiran

    2016-02-10

    A highly efficient inverted polymer solar cell (PSC) has been successfully demonstrated by using a ZnO nanoparticle (NP) and poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) bilayer structure as an effective electron collecting layer. This ZnO/PFN bilayer structure is designed to combine the advantages of both ZnO and PFN, based on the performance comparison of ZnO-only, PFN-only, and ZnO/PFN bilayer devices in our work. ZnO NPs can serve as an efficient electron transport and buffer layer for reduced series resistance, while the PFN interlayer can improve the energy level alignment of devices through the formation of an interfacial dipole. With the enhanced electron extraction induced by the ZnO/PFN bilayer structure and PTB7:ICBA:PC71BM ternary system, the corresponding inverted PSC device shows a high PCE of 9.3%, which is more than a 15% improvement compared to the ZnO- or PFN-only devices.

  17. Achieving 15% Tandem Polymer Solar Cells

    DTIC Science & Technology

    2015-06-23

    AFRL-OSR-VA-TR-2015-0145 Achieving 1% Tandem Polymer Solar Cells Yang Yang UNIVERSITY OF CALIFORNIA LOS ANGELES Final Report 06/23/2015 DISTRIBUTION...15% tandem polymer solar cells 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1-0074 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...1) develop novel low bandgap conjugated polymers for high efficiency tandem solar cell – single junction cell with 9% PCE achieved (2) develop

  18. Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells

    PubMed Central

    Deng, Dan; Zhang, Yajie; Zhang, Jianqi; Wang, Zaiyu; Zhu, Lingyun; Fang, Jin; Xia, Benzheng; Wang, Zhen; Lu, Kun; Ma, Wei; Wei, Zhixiang

    2016-01-01

    Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule. PMID:27991486

  19. Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells.

    PubMed

    Deng, Dan; Zhang, Yajie; Zhang, Jianqi; Wang, Zaiyu; Zhu, Lingyun; Fang, Jin; Xia, Benzheng; Wang, Zhen; Lu, Kun; Ma, Wei; Wei, Zhixiang

    2016-12-19

    Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule.

  20. Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells

    NASA Astrophysics Data System (ADS)

    Deng, Dan; Zhang, Yajie; Zhang, Jianqi; Wang, Zaiyu; Zhu, Lingyun; Fang, Jin; Xia, Benzheng; Wang, Zhen; Lu, Kun; Ma, Wei; Wei, Zhixiang

    2016-12-01

    Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule.

  1. Disodium edetate as a promising interfacial material for inverted organic solar cells and the device performance optimization.

    PubMed

    Li, Xiaodong; Zhang, Wenjun; Wang, Xueyan; Gao, Feng; Fang, Junfeng

    2014-12-10

    Disodium edetate (EDTA-Na), a popular hexadentate ligand in analytical chemistry, was successfully introduced in organic solar cells (OSCs) as cathode interfacial layer. The inverted OSCs with EDTA-Na showed superior performance both in power conversion efficiency and devices stability compared with conventional devices. Interestingly, we found that the performance of devices with EDTA-Na could be optimized through external bias treatment. After optimization, the efficiency of inverted OSCs with device structure of ITO/EDTA-Na/polymer thieno[3,4-b]thiophene/benzodithiophene (PTB7):PC71BM/MoO3/Al was significantly increased to 8.33% from an initial value of 6.75%. This work introduces a new class of interlayer materials, small molecule electrolytes, for organic solar cells.

  2. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures.

    PubMed

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, SenPo; Xiu, Fei; Ho, Johnny C

    2016-09-27

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices.

  3. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

    NASA Astrophysics Data System (ADS)

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, Senpo; Xiu, Fei; Ho, Johnny C.

    2016-09-01

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices.

  4. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

    PubMed Central

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, SenPo; Xiu, Fei; Ho, Johnny C.

    2016-01-01

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices. PMID:27671709

  5. Au nanorods-incorporated plasmonic-enhanced inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Peng, Ling; Mei, Yang; Chen, Shu-Fen; Zhang, Yu-Pei; Hao, Jing-Yu; Deng, Ling-Ling; Huang, Wei

    2015-11-01

    The effect of Au nanorods (NRs) on optical-to-electric conversion efficiency is investigated in inverted polymer solar cells, in which Au NRs are sandwiched between two layers of ZnO. Accompanied by the optimization of thickness of ZnO covered on Au NRs, a high-power conversion efficiency of 3.60% and an enhanced short-circuit current density (JSC) of 10.87 mA/cm2 are achieved in the poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC60BM)-based inverted cell and the power conversion efficiency (PCE) is enhanced by 19.6% compared with the control device. The detailed analyses of the light absorption characteristics, the simulated scattering induced by Au NRs, and the electromagnetic field around Au NRs show that the absorption improvement in the photoactive layer due to the light scattering from the longitudinal axis and the near-field increase around Au NRs induced by localized surface plasmon resonance plays a key role in enhancing the performances. Project supported by the Ministry of Science and Technology, China (Grant No. 2012CB933301), the National Natural Science Foundation of China (Grant Nos. 61274065, 51173081, 61136003, BZ2010043, 51372119, and 51172110), and the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions and Synergetic Innovation Center for Organic Electronics and Information Displays, China.

  6. Pathway to 50% efficient inverted metamorphic concentrator solar cells

    NASA Astrophysics Data System (ADS)

    Geisz, John F.; Steiner, Myles A.; Jain, Nikhil; Schulte, Kevin L.; France, Ryan M.; McMahon, William E.; Perl, Emmett E.; Horowitz, Kelsey A. W.; Friedman, Daniel J.

    2017-09-01

    Series-connected five (5J) and six junction (6J) concentrator solar cell strategies have the realistic potential to exceed 50% efficiency to enable low-cost CPV systems. We propose three strategies for developing a practical 6J device. We have overcome many of the challenges required to build such concentrator solar cell devices: We have developed 2.1 eV AlGaInP, 1.7 eV AlGaAs, and 1.7 eV GaInAsP junctions with external radiative efficiency greater than 0.1%. We have developed a transparent tunnel junction that absorbs minimal light intended for the second junction yet resists degradation under thermal load. We have developed metamorphic grades from the GaAs to the InP lattice constant that are transparent to sub-GaAs bandgap light. We have grown and compared low bandgap junctions (0.7eV - 1.2 eV) using metamorphic GaInAs, metamorphic GaInAsP, and GaInAsP lattice-matched to InP. And finally, we have demonstrated excellent performance in a high voltage, low current 4 junction inverted metamorphic device using 2.1, 1.7, 1.4, and 1.1 eV junctions with over 8.7 mA/cm2 one-sun current density that operates up to 1000 suns without tunnel junction failure.

  7. Interfacial thermal degradation in inverted organic solar cells

    SciTech Connect

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain

    2015-12-28

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO{sub 3} and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  8. Interfacial thermal degradation in inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain

    2015-12-01

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO3 and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  9. High-efficiency inverted semi-transparent planar perovskite solar cells in substrate configuration

    NASA Astrophysics Data System (ADS)

    Fu, Fan; Feurer, Thomas; Weiss, Thomas Paul; Pisoni, Stefano; Avancini, Enrico; Andres, Christian; Buecheler, Stephan; Tiwari, Ayodhya N.

    2017-01-01

    The ability to grow perovskite solar cells in substrate configuration, where light enters the devices from the film side, allows the use of non-transparent flexible polymer and metal substrates. Furthermore, this configuration could facilitate processing directly on Cu(In,Ga)Se2 solar cells to realize ultrahigh-efficiency polycrystalline all-thin-film tandem devices. However, the inversion of conventional superstrate architecture imposes severe constraints on device processing and limits the electronic quality of the absorber and charge selective contacts. Here we report a device architecture that allows inverted semi-transparent planar perovskite solar cells with a high open-circuit voltage of 1.116 V and substantially improved efficiency of 16.1%. The substrate configuration perovskite devices show a temperature coefficient of -0.18% °C-1 and promising thermal and photo-stability. Importantly, the device exhibits a high average transmittance of 80.4% between 800 and 1,200 nm, which allows us to demonstrate polycrystalline all-thin-film tandem devices with efficiencies of 22.1% and 20.9% for Cu(In,Ga)Se2 and CuInSe2 bottom cells, respectively.

  10. A pyridine-functionalized pyrazolinofullerene used as a buffer layer in polymer solar cells.

    PubMed

    Yang, Pingao; Chen, Shan; Liu, Yu; Xiao, Zuo; Ding, Liming

    2013-10-28

    A pyridine-functionalized pyrazolinofullerene (1) was synthesized in 42% yield via an improved one-pot reaction of C60, 3,6-di(2-pyridyl)-1,2,4,5-tetrazine, and water. The structure of 1 was unambiguously determined by X-ray diffraction of its single crystal. Due to the coordination capability of the functional groups on fullerene, compound 1 was used as a buffer layer to modify ZnO in inverted polymer solar cells. The power conversion efficiency was improved from 3.65% to 4.18% for inverted P3HT:PC61BM solar cells.

  11. Fullerene surfactants and their use in polymer solar cells

    SciTech Connect

    Jen, Kwan-Yue; Yip, Hin-Lap; Li, Chang-Zhi

    2015-12-15

    Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.

  12. Diketopyrrolopyrrole Polymers for Organic Solar Cells.

    PubMed

    Li, Weiwei; Hendriks, Koen H; Wienk, Martijn M; Janssen, René A J

    2016-01-19

    Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a result, the power conversion efficiencies (PCEs) of solar cells based on conjugated polymers as electron donor and fullerene derivatives as electron acceptor have exceeded 10% in single-junction and 11% in multijunction devices. Despite these efforts, it is notoriously difficult to establish thorough structure-property relationships that will be required to further optimize existing high-performance polymers to their intrinsic limits. In this Account, we highlight progress on the development and our understanding of diketopyrrolopyrrole (DPP) based conjugated polymers for polymer solar cells. The DPP moiety is strongly electron withdrawing and its polar nature enhances the tendency of DPP-based polymers to crystallize. As a result, DPP-based conjugated polymers often exhibit an advantageously broad and tunable optical absorption, up to 1000 nm, and high mobilities for holes and electrons, which can result in high photocurrents and good fill factors in solar cells. Here we focus on the structural modifications applied to DPP polymers and rationalize and explain the relationships between chemical structure and organic photovoltaic performance. The DPP polymers can be tuned via their aromatic substituents, their alkyl side chains, and the nature of the π-conjugated segment linking the units along the polymer chain. We show that these building blocks work together in determining the molecular conformation, the optical properties, the charge carrier mobility, and the solubility of the polymer. We identify the latter as a decisive parameter for DPP-based organic solar cells because it regulates the diameter of the semicrystalline DPP polymer fibers that form in the photovoltaic blends with

  13. Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System

    SciTech Connect

    Agamy, Mohammed

    2015-10-27

    The “Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System” program is focused on developing innovative concepts for residential photovoltaic (PV) systems with the following objectives: to create an Innovative micro-inverter topology that reduces the cost from the best in class micro-inverter and provides high efficiency (>96% CEC - California Energy Commission), and 25+ year warranty, as well as reactive power support; integrate micro-inverter and PV module to reduce system price by at least $0.25/W through a) accentuating dual use of the module metal frame as a large area heat spreader reducing operating temperature, and b) eliminating redundant wiring and connectors; and create micro-inverter controller handles smart grid and safety functions to simplify implementation and reduce cost.

  14. An Azaacene Derivative as Promising Electron-Transport Layer for Inverted Perovskite Solar Cells.

    PubMed

    Gu, Pei-Yang; Wang, Ning; Wu, Anyang; Wang, Zilong; Tian, Miaomiao; Fu, Zhisheng; Sun, Xiao Wei; Zhang, Qichun

    2016-08-05

    It is highly desirable to develop novel n-type organic small molecules as an efficient electron-transport layer (ETL) for the replacement of PCBM to obtain high-performance metal-oxide-free, solution-processed inverted perovskite solar cells (PSCs) because this type of solar cells with a low-temperature and solution-based process would make their fabrication more feasible and practical. In this research, the new azaacene QCAPZ has been synthesized and employed as non-fullerene ETL material for inverted PSCs through a solution-based process without the need for additional dopants or additives. The as-fabricated inverted PSCs show a power conversion efficiency up to 10.26 %. Our results clearly suggest that larger azaacenes could be promising electron-transport materials to achieve high-performance solution-processed inverted PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. High performance polymer tandem solar cell

    PubMed Central

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2015-01-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. PMID:26669577

  16. Three-phase multilevel solar inverter for motor drive system

    NASA Astrophysics Data System (ADS)

    Bhasagare, Mayuresh P.

    This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.

  17. Development of Manufacturable Process to Deposit Metal Matrix Composites on Inverted Metamorphic Multijunction Solar Cells

    DTIC Science & Technology

    2015-01-14

    Composites on Inverted Metamorphic Multijunction Solar Cells 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) 5d. PROJECT NUMBER 8809 Sang...MULTIJUNCTION SOLAR CELLS Sang M. Han University of New Mexico 1700 Lomas Blvd. NE, Suite 2200 Albuquerque, NM 87131-0001 14 Jan 2015 Final...multijunction (IMM) space solar cells . The IMM cells fracture during packaging or after prolonged cycles of temperature fluctuations encountered in

  18. High-efficiency inverted organic solar cells with polyethylene oxide-modified Zn-doped TiO2 as an interfacial electron transport layer.

    PubMed

    Thambidurai, M; Kim, Jun Young; Ko, Youngjun; Song, Hyung-Jun; Shin, Hyeonwoo; Song, Jiyun; Lee, Yeonkyung; Muthukumarasamy, N; Velauthapillai, Dhayalan; Lee, Changhee

    2014-08-07

    High efficiency inverted organic solar cells are fabricated using the PTB7:PC71BM polymer by incorporating Zn-doped TiO2 (ZTO) and 0.05 wt% PEO:ZTO as interfacial electron transport layers. The 0.05 wt% PEO-modified ZTO device shows a significantly increased power conversion efficiency (PCE) of 8.10%, compared to that of the ZTO (7.67%) device.

  19. Evaluation of photovoltaic power generation system using spherical silicon solar cells and SiC-FET inverter

    NASA Astrophysics Data System (ADS)

    Matsumoto, Taisuke; Oku, Takeo; Hiramatsu, Koichi; Yasuda, Masashi; Shirahata, Yasuhiro; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2016-02-01

    A photovoltaic power generation system using spherical silicon (Si) solar cells and silicon carbide (SiC) field effect transistor (FET) inverter for photovoltaic applications was constructed and evaluated. The spherical Si solar cells were connected to the SiC-FET inverter and were used as a power source. Comparing the photovoltaic power generation system using an ordinary Si-FET inverter, direct current-alternating current conversion efficiencies of the SiC-FET inverter were improved due to reduction of power loss in the SiC-FET inverter.

  20. Construction and characterization of spherical Si solar cells combined with SiC electric power inverter

    NASA Astrophysics Data System (ADS)

    Oku, Takeo; Matsumoto, Taisuke; Hiramatsu, Kouichi; Yasuda, Masashi; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2015-02-01

    Spherical silicon (Si) photovoltaic solar cell systems combined with an electric power inverter using silicon carbide (SiC) field-effect transistor (FET) were constructed and characterized, which were compared with an ordinary Si-based converter. The SiC-FET devices were introduced in the direct current-alternating current (DC-AC) converter, which was connected with the solar panels. The spherical Si solar cells were used as the power sources, and the spherical Si panels are lighter and more flexible compared with the ordinary flat Si solar panels. Conversion efficiencies of the spherical Si solar cells were improved by using the SiC-FET.

  1. EMCORE four-junction inverted metamorphic solar cell development

    NASA Astrophysics Data System (ADS)

    Miller, Nate; Patel, Pravin; Struempel, Claudia; Kerestes, Chris; Aiken, Dan; Sharps, Paul

    2014-09-01

    EMCORE grown and tested four-junction terrestrial concentrator inverted metamorphic multijunction (CIMM) devices have been demonstrated with internally measured typical efficiencies of ˜44% and peak efficiencies as high as ˜47%, which are in the realm of world record performance. Improved internal testing as well as external validation by NREL are in progress.

  2. Materials, device, and interface engineering to improve polymer-based solar cells

    NASA Astrophysics Data System (ADS)

    Hau, Steven Kin

    The continued depletion of fossil fuel resources has lead to the rise in energy production costs which has lead to the search for an economically viable alternative energy source. One alternative of particular interest is solar energy. A promising alternative to inorganic materials is organic semiconductor polymer solar cells due to their advantages of being cheaper, light weight, flexible and made into large areas by roll-to-roll processing. In this dissertation, an integrated approach is taken to improve the overall performance of polymer-based solar cells by the development of new polymer materials, device architectures, and interface engineering of the contacts between layers. First, a new class of metallated conjugated polymers is explored as potential solar cell materials. Systematic modifications to the molecular units on the main chain of amorphous metallated Pt-polymers show a correlation that improving charge carrier mobility also improves solar cell performance leading to mobilities as high as 1 x 10-2 cm2/V·s and efficiencies as high as 4.1%. Second, an inverted device architecture using a more air stable electrode (Ag) is demonstrated to improve the ambient stability of unencapsulated P3HT:PCBM devices showing over 80% efficiency retention after 40 days of exposure. To further demonstrate the potential for roll-to-roll processing of polymer solar cells, solution processed Ag-nanoparticles were used to replace the vacuum deposited Ag anode electrode for inverted solar cells showing efficiencies as high as 3%. In addition, solution processed polymer based electrodes were demonstrated as a replacement to the expensive and brittle indium tin oxide showing efficiencies of 3% on flexible substrate solar cells. Third, interface engineering of the n-type (high temperature sol-gel processed TiO2 or ZnO, low temperature processed ZnO nanoparticles) electron selective metal oxide contacts in inverted solar cells with self-assembled monolayers (SAM) show improved

  3. Inverted amorphous silicon solar cell utilizing cermet layers

    DOEpatents

    Hanak, Joseph J.

    1979-01-01

    An amorphous silicon solar cell incorporating a transparent high work function metal cermet incident to solar radiation and a thick film cermet contacting the amorphous silicon opposite to said incident surface.

  4. Indium-free bottom electrodes for inverted organic solar cells with simplified cell architectures

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Winkler, T.; Baumann, I.; Schmale, S.; Flügge, H.; Johannes, H.-H.; Hamwi, S.; Rabe, T.; Riedl, T.; Kowalsky, W.

    2011-07-01

    Inverted organic bulk heterojunction solar cells employing a multilayer electrode comprising of a thin Ag layer embedded between layers of zinc tin oxide (ZTO) are compared to cells using an indium tin oxide electrode. The In-free ZTO/Ag/ZTO (ZAZ) electrodes exhibit a favorable work function of 4.3 eV and are shown to allow for excellent electron extraction even without a further interlayer. As a result, issues like transient cell characteristics known from cells comprising titania can be readily avoided. This renders ZAZ a perfectly suited bottom electrode for inverted organic solar cells with a simplified cell architecture.

  5. Polymer-fullerene composite solar cells.

    PubMed

    Thompson, Barry C; Fréchet, Jean M J

    2008-01-01

    Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Polymer-based organic photovoltaic systems hold the promise for a cost-effective, lightweight solar energy conversion platform, which could benefit from simple solution processing of the active layer. The function of such excitonic solar cells is based on photoinduced electron transfer from a donor to an acceptor. Fullerenes have become the ubiquitous acceptors because of their high electron affinity and ability to transport charge effectively. The most effective solar cells have been made from bicontinuous polymer-fullerene composites, or so-called bulk heterojunctions. The best solar cells currently achieve an efficiency of about 5%, thus significant advances in the fundamental understanding of the complex interplay between the active layer morphology and electronic properties are required if this technology is to find viable application.

  6. A futuristic approach towards interface layer modifications for improved efficiency in inverted organic solar cells

    SciTech Connect

    Tiwari, J. P. E-mail: tiwarijp@mail.nplindia.org; Ali, Farman; Sharma, Abhishek; Chand, Suresh; Pillai, Sriraj; Parakh, Sonal

    2014-01-27

    Inverted polymer Solar Cells of the classical poly (3-hexylthiophene) (P3HT):(6,6)-phenyl-C{sub 61}butyric acid methyl ester (PC{sub 61}BM) blend on indium tin oxide substrates were fabricated, which shows improved device performance, by using a facile solution–processed ZnO-polyelectrolytes [poly (diallyldimethylammonium chloride) (PDADMAC), Poly (acrylic acid sodium salt) (PAS), poly (4-styrenesulfonic acid) (PSS), and Polyvinylpyrrolidone (PVP)] nanocomposite as a cathode interface layer compared to devices using pristine ZnO as cathode buffer layer in ambient conditions. The devices with different combinations of polyelectrolyte with ZnO show different improvements in the device efficiency. The combinations of ZnO with PVP and PDADMAC show highest amount of improvements in the efficiency by a factor of ∼17–19. The improvement of the efficiency may be due to various phenomena, such as the passivation of ZnO surface as well as bulk traps, work function modification, improved energy level alignment, improved electronic coupling of the inorganic/organic interface, improved light harvesting, and decrease of surface as well as bulk charge recombination in the device. The introduction of polyelectrolyte into ZnO inhibits the aggregation of ZnO nanoparticles yielding the large area ZnO nanoclusters; and hence, forming the uniform film of ZnO resulting in the modifications of morphology as well as electronic structure of ZnO-polyelectrolyte nano-composite favouring better electronic coupling between cathode and active layer and hence enhancing the current and, consequently, the efficiency. This simple low temperature ZnO-polyelectrolyte nanocomposite based protocol proposed for cathode interface layer modification may be very much useful for roll to roll industrial manufacturing of organic solar cells.

  7. Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.

    PubMed

    Long, Guankui; Wu, Bo; Yang, Xuan; Kan, Bin; Zhou, Ye-Cheng; Chen, Li-Chuan; Wan, Xiangjian; Zhang, Hao-Li; Sum, Tze Chien; Chen, Yongsheng

    2015-09-30

    Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.

  8. Highly efficient inverted polymer light-emitting diodes using surface modifications of ZnO layer.

    PubMed

    Lee, Bo Ram; Jung, Eui Dae; Park, Ji Sun; Nam, Yun Seok; Min, Sa Hoon; Kim, Byeong-Su; Lee, Kyung-Min; Jeong, Jong-Ryul; Friend, Richard H; Kim, Ji-Seon; Kim, Sang Ouk; Song, Myoung Hoon

    2014-09-10

    Organic light-emitting diodes have been recently focused for flexible display and solid-state lighting applications and so much effort has been devoted to achieve highly efficient organic light-emitting diodes. Here, we improve the efficiency of inverted polymer light-emitting diodes by introducing a spontaneously formed ripple-shaped nanostructure of ZnO and applying an amine-based polar solvent treatment to the nanostructure of ZnO. The nanostructure of the ZnO layer improves the extraction of the waveguide modes inside the device structure, and a 2-ME+EA interlayer enhances the electron injection and hole blocking in addition to reducing exciton quenching between the polar-solvent-treated ZnO and the emissive layer. Therefore, our optimized inverted polymer light-emitting diodes have a luminous efficiency of 61.6 cd A(-1) and an external quantum efficiency of 17.8%, which are the highest efficiency values among polymer-based fluorescent light-emitting diodes that contain a single emissive layer.

  9. All solution processible polymer multijunction solar cells

    NASA Astrophysics Data System (ADS)

    Siddiki, Mahbube Khoda

    Conjugated polymer based organic solar cells are a promising alternative to conventional silicon solar cells due to low material and fabrication cost, ease of processability, and mechanical flexibility, while solar cells with a multijunction structure have high potential to achieve enhanced efficiency and cost effectiveness. The goal of this dissertation was to stack narrow band absorbers with efficient interfacial layers in multiple junctions for broad spectrum light harvesting to achieve cost effectiveness. Specific objectives were to develop cost effective interfacial layers, and to design and fabricate solution processible polymer single and multijunction solar cells to achieve 10 % efficiency. A novel recombination layer of Nb2O5-PEDOT:PSS was developed along with single and double junction solar cells using a MDMO-PPV:PC 60BM, P3HT:PC60BM and PSBTBT:PC70BM polymer blend. Simulations showed that the maximum achievable efficiency for single, double, triple, and quadruple junction polymer solar cells were 13 %, 19 %, 22 %, and 24 % respectively, indicating the potential of multijunction devices. XRD reveled that the Nb2O5 used as the recombination layer was amorphous and AFM and KFM microscopic studies showed that the charge transfer barrier from PC60BM to Nb2O5 was only ˜0.2 eV. A MDMO-PPV:PC60BM based double junction solar cell using Nb2O5 electron transport layer exhibited a Voc of 1.30 V, which was close to the sum of the Voc’s of the individual subcells. Simulation results showed that cell efficiency using Nb2O5 as an electron transport layer could be significantly increased by reducing the series resistance (Rse) and matching the current densities of the individual subcells. Nb2O5-PEDOT:PSS was used in a high band gap P3HT and low band gap polymer based double junction solar cell, and the performance obtained was very promising though the PSBTBT:PC 70BM back subcell appeared to be the performance limiting cell with low FF and high series and low shunt

  10. Indium tin oxide-free tandem polymer solar cells on opaque substrates with top illumination.

    PubMed

    Gupta, Dhritiman; Wienk, Martijn M; Janssen, René A J

    2014-08-27

    Top-illuminated, indium tin oxide (ITO)-free, tandem polymer solar cells are fabricated on opaque substrates in an inverted device configuration. In the tandem cell, a wide band gap subcell, consisting of poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) blended with [70]PCBM is combined with a small band gap subcell consisting of a mixture of poly[{2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl}-alt-{[2,2'-(1,4-phenylene)bisthiophene]-5,5'-diyl}] (PDPPTPT) and [60]PCBM. Compared to the more common bottom-illuminated inverted tandem polymer solar cells on transparent ITO substrates, the front and back cells must be reversed when using opaque substrates and a transparent and conductive top contact must be employed to enable top illumination. A high conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer in combination with Ag lines surrounding the active area as current collection electrode is used for this purpose. The tandem polymer solar cell on an opaque glass/metal substrate yields a power conversion efficiency of 6.1% when the thicknesses of the photoactive layers are balanced for optimum performance. This is similar to the equivalent inverted tandem device fabricated on a transparent glass/ITO substrate.

  11. Molded polymer solar water heater

    DOEpatents

    Bourne, Richard C.; Lee, Brian E.

    2004-11-09

    A solar water heater has a rotationally-molded water box and a glazing subassembly disposed over the water box that enhances solar gain and provides an insulating air space between the outside environment and the water box. When used with a pressurized water system, an internal heat exchanger is integrally molded within the water box. Mounting and connection hardware is included to provide a rapid and secure method of installation.

  12. Development of Efficient and Stable Inverted Bulk Heterojunction (BHJ) Solar Cells Using Different Metal Oxide Interfaces

    PubMed Central

    Litzov, Ivan; Brabec, Christoph J.

    2013-01-01

    Solution-processed inverted bulk heterojunction (BHJ) solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeOx) play an important role as the dominant class for solution-processed interface materials in this development, due to their excellent optical transparency, their relatively high electrical conductivity and their tunable work function. This article reviews the advantages and disadvantages of the most common synthesis methods used for the wet chemical preparation of the most relevant n-type- and p-type-like MeOx interface materials consisting of binary compounds AxBy. Their performance for applications as electron transport/extraction layers (ETL/EEL) and as hole transport/extraction layers (HTL/HEL) in inverted BHJ solar cells will be reviewed and discussed. PMID:28788423

  13. Effect of bathocuproine buffer layer in small molecule organic solar cells with inverted structure

    NASA Astrophysics Data System (ADS)

    Hao, Xia; Wang, Shenghao; Sakurai, Takeaki; Akimoto, Katsuhiro

    2015-04-01

    Inverted organic solar cells (OSCs) based on boron subphthalocynine chloride (SubPc) and fullerene (C60) were fabricated and the device structure was optimized by inserting a bathocuproine (C26H20N2) buffer layer. The power conversion efficiency was greatly improved from 0.8 to 1.6%. The roles of bathocuproine in this inverted device were investigated by photoluminescence and transient photovoltage/photocurrent measurements. The results show that the bathocuproine in the device not only blocks the exciton quenching, but also prohibits the build-up of charge trapping and suppresses the trap-assisted recombination.

  14. Hybrid nanorod-polymer solar cells.

    PubMed

    Huynh, Wendy U; Dittmer, Janke J; Alivisatos, A Paul

    2002-03-29

    We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum. A photovoltaic device consisting of 7-nanometer by 60-nanometer CdSe nanorods and the conjugated polymer poly-3(hexylthiophene) was assembled from solution with an external quantum efficiency of over 54% and a monochromatic power conversion efficiency of 6.9% under 0.1 milliwatt per square centimeter illumination at 515 nanometers. Under Air Mass (A.M.) 1.5 Global solar conditions, we obtained a power conversion efficiency of 1.7%.

  15. Plasmonic ITO-free polymer solar cell.

    PubMed

    Lin, Ming-Yi; Kang, Yu Ling; Chen, Yu-Cheng; Tsai, Tsung-Han; Lin, Shih-Chieh; Huang, Yi-Hsiang; Chen, Yi-Jiun; Lu, Chun-Yang; Lin, Hoang Yan; Wang, Lon A; Wu, Chung-Chih; Lee, Si-Chen

    2014-03-10

    The aluminum and sliver multilayered nano-grating structure is fabricated by laser interference lithography and the intervals between nanoslits is filled with modified PEDOT:PSS. The grating structured transparent electrode functions as the anti-reflection layer which not only decreases the reflected light but also increases the absorption of the active layer. The performances of P3HT:PC₆₁BM solar cells are studied experimentally and theoretically in detail. The field intensities of the transverse magnetic (TM) and transverse electrical (TE) waves distributed in the active layer are simulated by rigorous coupled wave analysis (RCWA). The power conversion efficiency of the plasmonic ITO-free polymer solar cell can reach 3.64% which is higher than ITO based polymer solar cell with efficiency of 3.45%.

  16. Simulation of an inverted perovskite solar cell with inorganic electron and hole transfer layers

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohamad; Banihashemi, Mehdi

    2017-04-01

    We use solar cell capacitance simulator-1D to simulate a fabricated inverted perovskite solar cell. The perovskite solar cell employs solution-processed inorganic hole and electron transfer layers. According to our simulations, surface defect densities at the interfaces of the perovskite active layer and inorganic hole/electron transfer materials in solution-based fabrication method are two orders of magnitude greater than that in the vapor deposition fabrication method. Increase of the surface defect densities reduces the circuit current, fill factor, and power conversion efficiency.

  17. Stability of polymer solar cells.

    PubMed

    Jørgensen, Mikkel; Norrman, Kion; Gevorgyan, Suren A; Tromholt, Thomas; Andreasen, Birgitta; Krebs, Frederik C

    2012-02-02

    Organic photovoltaics (OPVs) evolve in an exponential manner in the two key areas of efficiency and stability. The power conversion efficiency (PCE) has in the last decade been increased by almost a factor of ten approaching 10%. A main concern has been the stability that was previously measured in minutes, but can now, in favorable circumstances, exceed many thousands of hours. This astonishing achievement is the subject of this article, which reviews the developments in stability/degradation of OPVs in the last five years. This progress has been gained by several developments, such as inverted device structures of the bulk heterojunction geometry device, which allows for more stable metal electrodes, the choice of more photostable active materials, the introduction of interfacial layers, and roll-to-roll fabrication, which promises fast and cheap production methods while creating its own challenges in terms of stability. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Size-Tuning of WSe2 Flakes for High Efficiency Inverted Organic Solar Cells.

    PubMed

    Kakavelakis, George; Del Rio Castillo, Antonio Esau; Pellegrini, Vittorio; Ansaldo, Alberto; Tzourmpakis, Pavlos; Brescia, Rosaria; Prato, Mirko; Stratakis, Emmanuel; Kymakis, Emmanuel; Bonaccorso, Francesco

    2017-04-25

    The development of large-scale production methods of two-dimensional (2D) crystals, with on-demand control of the area and thickness, is mandatory to fulfill the potential applications of such materials for photovoltaics. Inverted bulk heterojunction (BHJ) organic solar cell (OSC), which exploits a polymer-fullerene binary blend as the active material, is one potentially important application area for 2D crystals. A large ongoing effort is indeed currently devoted to the introduction of 2D crystals in the binary blend to improve the charge transport properties. While it is expected that the nanoscale domains size of the different components of the blend will significantly impact the performance of the OSC, to date, there is no evidence of quantitative information on the interplay between 2D crystals and fullerene domains size. Here, we demonstrate that by matching the size of WSe2 few-layer 2D crystals, produced by liquid-phase exfoliation, with that of the PC71BM fullerene domain in BHJ OSCs, we obtain power conversion efficiencies (PCEs) of ∼9.3%, reaching a 15% improvement with respect to standard binary devices (PCE = 8.10%), i.e., without the addition of WSe2 flakes. This is the highest ever reported PCE for 2D material-based OSCs, obtained thanks to the enhanced exciton generation and exciton dissociation at the WSe2-fullerene interface and also electron extraction to the back metal contact as a consequence of a balanced charge carriers mobility. These results push forward the implementation of transition-metal dichalcogenides to boost the performance of BHJ OSCs.

  19. Tandem Polymer Solar Cells Featuring a Spectrally Matched Low-Bandgap Polymer

    SciTech Connect

    Dou, L.; You, J.; Yang, J.; Chen, C. C.; He, Y.; Murase, S.; Moriarty, T.; Emery, K.; Li, G.; Yang, Y.

    2012-03-01

    Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of a suitable low-bandgap polymer. Here, we demonstrate highly efficient single and tandem polymer solar cells featuring a low-bandgap conjugated polymer (PBDTT-DPP: bandgap, {approx}1.44 eV). A single-layer device based on the polymer provides a power conversion efficiency of {approx}6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which is, to the best of our knowledge, the highest certified efficiency for a polymer solar cell to date.

  20. Hybrid silicon nanocone-polymer solar cells.

    PubMed

    Jeong, Sangmoo; Garnett, Erik C; Wang, Shuang; Yu, Zongfu; Fan, Shanhui; Brongersma, Mark L; McGehee, Michael D; Cui, Yi

    2012-06-13

    Recently, hybrid Si/organic solar cells have been studied for low-cost Si photovoltaic devices because the Schottky junction between the Si and organic material can be formed by solution processes at a low temperature. In this study, we demonstrate a hybrid solar cell composed of Si nanocones and conductive polymer. The optimal nanocone structure with an aspect ratio (height/diameter of a nanocone) less than two allowed for conformal polymer surface coverage via spin-coating while also providing both excellent antireflection and light trapping properties. The uniform heterojunction over the nanocones with enhanced light absorption resulted in a power conversion efficiency above 11%. Based on our simulation study, the optimal nanocone structures for a 10 μm thick Si solar cell can achieve a short-circuit current density, up to 39.1 mA/cm(2), which is very close to the theoretical limit. With very thin material and inexpensive processing, hybrid Si nanocone/polymer solar cells are promising as an economically viable alternative energy solution.

  1. Solvent-responsive self-assembly of amphiphilic invertible polymers determined with SANS.

    PubMed

    Kudina, Olena; Kohut, Ananiy; Tarnavchyk, Ihor; Hevus, Ivan; Voronov, Andriy

    2014-04-01

    Amphiphilic invertible polymers (AIPs) are a new class of macromolecules that self-assemble into micellar structures and rapidly change structure in response to changes in solvent polarity. Using small-angle neutron scattering (SANS) data, we obtained a quantitative description of the invertible micellar assemblies (IMAs). The detailed composition and size of the assemblies (including the effect of temperature) were measured in aqueous and toluene polymer solutions. The results show that the invertible macromolecules self-assemble into cylindrical core-shell micellar structures. The composition of the IMAs in aqueous and toluene solutions was used to reveal the inversion mechanism by changing the polarity of the medium. Our experiments demonstrate that AIP unimers self-assemble into IMAs in aqueous solution, predominantly through interactions between the hydrophobic moieties of macromolecules. The hydrophobic effect (or solvophobic interaction) is the major driving force for self-assembly. When the polarity of the environment is changed from polar to nonpolar, poly(ethylene glycol) (PEG) and aliphatic dicarboxylic acid fragments of AIP macromolecules tend to replace each other in the core and the shell of the IMAs. However, neither the interior nor the exterior of the IMAs consists of fragments of a single component of the macromolecule. In aqueous solution, with the temperature increasing from 15 to 35 °C, the IMAs' mixed core from aliphatic dicarboxylic acid and PEG moieties and PEG-based shell change the structure. As a result of the progressive dehydration of the macromolecules, the hydration level (water content) in the micellar core decreases at 25 °C, followed by dehydrated PEG fragments entering the interior of the IMAs when the temperature increases to 35 °C.

  2. Nanoparticle Polymer Hybrids for Solar Cells

    NASA Astrophysics Data System (ADS)

    Mackay, Michael

    Polymer-based solar cells are unique since their processing is extremely cost effective compared to silicon-based solar cells. They are also much less energy intensive to manufacture. However, their power conversion efficiency is low. Discussion of what affects this property in the context of the morphology characterized through thermal analysis as well as x-ray and neutron scattering will be given. Support is gratefully acknowledged from the Department of Materials Science and NIST Award 70NANB10H256 through the Center for Neutron Science at the University of Delaware.

  3. Small molecule solution-processed bulk heterojunction solar cells with inverted structure using porphyrin donor

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takaki; Hatano, Junichi; Nakagawa, Takafumi; Yamaguchi, Shigeru; Matsuo, Yutaka

    2013-01-01

    Utilizing tetraethynyl porphyrin derivative (TE-Por) as a small molecule donor material, we fabricated a small molecule solution-processed bulk heterojunction (BHJ) solar cell with inverted structure, which exhibited 1.6% power conversion efficiency (JSC (short-circuit current) = 4.6 mA/cm2, VOC (open-circuit voltage) = 0.90 V, and FF (fill factor) = 0.39) in the device configuration indium tin oxide/TiOx (titanium sub-oxide)/[6,6]-phenyl-C61-butyric acid methyl ester:TE-Por (5:1)/MoOx (molybdenum sub-oxide)/Au under AM1.5 G illumination at 100 mW/cm2. Without encapsulation, the small molecule solution-processed inverted BHJ solar cell also showed remarkable durability to air, where it kept over 73% of its initial power conversion efficiency after storage for 28 days under ambient atmosphere in the dark.

  4. A novel organic-inorganic hybrid tandem solar cell with inverted structure

    NASA Astrophysics Data System (ADS)

    Bahrami, A.; Faez, R.

    2017-04-01

    A novel organic-inorganic hybrid tandem solar cell with inverted structure is proposed. This efficient double-junction hybrid tandem solar cell consists of a single-junction hydrogenated amorphous silicon (a-Si:H) subcell with n-i-p structure as front cell and a P3HT:PCBM organic subcell with inverted structure as back cell. In order to optimize the hybrid tandem cell, we have performed a simulation based on transfer matrix method. We have compared the characteristics of this novel structure with a conventional structure. As a result, a power conversion efficiency (PCE) of 6.1 and 24% improvement compared to the conventional hybrid tandem cell was achieved. We also discuss the high potential of this novel structure for realizing high-stability organic-inorganic hybrid photovoltaic devices.

  5. Inverted Organic Solar Cells with Improved Performance using Varied Cathode Buffer Layers

    NASA Astrophysics Data System (ADS)

    Guan, Zhi-qiang; Yu, Jun-sheng; Zang, Yue; Zeng, Xing-xin

    2012-10-01

    Organic solar cells with inverted planar heterojunction structure based on subphthalocyanine and C60 were fabricated using several kinds of materials as cathode buffer layer (CBL), including tris-8-hydroxy-quinolinato aluminum (Alq3), bathophenanthroline (Bphen), bathocuproine, 2,3,8,9,14,15-hexakis-dodecyl-sulfanyl-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA), and an inorganic compound of Cs2CO3. The influence of the lowest unoccupied molecular orbital level and the electron mobility of organic CBL on the solar cells performance was compared. The results showed that Alq3, Bphen, and HATNA could significantly improve the device performance. The highest efficiency was obtained from device with annealed HATNA as CBL and increased for more than 7 times compared with device without CBL. Furthermore, the simulation results with space charge-limited current theory indicated that the Schottky barrier at the organic/electrode interface in inverted OSC structure was reduced for 27% by inserting HATNA CBL.

  6. Rational molecular engineering towards efficient non-fullerene small molecule acceptors for inverted bulk heterojunction organic solar cells.

    PubMed

    Zheng, Yu-Qing; Dai, Ya-Zhong; Zhou, Yan; Wang, Jie-Yu; Pei, Jian

    2014-02-14

    Two non-fullerene small molecules based on fluoranthene-fused imide were developed as acceptors for solution-processed inverted organic bulk heterojunction (BHJ) solar cells, which showed good power conversion efficiency and high open-circuit voltage.

  7. Recent Advances in the Inverted Planar Structure of Perovskite Solar Cells.

    PubMed

    Meng, Lei; You, Jingbi; Guo, Tzung-Fang; Yang, Yang

    2016-01-19

    Inorganic-organic hybrid perovskite solar cells research could be traced back to 2009, and initially showed 3.8% efficiency. After 6 years of efforts, the efficiency has been pushed to 20.1%. The pace of development was much faster than that of any type of solar cell technology. In addition to high efficiency, the device fabrication is a low-cost solution process. Due to these advantages, a large number of scientists have been immersed into this promising area. In the past 6 years, much of the research on perovskite solar cells has been focused on planar and mesoporous device structures employing an n-type TiO2 layer as the bottom electron transport layer. These architectures have achieved champion device efficiencies. However, they still possess unwanted features. Mesoporous structures require a high temperature (>450 °C) sintering process for the TiO2 scaffold, which will increase the cost and also not be compatible with flexible substrates. While the planar structures based on TiO2 (regular structure) usually suffer from a large degree of J-V hysteresis. Recently, another emerging structure, referred to as an "inverted" planar device structure (i.e., p-i-n), uses p-type and n-type materials as bottom and top charge transport layers, respectively. This structure derived from organic solar cells, and the charge transport layers used in organic photovoltaics were successfully transferred into perovskite solar cells. The p-i-n structure of perovskite solar cells has shown efficiencies as high as 18%, lower temperature processing, flexibility, and, furthermore, negligible J-V hysteresis effects. In this Account, we will provide a comprehensive comparison of the mesoporous and planar structures, and also the regular and inverted of planar structures. Later, we will focus the discussion on the development of the inverted planar structure of perovskite solar cells, including film growth, band alignment, stability, and hysteresis. In the film growth part, several

  8. Industry Perspectives on Advanced Inverters for U.S. Solar Photovoltaic Systems. Grid Benefits, Deployment Challenges, and Emerging Solutions

    SciTech Connect

    Reiter, Emerson; Ardani, Kristen; Margolis, Robert; Edge, Ryan

    2015-09-01

    To clarify current utility strategies and other considerations related to advanced inverter deployment, we interviewed 20 representatives from 11 leading organizations closely involved with advanced inverter pilot testing, protocols, and implementation. Included were representatives from seven utilities, a regional transmission operator, an inverter manufacturer, a leading solar developer, and a consortium for grid codes and standards. Interview data represent geographically the advanced inverter activities identified in SEPA's prior survey results--most interviewed utilities serve California, Arizona, and Hawaii, though we also interviewed others from the Northeast, Mid-Atlantic, and Southeast.

  9. Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Choi, Hyosung; Mai, Cheng-Kang; Kim, Hak-Beom; Jeong, Jaeki; Song, Seyeong; Bazan, Guillermo C.; Kim, Jin Young; Heeger, Alan J.

    2015-06-01

    Organic-inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic PEDOT:PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to PEDOT:PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cells.

  10. Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells.

    PubMed

    Choi, Hyosung; Mai, Cheng-Kang; Kim, Hak-Beom; Jeong, Jaeki; Song, Seyeong; Bazan, Guillermo C; Kim, Jin Young; Heeger, Alan J

    2015-06-17

    Organic-inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cells.

  11. A comparative study of inverted-opal titania photonic crystals made from polymer and silica colloidal crystal templates

    SciTech Connect

    Kuai, S.-L.; Truong, V.-V.; Hache, Alain; Hu, X.-F.

    2004-12-01

    Photonic crystals with an inverted-opal structure using polymer and silica colloidal crystal templates were prepared and compared. We show that the behaviors of the template during the removal process and heat treatment are determinant factors on the crystal formation. While both templates result in ordered macroporous structures, the optical quality in each case is quite different. The removal of the polymer template by sintering causes a large shrinkage of the inverted framework and produces a high density of cracks in the sample. With a silica template, sintering actually improves the quality of the inverted structure by enhancing the template's mechanical stability, helping increase the filling fraction, and consolidating the titania framework. The role of the other important factors such as preheating and multiple infiltrations is also investigated.

  12. Polymers in solar energy utilization

    NASA Technical Reports Server (NTRS)

    Liang, R. H.; Coulter, D. R.; Dao, C.; Gupta, A.

    1983-01-01

    A laser photoacoustic technique (LPAT) has been verified for performing accelerated life testing of outdoor photooxidation of polymeric materials used in solar energy applications. Samples of the material under test are placed in a chamber with a sensitive microphone, then exposed to chopped laser radiation. The sample absorbs the light and converts it to heat by a nonradiative deexcitation process, thereby reducing pressure fluctuations within the cell. The acoustic signal detected by the microphone is directly proportional to the amount of light absorbed by the specimen. Tests were performed with samples of ethylene/methylacrylate copolymer (EMA) reprecipitated from hot cyclohexane, compressed, and molded into thin (25-50 microns) films. The films were exposed outdoors and sampled by LPAT weekly. The linearity of the light absorbed with respect to the acoustic signal was verified.Correlations were established between the photoacoustic behavior of the materials aged outdoors and the same kinds of samples cooled and heated in a controlled environment reactor. The reactor tests were validated for predicting outdoor exosures up to 55 days.

  13. Polymers in solar energy utilization

    NASA Technical Reports Server (NTRS)

    Liang, R. H.; Coulter, D. R.; Dao, C.; Gupta, A.

    1983-01-01

    A laser photoacoustic technique (LPAT) has been verified for performing accelerated life testing of outdoor photooxidation of polymeric materials used in solar energy applications. Samples of the material under test are placed in a chamber with a sensitive microphone, then exposed to chopped laser radiation. The sample absorbs the light and converts it to heat by a nonradiative deexcitation process, thereby reducing pressure fluctuations within the cell. The acoustic signal detected by the microphone is directly proportional to the amount of light absorbed by the specimen. Tests were performed with samples of ethylene/methylacrylate copolymer (EMA) reprecipitated from hot cyclohexane, compressed, and molded into thin (25-50 microns) films. The films were exposed outdoors and sampled by LPAT weekly. The linearity of the light absorbed with respect to the acoustic signal was verified.Correlations were established between the photoacoustic behavior of the materials aged outdoors and the same kinds of samples cooled and heated in a controlled environment reactor. The reactor tests were validated for predicting outdoor exosures up to 55 days.

  14. Inverter Load Rejection Over-Voltage Testing: SolarCity CRADA Task 1a Final Report

    SciTech Connect

    Nelson, A.; Hoke, A.; Chakraborty, S.; Chebahtah, J.; Wang, T.; Zimmerly, B.

    2015-02-01

    Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of electric power systems. One of the urgent areas for additional research - as identified by inverter manufacturers, installers, and utilities - is the potential for transient over-voltage from PV inverters. In one stage of a cooperative tests were repeated a total of seven times. The maximum over-voltage measured in any test did not exceed 200% of nominal, and typical over-voltage levels were significantly lower. The total voltage duration and the maximum continuous time above each threshold are presented here, as well as the time to disconnect for each test. Finally, we present a brief investigation into the effect of DC input voltage as well as a series of no-load tests. This report describes testing conducted at NREL to determine the duration and magnitude of transient over-voltages created by several commercial PV inverters during load-rejection conditions. For this work, a test plan that is currently under development by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Through a cooperative research and development agreement, NREL is working with SolarCity to address two specific types of transient overvoltage: load rejection overvoltage (LRO) and ground fault overvoltage (GFO). Additional partners in this effort include the Hawaiian Electric Companies, Northern Plains Power Technologies, and the Electric Power Research Institute.

  15. Improved PEDOT:PSS/c-Si hybrid solar cell using inverted structure and effective passivation

    PubMed Central

    Zhang, Xisheng; Yang, Dong; Yang, Zhou; Guo, Xiaojia; Liu, Bin; Ren, Xiaodong; Liu, Shengzhong (Frank)

    2016-01-01

    The PEDOT:PSS is often used as the window layer in the normal structured PEDOT:PSS/c-Si hybrid solar cell (HSC), leading to significantly reduced response, especially in red and near-infrared region. By depositing the PEDOT:PSS on the rear side of the c-Si wafer, we developed an inverted structured HSC with much higher solar cell response in the red and near-infrared spectrum. Passivating the other side with hydrogenated amorphous silicon (a-Si:H) before electrode deposition, the minority carrier lifetime has been significantly increased and the power conversion efficiency (PCE) of the inverted HSC is improved to as high as 16.1% with an open-circuit voltage (Voc) of 634 mV, fill factor (FF) of 70.5%, and short-circuit current density (Jsc) of 36.2 mA cm−2, an improvement of 33% over the control device. The improvements are ascribed to inverted configuration and a-Si:H passivation, which can increase photon carrier generation and reduce carrier recombination, respectively. Both of them will benefit the photovoltaic performance and should be considered as effective design strategies to improve the performance of organic/c-Si HSCs. PMID:27725714

  16. Improved PEDOT:PSS/c-Si hybrid solar cell using inverted structure and effective passivation

    NASA Astrophysics Data System (ADS)

    Zhang, Xisheng; Yang, Dong; Yang, Zhou; Guo, Xiaojia; Liu, Bin; Ren, Xiaodong; Liu, Shengzhong (Frank)

    2016-10-01

    The PEDOT:PSS is often used as the window layer in the normal structured PEDOT:PSS/c-Si hybrid solar cell (HSC), leading to significantly reduced response, especially in red and near-infrared region. By depositing the PEDOT:PSS on the rear side of the c-Si wafer, we developed an inverted structured HSC with much higher solar cell response in the red and near-infrared spectrum. Passivating the other side with hydrogenated amorphous silicon (a-Si:H) before electrode deposition, the minority carrier lifetime has been significantly increased and the power conversion efficiency (PCE) of the inverted HSC is improved to as high as 16.1% with an open-circuit voltage (Voc) of 634 mV, fill factor (FF) of 70.5%, and short-circuit current density (Jsc) of 36.2 mA cm‑2, an improvement of 33% over the control device. The improvements are ascribed to inverted configuration and a-Si:H passivation, which can increase photon carrier generation and reduce carrier recombination, respectively. Both of them will benefit the photovoltaic performance and should be considered as effective design strategies to improve the performance of organic/c-Si HSCs.

  17. Improved PEDOT:PSS/c-Si hybrid solar cell using inverted structure and effective passivation.

    PubMed

    Zhang, Xisheng; Yang, Dong; Yang, Zhou; Guo, Xiaojia; Liu, Bin; Ren, Xiaodong; Liu, Shengzhong Frank

    2016-10-11

    The PEDOT:PSS is often used as the window layer in the normal structured PEDOT:PSS/c-Si hybrid solar cell (HSC), leading to significantly reduced response, especially in red and near-infrared region. By depositing the PEDOT:PSS on the rear side of the c-Si wafer, we developed an inverted structured HSC with much higher solar cell response in the red and near-infrared spectrum. Passivating the other side with hydrogenated amorphous silicon (a-Si:H) before electrode deposition, the minority carrier lifetime has been significantly increased and the power conversion efficiency (PCE) of the inverted HSC is improved to as high as 16.1% with an open-circuit voltage (Voc) of 634 mV, fill factor (FF) of 70.5%, and short-circuit current density (Jsc) of 36.2 mA cm(-2), an improvement of 33% over the control device. The improvements are ascribed to inverted configuration and a-Si:H passivation, which can increase photon carrier generation and reduce carrier recombination, respectively. Both of them will benefit the photovoltaic performance and should be considered as effective design strategies to improve the performance of organic/c-Si HSCs.

  18. Top laminated graphene electrode in a semitransparent polymer solar cell by simultaneous thermal annealing/releasing method.

    PubMed

    Lee, Yu-Ying; Tu, Kun-Hua; Yu, Chen-Chieh; Li, Shao-Sian; Hwang, Jeong-Yuan; Lin, Chih-Cheng; Chen, Kuei-Hsien; Chen, Li-Chyong; Chen, Hsuen-Li; Chen, Chun-Wei

    2011-08-23

    In this article, we demonstrate a semitransparent inverted-type polymer solar cell using a top laminated graphene electrode without damaging the underlying organic photoactive layer. The lamination process involves the simultaneous thermal releasing deposition of the graphene top electrode during thermal annealing of the photoactive layer. The resulting semitransparent polymer solar cell exhibits a promising power conversion efficiency of approximately 76% of that of the standard opaque device using an Ag metal electrode. The asymmetric photovoltaic performances of the semitransparent solar cell while illuminated from two respective sides were further analyzed using optical simulation and photocarrier recombination measurement. The devices consisting of the top laminated transparent graphene electrode enable the feasible roll-to-roll manufacturing of low-cost semitransparent polymer solar cells and can be utilized in new applications such as power-generated windows or multijunction or bifacial photovoltaic devices.

  19. Film Grain-Size Related Long-Term Stability of Inverted Perovskite Solar Cells.

    PubMed

    Chiang, Chien-Hung; Wu, Chun-Guey

    2016-09-22

    The power conversion efficiency (PCE) of the perovskite solar cell is high enough to be commercially viable. The next important issue is the stability of the device. This article discusses the effect of the perovskite grain-size on the long-term stability of inverted perovskite solar cells. Perovskite films composed of various sizes of grains were prepared by controlling the solvent annealing time. The grain-size related stability of the inverted cells was investigated both in ambient atmosphere at relative humidity of approximately 30-40 % and in a nitrogen filled glove box (H2 O<0.1 ppm, O2 <10 ppm). The PCE of the solar cell based on a perovskite film having the grain size larger than 1 μm (D-10) decreases less than 10 % with storage in a glove box and less than 15 % when it was stored under an ambient atmosphere for 30 days. However, the cell using the perovskite film composed of small (∼100 nm) perovskite grains (D-0) exhibits complete loss of PCE after storage under the ambient atmosphere for only 15 days and a PCE loss of up to 70 % with storage in the glove box for 30 days. These results suggest that, even under H2 O-free conditions, the chemical- and thermal-induced production of pin holes at the grain boundaries of the perovskite film could be the reason for long-term instability of inverted perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Plasmonic effect of spray-deposited Au nanoparticles on the performance of inverted organic solar cells.

    PubMed

    Chaturvedi, Neha; Swami, Sanjay Kumar; Dutta, Viresh

    2014-09-21

    Gold nanoparticles with varying sizes were prepared by the spray process under an electric field (DC voltages of 0 V and 1 kV applied to the nozzle) for studying their role in inverted organic solar cells (ITO/Au/ZnO/P3HT:PCBM/Ag). The application of electric field during the spray process resulted in a smaller size (35 nm as compared to 70 nm without the electric field) of the nanoparticles with more uniform distribution. This gave rise to a difference in the surface plasmon resonance (SPR) effect created by the gold nanoparticles (Au NPs), which then affected the solar cell performance. The photovoltaic performances of plasmonic inverted organic solar cells (ITO/Au/ZnO/P3HT:PCBM/Ag) using spray-deposited Au and ZnO layers (both at 1 kV) showed improved efficiency. Fast exciton quenching in the P3HT:PCBM layer was achieved by using a spray-deposited Au layer in between ITO and ZnO layers. The absorption spectra and internal power conversion efficiency (IPCE) curve showed that the Au nanoparticles provide significant plasmonic broadband light absorption enhancement which resulted in the enhancement of the JSC value. Maximum efficiency of 3.6% was achieved for the inverted organic solar cell (IOSC) with an exceptionally high short circuit current density of ∼15 mA cm(-2) which is due to the additional photon absorption and the corresponding increase observed in the IPCE spectrum. The spray technique can be easily applied for the direct formation of Au nanoparticles in the fabrication of IOSC with improved performance over a large area.

  1. Plasmonic effect of spray-deposited Au nanoparticles on the performance of inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Neha; Swami, Sanjay Kumar; Dutta, Viresh

    2014-08-01

    Gold nanoparticles with varying sizes were prepared by the spray process under an electric field (DC voltages of 0 V and 1 kV applied to the nozzle) for studying their role in inverted organic solar cells (ITO/Au/ZnO/P3HT:PCBM/Ag). The application of electric field during the spray process resulted in a smaller size (35 nm as compared to 70 nm without the electric field) of the nanoparticles with more uniform distribution. This gave rise to a difference in the surface plasmon resonance (SPR) effect created by the gold nanoparticles (Au NPs), which then affected the solar cell performance. The photovoltaic performances of plasmonic inverted organic solar cells (ITO/Au/ZnO/P3HT:PCBM/Ag) using spray-deposited Au and ZnO layers (both at 1 kV) showed improved efficiency. Fast exciton quenching in the P3HT:PCBM layer was achieved by using a spray-deposited Au layer in between ITO and ZnO layers. The absorption spectra and internal power conversion efficiency (IPCE) curve showed that the Au nanoparticles provide significant plasmonic broadband light absorption enhancement which resulted in the enhancement of the JSC value. Maximum efficiency of 3.6% was achieved for the inverted organic solar cell (IOSC) with an exceptionally high short circuit current density of ~15 mA cm-2 which is due to the additional photon absorption and the corresponding increase observed in the IPCE spectrum. The spray technique can be easily applied for the direct formation of Au nanoparticles in the fabrication of IOSC with improved performance over a large area.

  2. Stable inverted small molecular organic solar cells using a p-doped optical spacer.

    PubMed

    Lee, Sang-Hoon; Seo, Ji-Won; Lee, Jung-Yong

    2015-01-07

    We report inverted small molecular organic solar cells using a doped window layer as an optical spacer. The optical spacer was used to shift the optical field distribution inside the active layers, generating more charge carriers from sunlight. In this report, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD) was doped with 2,2-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ), a p-type dopant material. P-doped MeO-TPD was adopted as an optical spacer because it has a large energy band gap, and its conductivity can be increased by several orders of magnitude through a doping process. As a result, a power conversion efficiency of 4.15% was achieved with the doped window layer of optimized thickness. Lastly, we present significantly improved stability of the inverted devices with the MeO-TPD layer.

  3. Understanding the Light Soaking Effects in Inverted Organic Solar Cells Functionalized with Conjugated Macroelectrolyte Electron‐Collecting Interlayers

    PubMed Central

    Xu, Weidong; Xia, Ruidong; Ye, Tengling; Zhao, Li; Kan, Zhipeng; Mei, Yang; Yan, Congfei; Zhang, Xin‐Wen

    2015-01-01

    Three kinds of charged star‐shaped conjugated macroelectrolytes, named as PhNBr, TPANBr, and TrNBr, are synthesized as electron‐collecting interlayers for inverted polymer solar cells (i‐PSCs). Based on these well‐defined structured interlayer materials, the light soaking (LS) effect observed in i‐PSCs was studied systematically and accurately. The general character of the LS effect is further verified by studying additional i‐PSC devices functionalized with other common interlayers. The key‐role of UV photons was confirmed by electrochemical impedance spectroscopy and electron‐only devices. In addition, the ultraviolet photoelectron spectroscopy measurements indicate that the work function of the indium tin oxide (ITO)/interlayer cathode is significantly reduced after UV treatment. In these i‐PSC devices the LS effect originates from the adsorbed oxygen on the ITO substrates when oxygen plasma is used; however, even a small amount of oxygen from the ambient is also enough for triggering the LS effect, albeit with a weaker intensity. Our results suggest that the effect of adsorbed oxygen on ITO needs to be considered with attention while preparing i‐PSCs. This is an important finding that can aid the large‐scale manufacturing of organic solar cells via printing technologies, which do not always ensure the full protection of the device electrode substrates from oxygen. PMID:27981016

  4. Understanding the Light Soaking Effects in Inverted Organic Solar Cells Functionalized with Conjugated Macroelectrolyte Electron-Collecting Interlayers.

    PubMed

    Xu, Weidong; Xia, Ruidong; Ye, Tengling; Zhao, Li; Kan, Zhipeng; Mei, Yang; Yan, Congfei; Zhang, Xin-Wen; Lai, Wen-Yong; Keivanidis, Panagiotis E; Huang, Wei

    2016-02-01

    Three kinds of charged star-shaped conjugated macroelectrolytes, named as PhNBr, TPANBr, and TrNBr, are synthesized as electron-collecting interlayers for inverted polymer solar cells (i-PSCs). Based on these well-defined structured interlayer materials, the light soaking (LS) effect observed in i-PSCs was studied systematically and accurately. The general character of the LS effect is further verified by studying additional i-PSC devices functionalized with other common interlayers. The key-role of UV photons was confirmed by electrochemical impedance spectroscopy and electron-only devices. In addition, the ultraviolet photoelectron spectroscopy measurements indicate that the work function of the indium tin oxide (ITO)/interlayer cathode is significantly reduced after UV treatment. In these i-PSC devices the LS effect originates from the adsorbed oxygen on the ITO substrates when oxygen plasma is used; however, even a small amount of oxygen from the ambient is also enough for triggering the LS effect, albeit with a weaker intensity. Our results suggest that the effect of adsorbed oxygen on ITO needs to be considered with attention while preparing i-PSCs. This is an important finding that can aid the large-scale manufacturing of organic solar cells via printing technologies, which do not always ensure the full protection of the device electrode substrates from oxygen.

  5. Device characterization for design optimization of 4 junction inverted metamorphic concentrator solar cells

    SciTech Connect

    Geisz, John F.; France, Ryan M.; Steiner, Myles A.; Friedman, Daniel J.; García, Iván

    2014-09-26

    Quantitative electroluminescence (EL) and luminescent coupling (LC) analysis, along with more conventional characterization techniques, are combined to completely characterize the subcell JV curves within a fourjunction (4J) inverted metamorphic solar cell (IMM). The 4J performance under arbitrary spectral conditions can be predicted from these subcell JV curves. The internal radiative efficiency (IRE) of each junction has been determined as a function of current density from the external radiative efficiency using optical modeling, but this required the accurate determination of the individual junction current densities during the EL measurement as affected by LC. These measurement and analysis techniques can be applied to any multijunction solar cell. The 4J IMM solar cell used to illustrate these techniques showed excellent junction quality as exhibited by high IRE and a one-sun AM1.5D efficiency of 36.3%. This device operates up to 1000 suns without limitations due to any of the three tunnel junctions.

  6. Complementary p- and n-type polymer doping for ambient stable graphene inverter.

    PubMed

    Yun, Je Moon; Park, Seokhan; Hwang, Young Hwan; Lee, Eui-Sup; Maiti, Uday; Moon, Hanul; Kim, Bo-Hyun; Bae, Byeong-Soo; Kim, Yong-Hyun; Kim, Sang Ouk

    2014-01-28

    Graphene offers great promise to complement the inherent limitations of silicon electronics. To date, considerable research efforts have been devoted to complementary p- and n-type doping of graphene as a fundamental requirement for graphene-based electronics. Unfortunately, previous efforts suffer from undesired defect formation, poor controllability of doping level, and subtle environmental sensitivity. Here we present that graphene can be complementary p- and n-doped by simple polymer coating with different dipolar characteristics. Significantly, spontaneous vertical ordering of dipolar pyridine side groups of poly(4-vinylpyridine) at graphene surface can stabilize n-type doping at room-temperature ambient condition. The dipole field also enhances and balances the charge mobility by screening the impurity charge effect from the bottom substrate. We successfully demonstrate ambient stable inverters by integrating p- and n-type graphene transistors, which demonstrated clear voltage inversion with a gain of 0.17 at a 3.3 V input voltage. This straightforward polymer doping offers diverse opportunities for graphene-based electronics, including logic circuits, particularly in mechanically flexible form.

  7. Pathway for recovery of photo-degraded polymer solar cells by post degradation thermal anneal

    DOE PAGES

    Bhattacharya, J.; Joshi, P. H.; Biswas, Rana; ...

    2017-02-16

    The photo-degradation of polymer solar cells is a critical challenge preventing its commercial deployment. We experimentally fabricate organic solar cells and characterize their degradation under solar simulators in an environmental chamber under nitrogen flow, without exposure to oxygen and moisture. We have developed a thermally stable inverted organic solar cell architecture in which light induced degradation of device characteristics can be reversibly annealed to the pristine values. The stable inverted cells utilized MoOx layers that are thermally treated immediately after their deposition on the organic layer, and before metal cathode deposition. Organic solar cells that are photo-degraded in the presencemore » of oxygen, however show irreversible degradation that cannot be thermally recovered. The decrease of organic solar cell characteristics correlates with increases in mid-gap electronic states, measured using capacitance spectroscopy and dark current. It is likely the photo-induced defect states caused by local H motion from the alkyl chains to the aromatic backbone, can be reversibly annealed at elevated temperatures after photo-degradation. Finally, our results provide a pathway for improving the stability of organic photovoltaics.« less

  8. Carbon Nanotubes Versus Graphene as Flexible Transparent Electrodes in Inverted Perovskite Solar Cells.

    PubMed

    Jeon, Il; Yoon, Jungjin; Ahn, Namyoung; Atwa, Mohamed; Delacou, Clement; Anisimov, Anton; Kauppinen, Esko I; Choi, Mansoo; Maruyama, Shigeo; Matsuo, Yutaka

    2017-10-10

    Transparent carbon electrodes composed of single-walled carbon nanotubes or graphene were used as the bottom electrode in flexible inverted perovskite solar cells. Their photovoltaic performance and mechanical resilience were compared and analyzed using various techniques. Whereas a conventional inverted perovskite solar cells using indium tin oxide showed a power conversion efficiency of 17.8%, the carbon nanotube- and graphene-based cells showed efficiencies of 12.8% and 14.2%, respectively. A thin layer of MoO3 was used for its stable doping effect. The difference in photovoltaic performance between the carbon nanotube- and graphene-based cells was due to the inferior morphology and lower transmittance of the carbon nanotube films compared with the graphene films. Raman spectroscopy and four-probe measurements after strain application revealed that the graphene-based cells were more susceptible to strain than the carbon nanotube-based cells for a given magnitude of strain. Cyclic flexural testing also showed higher resilience of the carbon nanotube-based cells compared with graphene-based cells, though the difference was marginal. Overall, graphene is a better option than carbon nanotubes as the bottom transparent electrode in perovskite solar cells. However, the transfer step for graphene has lower reproducibility, and thus the development of better graphene transfer methods would help maximize the current capacity of graphene-based cells.

  9. Improved Performance and Stability of Inverted Planar Perovskite Solar Cells Using Fulleropyrrolidine Layers.

    PubMed

    Tian, Chengbo; Castro, Edison; Wang, Tan; Betancourt-Solis, German; Rodriguez, Gloria; Echegoyen, Luis

    2016-11-16

    Inverted planar structure perovskite solar cells (PSCs), due to their low-temperature precessing and lack of hysteretic problems, are attracting increased attention by researchers around the world. Fullerene derivatives are the most widely used electron transport materials (ETMs) in inverted planar perovskite solar cells, especially [6,6]-phenyl-C61-butyric acid methylester (PC61BM), which exhibits very good performance. However, to the best of our knowledge, the influence of adducts on fullerene-based PSCs performance has not been fully explored to date. In this work, two fullerene derivatives, 2,5-(dimethyl ester) C60 fulleropyrrolidine (DMEC60) and the analogous C70 derivative (DMEC70), were synthesized in high yield via a 1,3-dipolar cycloaddition reaction at room temperature and incorporated into CH3NH3PbI3 perovskite solar cells as electron transport materials. Possibly because the attached pyrrolidine ester groups are able to coordinate with the perovskite layer, the devices based on DMEC60 and DMEC70 achieved power conversion efficiencies (PCE) of 15.2% and 16.4%, respectively. Not only were both devices' efficiencies higher than those based on PC61BM and PC71BM, but their stabilities were also higher than those for PCBM-based devices. The results suggest that DMEC60 and DMEC70 are better alternatives than PC61BM and PC71BM for the ETMs in PSCs.

  10. Flexible, highly efficient all-polymer solar cells.

    PubMed

    Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J

    2015-10-09

    All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices.

  11. Flexible, highly efficient all-polymer solar cells

    PubMed Central

    Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J.

    2015-01-01

    All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices. PMID:26449658

  12. Novel Semiconducting Polymers for Highly Efficient Solar Energy Harvesting

    DTIC Science & Technology

    2014-03-11

    energy PCE to polymers disclosed in literature in BHJ polymer solar cells in combination with fullerene derivatives as acceptors. Solar power... fullerene derivatives are the best candidates so far due to their high electron affinity, superior electron mobility and their three dimensional...structure, providing unique packing ability in blend to efficiently form electron transport channels. 13 The original fullerenes do not have enough

  13. Cost Effective Polymer Solar Cells Research and Education

    SciTech Connect

    Sun, Sam-Shajing

    2015-10-13

    The technical or research objective of this project is to investigate and develop new polymers and polymer based optoelectronic devices for potentially cost effective (or cost competitive), durable, lightweight, flexible, and high efficiency solar energy conversion applications. The educational objective of this project includes training of future generation scientists, particularly young, under-represented minority scientists, working in the areas related to the emerging organic/polymer based solar energy technologies and related optoelectronic devices. Graduate and undergraduate students will be directly involved in scientific research addressing issues related to the development of polymer based solar cell technology.

  14. Suppressed decomposition of organometal halide perovskites by impermeable electron-extraction layers in inverted solar cells.

    PubMed

    Brinkmann, K O; Zhao, J; Pourdavoud, N; Becker, T; Hu, T; Olthof, S; Meerholz, K; Hoffmann, L; Gahlmann, T; Heiderhoff, R; Oszajca, M F; Luechinger, N A; Rogalla, D; Chen, Y; Cheng, B; Riedl, T

    2017-01-09

    The area of thin-film photovoltaics has been overwhelmed by organometal halide perovskites. Unfortunately, serious stability concerns arise with perovskite solar cells. For example, methyl-ammonium lead iodide is known to decompose in the presence of water and, more severely, even under inert conditions at elevated temperatures. Here, we demonstrate inverted perovskite solar cells, in which the decomposition of the perovskite is significantly mitigated even at elevated temperatures. Specifically, we introduce a bilayered electron-extraction interlayer consisting of aluminium-doped zinc oxide and tin oxide. We evidence tin oxide grown by atomic layer deposition does form an outstandingly dense gas permeation barrier that effectively hinders the ingress of moisture towards the perovskite and-more importantly-it prevents the egress of decomposition products of the perovskite. Thereby, the overall decomposition of the perovskite is significantly suppressed, leading to an outstanding device stability.

  15. Suppressed decomposition of organometal halide perovskites by impermeable electron-extraction layers in inverted solar cells

    PubMed Central

    Brinkmann, K.O.; Zhao, J.; Pourdavoud, N.; Becker, T.; Hu, T.; Olthof, S.; Meerholz, K.; Hoffmann, L.; Gahlmann, T.; Heiderhoff, R.; Oszajca, M. F.; Luechinger, N. A.; Rogalla, D.; Chen, Y.; Cheng, B.; Riedl, T

    2017-01-01

    The area of thin-film photovoltaics has been overwhelmed by organometal halide perovskites. Unfortunately, serious stability concerns arise with perovskite solar cells. For example, methyl-ammonium lead iodide is known to decompose in the presence of water and, more severely, even under inert conditions at elevated temperatures. Here, we demonstrate inverted perovskite solar cells, in which the decomposition of the perovskite is significantly mitigated even at elevated temperatures. Specifically, we introduce a bilayered electron-extraction interlayer consisting of aluminium-doped zinc oxide and tin oxide. We evidence tin oxide grown by atomic layer deposition does form an outstandingly dense gas permeation barrier that effectively hinders the ingress of moisture towards the perovskite and—more importantly—it prevents the egress of decomposition products of the perovskite. Thereby, the overall decomposition of the perovskite is significantly suppressed, leading to an outstanding device stability. PMID:28067308

  16. Suppressed decomposition of organometal halide perovskites by impermeable electron-extraction layers in inverted solar cells

    NASA Astrophysics Data System (ADS)

    Brinkmann, K. O.; Zhao, J.; Pourdavoud, N.; Becker, T.; Hu, T.; Olthof, S.; Meerholz, K.; Hoffmann, L.; Gahlmann, T.; Heiderhoff, R.; Oszajca, M. F.; Luechinger, N. A.; Rogalla, D.; Chen, Y.; Cheng, B.; Riedl, T.

    2017-01-01

    The area of thin-film photovoltaics has been overwhelmed by organometal halide perovskites. Unfortunately, serious stability concerns arise with perovskite solar cells. For example, methyl-ammonium lead iodide is known to decompose in the presence of water and, more severely, even under inert conditions at elevated temperatures. Here, we demonstrate inverted perovskite solar cells, in which the decomposition of the perovskite is significantly mitigated even at elevated temperatures. Specifically, we introduce a bilayered electron-extraction interlayer consisting of aluminium-doped zinc oxide and tin oxide. We evidence tin oxide grown by atomic layer deposition does form an outstandingly dense gas permeation barrier that effectively hinders the ingress of moisture towards the perovskite and--more importantly--it prevents the egress of decomposition products of the perovskite. Thereby, the overall decomposition of the perovskite is significantly suppressed, leading to an outstanding device stability.

  17. A Fiber Bragg Grating—Bimetal Temperature Sensor for Solar Panel Inverters

    PubMed Central

    Ismail, Mohd Afiq; Tamchek, Nizam; Hassan, Muhammad Rosdi Abu; Dambul, Katrina D.; Selvaraj, Jeyrai; Rahim, Nasrudin Abd; Sandoghchi, Reza; Adikan, Faisal Rafiq Mahamd

    2011-01-01

    This paper reports the design, characterization and implementation of a Fiber Bragg Grating (FBG)-based temperature sensor for an Insulted-Gate Bipolar Transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher Coefficient of Thermal Expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature. PMID:22164098

  18. A fiber Bragg grating--bimetal temperature sensor for solar panel inverters.

    PubMed

    Ismail, Mohd Afiq; Tamchek, Nizam; Hassan, Muhammad Rosdi Abu; Dambul, Katrina D; Selvaraj, Jeyrai; Rahim, Nasrudin Abd; Sandoghchi, Reza; Adikan, Faisal Rafiq Mahamd

    2011-01-01

    This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG)-based temperature sensor for an insulted-gate Bipolar transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher coefficient of thermal expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature.

  19. The research of the solar panels-commutator-inverter-load system with the pulse-amplitude control

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2014-11-01

    The system "solar panels-commutator-inverter-load" with amplitude-impulse control was researched. It was shown that if the solar panels are located in a certain way at the input of the inverter, it will be possible to get multilevel voltage close to sine wave with the help of amplitude-impulse control of commutator at the output of inverter. Herewith the effect is saving of solar panels depending on the quantity of voltage level, and also the enhanced voltage distortion coefficient (THD). For instance, with 8-level of voltage 28,2% and THD=4,64%, with 13-level of voltage, 30,5% and THD=2,65%, and with 26-level of voltage 31,7% and THD=1,22%. The given results were obtained through computer modeling and experimental research.

  20. The effect of modified layers on the performance of inverted ZnO nanorods/MEH-PPV solar cells

    NASA Astrophysics Data System (ADS)

    Yan, Yue; Zhao, SuLing; Xu, Zheng; Wei, Gong; Wang, LiHui

    2011-03-01

    We fabricate inverted organic/inorganic hybrid solar cells based on vertically oriented ZnO nanorods and polymer MEH-PPV. The morphology of ZnO nanorods and ZnO nanorods/MEH-PPV hybrid structure is depicted by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic force microscope (AFM), respectively. It is observed that ZnO nanorods array grows primarily aligned along the perpendicular direction of the ITO substrate. The MEH-PPV molecule does not enter the interspace between ZnO nanorods completely according to SEM picture. It results in the small and bad contact area between ZnO nanorods and MEH-PPV. To improve the photovoltaic performance, we also fabricate another kind of photovoltaic (PV) device modified by N719 dye, and exploit the effect of N719. After the modification of ZnO nanorods by N719, not only J sc increases from 0.257 mA/cm2 to 0.42 mA/cm2, but also V oc enhances from 0.37 V to 0.42 V. Insert LiF buffer layer between MEH-PPV and anode, J sc of 1.05 mA/cm2 is obtained, and it is 2.5 times that the device without LiF.

  1. Inverted organic solar cells with ZnO nanowalls prepared using wet chemical etching in a KOH solution.

    PubMed

    Shin, Kyung-Sik; Park, Hye-Jeong; Kumar, Brijesh; Kim, Kwon-Ho; Kim, Sang-Hyeob; Kim, Sang-Woo

    2012-02-01

    We report on the photovoltaic (PV) performances of inverted organic solar cells (IOSCs) that were fabricated from PCBM:P3HT polymer with a ZnO thin film and ZnO nanowalls as electron transport and hole block layers. ZnO thin film on ITO/glass substrate was deposited using a simply aqueous solution route. ZnO nanowall structures were obtained via wet chemical etching of ZnO thin films in a KOH solution. The power conversion efficiency (PCE) of the IOSC with ZnO nanowalls was significantly improved by 44% from 1.254% to 1.811% compared to that of the IOSC with ZnO thin film. The short circuit current in IOSCs fabricated with the ZnO nanowalls was increased mainly due to the increase in the charge transport interface area, as a result of enhancement in the PCE. This work suggests a method for fabricating efficient PV devices with a larger charge transport area for future prospects.

  2. Constructing bulk heterojunction with componential gradient for enhancing the efficiency of polymer solar cells

    NASA Astrophysics Data System (ADS)

    Lu, Shudi; Liu, Kong; Chi, Dan; Yue, Shizhong; Li, Yanpei; Kou, Yanlei; Lin, Xuechun; Wang, Zhijie; Qu, Shengchun; Wang, Zhanguo

    2015-12-01

    Herein, high-efficient PTB7:PC71BM solar cells with bulk heterojunction being optimized by componential distribution have been realized by solvent treating the active layer with a series of alcohols. Subsequent characterizations including X-ray photoelectron spectroscopy (XPS) and Kelvin probe force microscopy (KPFM) reveal that such treatment adjusts the distribution of PC71BM in the bulk heterojunction by making the concentration of PC71BM higher at the solvent treated surface in comparison with that close to the bottom electrode. Such morphological transformation enables the conventional structured devices with great advantages in exciton separation and charge transfer. Therefore, the power conversion efficiency could be remarkably improved from 6.57% to 7.74%. However, for the inverted structured polymer solar cells, the morphology evolution deteriorates the relevant performance, particularly in exciton separation and charge transfer. We attribute these contrary observations to the matching degree of charge transfer direction in the active layer with the charge collection direction in the entire device. Not only providing a designing principle for optimizing the structure of polymer solar cells according to the morphology of active layer, this paper also offers a comprehensive understanding about the influence of solvent treatment on the performance of polymer solar cells.

  3. Hot exciton dissociation in polymer solar cells.

    PubMed

    Grancini, G; Maiuri, M; Fazzi, D; Petrozza, A; Egelhaaf, H-J; Brida, D; Cerullo, G; Lanzani, G

    2013-01-01

    The standard picture of photovoltaic conversion in all-organic bulk heterojunction solar cells predicts that the initial excitation dissociates at the donor/acceptor interface after thermalization. Accordingly, on above-gap excitation, the excess photon energy is quickly lost by internal dissipation. Here we directly target the interfacial physics of an efficient low-bandgap polymer/PC(60)BM system. Exciton splitting occurs within the first 50 fs, creating both interfacial charge transfer states (CTSs) and polaron species. On high-energy excitation, higher-lying singlet states convert into hot interfacial CTSs that effectively contribute to free-polaron generation. We rationalize these findings in terms of a higher degree of delocalization of the hot CTSs with respect to the relaxed ones, which enhances the probability of charge dissociation in the first 200 fs. Thus, the hot CTS dissociation produces an overall increase in the charge generation yield.

  4. Temperature-Dependent Measurements of an Inverted Metamorphic Multijunction (IMM) Solar Cell: Preprint

    SciTech Connect

    Steiner, M. A.; Geisz, J. F.; Friedman, D. J.; Olavarria, W. J.; Duda, A.; Moriarty, T. E.

    2011-07-01

    The inverted metamorphic multijunction (IMM) solar cell has demonstrated efficiencies as high as 40.8% at 25 degrees C and 326 suns concentration. The actual operating temperature in a commercial module, however, is likely to be as much as 50-70 degrees C hotter, reaching as high as 100 degrees C. In order to be able to evaluate the cell performance under these real-world operating conditions, we have measured the open-circuit voltage, short-circuit current density and efficiency at temperatures up to 125 degrees C and concentrations up to 1000 suns, as well as the temperature coefficients of these parameters. Spectral response and one-sun current-voltage characteristics were measured by carefully adjusting the incident spectrum to selectively current-limit the different subcells. Concentrator measurements were taken on a pulsed solar simulator to minimize any additional heating due to the high intensity illumination. We compare our measured values to predictions based on detailed models of various triple junction solar cells. By choosing the optimum bandgaps for high temperature operation, the IMM can potentially result in greater energy production and lower temperature sensitivity under real operating conditions than a Ge-based solar cell.

  5. Conjugated polyelectrolyte hole transport layer for inverted-type perovskite solar cells

    PubMed Central

    Choi, Hyosung; Mai, Cheng-Kang; Kim, Hak-Beom; Jeong, Jaeki; Song, Seyeong; Bazan, Guillermo C.; Kim, Jin Young; Heeger, Alan J.

    2015-01-01

    Organic–inorganic hybrid perovskite materials offer the potential for realization of low-cost and flexible next-generation solar cells fabricated by low-temperature solution processing. Although efficiencies of perovskite solar cells have dramatically improved up to 19% within the past 5 years, there is still considerable room for further improvement in device efficiency and stability through development of novel materials and device architectures. Here we demonstrate that inverted-type perovskite solar cells with pH-neutral and low-temperature solution-processable conjugated polyelectrolyte as the hole transport layer (instead of acidic PEDOT:PSS) exhibit a device efficiency of over 12% and improved device stability in air. As an alternative to PEDOT:PSS, this work is the first report on the use of an organic hole transport material that enables the formation of uniform perovskite films with complete surface coverage and the demonstration of efficient, stable perovskite/fullerene planar heterojunction solar cells. PMID:26081865

  6. Understanding low bandgap polymer PTB7 and optimizing polymer solar cells based on it.

    PubMed

    Lu, Luyao; Yu, Luping

    2014-07-09

    Solution processed single junction polymer solar cells (PSCs) have been developed from less than 1% power conversion efficiency (PCE) to beyond 9% PCE in the last decade. The significant efficiency improvement comes from progress in both rational design of donor polymers and innovation of device architectures. Among all the novel high efficient donor polymers, PTB7 stands out as the most widely used one for solar cell studies. Herein the recent development of PTB7 solar cells is reviewed. Detailed discussion of basic property, structure property relationship, morphology study, interfacial engineering, and inorganic nanomaterials incorporation is provided. Possible future directions for further increasing the performance of PTB7 solar cells are discussed.

  7. Enhanced Power-Conversion Efficiency in Inverted Bulk Heterojunction Solar Cells using Liquid-Crystal-Conjugated Polyelectrolyte Interlayer.

    PubMed

    Liu, Chao; Tan, Yun; Li, Chunquan; Wu, Feiyan; Chen, Lie; Chen, Yiwang

    2015-09-02

    Two novel liquid-crystal-conjugated polyelectrolytes (LCCPEs) poly[9,9-bis[6-(4-cyanobiphenyloxy)-hexyl]-fluorene-alt-9,9-bis(6-(N,N-diethylamino)-hexyl)-fluorene] (PF6Ncbp) and poly[9,9-bis[6-(4-cyanobiphenyloxy)-hexyl]-fluorene-alt-9,9-bis(6-(N-methylimidazole)-hexyl]-fluorene] (PF6lmicbp) are obtained by covalent linkage of the cyanobiphenyl mesogen polar groups onto conjugated polyelectrolytes. After deposition a layer of LCCPEs on ZnO interlayer, the spontaneous orientation of liquid-crystal groups can induce a rearrangement of dipole moments at the interface, subsequently leading to the better energy-level alignment. Moreover, LCCPEs favors intimate interfacial contact between ZnO and the photon harvesting layer and induce active layer to form the nanofibers morphology for the enhancement of charge extraction, transportation and collection. The water/alcohol solubility of the LCCPEs also enables them to be environment-accepted solvent processability. On the basis of these advantages, the poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C60-butyric acid methyl ester (PC60BM)-based inverted polymer solar cells (PSCs) combined with ZnO/PF6Ncbp and ZnO/PF6lmicbp bilayers boost the power conversion efficiency (PCE) to 3.9% and 4.2%, respectively. Incorporation of the ZnO/PF6lmicbp into the devices based on a blend of a narrow band gap polymer thieno[3,4-b]thiophene/benzodithiophene (PTB7) with [6,6]-phenyl C70-butyric acid methyl ester (PC71BM) affords a notable efficiency of 7.6%.

  8. Polymers in solar technologies: an R and D strategy

    SciTech Connect

    Carroll, W.F.; Schissel, P.

    1980-07-01

    The use of polymers can increase the cost-effectiveness of solar technologies. The potential impact of polymers may be enhanced earlier if R and D is carried out according to a plan. The purpose of this plan is to present a five-year program consisting of 20 tasks categorized into six major problem areas: response to combined stresses; photochemistry; permeability/adhesion; surface properties; mechanical properties; and development of polymers. A budget required for each task is estimated and summarized for each problem area. It is shown that the potential future impact of polymers on the economics of solar technologies justifies the proposed expenditures.

  9. Polymer Based Nanocomposites for Solar Energy Conversion

    SciTech Connect

    Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C.; Rumbles, G.; Gregg, B.; Ginley, D.

    2005-01-01

    Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.

  10. Tailoring the photovoltaic performance of inverted hybrid solar cells by replacing PEDOT:PSS with V2Ox as hole-extraction layer

    NASA Astrophysics Data System (ADS)

    Lee, Hock Beng; Tan, Sin Tee; Ginting, Riski Titian; Tan, Chun Hui; Oleiwi, Hind Fadhil; Yap, Chi Chin; Jumali, Mohd. Hafizuddin Haji

    2016-11-01

    For nanoscale fabrication of organic photovoltaic device, the utilization of a hole extraction layer (HEL) is essential to prevent the wrong flow of charge carriers and overcome the Schottky barrier at electrode-polymer interface. In recent years, the degradation issue of PEDOT:PSS based device which arises from its acidic nature and extremely hygroscopic properties has prompted researchers to find an appropriate transition metal oxide as replacement. In current work, we introduced an entirely solution-processed substoichiometric vanadium oxide (V2Ox) as HEL in inverted polymer:fullerene based device. We demonstrated the efficiency of substoichiometric V2Ox layer in enhancing the device performance of inverted organic solar cells, with the PCE of the device increased from 1.91 to 2.89%. The V2Ox prepared herein was found to exhibit broad optical absorption, highly selective charge transporting properties and excellent film transparency. A robust correlation between the hole extraction nature and electronic band structure of V2Ox was also established in this work.

  11. Efficient Inverted Organic Solar Cells Based on a Fullerene Derivative-Modified Transparent Cathode.

    PubMed

    Wang, Yifan; Cong, Hailin; Yu, Bing; Zhang, Zhiguo; Zhan, Xiaowei

    2017-09-11

    Indium tin oxide (ITO) is a transparent conductive material which is extensively used in organic solar cells (OSCs) as electrodes. In inverted OSCs, ITO is usually employed as a cathode, which should be modified by cathode buffer layers (CBLs) to achieve better contact with the active layers. In this paper, an amine group functionalized fullerene derivative (DMAPA-C60) is used as a CBL to modify the transparent cathode ITO in inverted OSCs based on PTB7 as a donor and PC71BM as an acceptor. Compared with traditional ZnO CBL, DMAPA-C60 exhibited comparable transmittance. OSCs based on DMAPA-C60 show much better device performance compared with their ZnO counterparts (power conversion efficiencies (PCEs) improved from 6.24 to 7.43%). This is mainly because a better contact between the DMAPA-C60 modified ITO and the active layer is formed, which leads to better electron transport and collection. Nanoscale morphologies also demonstrate that the surface of DMAPA-C60-modified ITO is plainer than the ZnO counterparts, which also leads to the better device performance.

  12. Efficient Inverted Organic Solar Cells Based on a Fullerene Derivative-Modified Transparent Cathode

    PubMed Central

    Wang, Yifan; Yu, Bing; Zhang, Zhiguo

    2017-01-01

    Indium tin oxide (ITO) is a transparent conductive material which is extensively used in organic solar cells (OSCs) as electrodes. In inverted OSCs, ITO is usually employed as a cathode, which should be modified by cathode buffer layers (CBLs) to achieve better contact with the active layers. In this paper, an amine group functionalized fullerene derivative (DMAPA-C60) is used as a CBL to modify the transparent cathode ITO in inverted OSCs based on PTB7 as a donor and PC71BM as an acceptor. Compared with traditional ZnO CBL, DMAPA-C60 exhibited comparable transmittance. OSCs based on DMAPA-C60 show much better device performance compared with their ZnO counterparts (power conversion efficiencies (PCEs) improved from 6.24 to 7.43%). This is mainly because a better contact between the DMAPA-C60 modified ITO and the active layer is formed, which leads to better electron transport and collection. Nanoscale morphologies also demonstrate that the surface of DMAPA-C60-modified ITO is plainer than the ZnO counterparts, which also leads to the better device performance. PMID:28891990

  13. Direct solar-to-hydrogen conversion via inverted metamorphic multi-junction semiconductor architectures

    DOE PAGES

    Young, James L.; Steiner, Myles A.; Döscher, Henning; ...

    2017-03-13

    Solar water splitting via multi-junction semiconductor photoelectrochemical cells provides direct conversion of solar energy to stored chemical energy as hydrogen bonds. Economical hydrogen production demands high conversion efficiency to reduce balance-of-systems costs. For sufficient photovoltage, water-splitting efficiency is proportional to the device photocurrent, which can be tuned by judicious selection and integration of optimal semiconductor bandgaps. Here, we demonstrate highly efficient, immersed water-splitting electrodes enabled by inverted metamorphic epitaxy and a transparent graded buffer that allows the bandgap of each junction to be independently varied. Voltage losses at the electrolyte interface are reduced by 0.55 V over traditional, uniformly p-dopedmore » photocathodes by using a buried p-n junction. Lastly, advanced on-sun benchmarking, spectrally corrected and validated with incident photon-to-current efficiency, yields over 16% solar-to-hydrogen efficiency with GaInP/GaInAs tandem absorbers, representing a 60% improvement over the classical, high-efficiency tandem III-V device.« less

  14. Direct solar-to-hydrogen conversion via inverted metamorphic multi-junction semiconductor architectures

    NASA Astrophysics Data System (ADS)

    Young, James L.; Steiner, Myles A.; Döscher, Henning; France, Ryan M.; Turner, John A.; Deutsch, Todd G.

    2017-03-01

    Solar water splitting via multi-junction semiconductor photoelectrochemical cells provides direct conversion of solar energy to stored chemical energy as hydrogen bonds. Economical hydrogen production demands high conversion efficiency to reduce balance-of-systems costs. For sufficient photovoltage, water-splitting efficiency is proportional to the device photocurrent, which can be tuned by judicious selection and integration of optimal semiconductor bandgaps. Here, we demonstrate highly efficient, immersed water-splitting electrodes enabled by inverted metamorphic epitaxy and a transparent graded buffer that allows the bandgap of each junction to be independently varied. Voltage losses at the electrolyte interface are reduced by 0.55 V over traditional, uniformly p-doped photocathodes by using a buried p-n junction. Advanced on-sun benchmarking, spectrally corrected and validated with incident photon-to-current efficiency, yields over 16% solar-to-hydrogen efficiency with GaInP/GaInAs tandem absorbers, representing a 60% improvement over the classical, high-efficiency tandem III-V device.

  15. Inverted perovskite solar cells based on lithium-functionalized graphene oxide as an electron-transporting layer.

    PubMed

    Nouri, Esmaiel; Mohammadi, Mohammad Reza; Lianos, Panagiotis

    2017-02-04

    Perovskite solar cells with an inverted p-i-n architecture were constructed under ambient conditions by employing materials of lower cost than standard cells. Thus, graphene oxide was used as a hole transporting material and Li-modified graphene oxide as an electron transporting material, while Al was used as a counter electrode. A maximum solar conversion efficiency of 10.2% was achieved by adding a Ti-based sol on the top of the Li-modified graphene oxide layer.

  16. Improve the operational stability of the inverted organic solar cells using bilayer metal oxide structure.

    PubMed

    Chang, Jingjing; Lin, Zhenhua; Jiang, Changyun; Zhang, Jie; Zhu, Chunxiang; Wu, Jishan

    2014-11-12

    Operational stability is a big obstacle for the application of inverted organic solar cells (OSCs), however, less talked about in the research reports. Due to photoinduced degradation of the metal oxide interlayer, which can cause shunts generation and degeneration in ZnO interlayer, a significant degradation of open circuit voltage (Voc) and fill factor (FF) has been observed by in situ periodic measurements of the device current density-voltage (J-V) curves with light illumination. By combining TiOx and ZnO to form bilayer structures on ITO, the photovoltaic performance is improved and the photoinduced degradation is reduced. It was found that the device based on ZnO/TiOx bilayer structure achieved better operational stability as compared to that with ZnO or TiOx interlayer.

  17. Highly efficient uniform ZnO nanostructures for an electron transport layer of inverted organic solar cells.

    PubMed

    Kim, Sarah; Kim, Chul-Hyun; Lee, Sang Kyu; Jeong, Jun-Ho; Lee, Jihye; Jin, Sung-Ho; Shin, Won Suk; Song, Chang Eun; Choi, Jun-Hyuk; Jeong, Jong-Ryul

    2013-07-11

    A highly uniform and predesigned ZnO nanostructure fabricated by single step direct nanoimprinting was used as the efficient electron transport layer (ETL) in inverted bulk heterojunction organic solar cells. Improved photovoltaic cell efficiency with long-term stability can be observed due to the large interface between the active layer and nanostructured ZnO ETL.

  18. Non-fullerene acceptors containing fluoranthene-fused imides for solution-processed inverted organic solar cells.

    PubMed

    Zhou, Yan; Dai, Ya-Zhong; Zheng, Yu-Qing; Wang, Xiao-Ye; Wang, Jie-Yu; Pei, Jian

    2013-06-28

    Six fluoranthene-fused imide derivatives were employed as acceptors in solution processed inverted BHJ solar cells with P3HT as the donor. The PCEs of all devices vary from 2.14% to 2.89%. All acceptors are in their amorphous state with low electron mobility, but achieving high PCEs.

  19. Efficient, flexible and mechanically robust perovskite solar cells on inverted nanocone plastic substrates

    NASA Astrophysics Data System (ADS)

    Tavakoli, Mohammad Mahdi; Lin, Qingfeng; Leung, Siu-Fung; Lui, Ga Ching; Lu, Hao; Li, Liang; Xiang, Bin; Fan, Zhiyong

    2016-02-01

    Utilization of nanostructures on photovoltaic devices can significantly improve the device energy conversion efficiency by enhancing the device light harvesting capability as well as carrier collection efficiency. However, improvements in device mechanical robustness and reliability, particularly for flexible devices, have rarely been reported with in-depth understanding. In this work, we fabricated efficient, flexible and mechanically robust organometallic perovskite solar cells on plastic substrates with inverted nanocone (i-cone) structures. Compared with the reference cell that was fabricated on a flat substrate, it was shown that the device power conversion efficiency could be improved by 37%, and reached up to 11.29% on i-cone substrates. More interestingly, it was discovered that the performance of an i-cone device remained more than 90% of the initial value even after 200 mechanical bending cycles, which is remarkably better than for the flat reference device, which degraded down to only 60% in the same test. Our experiments, coupled with mechanical simulation, demonstrated that a nanostructured template can greatly help in relaxing stress and strain upon device bending, which suppresses crack nucleation in different layers of a perovskite solar cell. This essentially leads to much improved device reliability and robustness and will have significant impact on practical applications.Utilization of nanostructures on photovoltaic devices can significantly improve the device energy conversion efficiency by enhancing the device light harvesting capability as well as carrier collection efficiency. However, improvements in device mechanical robustness and reliability, particularly for flexible devices, have rarely been reported with in-depth understanding. In this work, we fabricated efficient, flexible and mechanically robust organometallic perovskite solar cells on plastic substrates with inverted nanocone (i-cone) structures. Compared with the reference cell

  20. A Difluorobenzoxadiazole Building Block for Efficient Polymer Solar Cells.

    PubMed

    Zhao, Jingbo; Li, Yunke; Hunt, Adrian; Zhang, Jianquan; Yao, Huatong; Li, Zhengke; Zhang, Jie; Huang, Fei; Ade, Harald; Yan, He

    2016-03-02

    A difluorobenzoxadiazole building block is synthesized and utilized to construct a conjugated polymer leading to high-performance thick-film polymer solar cells with a V(OC) of 0.88 V and a power conversion efficiency of 9.4%. This new building block can be used in many possible polymer structures for various organic electro-nic applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Real function of semiconducting polymer in GaAs/polymer planar heterojunction solar cells.

    PubMed

    Yan, Liang; You, Wei

    2013-08-27

    We systematically investigated GaAs/polymer hybrid solar cells in a simple planar junction, aiming to fundamentally understand the function of semiconducting polymers in GaAs/polymer-based heterojunction solar cells. A library of semiconducting polymers with different band gaps and energy levels were evaluated in GaAs/polymer planar heterojunctions. The optimized thickness of the active polymer layer was discovered to be ultrathin (~10 nm). Further, the open-circuit voltage (Voc) of such GaAs/polymer planar heterojunctions was fixed around 0.6 V, regardless of the HOMO energy level of the polymer employed. On the basis of this evidence and others, we conclude that n-type GaAs/polymer planar heterojunctions are not type II heterojunctions as originally assumed. Instead, n-type GaAs forms a Schottky barrier with its corresponding anode, while the semiconducting polymer of appropriate energy levels can function as hole transport layer and/or electron blocking layer. Additionally, we discover that both GaAs surface passivation and thermal annealing can improve the performance of GaAs/polymer hybrid solar cells.

  2. Device Stability and Light-Soaking Characteristics of High-Efficiency Benzodithiophene-Thienothiophene Copolymer-Based Inverted Organic Solar Cells with F-TiO(x) Electron-Transport Layer.

    PubMed

    Lim, Fang Jeng; Krishnamoorthy, Ananthanarayanan; Ho, Ghim Wei

    2015-06-10

    Organic solar cells (OSC) based on low-band-gap thienothiophene-benzodithiophene copolymer have achieved relatively high efficiency (7-9%) in recent times. Among this class of material, poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB-7) is one of the high-efficiency materials reported for OSC. However, this material seems to be intrinsically unstable compared to the commonly used workhorse polymer, poly(3-hexylthiophene) (P3HT), especially when illuminated in air. Inverted device architecture is usually adopted to improve device stability, but the device stability using PTB-7 is not yet well-understood. In this work, a systematic degradation study on a PTB-7:PC71BM-based inverted OSC employing F-TiO(x) as electron-transport layer (ETL) was conducted for the first time. Air stability, photostability in inert atmosphere, and photostability under ambient conditions of the device were separately carried out to understand better the polymer behavior in inverted OSC. The device's air stability with different polymer absorber layers was studied by exposing the devices in air for up to 1500 h. Because of the long and easily cleavable alkoxy side chains in the polymer backbone, a PTB-7:PC71BM-based inverted OSC device is highly susceptible to oxygen and moisture when compared to a P3HT:PC61BM-based device. In addition, with the presence of F-TiO(x) ETL, a significant reduction in light-soaking time was also observed in PTB-7:PC71BM inverted OSC for the first time. The TiO(x)/organic interface was found to be responsible for the reduction in the light-soaking time.

  3. Roles of interfacial modifiers in hybrid solar cells: inorganic/polymer bilayer vs inorganic/polymer:fullerene bulk heterojunction.

    PubMed

    Eom, Seung Hun; Baek, Myung-Jin; Park, Hanok; Yan, Liang; Liu, Shubin; You, Wei; Lee, Soo-Hyoung

    2014-01-22

    Hybrid solar cells (HSCs) incorporating both organic and inorganic materials typically have significant interfacial issues which can significantly limit the device efficiency by allowing charge recombination, macroscopic phase separation, and nonideal contact. All these issues can be mitigated by applying carefully designed interfacial modifiers (IMs). In an attempt to further understand the function of these IMs, we investigated two IMs in two different HSCs structures: an inverted bilayer HSC of ZnO:poly(3-hexylthiophene) (P3HT) and an inverted bulk heterojunction (BHJ) solar cell of ZnO/P3HT:[6,6]-phenyl C61-butyric acid methyl ester (PCBM). In the former device configuration, ZnO serves as the n-type semiconductor, while in the latter device configuration, it functions as an electron transport layer (ETL)/hole blocking layer (HBL). In the ZnO:P3HT bilayer device, after the interfacial modification, a power conversion efficiency (PCE) of 0.42% with improved Voc and FF and a significantly increased Jsc was obtained. In the ZnO/P3HT:PCBM based BHJ device, including IMs also improved the PCE to 4.69% with an increase in Voc and FF. Our work clearly demonstrates that IMs help to reduce both the charge recombination and leakage current by minimizing the number of defect sites and traps and to increase the compatibility of hydrophilic ZnO with the organic layers. Furthermore, the major role of IMs depends on the function of ZnO in different device configurations, either as n-type semiconductor in bilayer devices or as ETL/HBL in BHJ devices. We conclude by offering insights for designing ideal IMs in future efforts, in order to achieve high-efficiency in both ZnO:polymer bilayer structure and ZnO/polymer:PCBM BHJ devices.

  4. Decohesion kinetics in polymer organic solar cells.

    PubMed

    Bruner, Christopher; Novoa, Fernando; Dupont, Stephanie; Dauskardt, Reinhold

    2014-12-10

    We investigate the role of molecular weight (MW) of the photoactive polymer poly(3-hexylthiophene) (P3HT) on the temperature-dependent decohesion kinetics of bulk heterojunction (BHJ) organic solar cells (OSCs). The MW of P3HT has been directly correlated to its carrier field effect mobilities and the ambient temperature also affects OSC in-service performance and P3HT arrangement within the BHJ layer. Under inert conditions, time-dependent decohesion readily occurs within the BHJ layer at loads well below its fracture resistance. We observe that by increasing the MW of P3HT, greater resistance to decohesion is achieved. However, failure consistently occurs within the BHJ layer representing the weakest layer within the device stack. Additionally, it was found that at temperatures below the glass transition temperature (∼41-45 °C), decohesion was characterized by brittle failure via molecular bond rupture. Above the glass transition temperature, decohesion growth occurred by a viscoelastic process in the BHJ layer, leading to a significant degree of viscoelastic deformation. We develop a viscoelastic model based on molecular relaxation to describe the resulting behavior. The study has implications for OSC long-term reliability and device performance, which are important for OSC production and implementation.

  5. Sol-gel derived ZnO as an electron transport layer (ETL) for inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Tiwari, D. C.; Dwivedi, Shailendra Kumar; Dipak, Phukhrambam; Chandel, Tarun; Sharma, Rishi

    2017-05-01

    In this work, we present the study of the fabrication process of the sol-gel derived zinc oxide (ZnO) as an electron transport layer (ETL.). The solution processed inverted bulk heterojunction organic solar cells based on a thin film blend of poly (3-hexylthiophene 2, 5-diyl) and [6,6]-phenyl-C61-butyric acid methyl ester is prepared. ZnO thin films are annealed at different temperature to optimize the solar cell performance and their characterization for their structural and optical properties are carried out. We have observed Voc=70mV, Jsc=1.33 µA/cm2 and FF=26% from the inverted heterojunction solar cell.

  6. Inverted organic electronic and optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Small, Cephas E.

    The research and development of organic electronics for commercial application has received much attention due to the unique properties of organic semiconductors and the potential for low-cost high-throughput manufacturing. For improved large-scale processing compatibility and enhanced device stability, an inverted geometry has been employed for devices such as organic light emitting diodes and organic photovoltaic cells. These improvements are attributed to the added flexibility to incorporate more air-stable materials into the inverted device geometry. However, early work on organic electronic devices with an inverted geometry typically showed reduced device performance compared to devices with a conventional structure. In the case of organic light emitting diodes, inverted devices typically show high operating voltages due to insufficient carrier injection. Here, a method for enhancing hole injection in inverted organic electronic devices is presented. By incorporating an electron accepting interlayer into the inverted device, a substantial enhancement in hole injection efficiency was observed as compared to conventional devices. Through a detailed carrier injection study, it is determined that the injection efficiency enhancements in the inverted devices are due to enhanced charge transfer at the electron acceptor/organic semiconductor interface. A similar situation is observed for organic photovoltaic cells, in which devices with an inverted geometry show limited carrier extraction in early studies. In this work, enhanced carrier extraction is demonstrated for inverted polymer solar cells using a surface-modified ZnO-polymer composite electron-transporting layer. The insulating polymer in the composite layer inhibited aggregation of the ZnO nanoparticles, while the surface-modification of the composite interlayer improved the electronic coupling with the photoactive layer. As a result, inverted polymer solar cells with power conversion efficiencies of over 8

  7. Efficient, flexible and mechanically robust perovskite solar cells on inverted nanocone plastic substrates.

    PubMed

    Tavakoli, Mohammad Mahdi; Lin, Qingfeng; Leung, Siu-Fung; Lui, Ga Ching; Lu, Hao; Li, Liang; Xiang, Bin; Fan, Zhiyong

    2016-02-21

    Utilization of nanostructures on photovoltaic devices can significantly improve the device energy conversion efficiency by enhancing the device light harvesting capability as well as carrier collection efficiency. However, improvements in device mechanical robustness and reliability, particularly for flexible devices, have rarely been reported with in-depth understanding. In this work, we fabricated efficient, flexible and mechanically robust organometallic perovskite solar cells on plastic substrates with inverted nanocone (i-cone) structures. Compared with the reference cell that was fabricated on a flat substrate, it was shown that the device power conversion efficiency could be improved by 37%, and reached up to 11.29% on i-cone substrates. More interestingly, it was discovered that the performance of an i-cone device remained more than 90% of the initial value even after 200 mechanical bending cycles, which is remarkably better than for the flat reference device, which degraded down to only 60% in the same test. Our experiments, coupled with mechanical simulation, demonstrated that a nanostructured template can greatly help in relaxing stress and strain upon device bending, which suppresses crack nucleation in different layers of a perovskite solar cell. This essentially leads to much improved device reliability and robustness and will have significant impact on practical applications.

  8. Ultrathin Epitaxial Silicon Solar Cells with Inverted Nanopyramid Arrays for Efficient Light Trapping.

    PubMed

    Gaucher, Alexandre; Cattoni, Andrea; Dupuis, Christophe; Chen, Wanghua; Cariou, Romain; Foldyna, Martin; Lalouat, Loı̈c; Drouard, Emmanuel; Seassal, Christian; Roca I Cabarrocas, Pere; Collin, Stéphane

    2016-09-14

    Ultrathin c-Si solar cells have the potential to drastically reduce costs by saving raw material while maintaining good efficiencies thanks to the excellent quality of monocrystalline silicon. However, efficient light trapping strategies must be implemented to achieve high short-circuit currents. We report on the fabrication of both planar and patterned ultrathin c-Si solar cells on glass using low temperature (T < 275 °C), low-cost, and scalable techniques. Epitaxial c-Si layers are grown by PECVD at 160 °C and transferred on a glass substrate by anodic bonding and mechanical cleavage. A silver back mirror is combined with a front texturation based on an inverted nanopyramid array fabricated by nanoimprint lithography and wet etching. We demonstrate a short-circuit current density of 25.3 mA/cm(2) for an equivalent thickness of only 2.75 μm. External quantum efficiency (EQE) measurements are in very good agreement with FDTD simulations. We infer an optical path enhancement of 10 in the long wavelength range. A simple propagation model reveals that the low photon escape probability of 25% is the key factor in the light trapping mechanism. The main limitations of our current technology and the potential efficiencies achievable with contact optimization are discussed.

  9. Characteristics of Sputtered ZnO Thin Films for an Inverted Organic Solar Cell.

    PubMed

    Park, Yong Seob; Park, Chul Min; Lee, Jaehyeong

    2016-05-01

    Several research groups have claimed high energy conversion efficiency in organic solar cells. However, it still has low efficiency and is unstable, because organic materials are easily oxidized by atmospheric humidity and UV light. In this work, ZnO thin film as the blocking layer attributed to the interference of the injection of the hole from the P3HT and no charge carrier recombination. We obtained the maximum power conversion efficiency of 1.9% under AM 1.5 G spectral illumination of 100 MWcm(-2), when we used a ZnO film of 60 nm and the optimized P3HT:PCBM, and Au as the back electrode to solve the reaction problem of Al electrode and to control the work function between the HOMO level of P3HT and the energy level of the metal electrode. Power conversion efficiency of inverted organic solar cell (IOSC) is significantly dependent on the thickness of the ZnO thin film deposited by unbalanced magnetron sputtering method. Also, the stability of IOSC is measured under ambient conditions.

  10. Silver nanowire-graphene hybrid transparent conductive electrodes for highly efficient inverted organic solar cells.

    PubMed

    Ye, Neng; Yan, Jielin; Xie, Shuang; Kong, Yuhan; Liang, Tao; Chen, Hongzheng; Xu, Mingsheng

    2017-07-28

    Silver nanowires (AgNWs) and graphene are both promising candidates as a transparent conductive electrode (TCE) to replace expensive and fragile indium tin oxide (ITO) TCE. A synergistically optimized performance is expected when the advantages of AgNWs and graphene are combined. In this paper, the AgNW-graphene hybrid electrode is constructed by depositing a graphene layer on top of the network of AgNWs. Compared with the pristine AgNWs electrode, the AgNW-graphene TCE exhibits reduced sheet resistance, lower surface roughness, excellent long-term stability, and corrosion resistance in corrosive liquids. The graphene layer covering the AgNWs provides additional conduction pathways for electron transport and collection by the electrode. Benefiting from these advantages of the hybrid electrodes, we achieve a power conversion efficiency of 8.12% of inverted organic solar cells using PTB7:PC71BM as the active layer, which is compared to that of the solar cells based on standard ITO TCE but about 10% higher than that based on AgNWs TCE.

  11. Improving performance of inverted organic solar cells using ZTO nanoparticles as cathode buffer layer

    NASA Astrophysics Data System (ADS)

    Tsai, Meng-Yen; Cheng, Wen-Hui; Jeng, Jiann-Shing; Chen, Jen-Sue

    2016-06-01

    In this study, a low-temperature solution-processed zinc tin oxide (ZTO) films are successfully utilized as the cathode buffer layer in the inverted organic P3HT:PCBM bulk heterojunction solar cells. ZTO film cathode buffer layer with an appropriate Sn-doping concentration outperforms the zinc oxide (ZnO) film with an improved power conversion efficiency (1.96% (ZTO film) vs. 1.56% (ZnO film)). Furthermore, ZTO nanoparticles (NPs) are also synthesized via low-temperature solution route and the device with ZTO NPs buffer layer exhibits a significant improvement in device performance to reach a PCE of 2.60%. The crystallinity of the cathode buffer layer plays an influential factor in the performance. From impedance spectroscopy analysis, a correlation between short circuit current (Jsc), carrier life time (τavg) and, thus, PCE is observed. The interplay between composition and crystallinity of the cathode buffer layers is discussed to find their influences on the solar cell performance.

  12. Inverted organic solar cells enhanced by grating-coupled surface plasmons and waveguide modes.

    PubMed

    Hara, Kazuma; Lertvachirapaiboon, Chutiparn; Ishikawa, Ryousuke; Ohdaira, Yasuo; Shinbo, Kazunari; Kato, Keizo; Kaneko, Futao; Baba, Akira

    2017-01-25

    In this study, we demonstrate improved photovoltaic properties in inverted organic thin-film solar cells by simultaneous excitation of grating-coupled surface plasmons and grating-coupled waveguide modes on gold grating surfaces. The cell consists of a glass-ITO substrate/titanium dioxide/poly(3-hexylthiophene-2,5-diyl):phenyl-C61-butyric acid methyl ester/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/gold structure. The grating structures were fabricated on P3HT:PCBM layers using a nanoimprinting technique with a PDMS stamp. The grating-structured PDMS stamps were fabricated using a DVD-R grating template with a grating pitch, Λ, of 740 nm. Reflectivity measurements made using p-polarized light clearly indicate 2 types of excitation modes, i.e., surface plasmons and waveguide modes, while s-polarized light produces only waveguide modes. Incident photon-to-current efficiency measurements exhibited increased photocurrent wavelengths corresponding to the wavelengths of surface plasmon excitations and waveguide mode excitations. Through the simultaneous excitation of surface plasmons and waveguide modes, short-circuit photocurrents in the grating-structured cells exhibited an improvement of up to 11% in the solar cells, leading to an efficiency increase of 16%.

  13. Silver nanowire-graphene hybrid transparent conductive electrodes for highly efficient inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Ye, Neng; Yan, Jielin; Xie, Shuang; Kong, Yuhan; Liang, Tao; Chen, Hongzheng; Xu, Mingsheng

    2017-07-01

    Silver nanowires (AgNWs) and graphene are both promising candidates as a transparent conductive electrode (TCE) to replace expensive and fragile indium tin oxide (ITO) TCE. A synergistically optimized performance is expected when the advantages of AgNWs and graphene are combined. In this paper, the AgNW-graphene hybrid electrode is constructed by depositing a graphene layer on top of the network of AgNWs. Compared with the pristine AgNWs electrode, the AgNW-graphene TCE exhibits reduced sheet resistance, lower surface roughness, excellent long-term stability, and corrosion resistance in corrosive liquids. The graphene layer covering the AgNWs provides additional conduction pathways for electron transport and collection by the electrode. Benefiting from these advantages of the hybrid electrodes, we achieve a power conversion efficiency of 8.12% of inverted organic solar cells using PTB7:PC71BM as the active layer, which is compared to that of the solar cells based on standard ITO TCE but about 10% higher than that based on AgNWs TCE.

  14. Performance Enhancement of Polymer Solar Cells by Using Two Polymer Donors with Complementary Absorption Spectra.

    PubMed

    Lu, Heng; Zhang, Xuejuan; Li, Cuihong; Wei, Hedi; Liu, Qian; Li, Weiwei; Bo, Zhishan

    2015-07-01

    Performance enhancement of polymer solar cells (PSCs) is achieved by expanding the absorption of the active layer of devices. To better match the spectrum of solar radiation, two polymers with different band gaps are used as the donor material to fabricate ternary polymer cells. Ternary blend PSCs exhibit an enhanced short-circuit current density and open-circuit voltage in comparison with the corresponding HD-PDFC-DTBT (HD)- and DT-PDPPTPT (DPP)-based binary polymer solar cells, respectively. Ternary PSCs show a power conversion efficiency (PCE) of 6.71%, surpassing the corresponding binary PSCs. This work demonstrates that the fabrication of ternary PSCs by using two polymers with complementary absorption is an effective way to improve the device performance.

  15. From Morphology to Interfaces to Tandem Geometries: Enhancing the Performance of Perovskite/Polymer Solar Cells

    NASA Astrophysics Data System (ADS)

    Russell, Thomas

    We have taken a new approach to develop mesoporous lead iodide scaffolds, using the nucleation and growth of lead iodide crystallites in a wet film. A simple time-dependent growth control enabled the manipulation of the mesoporous lead iodide layer quality in a continuous manner. The morphology of lead iodide is shown to influence the subsequent crystallization of methyamoniumleadiodide film by using angle-dependent grazing incidence x-ray scattering. The morphology of lead iodide film can be fine-tuned, and thus the methyamoniumleadiodide film quality can be effectively controlled, leading to an optimization of the perovskite active layer. Using this strategy, perovskite solar cells with inverted PHJ structure showed a PCE of 15.7 per cent with little hysteresis. Interface engineering is critical for achieving efficient solar cells, yet a comprehensive understanding of the interface between metal electrode and electron transport layer (ETL) is lacking. A significant power conversion efficiency (PCE) improvement of fullerene/perovskite planar heterojunction solar cells was achieved by inserting a fulleropyrrolidine interlayer between the silver electrode and electron transport layer. The interlayer was found to enhance recombination resistance, increases electron extraction rate and prolongs free carrier lifetime. We also uncovered a facile solution-based fabrication of high performance tandem perovskite/polymer solar cells where the front sub-cell consists of perovskite and the back sub-cell is a polymer-based layer. A record maximum PCE of 15.96 per cent was achieved, demonstrating the synergy between the perovskite and semiconducting polymers. This design balances the absorption of the perovskite and the polymer, eliminates the adverse impact of thermal annealing during perovskite fabrication, and affords devices with no hysteresis. This work was performed in collaboration with Y. Liu, Z. Page, D. Venkataraman and T. Emrick (UMASS), F. Liu (LBNL) and Q. Hu and R

  16. Visibly transparent polymer solar cells produced by solution processing.

    PubMed

    Chen, Chun-Chao; Dou, Letian; Zhu, Rui; Chung, Choong-Heui; Song, Tze-Bin; Zheng, Yue Bing; Hawks, Steve; Li, Gang; Weiss, Paul S; Yang, Yang

    2012-08-28

    Visibly transparent photovoltaic devices can open photovoltaic applications in many areas, such as building-integrated photovoltaics or integrated photovoltaic chargers for portable electronics. We demonstrate high-performance, visibly transparent polymer solar cells fabricated via solution processing. The photoactive layer of these visibly transparent polymer solar cells harvests solar energy from the near-infrared region while being less sensitive to visible photons. The top transparent electrode employs a highly transparent silver nanowire-metal oxide composite conducting film, which is coated through mild solution processes. With this combination, we have achieved 4% power-conversion efficiency for solution-processed and visibly transparent polymer solar cells. The optimized devices have a maximum transparency of 66% at 550 nm.

  17. Enhanced performance of polymer solar cell with ZnO nanoparticle electron transporting layer passivated by in situ cross-linked three-dimensional polymer network

    NASA Astrophysics Data System (ADS)

    Wu, Zhongwei; Song, Tao; Xia, Zhouhui; Wei, Huaixin; Sun, Baoquan

    2013-12-01

    An in situ cross-linked three-dimensional polymer network has been developed to passivate ZnO nanoparticles as an electron transporting layer (ETL) to improve the performance of inverted organic solar cells. The passivated ZnO ETL-based devices achieve efficiencies of 3.26% for poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and 7.37% for poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  18. Role of additional PCBM layer between ZnO and photoactive layers in inverted bulk-heterojunction solar cells.

    PubMed

    Cho, Shinuk; Kim, Kwang-Dae; Heo, Jinhee; Lee, Joo Yul; Cha, Gihoon; Seo, Bo Yeol; Kim, Young Dok; Kim, Yong Soo; Choi, Si-young; Lim, Dong Chan

    2014-03-07

    In order to induce greater light absorption, nano-patterning is often applied to the metal-oxide buffer layer in inverted bulk-heterojunction(BHJ) solar cells. However, current homogeneity was significantly disturbed at the interface, leading to an efficiency that was not fully optimized. In this work, an additional PC61BM layer was inserted between the ZnO ripple and the photoactive layer to enhance the electron extraction. The insertion of additional PC61BM layer provided substantial advantages in the operation of inverted BHJ solar cells; specifically, it enhanced current homogeneity and lowered accumulation and trapping of photogenerated charges at the ZnO interface. Inclusion of the additional PC61BM layer led to effective quenching of electron-hole recombination by a reduction in the number of accumulated charges at the surface of ZnO ripples. This resulted in a 16% increase in the efficiency of inverted BHJ solar cells to 7.7%, compared to solar cells without the additional PC61BM layer.

  19. Role of additional PCBM layer between ZnO and photoactive layers in inverted bulk-heterojunction solar cells

    PubMed Central

    Cho, Shinuk; Kim, Kwang-Dae; Heo, Jinhee; Lee, Joo Yul; Cha, Gihoon; Seo, Bo Yeol; Kim, Young Dok; Kim, Yong Soo; Choi, Si-young; Lim, Dong Chan

    2014-01-01

    In order to induce greater light absorption, nano-patterning is often applied to the metal-oxide buffer layer in inverted bulk-heterojunction(BHJ) solar cells. However, current homogeneity was significantly disturbed at the interface, leading to an efficiency that was not fully optimized. In this work, an additional PC61BM layer was inserted between the ZnO ripple and the photoactive layer to enhance the electron extraction. The insertion of additional PC61BM layer provided substantial advantages in the operation of inverted BHJ solar cells; specifically, it enhanced current homogeneity and lowered accumulation and trapping of photogenerated charges at the ZnO interface. Inclusion of the additional PC61BM layer led to effective quenching of electron–hole recombination by a reduction in the number of accumulated charges at the surface of ZnO ripples. This resulted in a 16% increase in the efficiency of inverted BHJ solar cells to 7.7%, compared to solar cells without the additional PC61BM layer. PMID:24603531

  20. Multi-source/component spray coating for polymer solar cells.

    PubMed

    Chen, Li-Min; Hong, Ziruo; Kwan, Wei Lek; Lu, Cheng-Hsueh; Lai, Yi-Feng; Lei, Bao; Liu, Chuan-Pu; Yang, Yang

    2010-08-24

    A multi-source/component spray coating process to fabricate the photoactive layers in polymer solar cells is demonstrated. Well-defined domains consisting of polymer:fullerene heterojunctions are constructed in ambient conditions using an alternating spray deposition method. This approach preserves the integrity of the layer morphology while forming an interpenetrating donor (D)/acceptor (A) network to facilitate charge transport. The formation of multi-component films without the prerequisite of a common solvent overcomes the limitations in conventional solution processes for polymer solar cells and enables us to process a wide spectrum of materials. Polymer solar cells based on poly(3-hexylthiophene):[6,6]-phenyl C(61) butyric acid methyl ester spray-coated using this alternating deposition method deliver a power conversion efficiency of 2.8%, which is comparable to their blend solution counterparts. More importantly, this approach offers the versatility to independently select the optimal solvents for the donor and acceptor materials that will deliver well-ordered nanodomains. This method also allows the direct stacking of multiple photoactive polymers with controllable absorption in a tandem structure even without an interconnecting junction layer. The introduction of multiple photoactive materials through multisource/component spray coating offers structural flexibility and tenability of the photoresponse for future polymer solar cell applications.

  1. Alkenyl Carboxylic Acid: Engineering the Nanomorphology in Polymer-Polymer Solar Cells as Solvent Additive.

    PubMed

    Zhang, Yannan; Yuan, Jianyu; Sun, Jianxia; Ding, Guanqun; Han, Lu; Ling, Xufeng; Ma, Wanli

    2017-04-19

    We have investigated a series of commercially available alkenyl carboxylic acids with different alkenyl chain lengths (trans-2-hexenoic acid (CA-6), trans-2-decenoic acid (CA-10), 9-tetradecenoic acid (CA-14)) for use as solvent additives in polymer-polymer non-fullerene solar cells. We systematically investigated their effect on the film absorption, morphology, carrier generation, transport, and recombination in all-polymer solar cells. We revealed that these additives have a significant impact on the aggregation of polymer acceptor, leading to improved phase segregation in the blend film. This in-depth understanding of the additives effect on the nanomorphology in all-polymer solar cell can help further boost the device performance. By using CA-10 with the optimal alkenyl chain length, we achieved fine phase separation, balanced charge transport, and suppressed recombination in all-polymer solar cells. As a result, an optimal power conversion efficiency (PCE) of 5.71% was demonstrated which is over 50% higher than that of the as-cast device (PCE = 3.71%) and slightly higher than that of devices with DIO treatment (PCE = 5.68%). Compared with widely used DIO, these halogen-free alkenyl carboxylic acids have a more sustainable processing as well as better performance, which may make them more promising candidates for use as processing additives in organic non-fullerene solar cells.

  2. Characterization of ALD Processed Gallium Doped TiO2 Hole Blocking Layer in an Inverted Organic Solar Cell

    NASA Astrophysics Data System (ADS)

    Lee, Eun Ju; Ryu, Sang Ouk

    2017-02-01

    To improve power conversion efficiency (PCE) of inverted structure organic solar cells a buffer layer, a hole blocking layer (HBL) was introduced between cathode and active photovoltaic layer. Gallium (Ga) doped TiO2 as a HBL was fabricated by means of atomic layer deposition. X-ray photoelectron spectroscopy showed the highest Ga-Ti complex binding characteristics was achieved at 5% doping concentration. Gallium doped TiO2 layer exhibited over 94% of optical transmittance at the process temperature of 200°C. The resulting PCE of inverted structure organic solar cell having 5% doping in the hole block layer was 2.7%. The PCE was improved 35% compared to the cell without gallium doping.

  3. Molecular Design and Device Application of Radical Polymers for Improved Charge Extraction in Organic Photovoltaic Cells

    DTIC Science & Technology

    2015-07-29

    proved that the conditions used to oxidize the protected polymer precursor to the radical polymer can lead to materials with vastly different charge...Core-Shell Nanoparticles for Enhanced Performance of Inverted Polymer Solar Cells,” Jaramillo, J.; Barrero, C.; Boudouris, B. W.; Jaramillo, F. 2015...Core-Shell Nanoparticles for Enhanced Performance of Inverted Polymer Solar Cells,” Jaramillo, J.; Barrero, C.; Boudouris, B. W.; Jaramillo, F. 2015

  4. Coating and surface finishing definition for the Solar Orbiter/METIS inverted external occulter

    NASA Astrophysics Data System (ADS)

    Landini, Federico; Romoli, Marco; Vives, Sebastien; Baccani, Cristian; Escolle, Clement; Pancrazzi, Maurizio; Focardi, Mauro; Da Deppo, Vania; Moses, John D.; Fineschi, Silvano

    2014-07-01

    The METIS coronagraph aboard the Solar Orbiter mission will undergo extreme environmental conditions (e.g., a thermal excursion of about 350 degrees throughout the various mission phases), due to the peculiar spacecraft trajectory that will reach a perihelion of 0.28 AUs. METIS is characterized by an innovative design for the occultation system that allows to halve the thermal load inside the instrument while guaranteeing the stray light reduction that is required for a solar coronagraph. The Inverted External Occulter (IEO) concept revolutionizes the classical scheme, by exchanging the usual positions of the entrance aperture (that is now the outermost element of the instrument facing the Sun) with the actual occulter (that is a spherical mirror inside the coronagraph boom). The chosen material for the IEO manufacturing is Titanium, as a trade o_ between light weight, strength and low thermal expansion coefficient. A 2 years long test campaign has been run to define the IEO geometry, and its results are addressed in previous dedicated papers. This work describes the results of a further campaign aimed at defining the IEO surface and edge finishing, the support flange geometry and the Titanium coating. Various edge finishing were installed on a prototype of the instrument occulting system and their performance in stray light reduction were compared. The support flange geometry was designed in order to reduce the overall weight, to control the thermal load and to accentuate its stray light suppression performance. The coating is a particularly delicate issue. A black coating is necessary in order to assess the stray light issues, typically critical for visible coronagraphs. Black coating of Titanium is not a standard process, thus several space qualified black coatings were experimented on Titanium and characterized. The impact of the IEO coatings was evaluated, the reflectivity and the BRDFs were measured and are addressed in the paper.

  5. Explaining Inverted-temperature Loops in the Quiet Solar Corona with Magnetohydrodynamic Wave-mode Conversion

    NASA Astrophysics Data System (ADS)

    Schiff, Avery J.; Cranmer, Steven R.

    2016-11-01

    Coronal loops trace out bipolar, arch-like magnetic fields above the Sun’s surface. Recent measurements that combine rotational tomography, extreme-ultraviolet imaging, and potential-field extrapolation have shown the existence of large loops with inverted-temperature profiles, i.e., loops for which the apex temperature is a local minimum, not a maximum. These “down loops” appear to exist primarily in equatorial quiet regions near solar minimum. We simulate both these and the more prevalent large-scale “up loops” by modeling coronal heating as a time-steady superposition of (1) dissipation of incompressible Alfvén wave turbulence and (2) dissipation of compressive waves formed by mode conversion from the initial population of Alfvén waves. We found that when a large percentage (>99%) of the Alfvén waves undergo this conversion, heating is greatly concentrated at the footpoints and stable “down loops” are created. In some cases we found loops with three maxima that are also gravitationally stable. Models that agree with the tomographic temperature data exhibit higher gas pressures for “down loops” than for “up loops,” which is consistent with observations. These models also show a narrow range of Alfvén wave amplitudes: 3 to 6 km s-1 at the coronal base. This is low in comparison to typical observed amplitudes of 20-30 km s-1 in bright X-ray loops. However, the large-scale loops we model are believed to compose a weaker diffuse background that fills much of the volume of the corona. By constraining the physics of loops that underlie quiescent streamers, we hope to better understand the formation of the slow solar wind.

  6. Versatile plasmonic-effects at the interface of inverted perovskite solar cells.

    PubMed

    Shalan, Ahmed Esmail; Oshikiri, Tomoya; Sawayanagi, Hiroki; Nakamura, Keisuke; Ueno, Kosei; Sun, Quan; Wu, Hui-Ping; Diau, Eric Wei-Guang; Misawa, Hiroaki

    2017-01-19

    Plasmonics is a highly promising approach to enhancing the light-harvesting properties of hybrid organic/inorganic perovskite solar cells. In the present work, our cells have a p-i-n inverted planar structure. An ultrathin NiO film with two different thicknesses of 5 and 10 nm prepared by a pulsed laser deposition process on an ITO substrate with a faceted and furrowed surface enabled the formation of a continuous and compact layer of well-crystallized CH3NH3PbI3via an anti-solvent chlorobenzene process. The coverage mechanism of the NiO film on the ITO was clearly demonstrated through the J-V and external quantum efficiency (EQE) curves. Moreover, the results demonstrated that the gold nanoislands (Au NIs) increased the power conversion efficiency to 5.1%, almost double that of the samples without Au NIs. This result is due to the excitation of surface plasmons, which is characterized by strong scattering and enhancement of the electric field in the vicinity of the Au NIs loaded at the interface between the NiO and perovskite films. Additionally, we observed an enhancement of the EQE at wavelengths shorter than the plasmon resonance peak. In the current state, we speculate that the plasmoelectric potential effect is considered to be a good explanation of the photocurrent enhancement at the off-resonance region. Our work provides good guidance for the design and fabrication of solar-energy-related devices employing NiO electrodes and plasmonic Au NIs.

  7. Photo annealing effect on p-doped inverted organic solar cell

    NASA Astrophysics Data System (ADS)

    Lafalce, Evan; Toglia, Patrick; Lewis, Jason E.; Jiang, Xiaomei

    2014-06-01

    We report the transient positive photo annealing effect in which over 600% boost of power conversion efficiency was observed in inverted organic photovoltaic devices (OPV) made from P3HT/PCBM by spray method, after 2 hrs of constant solar AM 1.5 irradiation at low temperature. This is opposite to usual photodegradation of OPV, and cannot be explained by thermal activation alone since the mere temperature effect could only account for 30% of the enhancement. We have investigated the temperature dependence, cell geometry, oxygen influence, and conclude that, for p-doped active layer at room temperature, the predominant mechanism is photo-desorption of O2, which eliminates electron traps and reduces space charge screening. As temperature decreases, thermal activation and deep trap-state filling start to show noticeable effect on the enhancement of photocurrent at intermediate low temperature (T = 125 K). At very low temperature, the dominant mechanism for photo annealing is trap-filling, which significantly reduces recombination between free and trapped carriers. At all temperature, photo annealing effect depends on illumination direction from cathode or anode. We also explained the large fluctuation of photocurrent by the capture/reemit of trapped electrons from shallow electron traps of O2- generated by photo-doping. Our study has demonstrated the dynamic process of photo-doping and photo-desorption, and shown that photo annealing in vacuum can be an efficient method to improve OPV device efficiency.

  8. Efficiency Enhancement of Inverted Structure Perovskite Solar Cells via Oleamide Doping of PCBM Electron Transport Layer.

    PubMed

    Xia, Fei; Wu, Qiliang; Zhou, Pengcheng; Li, Yi; Chen, Xiang; Liu, Qing; Zhu, Jun; Dai, Songyuan; Lu, Yalin; Yang, Shangfeng

    2015-06-24

    An amphiphilic surfactant, oleamide, was applied to dope the PCBM electron transport layer (ETL) of inverted structure perovskite solar cells (ISPSCs), resulting in a dramatic efficiency enhancement. Under the optimized oleamide doping ratio of 5.0 wt %, the power conversion efficiency of the CH3NH3PbIxCl(3-x) perovskite-based ISPSC device is enhanced from 10.05% to 12.69%, and this is primarily due to the increases of both fill factor and short-circuit current. According to the surface morphology study of the perovskite/PCBM bilayer film, oleamide doping improves the coverage of PCBM ETL onto the perovskite layer, and this is beneficial for the interfacial contact between the perovskite layer and the Ag cathode and consequently the electron transport from perovskite to the Ag cathode. Such an improved electron transport induced by oleamide doping is further evidenced by the impedance spectroscopic study, revealing the prohibited electron-hole recombination at the interface between the perovskite layer and the Ag cathode.

  9. Photo annealing effect on p-doped inverted organic solar cell

    SciTech Connect

    Lafalce, Evan; Toglia, Patrick; Lewis, Jason E.; Jiang, Xiaomei

    2014-06-28

    We report the transient positive photo annealing effect in which over 600% boost of power conversion efficiency was observed in inverted organic photovoltaic devices (OPV) made from P3HT/PCBM by spray method, after 2 hrs of constant solar AM 1.5 irradiation at low temperature. This is opposite to usual photodegradation of OPV, and cannot be explained by thermal activation alone since the mere temperature effect could only account for 30% of the enhancement. We have investigated the temperature dependence, cell geometry, oxygen influence, and conclude that, for p-doped active layer at room temperature, the predominant mechanism is photo-desorption of O{sub 2}, which eliminates electron traps and reduces space charge screening. As temperature decreases, thermal activation and deep trap-state filling start to show noticeable effect on the enhancement of photocurrent at intermediate low temperature (T = 125 K). At very low temperature, the dominant mechanism for photo annealing is trap-filling, which significantly reduces recombination between free and trapped carriers. At all temperature, photo annealing effect depends on illumination direction from cathode or anode. We also explained the large fluctuation of photocurrent by the capture/reemit of trapped electrons from shallow electron traps of O{sub 2}{sup -} generated by photo-doping. Our study has demonstrated the dynamic process of photo-doping and photo-desorption, and shown that photo annealing in vacuum can be an efficient method to improve OPV device efficiency.

  10. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Joong; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok; Kim, Han-Ki

    2015-10-01

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  11. Solution-processed hybrid cathode interlayer for inverted organic solar cells.

    PubMed

    Wu, Yulei; Zhang, Wenjun; Li, Xiaodong; Min, Chao; Jiu, Tonggang; Zhu, Yuejin; Dai, Ning; Fang, Junfeng

    2013-11-13

    A novel hybrid material CdS/2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (CdS·BCP) was prepared from the decomposition of its organic soluble precursor complex Cd(S2COEt)2·(BCP) by low-temperature treatment. CdS·BCP, which integrated the favorable properties of solvent durability, and high electron mobility of CdS as well as the good hole blocking property of BCP, was designed and developed as the interface modification material to improve electron collection in bulk heterojunction organic solar cells (OSCs). The inverted OSCs with CdS·BCP as buffer layer on ITO showed improved efficiency compared with the pure CdS or BCP. Devices with CdS·BCP as interlayer exhibited excellent stability, only 14.19% decay of power conversion efficiencies (PCEs) was observed (from 7.47% to 6.41%) after stored in glovebox for 3264 h (136 days). Our results demonstrate promising potentials of hybrid materials as the interface modification layers in OSCs, and provide new insights for the development of new interface modification materials in the future.

  12. Efficient flexible inverted small-bandgap organic solar cells with low-temperature zinc oxide interlayer

    NASA Astrophysics Data System (ADS)

    You, Hailong; Zhang, Junchi; Zhang, Chunfu; Lin, Zhenhua; Chen, Dazheng; Chang, Jingjing; Zhang, Jincheng

    2016-12-01

    In this work, we employ an aqueous solution-processed ZnO layer on indium tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) as an electron-selective layer in a flexible inverted organic solar cell (OSC) based on poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexy)carbonyl]thieno[3,4-b]thiophenediyl}):[6,6]-phenyl-C71-butyric acid methyl ester (PTB-7:PC71BM) blends. The electron-selective ZnO layer is prepared in a low-temperature process so that it can be compatible with a flexible substrate. An efficient flexible OSC with the configuration PET/ITO/ZnO/PTB7:PC71BM/MoO3/Ag with a power conversion efficiency (PCE) above 7.6% is obtained. The flexible device could maintain 85% of its initial PCE after 240 h when exposed under air ambient condition without any encapsulation and with a humidity of around 40%. This flexible device shows superior mechanical properties and could keep 93% of its original efficiency after 1000 bending cycles with a curvature radius of 0.8 cm. The results show that the ZnO layer deposited as the electron-selective layer through the aqueous solution is suitable for flexible OSCs.

  13. High Efficiency Inverted Organic Solar Cells with a Neutral Fulleropyrrolidine Electron-Collecting Interlayer.

    PubMed

    Xu, Weidong; Yan, Congfei; Kan, Zhipeng; Wang, Yang; Lai, Wen-Yong; Huang, Wei

    2016-06-08

    A novel fulleropyrrolidine derivative, named FPNOH, was designed, synthesized, and utilized as an efficient electron-collecting (EC) layer for inverted organic solar cells (i-OSCs). The grafted diethanolamino-polar moieties can not only trigger its function as an EC interlayer, but also induce orthogonal solubility that guarantees subsequent multilayer processing without interfacial mixing. A higher power conversion efficiency (PCE) value of 8.34% was achieved for i-OSC devices with ITO/FPNOH EC electrode, compared to that of the sol-gel ZnO based reference devices with an optimized PCE value of 7.92%. High efficiency exceeding 7.7% was still achieved even for the devices with a relatively thick FPNOH film (16.9 nm). It is worthwhile to mention that this kind of material exhibits less thickness dependent performance, in contrast to widely utilized p-type conjugated polyelectrolytes (CPEs) as well as the nonconjugated polyelectrolytes (NCPEs). Further investigation on illuminating intensity dependent parameters revealed the role of FPNOH in reducing interfacial trap-induced recombination at the ITO/active layer interface.

  14. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    SciTech Connect

    Kim, Hyo-Joong; Kim, Han-Ki; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok

    2015-10-15

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  15. Towards an understanding of light activation processes in titanium oxide based inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Chambon, S.; Destouesse, E.; Pavageau, B.; Hirsch, L.; Wantz, G.

    2012-11-01

    The light activation phenomenon in inverted P3HT:PCBM bulk heterojunction organic solar cells based on titanium oxide sublayer (TiOx) is characterized by fast acquisition of current-voltage (J-V) curves under light bias as function of time. TiOx layers were thermally treated under inert atmosphere at different temperatures prior active layer deposition and for every device an activation time was extracted. It is shown that the higher the TiOx annealing temperature, the faster the activation. The improvement of the overall device performances is also observed for devices with TiOx layers baked above 100 °C. The evolution of the characteristic of the organic semiconductors (OSC) device, from dielectric to diode, is attributed to the increase of TiOx conductivity by three orders of magnitude upon white light illumination. Additionally, devices based on baked TiOx present higher conductivity than those based on unbaked TiOx which would explain the gain in performances and the short activation time of the OSC. In order to understand the origin of the phenomenon, deactivation experiments were also performed under different conditions on OSC. The deactivation process was shown to be thermally dependent and fully reversible under inert atmosphere, which suggest that deep traps are responsible for the activation phenomenon. An optimal annealing temperature was found at 120 °C and gives a reasonable short activation time of approximately 1 min and photo conversion efficiency up to 4%.

  16. Lead-free inverted planar formamidinium tin triiodide perovskite solar cells achieving power conversion efficiencies up to 6.22%

    DOE PAGES

    Liao, Weiqiang; Zhao, Dewei; Yu, Yue; ...

    2016-08-29

    Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) of 5.41% ± 0.46% and a maximum PCE of 6.22% under forward voltage scan. Here, the PVSCs exhibit small photocurrent–voltage hysteresis and high reproducibility. The champion cell shows a steady-state efficiency of ≈6.00% for over 100 s.

  17. Self-assembly of interfacial and photoactive layers via one-step solution processing for efficient inverted organic solar cells.

    PubMed

    Kang, Hongkyu; Lee, Jinho; Jung, Suhyun; Yu, Kilho; Kwon, Sooncheol; Hong, Soonil; Kee, Seyoung; Lee, Seongyu; Kim, Dongwon; Lee, Kwanghee

    2013-12-07

    Vertically self-assembled bilayers with an interfacial bottom layer and a photoactive top layer are demonstrated via a single coating step of a blend composed of an amine-containing nonconjugated polyelectrolyte (NPE) and an organic electron donor-acceptor bulk heterojunction composite. The self-assembled NPE layer reduces the work function of an indium tin oxide (ITO) cathode, which leads to efficient inverted organic solar cells without any additional interface engineering of the ITO.

  18. Lead-Free Inverted Planar Formamidinium Tin Triiodide Perovskite Solar Cells Achieving Power Conversion Efficiencies up to 6.22%

    SciTech Connect

    Liao, Weiqiang; Zhao, Dewei; Yu, Yue; Grice, Corey R.; Wang, Changlei; Cimaroli, Alexander J.; Schulz, Philip; Meng, Weiwei; Zhu, Kai; Xiong, Ren-Gen; Yan, Yanfa

    2016-11-09

    Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) of 5.41% +/- 0.46% and a maximum PCE of 6.22% under forward voltage scan. The PVSCs exhibit small photocurrent-voltage hysteresis and high reproducibility. The champion cell showed a steady-state efficiency of almost equal to 6.00% for over 100 s.

  19. Increasing the efficiency of polymer solar cells by silicon nanowires.

    PubMed

    Eisenhawer, B; Sensfuss, S; Sivakov, V; Pietsch, M; Andrä, G; Falk, F

    2011-08-05

    Silicon nanowires have been introduced into P3HT:[60]PCBM solar cells, resulting in hybrid organic/inorganic solar cells. A cell efficiency of 4.2% has been achieved, which is a relative improvement of 10% compared to a reference cell produced without nanowires. This increase in cell performance is possibly due to an enhancement of the electron transport properties imposed by the silicon nanowires. In this paper, we present a novel approach for introducing the nanowires by mixing them into the polymer blend and subsequently coating the polymer/nanowire blend onto a substrate. This new onset may represent a viable pathway to producing nanowire-enhanced polymer solar cells in a reel to reel process.

  20. Morphology Studies of Polymer Bulk Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Moon, Ji Sun

    Energy is a prerequisite for creating and sustaining life. The need for energy increases globally as the world's population and economy grow. However, conventional energy sources---fossil fuels---generate carbon dioxide and contribute to global warming, perhaps the most serious environmental problem of our time. Carbon dioxide-free energy is required to stop global warming. Polymer solar cells have been attracting a great deal of interest as a source of renewable energy with a great potential for low cost. Polymer bulk heterojunction (BHJ) solar cells have been greatly improved; the power conversion efficiency is already up to 9.2% making the future of the polymer solar cell very promising. This thesis is a study of the morphology of polymer:fullerene BHJ, one of the most critical and challenging parts of high efficiency polymer solar cells. To discover the morphology, cross-section as well as top-down transmission electron microscopy were used. The contrast was achieved by utilizing phase contrast microscopy. Thermal annealing, dependence of BHJ thickness, processing additives, solution sequential process and solution sequential process with the use of cosolvent that affects/controls the BHJ morphology are studied in detail.

  1. Polymer Solar Cells: Solubility Controls Fiber Network Formation.

    PubMed

    van Franeker, Jacobus J; Heintges, Gaël H L; Schaefer, Charley; Portale, Giuseppe; Li, Weiwei; Wienk, Martijn M; van der Schoot, Paul; Janssen, René A J

    2015-09-16

    The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent-cosolvent mixture. The nanoscale dimensions of the polymer-fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.

  2. Comparison of arsenide and phosphide based graded buffer layers used in inverted metamorphic solar cells

    NASA Astrophysics Data System (ADS)

    Zakaria, A.; King, Richard R.; Jackson, M.; Goorsky, M. S.

    2012-07-01

    The effect of graded buffer layer (GBL) composition on inverted metamorphic 1.1-eV In0.24Ga0.76As single-junction solar cells, with applications as a subcell in high-efficiency multijunction solar cells, is investigated. In experiment A, AlxInyGa(1-x-y)As was used as a GBL to transition from the GaAs substrate lattice constant to that of the In0.24Ga0.76As cell. In experiment B, In1-xGaxP was employed. Both GBLs were deposited using growth conditions optimized for lattice-matched growth. Reciprocal space maps showed that the InGaAs cell was fully relaxed in both experiments. They also revealed that the AlInGaAs GBL relaxed very quickly after the start of growth (<0.1 μm). The InGaP GBL on the other hand remained partially strained throughout its structure and full relaxation was only achieved after growth of the InGaAs cell. Atomic force microscopy of the surface of the AlInGaAs GBL showed typical cross-hatch morphology with a roughness of 8.9 nm. The surface of the InGaP GBL was much rougher at 18.3 nm with unusual morphology, likely due to 3D island formation due to unrelieved strain. These findings were confirmed by transmission electron microscopy where the InGaAs cell of experiment A was largely free of imperfections with a defect density of 1.1 × 106 cm-2. Experiment B had defects readily seen throughout the GBL and the InGaAs cell above had a defect density of 1.5 × 109 cm-2. The hardness of the AlInGaAs GBL surface was measured to be 7.2 GPa and exhibited an indentation size effect. The hardness of the InGaP GBL surface was 10.2 GPa regardless of the depth of penetration of the indenter. The lack of indentation size effect in InGaP is due to the high density of dislocations already present in the material due to unrelieved strain. Solar cells fabricated from experiment A wafers exhibited excellent band gap-voltage offset Woc = (Eg/q) - Voc of 0.414 V. Cells from experiment B exhibited a poor Woc of 0.686 V, most likely due to the threading dislocations

  3. Hydrogenated amorphous silicon solar cell on organic polymer substrate

    NASA Astrophysics Data System (ADS)

    Okaniwa, H.; Nakatani, K.; Asano, M.; Suzuki, K.; Yano, M.; Hirasaka, M.; Hamakawa, Y.

    1983-01-01

    The basic properties of a solar cell based on an organic polymer film are reported and the characteristics peculiar to the organic polymer substrate are discussed. The electrical conductivity and activation energy of doped a-Si:H deposited on glass substrate at various temperatures and under various RF powers are shown. The open circuit voltage, short circuit current, fill factor, and conversion efficiency of solar cells on polyimide film and SUS plate in sunlight of 92.5 mW/sq cm are given, as are relative characteristic values of solar cells fabricated simultaneously on various substrates under that illumination. Compositional profiles of p-i-n structure solar cells on sp-SUS over SUS plate and SUS plate substrates are shown along with surface morphology of SUS plate, SUS/sp-SUS, and polyimide/sp-SUS substrates.

  4. Azulene methacrylate polymers: synthesis, electronic properties, and solar cell fabrication.

    PubMed

    Puodziukynaite, Egle; Wang, Hsin-Wei; Lawrence, Jimmy; Wise, Adam J; Russell, Thomas P; Barnes, Michael D; Emrick, Todd

    2014-08-06

    We report the synthesis of novel azulene-substituted methacrylate polymers by free radical polymerization, in which the azulene moieties represent hydrophobic dipoles strung pendant to the polymer backbone and impart unique electronic properties to the polymers. Tunable optoelectronic properties were realized by adjusting the azulene density, ranging from homopolymers (having one azulene group per repeat unit) to copolymers in which the azulene density was diluted with other pendant groups. Treating these polymers with organic acids revealed optical and excitonic behavior that depended critically on the azulene density along the polymer chain. Copolymers of azulene with zwitterionic methacrylates proved useful as cathode modification layers in bulk-heterojunction solar cells, where the relative azulene content affected the device metrics and the power conversion efficiency reached 7.9%.

  5. Development of polymer film solar collectors: A status report

    NASA Astrophysics Data System (ADS)

    Wilhelm, W. G.; Andrews, J. W.

    1982-08-01

    Solar energy collector panels using polymer film and laminate technology were developed which demonstrate low cost and high thermal performance for residential and commercial applications. This device uses common water in the absorber/heat exchanger which is constructed with polymer film adhesively laminated to aluminum foil as the outer surfaces. Stressed polymer films are also used for the outer window and back surface of the panel forming a high strength structural composite. Rigid polymer foam complements the design by contributing insulation and structural definition. This design resulted in very low weight (3.5 kg/m(2)), potentially very low manufacturing cost (aprox. $11/m(2)), and high thermal performance. The development of polymer materials for this technology will be a key to early commercial success.

  6. Recent developments of hybrid nanocrystal/polymer bulk heterojunction solar cells.

    PubMed

    Tang, Aiwei; Qu, Shengchun; Teng, Feng; Hou, Yanbing; Wang, Yongsheng; Wang, Zhanguo

    2011-11-01

    Hybrid nanocrystal/polymer bulk heterojunction (BHJ) solar cells consisting of colloidal inorganic semiconductor nanocrystals as electron acceptors and conjugated polymers as electron donors have been extensively investigated in the past few decades, which take advantage of the strongpoints of the inorganic semiconductor nanocrystals and the conjugated polymers. Currently, power conversion efficiency over 3% for the hybrid nanocrystal/polymer BHJ solar cells has been achieved. Although the development of hybrid nanocrystal/polymer BHJ solar cells lacks behind the international level, great progress in this research field has been made in China. In this article, we first review the general fabrication techniques and general working principles of hybrid nanocrystal/polymer BHJ solar cells. Secondly, we highlight the international and national developments of hybrid nanocrystal/polymer BHJ solar cells based on different types of semiconductor nanocrystals and conjugated polymers. Finally, we give a future outlook for the hybrid nanocrystal/polymer BHJ solar cells in the worldwide.

  7. Novel Solvent-free Perovskite Deposition in Fabrication of Normal and Inverted Architectures of Perovskite Solar Cells.

    PubMed

    Nejand, Bahram Abdollahi; Gharibzadeh, Saba; Ahmadi, Vahid; Shahverdi, H Reza

    2016-09-19

    We introduced a new approach to deposit perovskite layer with no need for dissolving perovskite precursors. Deposition of Solution-free perovskite (SFP) layer is a key method for deposition of perovskite layer on the hole or electron transport layers that are strongly sensitive to perovskite precursors. Using deposition of SFP layer in the perovskite solar cells would extend possibility of using many electron and hole transport materials in both normal and invert architectures of perovskite solar cells. In the present work, we synthesized crystalline perovskite powder followed by successful deposition on TiO2 and cuprous iodide as the non-sensitve and sensitive charge transport layers to PbI2 and CH3NH3I solution in DMF. The post compressing step enhanced the efficiency of the devices by increasing the interface area between perovskite and charge transport layers. The 9.07% and 7.71% cell efficiencies of the device prepared by SFP layer was achieved in respective normal (using TiO2 as a deposition substrate) and inverted structure (using CuI as deposition substrate) of perovskite solar cell. This method can be efficient in large-scale and low cost fabrication of new generation perovskite solar cells.

  8. Novel Solvent-free Perovskite Deposition in Fabrication of Normal and Inverted Architectures of Perovskite Solar Cells

    PubMed Central

    Nejand, Bahram Abdollahi; Gharibzadeh, Saba; Ahmadi, Vahid; Shahverdi, H. Reza

    2016-01-01

    We introduced a new approach to deposit perovskite layer with no need for dissolving perovskite precursors. Deposition of Solution-free perovskite (SFP) layer is a key method for deposition of perovskite layer on the hole or electron transport layers that are strongly sensitive to perovskite precursors. Using deposition of SFP layer in the perovskite solar cells would extend possibility of using many electron and hole transport materials in both normal and invert architectures of perovskite solar cells. In the present work, we synthesized crystalline perovskite powder followed by successful deposition on TiO2 and cuprous iodide as the non-sensitve and sensitive charge transport layers to PbI2 and CH3NH3I solution in DMF. The post compressing step enhanced the efficiency of the devices by increasing the interface area between perovskite and charge transport layers. The 9.07% and 7.71% cell efficiencies of the device prepared by SFP layer was achieved in respective normal (using TiO2 as a deposition substrate) and inverted structure (using CuI as deposition substrate) of perovskite solar cell. This method can be efficient in large-scale and low cost fabrication of new generation perovskite solar cells. PMID:27640991

  9. Novel Solvent-free Perovskite Deposition in Fabrication of Normal and Inverted Architectures of Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Nejand, Bahram Abdollahi; Gharibzadeh, Saba; Ahmadi, Vahid; Shahverdi, H. Reza

    2016-09-01

    We introduced a new approach to deposit perovskite layer with no need for dissolving perovskite precursors. Deposition of Solution-free perovskite (SFP) layer is a key method for deposition of perovskite layer on the hole or electron transport layers that are strongly sensitive to perovskite precursors. Using deposition of SFP layer in the perovskite solar cells would extend possibility of using many electron and hole transport materials in both normal and invert architectures of perovskite solar cells. In the present work, we synthesized crystalline perovskite powder followed by successful deposition on TiO2 and cuprous iodide as the non-sensitve and sensitive charge transport layers to PbI2 and CH3NH3I solution in DMF. The post compressing step enhanced the efficiency of the devices by increasing the interface area between perovskite and charge transport layers. The 9.07% and 7.71% cell efficiencies of the device prepared by SFP layer was achieved in respective normal (using TiO2 as a deposition substrate) and inverted structure (using CuI as deposition substrate) of perovskite solar cell. This method can be efficient in large-scale and low cost fabrication of new generation perovskite solar cells.

  10. Naphthalene diimide-difluorobenzene-based polymer acceptors for all-polymer solar cells.

    PubMed

    Deng, Ping; Ho, Carr Hoi Yi; Lu, Yong; Li, Ho-Wa; Tsang, Sai-Wing; So, Shu Kong; Ong, Beng S

    2017-03-18

    Regio-random (P1) and -regular (P2) difluorobenzene-naphthalene-containing polymer acceptors were developed for bulk-heterojunction all-polymer solar cells (all-PSCs). P2 exhibited significantly higher crystallinity in thin films, providing high spectral absorptivity and electron mobility than P1. When used in all-PSC devices, P2 afforded a respectably higher power conversion efficiency of over 5%.

  11. Alcohol-soluble Star-shaped Oligofluorenes as Interlayer for High Performance Polymer Solar Cells

    PubMed Central

    Zou, Yang; He, Zhicai; Zhao, Baofeng; Liu, Yuan; Yang, Chuluo; Wu, Hongbin; Cao, Yong

    2015-01-01

    Two star-shaped oligofluorenes with hexakis(fluoren-2-yl)benzene as core are designed and sythesized for interfacial materials in polymer solar cell. Diethanolamino groups are attached to the side chain of fluorene units for T0-OH and T1-OH to enable the alcohol solubility, and additional hydrophobic n-hexyl chains are also grafted on the increased fluorene arms for T1-OH. In conventional device with PCDTBT/PC71BM as active layer, a 50% enhanced PCE is obtained by incorporating T0-OH and T1-OH as the interlayer compared with device without interlayer. By optimizing the active material with PTB7 and with the inverted device structure, a maximum PCE of 9.30% is achieved, which is among the highest efficiencies for PTB7 based polymer solar cells. The work function of modified electrode, the surface morphology and the suraface properties are systematically studied. By modifying the structures of the star-shaped molecules, a balance between the hydrophobic and hydrophilic property is finely tuned, and thus facilitate the interlayer for high performance of PSCs. PMID:26612688

  12. Water Splitting with Series-Connected Polymer Solar Cells.

    PubMed

    Esiner, Serkan; van Eersel, Harm; van Pruissen, Gijs W P; Turbiez, Mathieu; Wienk, Martijn M; Janssen, René A J

    2016-10-12

    We investigate light-driven electrochemical water splitting with series-connected polymer solar cells using a combined experimental and modeling approach. The expected maximum solar-to-hydrogen conversion efficiency (ηSTH) for light-driven water splitting is modeled for two, three, and four series-connected polymer solar cells. In the modeling, we assume an electrochemical water splitting potential of 1.50 V and a polymer solar cell for which the external quantum efficiency and fill factor are both 0.65. The minimum photon energy loss (Eloss), defined as the energy difference between the optical band gap (Eg) and the open-circuit voltage (Voc), is set to 0.8 eV, which we consider a realistic value for polymer solar cells. Within these approximations, two series-connected single junction cells with Eg = 1.73 eV or three series-connected cells with Eg = 1.44 eV are both expected to give an ηSTH of 6.9%. For four series-connected cells, the maximum ηSTH is slightly less at 6.2% at an optimal Eg = 1.33 eV. Water splitting was performed with series-connected polymer solar cells using polymers with different band gaps. PTPTIBDT-OD (Eg = 1.89 eV), PTB7-Th (Eg = 1.56 eV), and PDPP5T-2 (Eg = 1.44 eV) were blended with [70]PCBM as absorber layer for two, three, and four series-connected configurations, respectively, and provide ηSTH values of 4.1, 6.1, and 4.9% when using a retroreflective foil on top of the cell to enhance light absorption. The reasons for deviations with experiments are analyzed and found to be due to differences in Eg and Eloss. Light-driven electrochemical water splitting was also modeled for multijunction polymer solar cells with vertically stacked photoactive layers. Under identical assumptions, an ηSTH of 10.0% is predicted for multijunction cells.

  13. High efficiency all-polymer tandem solar cells

    PubMed Central

    Yuan, Jianyu; Gu, Jinan; Shi, Guozheng; Sun, Jianxia; Wang, Hai-Qiao; Ma, Wanli

    2016-01-01

    In this work, we have reported for the first time an efficient all-polymer tandem cell using identical sub-cells based on P2F-DO:N2200. A high power conversion efficiency (PCE) of 6.70% was achieved, which is among the highest efficiencies for all polymer solar cells and 43% larger than the PCE of single junction cell. The largely improved device performance can be mainly attributed to the enhanced absorption of tandem cell. Meanwhile, the carrier collection in device remains efficient by optimizing the recombination layer and sub-cell film thickness. Thus tandem structure can become an easy approach to effectively boost the performance of current all polymer solar cells. PMID:27226354

  14. Potential use of photovolatile polymers in solar sails

    NASA Astrophysics Data System (ADS)

    Allred, Ronald E.; Harrah, Larry A.; Pollack, Steven K.; Willis, Paul B.

    2002-01-01

    Extremely thin films are required for solar sails: possibly too fragile for handling, storage, and deployment. This work explores the use of photovolatile polymer coatings for the reinforcement of solar sails. The concept is that thick polymer films may be used to support and deploy thin films, but then decompose in sunlight (photo-degrade) and evaporate into space leaving the fully deployed sail at a very low mass. Additionally, these remarkable polymers degrade in the presence of (solar) ultraviolet light to result in gaseous products. As the volatile gas departs from the substrate, a high percentage of mass is lost until an ultra-thin solar sail remains. In addition to mass loss, the photovolatile coating produces a thrust that augments the photon momentum propulsion and results in a ``propellantless'' system with enhanced specific impulse. The coating also provides the strength and durability to protect the fragile sail film during the packing, launching and deployment phases of the mission. This approach will result in films with areal densities of 1 to 5 grams per square meter, high durability, and passive propulsion capability. The developed technology will enable the fabrication of solar sails and also possibly sunshades booms, and other inflatable spacecraft currently included in programs coming out of many organizations. .

  15. Simulation of current-voltage curves for inverted planar structure perovskite solar cells using equivalent circuit model with inductance

    NASA Astrophysics Data System (ADS)

    Cojocaru, Ludmila; Uchida, Satoshi; Jayaweera, Piyankarage V. V.; Kaneko, Shoji; Toyoshima, Yasutake; Nakazaki, Jotaro; Kubo, Takaya; Segawa, Hiroshi

    2017-02-01

    Physical modeling of hysteretic behavior in current-voltage (I-V) curves of perovskite solar cells (PSCs) is necessary for further improving their power conversion efficiencies (PCEs). The reduction of hysteresis in inverted planar structure PSCs (p-PSCs) has been achieved by using a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) layer. In the cases, the opposite trend of the I-V hysteresis has been observed where the forward scan shows slightly higher efficiency than the reverse scan. In this paper, an equivalent circuit model with inductance is proposed. This model consists of a Schottky diode involving a parasitic inductance focusing PCBM/Al(Ca) interface and accurately represents the opposite trend of the I-V hysteresis of the p-PSC with an inverted structure.

  16. Real Time Selective Harmonic Minimization for Multilevel Inverters Connected to Solar Panels Using Artificial Neural Network Angle Generation

    SciTech Connect

    Tolbert, Leon M; Ozpineci, Burak; Filho, Faete; Cao, Yue

    2011-01-01

    This work approximates the selective harmonic elimination problem using artificial neural networks (ANNs) to generate the switching angles in an 11-level full-bridge cascade inverter powered by five varying dc input sources. Each of the five full bridges of the cascade inverter was connected to a separate 195-W solar panel. The angles were chosen such that the fundamental was kept constant and the low-order harmonics were minimized or eliminated. A nondeterministic method is used to solve the system for the angles and to obtain the data set for the ANN training. The method also provides a set of acceptable solutions in the space where solutions do not exist by analytical methods. The trained ANN is a suitable tool that brings a small generalization effect on the angles' precision and is able to perform in real time (50-/60-Hz time window).

  17. A polymer scaffold for self-healing perovskite solar cells

    PubMed Central

    Zhao, Yicheng; Wei, Jing; Li, Heng; Yan, Yin; Zhou, Wenke; Yu, Dapeng; Zhao, Qing

    2016-01-01

    Advancing of the lead halide perovskite solar cells towards photovoltaic market demands large-scale devices of high-power conversion efficiency, high reproducibility and stability via low-cost fabrication technology, and in particular resistance to humid environment for long-time operation. Here we achieve uniform perovskite film based on a novel polymer-scaffold architecture via a mild-temperature process. These solar cells exhibit efficiency of up to ∼16% with small variation. The unencapsulated devices retain high output for up to 300 h in highly humid environment (70% relative humidity). Moreover, they show strong humidity resistant and self-healing behaviour, recovering rapidly after removing from water vapour. Not only the film can self-heal in this case, but the corresponding devices can present power conversion efficiency recovery after the water vapour is removed. Our work demonstrates the value of cheap, long chain and hygroscopic polymer scaffold in perovskite solar cells towards commercialization. PMID:26732479

  18. A polymer scaffold for self-healing perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Zhao, Yicheng; Wei, Jing; Li, Heng; Yan, Yin; Zhou, Wenke; Yu, Dapeng; Zhao, Qing

    2016-01-01

    Advancing of the lead halide perovskite solar cells towards photovoltaic market demands large-scale devices of high-power conversion efficiency, high reproducibility and stability via low-cost fabrication technology, and in particular resistance to humid environment for long-time operation. Here we achieve uniform perovskite film based on a novel polymer-scaffold architecture via a mild-temperature process. These solar cells exhibit efficiency of up to ~16% with small variation. The unencapsulated devices retain high output for up to 300 h in highly humid environment (70% relative humidity). Moreover, they show strong humidity resistant and self-healing behaviour, recovering rapidly after removing from water vapour. Not only the film can self-heal in this case, but the corresponding devices can present power conversion efficiency recovery after the water vapour is removed. Our work demonstrates the value of cheap, long chain and hygroscopic polymer scaffold in perovskite solar cells towards commercialization.

  19. Inverted organic solar cells based on Cd-doped TiO2 as an electron extraction layer

    NASA Astrophysics Data System (ADS)

    Ranjitha, A.; Muthukumarasamy, N.; Thambidurai, M.; Velauthapillai, Dhayalan; Madhan Kumar, A.; Gasem, Zuhair M.

    2014-10-01

    Nanocrystalline Cd-doped TiO2 thin films have been prepared by sol-gel method. X-ray diffraction analysis reveals that TiO2 and Cd-doped TiO2 nanocrystalline thin films are of anatase phase. The average grain size of TiO2 and Cd-doped TiO2 nanocrystalline thin films was found to lie in the range of 15-18 nm. Solar cells have been fabricated with a device structure of ITO/Cd-doped TiO2/P3HT:PC71BM/MoO3/Al configuration. The power conversion efficiency of the inverted organic solar cell with Cd-doped TiO2 is 3.06% and is higher than that of TiO2 based organic solar cell (2.64%).

  20. Medium Bandgap Conjugated Polymer for High Performance Polymer Solar Cells Exceeding 9% Power Conversion Efficiency.

    PubMed

    Jung, Jae Woong; Liu, Feng; Russell, Thomas P; Jo, Won Ho

    2015-12-02

    Two medium-bandgap polymers composed of benzo[1,2-b:4,5-b']dithiohpene and 2,1,3-benzothiadiazole with 6-octyl-thieno[3,2-b]thiophene as a π-bridge unit are synthesized and their photovoltaic properties are analyzed. The two polymers have deep highest occupied molecular orbital energy levels, high crystallinity, optimal bulk-heterojunction morphology, and efficient charge transport, resulting in a power conversion efficiency of as high as 9.44% for a single-junction polymer solar-cell device. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A plasticized polymer-electrolyte-based photoelectrochemical solar cell

    SciTech Connect

    Mao, D.; Ibrahim, M.A.; Frank, A.J.

    1998-01-01

    A photoelectrochemical solar cell based on an n-GaAs/polymer-redox-electrolyte junction is reported. Di(ethylene glycol) ethyl ether acrylate containing ferrocene as a redox species and benzoin methyl ether as a photoinitiator is polymerized in situ. Propylene carbonate is used as a plasticizer to improve the conductivity of the polymer redox electrolyte. For thin (1 {micro}m) polymer electrolytes, the series resistance of the cell is negligible. However, the short-circuit photocurrent density of the cell at light intensities above 10 mW/cm{sup 2} is limited by mass transport of redox species within the polymer matrix. At a light intensity of 70 mW/cm{sup 2}, a moderate light-to-electrical energy conversion efficiency (3.1%) is obtained. The interfacial charge-transfer properties of the cell in the dark and under illumination are studied.

  2. Quasi Solid Polymer Electrolytes for Dye Sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Dissanayake, M. A. K. Lakshman

    2013-07-01

    Dye-sensitized solar cell (DSSC) has been considered as an alternative to the conventional silicon solar cell because of low cost, easy fabrication and relatively high conversion efficiency. A DSSC consists of a dye-sensitized nanoparticulated TiO2 electrode, an electrolyte containing redox couple and a Pt coated counter electrode. Such solar cells based on an I-/I3- redox couple in an organic solvent usually have conversion efficiencies reaching around 11%. However, a major drawback of these solution based solar cells, originally developed by Gratzel and coworkers is the lack of long-term stability due to liquid leakage, usage of volatile liquids such as acetonitrile, electrode corrosion, and photodecomposition of the dye in the solvent medium. Therefore considerable research efforts have been made in recent years to replace the liquid electrolytes with solid polymer or quasi-solid polymer (gel) electrolytes. Among these approaches, the use of gel polymer electrolytes appears to give rise to successful results in terms of conversion efficiency. Conventional poly (ethylene oxide)(PEO)-based solid polymer electrolytes exhibit poor ionic conductivities at room temperature, which is not sufficient for practical applications. Therefore, most of the recent studies have been directed to the preparation and characterization of gel polymer electrolytes which exhibit higher ionic conductivity at ambient temperature while maintain quai-solid structure. These gel polymer electrolytes prepared by incorporating a liquid electrolyte into a matrix polymer such as polyacrylonitrile(PAN), poly(vinylidene fluoride)(PVdF), poly (methyl methacrylate) (PMMA) and PEO have been employed in quasi-solid-state DSSCs to achieve power conversion efficiencies of more than 5%. Significant improvements have been achieved in recent years by modifications of the electrolytes by optimizing the ionic salt, introducing additives such as inorganic nanofillers, organic molecules and ionic liquids in

  3. Origin of Open-Circuit Voltage Loss in Polymer Solar Cells and Perovskite Solar Cells.

    PubMed

    Kim, Hyung Do; Yanagawa, Nayu; Shimazaki, Ai; Endo, Masaru; Wakamiya, Atsushi; Ohkita, Hideo; Benten, Hiroaki; Ito, Shinzaburo

    2017-06-14

    Herein, the open-circuit voltage (VOC) loss in both polymer solar cells and perovskite solar cells is quantitatively analyzed by measuring the temperature dependence of VOC to discuss the difference in the primary loss mechanism of VOC between them. As a result, the photon energy loss for polymer solar cells is in the range of about 0.7-1.4 eV, which is ascribed to temperature-independent and -dependent loss mechanisms, while that for perovskite solar cells is as small as about 0.5 eV, which is ascribed to a temperature-dependent loss mechanism. This difference is attributed to the different charge generation and recombination mechanisms between the two devices. The potential strategies for the improvement of VOC in both solar cells are further discussed on the basis of the experimental data.

  4. Experimental Evaluation of Load Rejection Over-Voltage from Grid-Tied Solar Inverters

    SciTech Connect

    Nelson, Austin; Hoke, Anderson; Chakraborty, Sudipta; Ropp, Michael; Chebahtah, Justin; Wang, Trudie; Zimmerly, Brian

    2015-06-14

    This paper investigates the impact of load rejection over-voltage (LRO) from commercially available grid-tied photovoltaic (PV) inverters. LRO can occur when a breaker opens and the power output from a distributed energy resource (DER) exceeds the load. Simplified models of current-controlled inverters can over-predict LRO magnitudes, thus it is useful to quantify the effect through laboratory testing. The load rejection event was replicated using a hardware testbed at the National Renewable Energy Laboratory (NREL), and a set of commercially available PV inverters was tested to quantify the impact of LRO for a range of generation-to-load ratios. The magnitude and duration of the over-voltage events are reported in this paper along with a discussion of characteristic inverter output behavior. The results for the inverters under test showed that maximum over-voltage magnitudes were less than 200% of nominal voltage, and much lower in many test cases. These research results are important because utilities that interconnect inverter-based DER need to understand their characteristics under abnormal grid conditions.

  5. Realization of high efficiency inverted polymer photovoltaic cells for roll-to-roll application

    NASA Astrophysics Data System (ADS)

    So, Franky

    2012-09-01

    Recent progress on solution processable polymeric photovoltaic (PV) cells has drawn a lot of attention in both industry and academia. Over 8% power conversion efficiencies (PCE) have been demonstrated. In order to realize the application of organic PV, high efficiency (~10%) is not the only criteria, but also the low material and processing costs and device stability. For mostly demonstrated laboratory high efficiency cells, the devices consists of high work-function bottom anode and low work-function top cathode, e.g. Al, which is well known that the oxidation of the cathode accelerates the device degradation. In order to accommodate the issue, recent effort has been focusing on developing inverted structure. In such case, the low work-function metal can be eliminated by using a composite electrode with a work-function modifying interlayer. Solution derived TiOx and ZnO nano-particles are widely used as the interlayer. It has been shown such interlayer can efficiently reduce the work-function of bottom ITO electrode and significantly improve the device stability. However, it is often found that the inverted cells processed a lower performance than their counterpart with conventional structure. Such low efficiency is caused by the surface trap states of the nanoparticles which introduce charge recombination.

  6. Polymer-fullerene bulk heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Deibel, Carsten; Dyakonov, Vladimir

    2010-09-01

    Organic solar cells have the potential to be low-cost and efficient solar energy converters, with a promising energy balance. They are made of carbon-based semiconductors, which exhibit favourable light absorption and charge generation properties, and can be manufactured by low temperature processes such as printing from solvent-based inks, which are compatible with flexible plastic substrates or even paper. In this review, we will present an overview of the physical function of organic solar cells, their state-of-the-art performance and limitations, as well as novel concepts to achieve a better material stability and higher power conversion efficiencies. We will also briefly review processing and cost in view of the market potential.

  7. Laser-patterned functionalized CVD-graphene as highly transparent conductive electrodes for polymer solar cells.

    PubMed

    La Notte, Luca; Villari, Enrica; Palma, Alessandro Lorenzo; Sacchetti, Alberto; Michela Giangregorio, Maria; Bruno, Giovanni; Di Carlo, Aldo; Bianco, Giuseppe Valerio; Reale, Andrea

    2017-01-07

    A five-layer (5L) graphene on a glass substrate has been demonstrated as a transparent conductive electrode to replace indium tin oxide (ITO) in organic photovoltaic devices. The required low sheet resistance, while maintaining high transparency, and the need of a wettable surface are the main issues. To overcome these, two strategies have been applied: (i) the p-doping of the multilayer graphene, thus reaching 25 Ω□(-1) or (ii) the O2-plasma oxidation of the last layer of the 5L graphene that results in a contact angle of 58° and a sheet resistance of 134 Ω□(-1). A Nd:YVO4 laser patterning has been implemented to realize the desired layout of graphene through an easy and scalable way. Inverted Polymer Solar Cells (PSCs) have been fabricated onto the patterned and modified graphene. The use of PEDOT:PSS has facilitated the deposition of the electron transport layer and a non-chlorinated solvent (ortho-xylene) has been used in the processing of the active layer. It has been found that the two distinct functionalization strategies of graphene have beneficial effects on the overall performance of the devices, leading to an efficiency of 4.2%. Notably, this performance has been achieved with an active area of 10 mm(2), the largest area reported in the literature for graphene-based inverted PSCs.

  8. Solution processed Al-doped ZnO nanoparticles/TiOx composite for highly efficient inverted organic solar cells.

    PubMed

    Gadisa, Abay; Hairfield, Travis; Alibabaei, Leila; Donley, Carrie L; Samulski, Edward T; Lopez, Rene

    2013-09-11

    We investigated the electrical properties of solution processed Al-doped ZnO (AZO) nanoparticles, stabilized by mixing with a TiOx complex. Thin solid films cast from the solution of AZO-TiOx (AZOTi) (Ti/Zn ∼0.4 in the bulk and ∼0.8 on its surface) is processable in inert environment, without a need for either ambient air exposure for hydrolysis or high temperature thermal annealing commonly applied to buffer layers of most metal-oxides. It was found that the electronic structure of AZOTi matches the electronic structure of several electron acceptor and donor materials used in organic electronic devices, such as solar cells. Inverted solar cells employing a bulk heterojunction film of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester, cast on an indium-tin-oxide/AZOTi electrode, and capped with a tungsten oxide/aluminum back electrode, give rise to a nearly 70% fill factor and an optimized open-circuit voltage as a result of efficient hole blocking behavior of AZOTi. The resulting electron collecting/blocking capability of this material solves crucial interfacial recombination issues commonly observed at the organic/metal-oxide interface in most inverted organic bulk heterojunction solar cells.

  9. N-Butyl acrylate polymer composition for solar cell encapsulation and method

    NASA Technical Reports Server (NTRS)

    Gupta, Amitava (Inventor); Ingham, John D. (Inventor); Yavrouian, Andre H. (Inventor)

    1983-01-01

    A polymer syrup for encapsulating solar cell assemblies. The syrup includes uncrosslinked poly(n-butyl)acrylate dissolved in n-butyl acrylate monomer. Preparation of the poly(n-butyl)acrylate and preparation of the polymer syrup is disclosed. Methods for applying the polymer syrup to solar cell assemblies as an encapsulating pottant are described. Also included is a method for solar cell construction utilizing the polymer syrup as a dual purpose adhesive and encapsulating material.

  10. Alternating polyfluorenes collect solar light in polymer photovoltaics.

    PubMed

    Inganäs, Olle; Zhang, Fengling; Andersson, Mats R

    2009-11-17

    The effort to improve the energy conversion efficiency of polymer solar cells has led to the design of novel donor polymers. To improve open circuit photovoltages (OCVs) and the spectral coverage of the solar spectrum, researchers have looked for materials with high HOMO values, an easily modified electronic structure, and sufficient electronic transport within the polymers. One advance in design from our laboratories has been the development of a class of alternating polyfluorene copolymers (APFOs), which can be combined with fullerenes to make bulk heterojunction materials for photovoltaic conversion. This Account describes copolymers of fluorene that we designed to expand the range the optical absorption of solar cells to include wavelengths out to 1000 nm. In most cases, we combine these polymers with acceptors from the fullerene family, typically the phenyl C(61) butyric acid methyl ester (PCBM) molecule, to generate solar cell materials. The synthesis of alternating copolymers of fluorene with various donor-acceptor-donor elements provides the opportunity to shift both HOMO and LUMO, which we have followed by electrochemical spectroscopy. Moving the LUMO of the APFOs farther from the vacuum level eventually leads to a situation where the driving force for photo-induced charge transfer from polymer donor to fullerene acceptor goes to zero, resulting in inefficient charge generation. Moving the HOMO level closer to the vacuum level reduces the OCV of devices made from bulk heterojunction blends. As we move the bandgap toward lower energies and increase the overlap of optical absorption with the solar spectrum, both these events eventually occur. In devices based on these APFO/fullerene blends, the performance depends on the OCV, the photocurrent under solar illumination, and the fill factor. The fill factor is influenced by electrical transport and charge generation. Optimizing these parameters requires new solutions to the perennial conflict between optically

  11. A Hybrid Tandem Solar Cell Combining a Dye-Sensitized and a Polymer Solar Cell.

    PubMed

    Shao, Zhipeng; Chen, Shuanghong; Zhang, Xuhui; Zhu, Liangzheng; Ye, Jiajiu; Dai, Songyuan

    2016-06-01

    A hybrid tandem solar cell was assambled by connecting a dye sensitized solar cell and a polymer solar cell in series. A N719 sensitized TiO2 was used as photocathode in dye-sensitized subcell, and a MEH-PPV/PCBM composite was used as active layer in the polymer subcell. The polymer subcell fabricated on the counter electrode of the dye sensitized solar cell. A solution processed TiO(x) layer was used as electron collection layer of the polymer sub cell and the charge recombination layer. The effects of the TiO(x) interlayer and the spectral overlap between the two sub cells have been studied and optimized. The results shows that a proper thickness of the TiO(x) layer is needed for tandem solar cells. Thick TiO(x) will enhance the series resistance, but too thin TiO(x), layer will damage the hole blocking effect and its hydrophilic. The resulting optimized tandem solar cells exhibited a power conversion efficiency of 1.28% with a V(oc) of 0.95 V under simulated 100 mW cm(-2) AM 1.5 illumination.

  12. EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

    SciTech Connect

    Russell, Thomas P.

    2016-12-08

    The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices with efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.

  13. Photoresponsive polymer design for solar concentrator self-steering heliostats

    NASA Astrophysics Data System (ADS)

    Barker, Jessica; Basnet, Amod; Bhaduri, Moinak; Burch, Caroline; Chow, Amenda; Li, Xue; Oates, William S.; Massad, Jordan E.; Smith, Ralph

    2014-03-01

    Concentrating solar energy and transforming it into electricity is clean, economical and renewable. One design of solar power plants consists of an array of heliostats which redirects sunlight to a fixed receiver tower and the generated heat is converted into electricity. Currently, the angles of elevation of heliostats are controlled by motors and drives that are costly and require diverting power that can otherwise be used for producing electricity. We consider replacing the motor and drive system of the heliostat with a photosensitive polymer design that can tilt the mirror using the ability of the polymer to deform when subjected to light. The light causes the underlying molecular structure to change and subsequently, the polymer deforms. The deformation of the polymer is quantified in terms of photostrictive constitutive relations. A mathematical model is derived governing the behaviour of the angle of elevation as the photostrain varies. Photostrain depends on the composition of the polymer, intensity and temperature of light and angle of light polarization. Preliminary findings show a photomechanical rod structural design can provide 60° elevation for temperatures of about 40°C. A photomechanical beam structural design can generate more tilt at lower temperatures. The mathematical analysis illustrates that photostrains on the order of 1% to 10% are desired for both rod and beam designs to produce sufficient tilt under most heliostat field conditions.

  14. Lead-Free Inverted Planar Formamidinium Tin Triiodide Perovskite Solar Cells Achieving Power Conversion Efficiencies up to 6.22.

    PubMed

    Liao, Weiqiang; Zhao, Dewei; Yu, Yue; Grice, Corey R; Wang, Changlei; Cimaroli, Alexander J; Schulz, Philip; Meng, Weiwei; Zhu, Kai; Xiong, Ren-Gen; Yan, Yanfa

    2016-11-01

    Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3 ) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) of 5.41% ± 0.46% and a maximum PCE of 6.22% under forward voltage scan. The PVSCs exhibit small photocurrent-voltage hysteresis and high reproducibility. The champion cell shows a steady-state efficiency of ≈6.00% for over 100 s. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Optimization of 3-junction inverted metamorphic solar cells for high-temperature and high-concentration operation

    NASA Astrophysics Data System (ADS)

    Geisz, John F.; Duda, Anna; France, Ryan M.; Friedman, Daniel J.; Garcia, Ivan; Olavarria, Waldo; Olson, Jerry M.; Steiner, Myles A.; Ward, J. Scott; Young, Michelle

    2012-10-01

    Four different band gap combinations of triple-junction inverted metamorphic solar cells are characterized as a function of temperature and concentration up to 120°C and ˜1000 suns. We demonstrate that the standard 1.82/1.40/1.00 eV combination is an excellent choice for typical operating conditions of 1000 suns and 75°C. Improved metal grids and thermal management in such a cell has achieved 42.6% efficiency at 327 suns and 40.9% at 1093 suns at 25°C.

  16. Lead-free inverted planar formamidinium tin triiodide perovskite solar cells achieving power conversion efficiencies up to 6.22%

    SciTech Connect

    Liao, Weiqiang; Zhao, Dewei; Yu, Yue; Grice, Corey R.; Wang, Changlei; Cimaroli, Alexander J.; Schulz, Philip; Meng, Weiwei; Zhu, Kai; Xiong, Ren -Gen; Yan, Yanfa

    2016-08-29

    Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversion efficiencies (PCEs) of 5.41% ± 0.46% and a maximum PCE of 6.22% under forward voltage scan. Here, the PVSCs exhibit small photocurrent–voltage hysteresis and high reproducibility. The champion cell shows a steady-state efficiency of ≈6.00% for over 100 s.

  17. Enhanced electrical property of Ni-doped CoOx hole transport layer for inverted perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Huang, Aibin; Lei, Lei; Yu, Yu; Liu, Yan; Yang, Songwang; Bao, Shanhu; Cao, Xun; Jin, Ping

    2017-05-01

    Ultrathin Ni doped CoOx films were prepared by direct current co-sputtering at room temperature as inorganic hole transport materials for inverted perovskite solar cells. P-type doping was designed to adjust the valence band position of CoOx to match the that of CH3NH3PbI3, which would effectively eliminate the interface barrier. Moreover, the hole extraction ability would be enhanced and the power conversion efficiency of the devices hence increased from 3.68% to 9.60%. The optimized performance was also accompanied by decent stability as a result of its intrinsic stability.

  18. Enhanced electrical property of Ni-doped CoOx hole transport layer for inverted perovskite solar cells.

    PubMed

    Huang, Aibin; Lei, Lei; Yu, Yu; Liu, Yan; Yang, Songwang; Bao, Shanhu; Cao, Xun; Jin, Ping

    2017-05-19

    Ultrathin Ni doped CoOx films were prepared by direct current co-sputtering at room temperature as inorganic hole transport materials for inverted perovskite solar cells. P-type doping was designed to adjust the valence band position of CoOx to match the that of CH3NH3PbI3, which would effectively eliminate the interface barrier. Moreover, the hole extraction ability would be enhanced and the power conversion efficiency of the devices hence increased from 3.68% to 9.60%. The optimized performance was also accompanied by decent stability as a result of its intrinsic stability.

  19. Enhancement of fill factor in air-processed inverted organic solar cells using self-assembled monolayer of fullerene catechol

    NASA Astrophysics Data System (ADS)

    Jeon, Il; Ogumi, Keisuke; Nakagawa, Takafumi; Matsuo, Yutaka

    2016-08-01

    [60]Fullerene catechol self-assembled monolayers were prepared and applied to inverted organic solar cells by an immersion method, and their energy conversion properties were measured. By introducing fullerenes at the surface, we improved the hole-blocking capability of electron-transporting metal oxide, as shown by the fill factor enhancement. The fullerene catechol-treated TiO x -containing device gave a power conversion efficiency (PCE) of 2.81% with a fill factor of 0.56 while the non treated device gave a PCE of 2.46% with a fill factor of 0.49. The solar cell efficiency improved by 13% compared with the non treated reference device.

  20. Improvement in the performance of inverted organic solar cell using electric field assisted spray deposited ZnO layer

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Neha; Swami, Sanjay Kumar; Dutta, Viresh

    2015-06-01

    ZnO film was deposited using spray technique. The application of electric field (applying a DC voltage = 700V to the nozzle) during spray deposition provide compact nanostructured film of ZnO as compared to agglomerated ZnO film deposited using spray process. The ZnO film deposited after applying DC voltage during spray process showed good crystallinity as well as transmittance in the visible range. Use of this crystalline, compact layer of ZnO in inverted organic solar cell (ITO/ZnO/P3HT: PCBM/Ag) provide improved efficiency of 2.8% with JSC of 14.0 mA/cm2, VOC of 0.55V and FF of 36%. Thus the process remove the need of any post deposition treatment to improve the film quality as well as solar cell performance.

  1. Precise Side-Chain Engineering of Thienylenevinylene-Benzotriazole-Based Conjugated Polymers with Coplanar Backbone for Organic Field Effect Transistors and CMOS-like Inverters.

    PubMed

    Lee, Min-Hye; Kim, Juhwan; Kang, Minji; Kim, Jihong; Kang, Boseok; Hwang, Hansu; Cho, Kilwon; Kim, Dong-Yu

    2017-01-25

    Two donor-acceptor (D-A) alternating conjugated polymers based on thienylenevinylene-benzotriazole (TV-BTz), PTV6B with a linear side chain and PTVEhB with a branched side chain, were synthesized and characterized for organic field effect transistors (OFETs) and complementary metal-oxide-semiconductor (CMOS)-like inverters. According to density functional theory (DFT), polymers based on TV-BTz exhibit a coplanar and rigid structure with no significant twists, which could cause to an increase in charge-carrier mobility in OFETs. Alternating alkyl side chains of the polymers impacted neither the band gap nor the energy level. However, it significantly affected the morphology and crystallinity when the polymer films were thermally annealed. To investigate the effect of thermal annealing on the morphology and crystallinity, we characterized the polymer films using atomic force microscopy (AFM) and 2D-grazing incidence X-ray diffraction (2D-GIWAXD). Fibrillary morphologies with larger domains and increased crystallinity were observed in the polymer films after thermal annealing. These polymers exhibited improved charge-carrier mobilities in annealed films at 200 °C and demonstrated optimal OFET device performance with p-type transport characteristics with charge-carrier mobilities of 1.51 cm(2)/(V s) (PTV6B) and 2.58 cm(2)/(V s) (PTVEhB). Furthermore, CMOS-like inorganic (ZnO)-organic (PTVEhB) hybrid bilayer inverter showed that the inverting voltage (Vinv) was positioned near the ideal switching point at half (1/2) of supplied voltage (VDD) due to fairly balanced p- and n-channels.

  2. Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells

    DOE PAGES

    Mo, Daize; Wang, Huan; Chen, Hui; ...

    2017-03-08

    Here, halogenation is an effective way to tune the energy levels of organic semiconducting materials. To date, fluorination of organic semiconducting materials to fabricate polymer solar cells (PSCs) has been used far more than chlorination; however, fluorine exchange reactions suffer from low yields and the resulting fluorinated polymer always comes with higher price, which will greatly hinder their commercial applications. Herein, we designed and synthesized a series of chlorinated donor-acceptor (D-A) type polymers, in which benzo[1,2-b:4,5- b]dithiophene and chlorinated benzothiadiazole units are connected by thiophene π-bridges with an asymmetric alkyl chain. These chlorinated polymers showed deep highest occupied molecular orbitalmore » energy levels, which promoted the efficiency of their corresponding PSCs by increasing the device open circuit voltage. The asymmetric alkyl chain on the thiophene moieties gave the final polymer sufficient solubility for solution processing and strong π-π stacking in films allowed for high mobility. Although the introduction of a large chlorine atom increased the torsion angle of the polymer backbone, the chlorinated polymers maintained high crystallinity and a favorable backbone orientation in the blended films. These factors contributed to respectable device performances from thick-film devices, which showed PCEs as high as 9.11% for a 250 nm-thick active layer. These results demonstrate that chlorination is a promising method to fine tune the energy levels of conjugated polymers, and chlorinated benzothiadiazole may be a versatile building block in materials for efficient solar energy conversion.« less

  3. Polymer Substrates For Lightweight, Thin-Film Solar Cells

    NASA Technical Reports Server (NTRS)

    Lewis, Carol R.

    1993-01-01

    Substrates survive high deposition temperatures. High-temperature-resistant polymers candidate materials for use as substrates of lightweight, flexible, radiation-resistant solar photovoltaic cells. According to proposal, thin films of copper indium diselenide or cadmium telluride deposited on substrates to serve as active semiconductor layers of cells, parts of photovoltaic power arrays having exceptionally high power-to-weight ratios. Flexibility of cells exploited to make arrays rolled up for storage.

  4. Low bandgap conjugated polymers for organic solar cells

    NASA Astrophysics Data System (ADS)

    Xu, Tao

    Organic solar cells are emerging as a potential solution to address the energy issue in the future. Functional materials that can achieve high performance are the main topics in my thesis. I went briefly to introduce the background and history first, emphasizing on the synthetic principles towards high performance copolymers. My second chapters is about the perturbation effect by introducing terminal chloroaryl in the side chain. A new type of monomer is presented in Chapter III and corresponding polymers are studied. Then we investigated the impact of polymerization conditions on the physical properties using PTB7 as the standard polymer. In the last, we further utilized TID unit to construct acceptor polymers and random copolymer. A PCE value of 7.55% was achieved.

  5. Rational Design of Molecular Hole-Transporting Materials for Perovskite Solar Cells: Direct versus Inverted Device Configurations.

    PubMed

    Grisorio, Roberto; Iacobellis, Rosabianca; Listorti, Andrea; De Marco, Luisa; Cipolla, Maria Pia; Manca, Michele; Rizzo, Aurora; Abate, Antonio; Gigli, Giuseppe; Suranna, Gian Paolo

    2017-07-26

    Due to a still limited understanding of the reasons making 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD) the state-of-the-art hole-transporting material (HTM) for emerging photovoltaic applications, the molecular tailoring of organic components for perovskite solar cells (PSCs) lacks in solid design criteria. Charge delocalization in radical cationic states can undoubtedly be considered as one of the essential prerequisites for an HTM, but this aspect has been investigated to a relatively minor extent. In marked contrast with the 3-D structure of Spiro-OMeTAD, truxene-based HTMs Trux1 and Trux2 have been employed for the first time in PSCs fabricated with a direct (n-i-p) or inverted (p-i-n) architecture, exhibiting a peculiar behavior with respect to the referential HTM. Notwithstanding the efficient hole extraction from the perovskite layer exhibited by Trux1 and Trux2 in direct configuration devices, their photovoltaic performances were detrimentally affected by their poor hole transport. Conversely, an outstanding improvement of the photovoltaic performances in dopant-free inverted configuration devices compared to Spiro-OMeTAD was recorded, ascribable to the use of thinner HTM layers. The rationalization of the photovoltaic performances exhibited by different configuration devices discussed in this paper can provide new and unexpected prospects for engineering the interface between the active layer of perovskite-based solar cells and the hole transporters.

  6. Engineering solutions for polymer composites solar water heaters production

    NASA Astrophysics Data System (ADS)

    Frid, S. E.; Arsatov, A. V.; Oshchepkov, M. Yu.

    2016-06-01

    Analysis of engineering solutions aimed at a considerable decrease of solar water heaters cost via the use of polymer composites in heaters construction and solar collector and heat storage integration into a single device representing an integrated unit results are considered. Possibilities of creating solar water heaters of only three components and changing welding, soldering, mechanical treatment, and assembly of a complicate construction for large components molding of polymer composites and their gluing are demonstrated. Materials of unit components and engineering solutions for their manufacturing are analyzed with consideration for construction requirements of solar water heaters. Optimal materials are fiber glass and carbon-filled plastics based on hot-cure thermosets, and an optimal molding technology is hot molding. It is necessary to manufacture the absorbing panel as corrugated and to use a special paint as its selective coating. Parameters of the unit have been optimized by calculation. Developed two-dimensional numerical model of the unit demonstrates good agreement with the experiment. Optimal ratio of daily load to receiving surface area of a solar water heater operating on a clear summer day in the midland of Russia is 130‒150 L/m2. Storage tank volume and load schedule have a slight effect on solar water heater output. A thermal insulation layer of 35‒40 mm is sufficient to provide an efficient thermal insulation of the back and side walls. An experimental model layout representing a solar water heater prototype of a prime cost of 70‒90/(m2 receiving surface) has been developed for a manufacturing volume of no less than 5000 pieces per year.

  7. Printed 2 V-operating organic inverter arrays employing a small-molecule/polymer blend

    NASA Astrophysics Data System (ADS)

    Shiwaku, Rei; Takeda, Yasunori; Fukuda, Takashi; Fukuda, Kenjiro; Matsui, Hiroyuki; Kumaki, Daisuke; Tokito, Shizuo

    2016-10-01

    Printed organic thin-film transistors (OTFTs) are well suited for low-cost electronic applications, such as radio frequency identification (RFID) tags and sensors. Achieving both high carrier mobility and uniform electrical characteristics in printed OTFT devices is essential in these applications. Here, we report on printed high-performance OTFTs and circuits using silver nanoparticle inks for the source/drain electrodes and a blend of dithieno[2,3-d2‧,3‧-d‧]benzo[1,2-b4,5-b‧]dithiophene (DTBDT-C6) and polystyrene for the organic semiconducting layer. A high saturation region mobility of 1.0 cm2 V-1 s-1 at low operation voltage of -5 V was obtained for relatively short channel lengths of 9 μm. All fifteen of the printed pseudo-CMOS inverter circuits were formed on a common substrate and operated at low operation voltage of 2 V with the total variation in threshold voltage of 0.35 V. Consequently, the printed OTFT devices can be used in more complex integrated circuit applications requiring low manufacturing cost over large areas.

  8. Printed 2 V-operating organic inverter arrays employing a small-molecule/polymer blend

    PubMed Central

    Shiwaku, Rei; Takeda, Yasunori; Fukuda, Takashi; Fukuda, Kenjiro; Matsui, Hiroyuki; Kumaki, Daisuke; Tokito, Shizuo

    2016-01-01

    Printed organic thin-film transistors (OTFTs) are well suited for low-cost electronic applications, such as radio frequency identification (RFID) tags and sensors. Achieving both high carrier mobility and uniform electrical characteristics in printed OTFT devices is essential in these applications. Here, we report on printed high-performance OTFTs and circuits using silver nanoparticle inks for the source/drain electrodes and a blend of dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene (DTBDT-C6) and polystyrene for the organic semiconducting layer. A high saturation region mobility of 1.0 cm2 V−1 s−1 at low operation voltage of −5 V was obtained for relatively short channel lengths of 9 μm. All fifteen of the printed pseudo-CMOS inverter circuits were formed on a common substrate and operated at low operation voltage of 2 V with the total variation in threshold voltage of 0.35 V. Consequently, the printed OTFT devices can be used in more complex integrated circuit applications requiring low manufacturing cost over large areas. PMID:27698493

  9. Printed 2 V-operating organic inverter arrays employing a small-molecule/polymer blend.

    PubMed

    Shiwaku, Rei; Takeda, Yasunori; Fukuda, Takashi; Fukuda, Kenjiro; Matsui, Hiroyuki; Kumaki, Daisuke; Tokito, Shizuo

    2016-10-04

    Printed organic thin-film transistors (OTFTs) are well suited for low-cost electronic applications, such as radio frequency identification (RFID) tags and sensors. Achieving both high carrier mobility and uniform electrical characteristics in printed OTFT devices is essential in these applications. Here, we report on printed high-performance OTFTs and circuits using silver nanoparticle inks for the source/drain electrodes and a blend of dithieno[2,3-d;2',3'-d']benzo[1,2-b;4,5-b']dithiophene (DTBDT-C6) and polystyrene for the organic semiconducting layer. A high saturation region mobility of 1.0 cm(2) V(-1) s(-1) at low operation voltage of -5 V was obtained for relatively short channel lengths of 9 μm. All fifteen of the printed pseudo-CMOS inverter circuits were formed on a common substrate and operated at low operation voltage of 2 V with the total variation in threshold voltage of 0.35 V. Consequently, the printed OTFT devices can be used in more complex integrated circuit applications requiring low manufacturing cost over large areas.

  10. Interface investigation of the alcohol-/water-soluble conjugated polymer PFN as cathode interfacial layer in organic solar cells

    NASA Astrophysics Data System (ADS)

    Zhong, Shu; Wang, Rui; Ying Mao, Hong; He, Zhicai; Wu, Hongbin; Chen, Wei; Cao, Yong

    2013-09-01

    In this work, in situ ultraviolet photoelectron spectroscopy measurements were used to investigate the working mechanism of an alcohol-/water-soluble conjugated polymer poly [(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode interfacial layer in organic solar cells from the view of interfacial energy level alignment. Fullerene (C60) was chosen as the model acceptor material in contact with PFN as well as two other cathode interfacial layers ZnO and TiO2 in the configuration of an inverted solar cell structure. Significant charge transfer between PFN modified ITO (indium tin oxide) electrode and C60 is observed due to the low work function of PFN. This results in the Fermi level of the substrate pinned very close to the lowest unoccupied molecular orbital of C60 as well as an additional electric field at the cathode/acceptor interface. Both of them facilitate the electron extraction from the acceptor C60 to the ITO cathode, as confirmed by the electrical measurements of the electron-only devices with PFN modification. The better electron extraction originated from the Fermi level pinning and the additional interface electric field are believed to contribute to the efficiency enhancement of the inverted organic solar cells employing PFN as cathode interfacial layer.

  11. Photovoltaic properties and morphology of organic solar cells based on liquid-crystal semiconducting polymer with additive

    SciTech Connect

    Suzuki, Atsushi; Zushi, Masahito; Suzuki, Hisato; Ogahara, Shinichi; Akiyama, Tsuyoshi; Oku, Takeo

    2014-02-20

    Bulk heterojunction organic solar cell based on liquid crystal semiconducting polymers of poly[9,9-dioctylfluorene-co-bithiophene] (F8T2) as p-type semiconductors and fullerenes (C{sub 60}) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as electron donor and acceptor has been fabricated and characterized for improving photovoltaic and optical properties. The photovoltaic performance including current voltage curves in the dark and illumination of the F8T2/C{sub 60} conventional and inverted bulk heterojunction solar cells were investigated. Relationship between the photovoltaic properties and morphological behavior was focused on tuning for optimization of photo-voltaic performance under annealing condition near glass transition temperature. Additive-effect of diiodooctane (DIO) and poly(3-hexylthiophene-2,5-diyl) (P3HT) on the photovoltaic performance and optical properties was investigated. Mechanism of the photovoltaic properties of the conventional and inverted solar cells will be discussed by the experimental results.

  12. Aqueous processing of low-band-gap polymer solar cells using roll-to-roll methods.

    PubMed

    Andersen, Thomas R; Larsen-Olsen, Thue T; Andreasen, Birgitta; Böttiger, Arvid P L; Carlé, Jon E; Helgesen, Martin; Bundgaard, Eva; Norrman, Kion; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-05-24

    Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b')dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5'-diyl] (P1), poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (P2), and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (P3) were prepared using ultrasonic treatment of a chloroform solution of the polymer and [6,6]-phenyl-C(61)-butyric acid methyl ester ([60]PCBM) mixed with an aqueous solution of sodium dodecylsulphate (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated films. The aqueous dispersions were dialyzed to remove excess detergent and concentrated to a solid content of approximately 60 mg mL(-1). The formation of films for solar cells using the aqueous dispersion required the addition of the nonionic detergent FSO-100 at a concentration of 5 mg mL(-1). This enabled slot-die coating of high quality films with a dry thickness of 126 ± 19, 500 ± 25, and 612 ± 22 nm P1, P2, and P3, respectively for polymer solar cells. Large area inverted polymer solar cells were thus prepared based on the aqueous inks. The power conversion efficiency (PCE) reached for each of the materials was 0.07, 0.55, and 0.15% for P1, P2, and P3, respectively. The devices were prepared using coating and printing of all layers including the metal back electrodes. All steps were carried out using roll-to-roll (R2R) slot-die and screen printing methods on flexible substrates. All five layers were processed using environmentally friendly methods and solvents. Two of the layers were processed entirely from water (the electron transport layer and the active

  13. Graphene-Enhanced Polymer-Bulk Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Yu, Fei

    ABSTRACT: Despite the growth of polymer based photovoltaic devices in the past decade, major challenges in devices performance improvement remain unsolved. To further improve the power conversion efficiency, charge mobility in the active layer needs to be greatly improved, and a reliable method to control the donor-acceptor blend morphology to a size scale similar to exciton diffusion length is necessary. Graphene is a novel material with superior physical properties. In this thesis, graphene is prepared through a solution exfoliation process and its dimensions and properties are characterized. The interaction between conjugated polymer chains and graphene nanosheets is studied by spectroscopic methods. The effect of graphene on polymer BHJ solar cell performance and OPV device physics are discussed when relatively low weight fraction of graphene is introduced into a modified P3HT:PCBM photovoltaic devices in order to improve OPV device properties. Strong influence on active layer morphology is observed along with the introduction of graphene, which also strongly contribute to OPV device performance improvement. The morphology of active layer is systemically investigated by a variety of characterization methods, including atomic force microscope (AFM), neutron reflectivity (NR), grazing incident-angle X-ray diffraction (GIXRD). Some other efforts to further improve the film morphology are also discussed in this thesis. The goal of this thesis is to demonstrate the possibility of using graphene to manipulate the active layer morphology and to enhance the performance of polymer based bulk-heterojunction solar cells, which has great potential to replace current generation of solar cells device.

  14. High resolution TEM and 3D imaging of polymer-based and dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Suh, Youngjoon

    Since 1950s, solar energy has been the most attractive energy source as an alternative to fossil fuels including oil and natural gas. However, these types of solar cells have high raw material and manufacturing costs. So, alternative solar cells using low cost materials and manufacturing processes have been actively studied for more than 10 years. The power conversion efficiency of some of the alternative solar cells has been recently improved so much as to be used for real life applications in the near future. However, their relatively short lifetime still remains as a bottleneck in their commercialized use. In this dissertation, we studied cross sections of three types of solar cells using TEM micrographs and TEM related analysis methods; selected area diffraction, energy dispersive spectroscopy, electron tomography, and nanobeam diffraction. A thin Ag layer used for a top metal electrode in an inverted polymer solar cell was broken down into particles. Absorption of water by the PEDOT:PSS layer followed by corrosion of the Ag layer was thought to be the main cause of this phenomenon. The structure and materials of the photoactive layer in hybrid polymer solar cells have an important influence on the performance of the solar cell devices. Three kinds of efforts were made to improve the electrical characteristics of the devices; removal of a dark TiO2 layer at the polymer/TiO2 interface, using bulk heterojunction structures, and coating a fullerene interlayer on the inorganic nanostructure. An optimum concentration of carbon nanotubes (CNTs) combined with Ru could increase the interface area of CNTs, and improve the performances of dye sensitized solar cells. In order to develop plastic solar cell, two different methods of mixing TiO2 particles with either nanoglues or PMMA were tried. Cross-sectional TEM microstructures were examined to come up with optimum processing parameters such as the sintering temperature and the amount of PMMA added into the structure

  15. Planar conjugated polymers containing 9,10-disubstituted phenanthrene units for efficient polymer solar cells.

    PubMed

    Li, Guangwu; Kang, Chong; Li, Cuihong; Lu, Zhen; Zhang, Jicheng; Gong, Xue; Zhao, Guangyao; Dong, Huanli; Hu, Wenping; Bo, Zhishan

    2014-06-01

    Four novel conjugated polymers (P1-4) with 9,10-disubstituted phenanthrene (PhA) as the donor unit and 5,6-bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low-lying HOMO energy levels (below -5.3 eV), and high hole mobilities (in the range of 3.6 × 10(-3) to 0.02 cm(2) V(-1) s(-1) ). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1-4:PC71 BM blends as the active layer and an alcohol-soluble fullerene derivative (FN-C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10-disubstituted PhA are potential donor materials for high-efficiency BHJ PSCs.

  16. Fullerene-bisadduct acceptors for polymer solar cells.

    PubMed

    Li, Yongfang

    2013-10-01

    Polymer solar cells (PSCs) have drawn great attention in recent years for their simple device structure, light weight, and low-cost fabrication in comparison with inorganic semiconductor solar cells. However, the power-conversion efficiency (PCE) of PSCs needs to be increased for their future application. The key issue for improving the PCE of PSCs is the design and synthesis of high-efficiency conjugated polymer donors and fullerene acceptors for the photovoltaic materials. For the acceptor materials, several fullerene-bisadduct acceptors with high LUMO energy levels have demonstrated excellent photovoltaic performance in PSCs with P3HT as a donor. In this Focus Review, recent progress in high-efficiency fullerene-bisadduct acceptors is discussed, including the bisadduct of PCBM, indene-C60 bisadduct (ICBA), indene-C70 bisadduct (IC70BA), DMPCBA, NCBA, and bisTOQC. The LUMO levels and photovoltaic performance of these bisadduct acceptors with P3HT as a donor are summarized and compared. In addition, the applications of an ICBA acceptor in new device structures and with other conjugated polymer donors than P3HT are also introduced and discussed.

  17. Development of inverted organic solar cells with TiO₂ interface layer by using low-temperature atomic layer deposition.

    PubMed

    Lin, Zhenhua; Jiang, Changyun; Zhu, Chunxiang; Zhang, Jie

    2013-02-01

    Organic solar cells (OSCs) with inverted structure have attracted much attention in recent years because of their improved device air stability due to the use of stable materials for electrodes and interface layers. In this work, TiO(2) films, fabricated using low temperature (e.g., 130-170 °C) atomic layer deposition (ALD) on ITO substrates, are used as electron selective interface layers to investigate inverted OSCs. It is found that though the as-deposited TiO(2) films are high resistive due to the presence of oxygen defects, the defects can be significantly reduced by light soaking. PV cells with 15-nm-thick amorphous-TiO(2) layers fabricated at low temperature show better performance than those with poly crystal TiO(2) with same thickness deposited at 250 °C. The low temperature ALD-grown TiO(2) films are dense, stable and robust with capability of conformal coating on nanostructural surfaces, showing a promising interface layer for achieving air-stable plastic OSCs with roll-to-roll mass production potential.

  18. Tuning the ITO work function by capacitively coupled plasma and its application in inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Fang, Ming; Zhang, Chunmei; Chen, Qiang

    2016-11-01

    In this paper, we investigated the performance of inverted organic solar cells (OSCs) with plasma-treated indium tin oxide (ITO) as the cathode for omitting an electron transport layer. The Ar plasma was produced by capcitively coupled plasma setup under 20 Pa chamber pressure. For the device with the structure of plasma-treated ITO/P3HT:PCBM/MoO3/Ag, a power conversion efficiency (PCE) of 3.22% was achieved, whereas PCE of 1.13% was recorded from the device fabricated with the pristine ITO. The photovoltaic performance was found to be dependent on the applied power of plasma. After analyzing by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), we concluded that the chemical component variation of ITOs surface resulted in the decrease of ITO work function, which meant that the ITO Fermi level became shallow relative to the vacuum level. The low work function of ITO should be responsible for the improvement of inverted OSCs because of the better energy level alignment between ITO and the photoactive layer.

  19. A water-processable organic electron-selective layer for solution-processed inverted organic solar cells

    SciTech Connect

    Chen, Dongcheng; Zhou, Hu; Cai, Ping; Sun, Shi; Ye, Hua; Su, Shi-Jian Cao, Yong

    2014-02-03

    A triazine- and pyridinium-containing water-soluble material of 1,1′,1″-(4,4′,4″-(1,3,5-triazine-2,4,6-triyl)tris(benzene-4,1-diyl)) tris(methylene)tripyridinium bromide (TzPyBr) was developed as an organic electron-selective layer in solution-processed inverted organic solar cells due to its strong anti-erosion capacity against non-polar organic solvents commonly used for the active layer. Ohmic-like contact with the adjacent active materials like fullerene derivatives is speculated to be formed, as confirmed by the work-function measurements with scanning Kelvin probe and ultraviolet photoelectron spectroscopy techniques. Besides, considering the deep highest occupied molecular orbital energy level of TzPyBr, excellent hole-blocking property of the electron-selective layer is also anticipated. The inverted organic photovoltaic devices based on the TzPyBr/ITO (indium tin oxide) bilayer cathode exhibit dramatically enhanced performance compared to the control devices with bare ITO as the cathode and even higher efficiency than the conventional type devices with ITO and Al as the electrodes.

  20. Aqueous-Processed Insulating Polymer/Nanocrystal Hybrid Solar Cells.

    PubMed

    Jin, Gan; Chen, Zhaolai; Dong, Chunwei; Cheng, Zhongkai; Du, Xiaohang; Zeng, Qingsen; Liu, Fangyuan; Sun, Haizhu; Zhang, Hao; Yang, Bai

    2016-03-23

    A novel kind of hybrid solar cell (HSC) was developed by introducing water-soluble insulating polymer poly(vinyl alcohol) (PVA) into nanocrystals (NCs), which revealed that the most frequently used conjugated polymer could be replaced by an insulating one. It was realized by strategically taking advantage of the characteristic of decomposition for the polymer at annealing temperature, and it was interesting to discover that partial decomposition of PVA left behind plenty of pits on the surfaces of CdTe NC films, enlarging surface contact area between CdTe NCs and subsequently evaporated MoO3. Moreover, the residual annealed PVA filled in the voids among spherical CdTe NCs, which led to the decrease of leakage current. An improved shunt resistance (increased by ∼80%) was achieved, indicating the charge-carrier recombination was effectively overcome. As a result, the new HSCs were endowed with increased Voc, fill factor, and power conversion efficiency compared with the pure NC device. This approach can be applied to other insulating polymers (e.g., PVP) with advantages in synthesis, type, economy, stability, and so on, providing a novel universal cost-effective way to achieve higher photovoltaic performance.

  1. Long-term stable polymer solar cells with significantly reduced burn-in loss.

    PubMed

    Kong, Jaemin; Song, Suhee; Yoo, Minji; Lee, Ga Young; Kwon, Obum; Park, Jin Kuen; Back, Hyungcheol; Kim, Geunjin; Lee, Seoung Ho; Suh, Hongsuk; Lee, Kwanghee

    2014-12-08

    The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called 'burn-in' loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and long-term stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications.

  2. Upright and Inverted Single-Junction GaAs Solar Cells Grown by Hydride Vapor Phase Epitaxy

    DOE PAGES

    Simon, John; Schulte, Kevin L.; Jain, Nikhil; ...

    2016-10-19

    Hydride vapor phase epitaxy (HVPE) is a low-cost alternative to conventional metal-organic vapor phase epitaxy (MOVPE) growth of III-V solar cells. In this work, we show continued improvement of the performance of HVPE-grown single-junction GaAs solar cells. We show over an order of magnitude improvement in the interface recombination velocity between GaAs and GaInP layers through the elimination of growth interrupts, leading to increased short-circuit current density and open-circuit voltage compared with cells with interrupts. One-sun conversion efficiencies as high as 20.6% were achieved with this improved growth process. Solar cells grown in an inverted configuration that were removed frommore » the substrate showed nearly identical performance to on-wafer cells, demonstrating the viability of HVPE to be used together with conventional wafer reuse techniques for further cost reduction. As a result, these devices utilized multiple heterointerfaces, showing the potential of HVPE for the growth of complex and high-quality III-V devices.« less

  3. Upright and Inverted Single-Junction GaAs Solar Cells Grown by Hydride Vapor Phase Epitaxy

    SciTech Connect

    Simon, John; Schulte, Kevin L.; Jain, Nikhil; Johnston, Steve; Young, Michelle; Young, Matthew R.; Young, David L.; Ptak, Aaron J.

    2016-10-19

    Hydride vapor phase epitaxy (HVPE) is a low-cost alternative to conventional metal-organic vapor phase epitaxy (MOVPE) growth of III-V solar cells. In this work, we show continued improvement of the performance of HVPE-grown single-junction GaAs solar cells. We show over an order of magnitude improvement in the interface recombination velocity between GaAs and GaInP layers through the elimination of growth interrupts, leading to increased short-circuit current density and open-circuit voltage compared with cells with interrupts. One-sun conversion efficiencies as high as 20.6% were achieved with this improved growth process. Solar cells grown in an inverted configuration that were removed from the substrate showed nearly identical performance to on-wafer cells, demonstrating the viability of HVPE to be used together with conventional wafer reuse techniques for further cost reduction. As a result, these devices utilized multiple heterointerfaces, showing the potential of HVPE for the growth of complex and high-quality III-V devices.

  4. CuSCN-Based Inverted Planar Perovskite Solar Cell with an Average PCE of 15.6%.

    PubMed

    Ye, Senyun; Sun, Weihai; Li, Yunlong; Yan, Weibo; Peng, Haitao; Bian, Zuqiang; Liu, Zhiwei; Huang, Chunhui

    2015-06-10

    Although inorganic hole-transport materials usually possess high chemical stability, hole mobility, and low cost, the efficiency of most of inorganic hole conductor-based perovskite solar cells is still much lower than that of the traditional organic hole conductor-based cells. Here, we have successfully fabricated high quality CH3NH3PbI3 films on top of a CuSCN layer by utilizing a one-step fast deposition-crystallization method, which have lower surface roughness and smaller interface contact resistance between the perovskite layer and the selective contacts in comparison with the films prepared by a conventional two-step sequential deposition process. The average efficiency of the CuSCN-based inverted planar CH3NH3PbI3 solar cells has been improved to 15.6% with a highest PCE of 16.6%, which is comparable to that of the traditional organic hole conductor-based cells, and may promote wider application of the inexpensive inorganic materials in perovskite solar cells.

  5. Electrodeposited cobalt sulfide hole collecting layer for polymer solar cells

    SciTech Connect

    Zampetti, Andrea; De Rossi, Francesca; Brunetti, Francesca; Reale, Andrea; Di Carlo, Aldo; Brown, Thomas M.

    2014-08-11

    In polymer solar cells based on the blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester, the hole collecting layer has to be endowed with its ionization potential close to or greater than that of P3HT (∼5 eV). Conductive polymer blends such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and metal oxides such as vanadium pentoxide (V{sub 2}O{sub 5}) and molybdenum trioxide (MoO{sub 3}) satisfy this requirement and have been the most common materials used so far in bulk heterojunction structures. We report here cobalt sulfide (CoS) to be a promising hole collecting material deposited by convenient and room temperature electrodeposition. By simply tuning the CoS electrodeposition parameters, power conversion efficiencies similar (within 15%) to a reference structure with PEDOT:PSS were obtained.

  6. Zinc oxide modified with benzylphosphonic acids as transparent electrodes in regular and inverted organic solar cell structures

    SciTech Connect

    Lange, Ilja; Reiter, Sina; Kniepert, Juliane; Piersimoni, Fortunato; Brenner, Thomas; Neher, Dieter; Pätzel, Michael; Hildebrandt, Jana; Hecht, Stefan

    2015-03-16

    An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices.

  7. Incorporation of quaternary ammonium salts containing different counterions to improve the performance of inverted perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Yan, Po-Ruei; Huang, Wei-Jie; Yang, Sheng-Hsiung

    2017-02-01

    In this research, three quaternary ammonium salts containing different counterions, including tetrabutylammonium bromide (TBABr), tetrabutylammonium tetrafluoroborate (TBABF4), and tetrabutylammonium hexafluorophosphate (TBAPF6), were incorporated into [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) as electron transporting layer (ETL). These salts-doped PCBM films revealed higher electron mobility and Fermi levels compared with the un-doped one. Better charge transfer at the interface between perovskite and salts-doped PCBM was also obtained from PL quenching experiments. Inverted perovskite solar cells with the configuration of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM + salts/Ag were fabricated, and the JSC and FF of devices were significantly enhanced using salts-doped PCBM as ETL. The best device based on TBABF4-doped PCBM delivered a power conversion efficiency (PCE) up to 13.41%, which was superior to the one with undoped PCBM layer (PCE = 8.77%).

  8. Inverted Hysteresis in CH3NH3PbI3 Solar Cells: Role of Stoichiometry and Band Alignment.

    PubMed

    Shen, Heping; Jacobs, Daniel A; Wu, Yiliang; Duong, The; Peng, Jun; Wen, Xiaoming; Fu, Xiao; Karuturi, Siva K; White, Thomas P; Weber, Klaus; Catchpole, Kylie R

    2017-06-15

    J-V hysteresis in perovskite solar cells is known to be strongly dependent on many factors ranging from the cell structure to the preparation methods. Here we uncover one likely reason for such sensitivity by linking the stoichiometry in pure CH3NH3PbI3 (MAPbI3) perovskite cells with the character of their hysteresis behavior through the influence of internal band offsets. We present evidence indicating that in some cells the ion accumulation occurring at large forward biases causes a temporary and localized increase in recombination at the MAPbI3/TiO2 interface, leading to inverted hysteresis at fast scan rates. Numerical semiconductor models including ion accumulation are used to propose and analyze two possible origins for these localized recombination losses: one based on band bending and the other on an accumulation of ionic charge in the perovskite bulk.

  9. An X-Ray Fluorescence Study on the Segregation of Cs and I in and Inverted Organic Solar Cell

    SciTech Connect

    Lindemann, William R.; Xiao, Teng; Wang, Wenjie; Berry, Jonna E.; Anderson, Nathaniel A.; Houk, Robert S.; Shinar, Ruth; Shinar, Joseph; Vaknin, David

    2013-10-08

    X-ray near-total-reflection fluorescence reveals that in multilayers of the inverted organic solar cell (ITO/CsI/P3HT:PCBM-based) Cs diffuses into the organic layer and iodide diffuses into the ITO. Laser ablation inductively coupled plasma mass spectrometry measurements, which integrate elemental concentration across the whole multilayer structure, indicate that the Cs:I ratio remains 1:1 confirming there is no loss of iodine from the sample. Iodide diffusion to the bulk ITO layer is also found in a similarly prepared ITO/NaI/P3HT:PCBM multilayer structure. Our results are consistent with recent XPS measurements which show that the Cs:I ratio at the ITO/CsI surface exceeds 8:1, and rationalize this observation.

  10. Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

    PubMed Central

    Seeboth, Arno; Ruhmann, Ralf; Mühling, Olaf

    2010-01-01

    The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field. PMID:28883374

  11. Achieving high performance polymer tandem solar cells via novel materials design

    NASA Astrophysics Data System (ADS)

    Dou, Letian

    Organic photovoltaic (OPV) devices show great promise in low-cost, flexible, lightweight, and large-area energy-generation applications. Nonetheless, most of the materials designed today always suffer from the inherent disadvantage of not having a broad absorption range, and relatively low mobility, which limit the utilization of the full solar spectrum. Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of suitable low-bandgap polymers (near-IR absorbing polymers). In this dissertation, in order to achieve high performance, we focus on design and synthesis of novel low bandgap polymers specifically for tandem solar cells. In Chapter 3, I demonstrate highly efficient single junction and tandem polymer solar cells featuring a spectrally matched low-bandgap conjugated polymer (PBDTT-DPP: bandgap, ˜1.44 eV). The polymer has a backbone based on alternating benzodithiophene and diketopyrrolopyrrole units. A single-layer device based on the polymer provides a power conversion efficiency of ˜6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which was the highest certified efficiency for a polymer solar cell. To further improve this material system, in Chapter 4, I show that the reduction of the bandgap and the enhancement of the charge transport properties of the low bandgap polymer PBDTT-DPP can be accomplished simultaneously by substituting the sulfur atoms on the DPP unit with selenium atoms. The newly designed polymer PBDTT-SeDPP (Eg = 1.38 eV) shows excellent photovoltaic performance in single junction devices with PCEs over 7% and photo-response up to 900 nm. Tandem polymer solar cells based on PBDTT-SeDPP are also demonstrated with a 9.5% PCE, which are more than 10

  12. Significant Stability Enhancement in High-Efficiency Polymer:Fullerene Bulk Heterojunction Solar Cells by Blocking Ultraviolet Photons from Solar Light.

    PubMed

    Jeong, Jaehoon; Seo, Jooyeok; Nam, Sungho; Han, Hyemi; Kim, Hwajeong; Anthopoulos, Thomas D; Bradley, Donal D C; Kim, Youngkyoo

    2016-04-01

    Achievement of extremely high stability for inverted-type polymer:fullerene solar cells is reported, which have bulk heterojunction (BHJ) layers consisting of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-alt-3-fluorothieno[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), by employing UV-cut filter (UCF) that is mounted on the front of glass substrates. The UCF can block most of UV photons below 403 nm at the expense of ≈20% reduction in the total intensity of solar light. Results show that the PTB7-Th:PC71BM solar cell with UCF exhibits extremely slow decay in power conversion efficiency (PCE) but a rapidly decayed PCE is measured for the device without UCF. The poor device stability without UCF is ascribed to the oxidative degradation of constituent materials in the BHJ layers, which give rise to the formation of PC71BM aggregates, as measured with high resolution and scanning transmission electron microscopy and X-ray photoelectron spectroscopy. The device stability cannot be improved by simply inserting poly(ethylene imine) (PEI) interfacial layer without UCF, whereas the lifetime of the PEI-inserted PTB7-Th:PC71BM solar cells is significantly enhanced when UCF is attached.

  13. Switchable Solar Window Devices Based on Polymer Dispersed Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Ma, Dakang; Munday, Jeremy

    Windows are an interesting target for photovoltaics due to the potential for large area of deployment and because glass is already a ubiquitous component of solar cell devices. Many demonstrations of solar windows in recent years have used photovoltaic devices which are semitransparent in the visible region. Much research has focused on enhancing device absorption in the UV and IR ranges as a means to circumvent the basic tradeoff between efficiency and transparency to visible light. Use of switchable solar window is a less investigated alternative approach; these windows utilize the visible spectrum but can toggle between high transparency and high efficiency as needed. We present a novel switchable solar window device based on Polymer Dispersed Liquid Crystals (PDLC). By applying an electric field to the PDLC layer, the device can be switched from an opaque, light diffusing, efficient photovoltaic cell to a clear, transparent window. In the off state (i.e. scattering state), these devices have the added benefits of increased reflectivity for reduced lighting and cooling costs and haze for privacy. Further, we demonstrate that these windows have the potential for self-powering due to the very low power required to maintain the on, or high transparency, state. Support From: University of Maryland and Maryland Nano-center and its Fablab.

  14. Crosslinkable low bandgap polymers for organic solar cells

    NASA Astrophysics Data System (ADS)

    Strohriegl, Peter; Saller, Christina; Knauer, Philipp; Köhler, Anna; Hahn, Tobias; Fischer, Florian; Kahle, Frank-Julian

    2016-09-01

    We present a number of polyfluorene based conjugated polymers with crosslinkable acrylate and oxetane units. These polymers can be crosslinked by free radical polymerization in the case of acrylates and by cationic ring opening polymerization for oxetanes. Upon polymerization densely crosslinked networks are formed which are completely insoluble. We show that the diffusion coefficient of C60 in polyfluorene is reduced by a factor of 1000 by crosslinking. MIS-CELIV measurements are used to monitor changes in the charge carrier mobility upon crosslinking. It shows that using appropriate conditions, e.g. low initiator concentrations or thermal crosslinking, the charge carrier mobility is not reduced by crosslinking. Solution processed three layer organic solar cells were realized with a crosslinkable fluorene based copolymer containing acrylate groups. The efficiency is increased from 1.4% for the reference to 1.8% in the three layer cell with a crosslinked exciton blocking layer. A critical issue of BHJ cells is the instability of the morphology of the polymer:fullerene blend over long operation times at elevated temperature. We present a crosslinkable derivative of the low bandgap polymer PFDTBT which contains oxetane units. BHJ cells with the crosslinked PFDTBT derivative and PCBM were tested in accelerated aging experiments at 100 °C for times up to 100 h. Stabilization was clearly observed in crosslinked BHJ cells compared to the non-crosslinked reference. We show for the first time that oxetane containing polymers can be thermally crosslinked without any added initiator. Initiator free crosslinking is particularly attractive as it avoids the formation of decomposition products, and thus potential electron traps and quenching sites from the initiator.

  15. Incorporation Effect of Silver Nanoparticles on Inverted Type Bulk-Heterojunction Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Matsumoto, Taisuke; Oku, Takeo; Akiyama, Tsuyoshi

    2013-04-01

    A series of bulk-heterojunction organic solar cells incorporating silver nanoparticles was fabricated and evaluated. Silver nanoparticles were incorporated in the hole-transport layer of the solar cells. Plasmonic absorption and the generation of localized surface plasmon resonance of silver nanoparticles were confirmed by absorption and surface enhanced Raman scattering spectra even in the hole-transport material. The incorporation of silver nanoparticles increased photoelectric conversion efficiencies, whose enhancement properties were varied by the incorporation amount of silver nanoparticles.

  16. Efficient, square-centimetre inverted organic solar cell using a metal grid coated transparent electrode (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Subbiah, Jegadesan; Wang, Haotian; Wong, Wallace W. H.; Jones, David J.

    2016-09-01

    The power conversion efficiencies (PCEs) of bulk heterojunction organic photovoltaic (OPV) devices have been reported more than 10%. Recently, in our group, we have achieved a PCE of greater than 11% with an inverted device geometry (device area 0.1 cm2) using a ternary blend comprising, an organic donor polymer, small molecule, and PC71BM, as an active layer. However, the device performance of OSC suffers significant drop with the device area scaling up due to sheet resistance of transparent electrode. In this work, we have used a thin layer of metal grid on top of transparent electrode to reduce the sheet resistance. Using this strategy, we fabricated inverted organic photovoltaic devices with an active layer composed of a ternary blend of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-co-3-fluorothieno[3,4-b] thiophene-2-carboxylate] (PTB7-Th) and small molecule (BTR)1 as the donors and PC71BM as the acceptor and we have achieved the PCE of greater than 8% for square centimetre active area devices. We also studied the role of metal grid thickness as well as geometry and annealing of active layer on the performance of OSCs. 1. K. Sun, Z. Xiao, S. Lu, W. Zajaczkowski, W. Pisula, E. Hanssen, J. M. White, R. M. Williamson, J. Subbiah, J. Ouyang, A. B. Holmes, W. W. H. Wong, D. J. Jones, Nat. Commun. 2015. (DOI: 10.1038/ncomms7013).

  17. Low-bandgap conjugated polymers enabling solution-processable tandem solar cells

    NASA Astrophysics Data System (ADS)

    Li, Gang; Chang, Wei-Hsuan; Yang, Yang

    2017-08-01

    The technology of polymer-based organic photovoltaic (OPV) cells has made great progress in the past decade, with the power conversion efficiency increasing from just a few per cent to around 12%, and the stability increasing from hours to years. One of the important milestones in this progress has been the invention of infrared-absorbing low-bandgap polymers, which allows the OPV cells to form effective tandem structures for harvesting near-infrared energy from the solar spectrum. In this Review, we focus on the progress in low-bandgap conjugated polymers and several tandem OPV cells enabled by these low-bandgap polymers. Specifically, we cover polymer-based tandem solar cells; hybrid tandem solar cells combining polymers with hydrogenated amorphous silicon; and unconventional solar cells. For each of these technologies, we address the challenges and offer our perspectives for future development.

  18. Enhance the light-harvesting capability of the ITO-free inverted small molecule solar cell by ZnO nanorods.

    PubMed

    Lin, Ming-Yi; Wu, Shang-Hsuan; Hsiao, Li-Jen; Budiawan, Widhya; Boopathi, Karunakara Moorthy; Tu, Wei-Chen; Chang, Yia-Chung; Chu, Chih-Wei

    2016-08-08

    The ITO-free inverted SMPV1:PC71BM solar cells with an Al doped ZnO (AZO) transparent electrodes are fabricated. The AZO thin film prepared by pulsed laser deposition (PLD) technique exhibits high transmission (>85%) and low sheet resistance (~30 Ω/sq) and the power conversion efficiency (PCE) of devices based on AZO electrode can reach around 4%. To further enhance the light harvesting of the absorption layer of solar cells, ZnO nanorods interlayer is grown on the AZO layer before the deposition the active layer. The absorption spectrums of devices under various conditions are also simulated by RCWA method to identify the optical saturation length of the ZnO nanorods. The PCE of ITO-free inverted small molecule solar cell improved with ZnO nanorods can reach 6.6%.

  19. Inverted planar NH2CH=NH2PbI3 perovskite solar cells with 13.56% efficiency via low temperature processing.

    PubMed

    Yuan, Da-Xing; Gorka, Adam; Xu, Mei-Feng; Wang, Zhao-Kui; Liao, Liang-Sheng

    2015-08-14

    In this work, NH2CH=NH2PbI3 (FAPbI3) was employed for light harvesting in inverted planer perovskite solar cells for the first time. Except for the silver cathode, all layers were solution-processed under or below 140 °C. The effect of the annealing process on device performance was investigated. The FAPbI3 solar cells based on a slowed-down annealing shows superior performance compared to the CH3NH3PbI3 (MAPbI3)-based devices, especially for the short circuit current density. A power conversion efficiency of 13.56% was obtained with high short circuit current density of 21.48 mA cm(-2). This work paves the way for low-temperature fabrication of efficient inverted planer structure FAPbI3 perovskite solar cells.

  20. High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.

    PubMed

    Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

    2016-05-19

    During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid ( PSS) as the hole transport material (HTM), the hydrophilicity of the PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PSS layer, indicating that CuOx could be a promising HTM for replacing PSS in inverted planar heterojunction perovskite solar cells.

  1. Controlling Active Layer Morphology in Polymer/Fullerene Solar Cells

    NASA Astrophysics Data System (ADS)

    Moungthai, Suchanun; Mahadevapuram, Nikhila; Stein, Gila

    2012-02-01

    The active layer in most polymer solar cells is based on the bulk heterojunction (BHJ) design. BHJs are prepared by arresting the phase separation of a polymer/fullerene blend to produce a nanoscale, interpenetrating network. Such non-equilibrium structures are very difficult to control and reproduce, posing a significant challenge for fundamental structure-property investigations. We demonstrate a new approach to control the active layer morphology with a simple two-step process: First, a thin film of poly(3-hexylthiophene) (P3HT) is cross-linked into stable nanostructures or microstructures with electron-beam lithography [1]. Second, a soluble fullerene is spun-cast on top of the patterned polymer to complete the heterojunction. Significantly, irradiated P3HT films retain good optoelectronic properties and bilayer P3HT/fullerene heterojunctions yield power-conversion efficiencies near 0.5%. We have performed preliminary studies with model nanostructured devices and we find that efficiency increases with interfacial area [2]. These model devices are very valuable for fundamental studies because the interfacial area is accurately measured with small-angle X-ray scattering, and the active layer can be ``deconstructed'' for imaging with atomic force microscopy. [4pt] [1] S. Holdcroft, Adv. Mater. 2001, 13, 1753-1765.[0pt] [2] He et al., Adv Funct. Mater. 2011, 21, 139-146.

  2. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping.

    PubMed

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-11-13

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs.

  3. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping

    PubMed Central

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-01-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs. PMID:26566176

  4. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping

    NASA Astrophysics Data System (ADS)

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-11-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs.

  5. Efficiency enhancement of solution-processed inverted organic solar cells with a carbon-nanotube-doped active layer

    NASA Astrophysics Data System (ADS)

    Lin, Wen-Kai; Su, Shui-Hsiang; Yeh, Meng-Cheng; Huang, Yang-Chan; Yokoyama, Meiso

    2016-01-01

    Solution-processed titanium-doped ZnO (TZO) is synthesized by the sol-gel method to be the electron-transporting layer (ETL) in an inverted organic solar cell (IOSC). Carbon nanotubes (CNTs) are doped into an active layer of poly(3-hexylthiophene):[6,6]-phenyl C 61 butyric acid methyl ester (P3HT:PCBM). The addition of CNTs in the P3HT:PCBM composite increases the conjugation length of P3HT:PCBM:CNTs, which simultaneously enhances the capacity of the composite to absorb solar energy radiation. Vanadium oxide (V2O5) was spin-coated onto the active layer to be a hole-transporting layer (HTL). The power conversion efficiency (PCE) results indicate that the V2O5 nanobelt structure possesses better phase separation and provides a more efficient surface area for the P3HT:PCBM:CNT active layer to increase photocurrent. The optimized IOSCs exhibited an open circuit voltage (Voc), a short-circuit current density (Jsc), a fill factor (FF), and a PCE of 0.55 V, 6.50 mA/cm2, 58.34%, and 2.20%, respectively, under simulated AM1.5G illumination of 100 mW/cm2.

  6. Solar cells based on organic molecules and polymers

    NASA Astrophysics Data System (ADS)

    Salinas, J. F.; Maldonado, J. L.; Ramos-Ortíz, G.; Rodríguez, M.; Meneses-Nava, M. A.; Barbosa-García, O.; Farfán, N.; Santillan, R.

    2009-09-01

    The search of clean, inexpensive and renewable energy sources is one of the most important challenges that the mankind is currently confronting. Recently there has been a notable interest of the scientific community to develop organic photovoltaic (OPV) technology as a mean of renewable energy source since it combines low-cost and easy fabrication. We have fabricated and tested plastic solar devices (OPVs) by using the bulk heterojunction approach. OPVs were prepared by blending 6-Nitro-3-(E)-3-(4-dimethylaminophenyl)allylidene)-2,3 dihydrobenzo[d][1,3,2]-oxazaborole (M1) and (E)-3-(4-Dimethylaminophenyl)allylidene)-2,3-dihydrobenzo[d]-[1,3,2]oxazaborole (M2), which are conjugated and non-linear low molecular weight molecules prepared in our laboratories, and the well known photoconductor polymer MEH-PPV; fullerene PC61BM was the sensitizer. The morphology of thin polymer films prepared by using the spin coating technique was analyzed by Atomic Force Microscopy (AFM). For the electric contact, commercial and transparent indium tin oxide (ITO) deposited on glass slides was used, and a metal alloy of Pb/Bi/Cd/Sn as cathode, was easily deposited on the polymer film by melting the alloy at 75 °C. Open circuit voltages (Voc) of ~ 700 mV and short circuit currents (Jsc) of ~ 0.75 mA/cm2 under solar (AM1.5) illumination were measured for MEH-PPV and M1 based samples. For OPVs cells based on mixtures of either M1 and MEH-PPV or M2 and MEH-PPV there was a large electrical enhancement showing Voc ~ 700 mV and Jsc ~ 2.0 mA/cm2. OPVs cells were also tested under Xe-lamp illumination. Measurements from the I-V curves gave electrical efficiencies close to 1%.

  7. High Efficiency Hybrid Silicon Nanopillar-Polymer Solar Cells

    PubMed Central

    Pudasaini, Pushpa Raj; Ruiz-Zepeda, Francisco; Sharma, Manisha; Elam, David; Ponce, Arturo; Ayon, Arturo A

    2014-01-01

    Recently, inorganic/organic hybrid solar cells have been considered as a viable alternative for low-cost photovoltaic devices because the Schottky junction between inorganic and organic materials can be formed employing low temperature processing methods. We present an efficient hybrid solar cell based on highly ordered silicon nanopillars (SiNPs) and poly (3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS). The proposed device is formed by spin coating the organic polymer PEDOT:PSS on a SiNP array fabricated using metal assisted electroless chemical etching process. The characteristics of the hybrid solar cells are investigated as a function of SiNP height. A maximum power conversion efficiency (PCE) of 9.65% has been achieved for an optimized SiNP array hybrid solar cell with nanopillar height of 400 nm, despite the absence of a back surface field enhancement. The effect of an ultrathin atomic layer deposition (ALD), grown aluminum oxide (Al2O3), as a passivation layer (recombination barrier) has also been studied for the enhanced electrical performance of the device. With the inclusion of the ultrathin ALD deposited Al2O3 between the SiNP array textured surface and the PEDOT:PSS layer, the PCE of the fabricated device was observed to increase to 10.56%, which is ~10% greater than the corresponding device without the Al2O3 layer. The device described herein is considered to be promising toward the realization of a low-cost, high-efficiency inorganic/organic hybrid solar cell. PMID:24032746

  8. High efficiency hybrid silicon nanopillar-polymer solar cells.

    PubMed

    Pudasaini, Pushpa Raj; Ruiz-Zepeda, Francisco; Sharma, Manisha; Elam, David; Ponce, Arturo; Ayon, Arturo A

    2013-10-09

    Recently, inorganic/organic hybrid solar cells have been considered as a viable alternative for low-cost photovoltaic devices because the Schottky junction between inorganic and organic materials can be formed employing low temperature processing methods. We present an efficient hybrid solar cell based on highly ordered silicon nanopillars (SiNPs) and poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS). The proposed device is formed by spin coating the organic polymer PEDOT:PSS on a SiNP array fabricated using metal assisted electroless chemical etching process. The characteristics of the hybrid solar cells are investigated as a function of SiNP height. A maximum power conversion efficiency (PCE) of 9.65% has been achieved for an optimized SiNP array hybrid solar cell with nanopillar height of 400 nm, despite the absence of a back surface field enhancement. The effect of an ultrathin atomic layer deposition (ALD), grown aluminum oxide (Al2O3), as a passivation layer (recombination barrier) has also been studied for the enhanced electrical performance of the device. With the inclusion of the ultrathin ALD deposited Al2O3 between the SiNP array textured surface and the PEDOT:PSS layer, the PCE of the fabricated device was observed to increase to 10.56%, which is ∼10% greater than the corresponding device without the Al2O3 layer. The device described herein is considered to be promising toward the realization of a low-cost, high-efficiency inorganic/organic hybrid solar cell.

  9. Third-generation Cu-In-Ga-(S, Se)-based solar inverters

    NASA Astrophysics Data System (ADS)

    Novikov, G. F.; Gapanovich, M. V.

    2017-02-01

    This paper reviews literature data on thin-film solar cells with absorber layers based on quaternary copper compounds Cu-In-Ga-(S, Se) (CIGS). The paper considers methods of preparation of CIGS layers and discusses the chemical composition, design features, and operating principles of CIGS-based solar cells. The bulk of the recent literature reveals how research in the field is starting to change: important results are being obtained by numerically simulating processes in thin-film solar cells; element concentration gradients in the CIGS structure, spatially nonuniform bandgap energy distribution, and layer grain boundaries are receiving increasing research attention for their respective roles, and the number of kinetic studies is increasing.

  10. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers.

    PubMed

    Inaba, Shusei; Vohra, Varun

    2017-05-09

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED-EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows.

  11. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers

    PubMed Central

    Inaba, Shusei; Vohra, Varun

    2017-01-01

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED–EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows. PMID:28772878

  12. Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

    PubMed

    He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-07-29

    This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

  13. High-Performance Nonfullerene Polymer Solar Cells based on Imide-Functionalized Wide-Bandgap Polymers.

    PubMed

    Fan, Baobing; Zhang, Kai; Jiang, Xiao-Fang; Ying, Lei; Huang, Fei; Cao, Yong

    2017-03-23

    High-performance nonfullerene polymer solar cells (PSCs) are developed by integrating the nonfullerene electron-accepting material 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophne) (ITIC) with a wide-bandgap electron-donating polymer PTzBI or PTzBI-DT, which consists of an imide functionalized benzotriazole (TzBI) building block. Detailed investigations reveal that the extension of conjugation can affect the optical and electronic properties, molecular aggregation properties, charge separation in the bulk-heterojunction films, and thus the overall photovoltaic performances. Single-junction PSCs based on PTzBI:ITIC and PTzBI-DT:ITIC exhibit remarkable power conversion efficiencies (PCEs) of 10.24% and 9.43%, respectively. To our knowledge, these PCEs are the highest efficiency values obtained based on electron-donating conjugated polymers consisting of imide-functionalized electron-withdrawing building blocks. Of particular interest is that the resulting device based on PTzBI exhibits remarkable PCE of 7% with the thickness of active layer of 300 nm, which is among the highest values of nonfullerene PSCs utilizing thick photoactive layer. Additionally, the device based on PTzBI:ITIC exhibits prominent stability, for which the PCE remains as 9.34% after thermal annealing at 130 °C for 120 min. These findings demonstrate the great promise of using this series of wide-bandgap conjugated polymers as electron-donating materials for high-performance nonfullerene solar cells toward high-throughput roll-to-roll processing technology.

  14. High-performance all-polymer solar cells via side-chain engineering of the polymer acceptor: the importance of the polymer packing structure and the nanoscale blend morphology.

    PubMed

    Lee, Changyeon; Kang, Hyunbum; Lee, Wonho; Kim, Taesu; Kim, Ki-Hyun; Woo, Han Young; Wang, Cheng; Kim, Bumjoon J

    2015-04-17

    The effectiveness of side-chain engineering is demonstrated to produce highly efficient all-polymer solar cells (efficiency of 5.96%) using a series of naphthalene diimide-based polymer acceptors with controlled side chains. The dramatic changes in the polymer packing, blend morphology, and electron mobility of all-polymer solar cells elucidate clear trends in the photovoltaic performances.

  15. Hexaazatrinaphthylene derivatives: Efficient electron-transporting materials with tunable energy levels for inverted perovskite solar cells

    DOE PAGES

    Zhao, Dongbing; Zhu, Zonglong; Kuo, Ming -Yu; ...

    2016-06-08

    Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6% with negligible hysteresis. Furthermore, this study provides one of the first nonfullerene small-moleculebased ETMs for high-performance p–i–n PVSCs.

  16. Dual-Source Precursor Approach for Highly Efficient Inverted Planar Heterojunction Perovskite Solar Cells.

    PubMed

    Luo, Deying; Zhao, Lichen; Wu, Jiang; Hu, Qin; Zhang, Yifei; Xu, Zhaojian; Liu, Yi; Liu, Tanghao; Chen, Ke; Yang, Wenqiang; Zhang, Wei; Zhu, Rui; Gong, Qihuang

    2017-03-15

    The highest efficiencies reported for perovskite solar cells so far have been obtained mainly with methylammonium and formamidinium mixed cations. Currently, high-quality mixed-cation perovskite thin films are normally made by use of antisolvent protocols. However, the widely used "antisolvent"-assisted fabrication route suffers from challenges such as poor device reproducibility, toxic and hazardous organic solvent, and incompatibility with scalable fabrication process. Here, a simple dual-source precursor approach is developed to fabricate high-quality and mirror-like mixed-cation perovskite thin films without involving additional antisolvent process. By integrating the perovskite films into the planar heterojunction solar cells, a power conversion efficiency of 20.15% is achieved with negligible current density-voltage hysteresis. A stabilized power output approaching 20% is obtained at the maximum power point. These results shed light on fabricating highly efficient perovskite solar cells via a simple process, and pave the way for solar cell fabrication via scalable methods in the near future.

  17. Hexaazatrinaphthylene Derivatives: Efficient Electron-Transporting Materials with Tunable Energy Levels for Inverted Perovskite Solar Cells.

    PubMed

    Zhao, Dongbing; Zhu, Zonglong; Kuo, Ming-Yu; Chueh, Chu-Chen; Jen, Alex K-Y

    2016-07-25

    Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6 % with negligible hysteresis. This study provides one of the first nonfullerene small-molecule-based ETMs for high-performance p-i-n PVSCs.

  18. Effects of Alkylthio and Alkoxy Side Chains in Polymer Donor Materials for Organic Solar Cells.

    PubMed

    Cui, Chaohua; Wong, Wai-Yeung

    2016-02-01

    Side chains play a considerable role not only in improving the solubility of polymers for solution-processed device fabrication, but also in affecting the molecular packing, electron affinity and thus the device performance. In particular, electron-donating side chains show unique properties when employed to tune the electronic character of conjugated polymers in many cases. Therefore, rational electron-donating side chain engineering can improve the photovoltaic properties of the resulting polymer donors to some extent. Here, a survey of some representative examples which use electron-donating alkylthio and alkoxy side chains in conjugated organic polymers for polymer solar cell applications will be presented. It is envisioned that an analysis of the effect of such electron-donating side chains in polymer donors would contribute to a better understanding of this kind of side chain behavior in solution-processed conjugated organic polymers for polymer solar cells.

  19. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    PubMed

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-05

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  20. Inverted bulk-heterojunction solar cell with cross-linked hole-blocking layer

    PubMed Central

    Udum, Yasemin; Denk, Patrick; Adam, Getachew; Apaydin, Dogukan H.; Nevosad, Andreas; Teichert, Christian; S. White, Matthew.; S. Sariciftci, Niyazi.; Scharber, Markus C.

    2014-01-01

    We have developed a hole-blocking layer for bulk-heterojunction solar cells based on cross-linked polyethylenimine (PEI). We tested five different ether-based cross-linkers and found that all of them give comparable solar cell efficiencies. The initial idea that a cross-linked layer is more solvent resistant compared to a pristine PEI layer could not be confirmed. With and without cross-linking, the PEI layer sticks very well to the surface of the indium–tin–oxide electrode and cannot be removed by solvents used to process PEI or common organic semiconductors. The cross-linked PEI hole-blocking layer functions for multiple donor–acceptor blends. We found that using cross-linkers improves the reproducibility of the device fabrication process. PMID:24817837

  1. Screen printed silver top electrode for efficient inverted organic solar cells

    SciTech Connect

    Kim, Junwoo; Duraisamy, Navaneethan; Lee, Taik-Min; Kim, Inyoung; Choi, Kyung-Hyun

    2015-10-15

    Highlights: • Screen printing of silver pattern. • X-ray diffraction pattern confirmed the face centered cubic structure of silver. • Uniform surface morphology of silver pattern with sheet resistance of 0.06 Ω/sq. • The power conversion efficiency of fabricated solar cell is found to be 2.58%. - Abstract: The present work is mainly focused on replacement of the vacuum process for top electrode fabrication in organic solar cells. Silver top electrode deposited through solution based screen printing on pre-deposited polymeric thin film. The solution based printing technology provides uniform top electrode without damaging the underlying organic layers. The surface crystallinity and surface morphology of silver top electrode are examined through X-ray diffraction, field-emission scanning electron microscope and atomic force microscope. The purity of silver is examined through X-ray energy dispersive spectroscopy. The top electrode exhibits face centered cubic structure with homogeneous morphology. The sheet resistance of top electrode is found to be 0.06 Ω/sq and an average pattern thickness of ∼15 μm. The power conversion efficiency is 2.58%. Our work demonstrates that the solution based screen printing is a significant role in the replacement of vacuum process for the fabrication of top electrode in organic solar cells.

  2. High Efficiency Inverted Planar Perovskite Solar Cells with Solution-Processed NiOx Hole Contact.

    PubMed

    Yin, Xuewen; Yao, Zhibo; Luo, Qiang; Dai, Xuezeng; Zhou, Yu; Zhang, Ye; Zhou, Yangying; Luo, Songping; Li, Jianbao; Wang, Ning; Lin, Hong

    2017-01-25

    NiOx is a promising hole-transporting material for perovskite solar cells due to its high hole mobility, good stability, and easy processability. In this work, we employed a simple solution-processed NiOx film as the hole-transporting layer in perovskite solar cells. When the thickness of the perovskite layer increased from 270 to 380 nm, the light absorption and photogenerated carrier density were enhanced and the transporting distance of electron and hole would also increase at the same time, resulting in a large charge transfer resistance and a long hole-extracted process in the device, characterized by the UV-vis, photoluminescence, and electrochemical impedance spectroscopy spectra. Combining both of these factors, an optimal thickness of 334.2 nm was prepared with the perovskite precursor concentration of 1.35 M. Moreover, the optimal device fabrication conditions were further achieved by optimizing the thickness of NiOx hole-transporting layer and PCBM electron selective layer. As a result, the best power conversion efficiency of 15.71% was obtained with a Jsc of 20.51 mA·cm(-2), a Voc of 988 mV, and a FF of 77.51% with almost no hysteresis. A stable efficiency of 15.10% was caught at the maximum power point. This work provides a promising route to achieve higher efficiency perovskite solar cells based on NiO or other inorganic hole-transporting materials.

  3. Single Wall Carbon Nanotube-polymer Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Castro, Stephanie L.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2005-01-01

    Investigation of single wall carbon nanotube (SWNT)-polymer solar cells has been conducted towards developing alternative lightweight, flexible devices for space power applications. Photovoltaic devices were constructed with regioregular poly(3-octylthiophene)-(P3OT) and purified, >95% w/w, laser-generated SWNTs. The P3OT composites were deposited on ITO-coated polyethylene terapthalate (PET) and I-V characterization was performed under simulated AM0 illumination. Fabricated devices for the 1.0% w/w SWNT-P3OT composites showed a photoresponse with an open-circuit voltage (V(sub oc)) of 0.98 V and a short-circuit current density (I(sub sc)) of 0.12 mA/sq cm. Optimization of carrier transport within these novel photovoltaic systems is proposed, specifically development of nanostructure-SWNT complexes to enhance exciton dissociation.

  4. Perovskite/polymer solar cells prepared using solution process

    NASA Astrophysics Data System (ADS)

    Rosa, E. S.; Shobih; Nursam, N. M.; Saputri, D. G.

    2016-11-01

    We report a simple solution-based process to fabricate a perovskite/polymer tandem solar cell using inorganic CH3NH3PM3 as an absorber and organic PCBM (6,6 phenyl C61- butyric acid methyl ester) as an electron transport layer. The absorber solution was prepared by mixing the CH3NH3I (methyl ammonium iodide) with PbI2 (lead iodide) in DMF (N,N- dimethyl formamide) solvent. The absorber and electron transport layer were deposited by spin coating method. The electrical characteristics generated from the cell under 50 mW/cm2 at 25 °C comprised of an open circuit voltage of 0.31 V, a short circuit current density of 2.53 mA/cm2, and a power conversion efficiency of 0.42%.

  5. Polythiophenes Comprising Conjugated Pendants for Polymer Solar Cells: A Review

    PubMed Central

    Wang, Hsing-Ju; Chen, Chih-Ping; Jeng, Ru-Jong

    2014-01-01

    Polythiophene (PT) is one of the widely used donor materials for solution-processable polymer solar cells (PSCs). Much progress in PT-based PSCs can be attributed to the design of novel PTs exhibiting intense and broad visible absorption with high charge carrier mobility to increase short-circuit current density (Jsc), along with low-lying highest occupied molecular orbital (HOMO) levels to achieve large open circuit voltage (Voc) values. A promising strategy to tailor the photophysical properties and energy levels via covalently attaching electron donor and acceptor pendants on PTs backbone has attracted much attention recently. The geometry, electron-donating capacity, and composition of conjugated pendants are supposed to be the crucial factors in adjusting the conformation, energy levels, and photovoltaic performance of PTs. This review will go over the most recent approaches that enable researchers to obtain in-depth information in the development of PTs comprising conjugated pendants for PSCs. PMID:28788575

  6. Fused Nonacyclic Electron Acceptors for Efficient Polymer Solar Cells.

    PubMed

    Dai, Shuixing; Zhao, Fuwen; Zhang, Qianqian; Lau, Tsz-Ki; Li, Tengfei; Liu, Kuan; Ling, Qidan; Wang, Chunru; Lu, Xinhui; You, Wei; Zhan, Xiaowei

    2017-01-25

    We design and synthesize four fused-ring electron acceptors based on 6,6,12,12-tetrakis(4-hexylphenyl)-indacenobis(dithieno[3,2-b;2',3'-d]thiophene) as the electron-rich unit and 1,1-dicyanomethylene-3-indanones with 0-2 fluorine substituents as the electron-deficient units. These four molecules exhibit broad (550-850 nm) and strong absorption with high extinction coefficients of (2.1-2.5) × 10(5) M(-1) cm(-1). Fluorine substitution downshifts the LUMO energy level, red-shifts the absorption spectrum, and enhances electron mobility. The polymer solar cells based on the fluorinated electron acceptors exhibit power conversion efficiencies as high as 11.5%, much higher than that of their nonfluorinated counterpart (7.7%). We investigate the effects of the fluorine atom number and position on electronic properties, charge transport, film morphology, and photovoltaic properties.

  7. Nanostructure control in polymer solar cells by self-organization.

    PubMed

    Tajima, Keisuke; Hashimoto, Kazuhito

    2011-02-01

    Recently, polymer solar cells (PSCs) based on "bulk heterojunctions" using a simple mixture of electron donor and acceptor materials in thin films have been extensively studied. Although relatively high power conversion efficiencies have been achieved by using this approach, further improvement is necessary to precisely construct stable, reproducible nanostructures that are suitable for both efficient charge separation and transport inside such films. For this purpose, it is highly desirable to utilize a bottom-up approach, such as the self-organized formation of inorganic and organic nanostructures. In this review, an overview of our recent studies on the control of nanostructures in PSCs is presented. Copyright © 2011 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

  8. Nanotube/Quantum Dot-Polymer Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Raffaelle, Ryne P.; Landi, Brian J.; Castro, Stephanie L.

    2005-01-01

    Single wall carbon nanotubes used or this study were synthesized using the pulse laser vaporization technique. The as-produced SWNTs were collected from the condensed region on the quartz tube outside the furnace and purified by modification of the previously reported procedure. Preparation of the SWNT-P3OT composite solutions was performed using a series of mixing and sonication steps as previously demonstrated for other SWNT-polymer systems. Device fabrication involved the use of commercially-obtained, high quality (i.e., less than 10 W/sq.) ITO-coated polyethylene terapthalate (PET) substrates. Initially, an intrinsic layer of pristine P3OT is spray deposited (approx. 1-2 mL of the 15 mg/mL solution) onto the masked, 1 sq in. active area of the substrate. This is followed with spray deposition of the SWNT-P3OT composite solutions at similar volumes. As seen completion of the solar cell occurs when aluminum contacts (typical thicknesses of l000A) are applied to the IT0 and SWNT-P3OT composite film layers. The homogeneous distribution of SWNTs in a polymer matrix is dependent upon the ability of the polymer chain to associate with the SWNT superstructure. Stable composite dispersions of 0.1 % and 1.0% w/w SWNTs in P3OT were produced and analyzed in this study. Optical spectroscopy was conducted to observe the SWNT doping level effects on the absorption properties and infer potential electronic interactions between dopant and polymer. Shown is an overlay of these spectra where the pristine P3OT shows strong optical absorption at energies less than 2 eV. As expected, variation in absorption properties for the SWNT-P3OT composites is observed as the doping level increases. Through modification of the SWNT doping level in the polymer, it is possible to alter the absorption pattern of these composite materials. In fact, at these relatively low doping levels, the P3OT shows a significant enhancement in absorption through the near-IR and visible regions. The gray curve

  9. Solution-processed inverted organic solar cell using V2O5 hole transport layer and vacuum free EGaIn anode

    NASA Astrophysics Data System (ADS)

    Ongul, Fatih

    2015-12-01

    In this study, the sol-gel V2O5 derived by a hydrothermal method to replace the PEDOT:PSS which is a hole transport layer between organic active layer and two different anodes in inverted organic solar cells with TiO2 as an electron transport layer was investigated. The power conversion efficiencies of inverted organic photovoltaic cells increased approximately twofold with using V2O5 instead of PEDOT:PSS on top of the photoactive layer. It was demonstrated that the power conversion efficiencies of inverted organic solar cells prepared with V2O5 solution which was diluted with isopropanol in certain proportions by volume were decreased by increasing ratio of isopropanol in total volume. It was reported for the first time that the inverted organic photovoltaic cells prepared using V2O5 interlayer and Eutectic Gallium-Indium alloy which was prepared using vacuum free simple brush-painted method and can be used as anode electrode as Ag electrode.

  10. Annealing Effect on (FAPbI₃)1-x(MAPbBr₃)x Perovskite Films in Inverted-Type Perovskite Solar Cells.

    PubMed

    Chen, Lung-Chien; Wu, Jia-Ren; Tseng, Zhong-Liang; Chen, Cheng-Chiang; Chang, Sheng Hsiung; Huang, Jun-Kai; Lee, King-Lien; Cheng, Hsin-Ming

    2016-09-03

    This study determines the effects of annealing treatment on the structure and the optical and electronic behaviors of the mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite system. The experimental results reveal that (FAPbI₃)1-x(MAPbBr₃)x (x ~ 0.2) is an effective light-absorbing material for use in inverted planar perovskite solar cells owing to its large absorbance and tunable band gap. Therefore, good band-matching between the (FAPbI₃)1-x(MAPbBr₃)x and C60 in photovoltaic devices can be controlled by annealing at various temperatures. Accordingly, an inverted mixed perovskite solar cell with a record efficiency of 12.0% under AM1.5G irradiation is realized.

  11. Effects of nanostructure geometry on polymer chain alignment and device performance in nanoimprinted polymer solar cell

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Mielczarek, Kamil; Zakhidov, Anvar; Hu, Walter

    2013-03-01

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. This article demonstrates our recent studies on the nanostructure geometry effects on the nanoimprint induced poly(3 hexylthiophene-2,5-diyl) (P3HT) chain alignment and photovoltaic performance. Out-of-plane and in-plane grazing incident X-ray diffractions are employed to characterize the chain orientations in P3HT nanogratings with different widths and heights. It is found that nanoimprint procedure changes the initial edge-on alignment in non-imprinted P3HT thin film to a vertical orientation which favors the hole transport, with an organization height H≥ 170 nm and width in the range of 60 nm<= W< 210 nm. Samples with better aligned molecules lead to a larger crystallite sizes as well. Imprinted P3HT/[6,6]-penyl-C61-butyric-acid-methyl-ester (PCBM) solar cells show an increase in power conversion efficiency (PCE) with the decrease of nanostructure width, and with the increase of height and junction area. Devices with the highest PCE are made by the fully aligned and highest P3HT nanostructures (width w= 60 nm, height h= 170 nm), allowing for the most efficient charge separation, transport and light absorption. We believe this work will contribute to the optimal geometry design of nanoimprinted polymer solar cells.

  12. A new class of semiconducting polymers for bulk heterojunction solar cells with exceptionally high performance.

    PubMed

    Liang, Yongye; Yu, Luping

    2010-09-21

    Solar cells based on the polymer-fullerene bulk heterojunction (BHJ) concept are an attractive class of low-cost solar energy harvesting devices. Because the power conversion efficiency (PCE) of these solar cells is still significantly lower than that of their inorganic counterparts, however, materials design and device engineering efforts are directed toward improving their output. A variety of factors limit the performance of BHJ solar cells, but the properties of the materials in the active layer are the primary determinant of their overall efficiency. The ideal polymer in a BHJ structure should exhibit the following set of physical properties: a broad absorption with high coefficient in the solar spectrum to efficiently harvest solar energy, a bicontinuous network with domain width within twice that of the exciton diffusion length, and high donor-acceptor interfacial area to favor exciton dissociation and efficient transport of separated charges to the respective electrodes. To facilitate exciton dissociation, the lowest unoccupied molecular orbital (LUMO) energy level of the donor must have a proper match with that of the acceptor to provide enough driving force for charge separation. The polymer should have a low-lying highest occupied molecular orbital (HOMO) energy level to provide a large open circuit voltage (V(oc)). All of these desired properties must be synergistically integrated to maximize solar cell performance. However, it is difficult to design a polymer to fulfill all these requirements. In this Account, we summarize our recent progress in developing a new class of semiconducting polymers, which represents the first polymeric system to generate solar PCE greater than 7%. The polymer system is composed of thieno[3,4-b]thiophene and benzodithiophene alternating units. These polymers have low bandgaps and exhibit efficient absorption throughout the region of greatest photon flux in the solar spectrum (around 700 nm). The stabilization of the

  13. Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Zhou, Suqiong; Yang, Zhenhai; Gao, Pingqi; Li, Xiaofeng; Yang, Xi; Wang, Dan; He, Jian; Ying, Zhiqin; Ye, Jichun

    2016-04-01

    Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm2, which is about 76 % higher than the flat counterpart (22.63 mA/cm2) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm2). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

  14. Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells.

    PubMed

    Zhou, Suqiong; Yang, Zhenhai; Gao, Pingqi; Li, Xiaofeng; Yang, Xi; Wang, Dan; He, Jian; Ying, Zhiqin; Ye, Jichun

    2016-12-01

    Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

  15. Fluorine Functionalized Graphene Nano Platelets for Highly Stable Inverted Perovskite Solar Cells.

    PubMed

    Kim, Gi-Hwan; Jang, Hyungsu; Yoon, Yung Jin; Jeong, Jaeki; Park, Song Yi; Walker, Bright; Jeon, In-Yup; Jo, Yimhyun; Yoon, Hyun; Kim, Minjin; Baek, Jong-Beom; Kim, Dong Suk; Kim, Jin Young

    2017-09-14

    Edged-selectively fluorine (F) functionalized graphene nanoplatelets (EFGnPs-F) with a p-i-n structure of perovskite solar cells achieved 82% stability relative to initial performance over 30 days of air exposure without encapsulation. The enhanced stability stems from F-substitution on EFGnPs; fluorocarbons such as polytetrafluoroethylene are well-known for their superhydrophobic properties and being impervious to chemical degradation. These hydrophobic moieties tightly protect perovskite layers from air degradation. To directly compare the effect of similar hydrophilic graphene layers, edge-selectively hydrogen functionalized graphene nanoplatelet (EFGnPs-H) treated devices were tested under the same conditions. Like the pristine MAPbI3 perovskite devices, EFGnPs-H treated devices were completely degraded after 10 days. The hydrophobic properties of EFGnPs-F were characterized by contact angle measurement. The test results showed great water repellency compared to pristine perovskite films or EFGnPs-H coated films. This resulted in highly air-stable p-i-n perovskite solar cells.

  16. Comparison between conventional and inverted solar cells using open circuit voltage decay transients

    NASA Astrophysics Data System (ADS)

    Verma, Upkar K.; Kumar, Sunil; Mohapatra, Y. N.

    2017-08-01

    In the development of new structures for solar cells, it has become important to extract the true ideality factor of a diode, disentangling it from other loss mechanisms in the device. We use the open circuit voltage decay (OCVD) transient to obtain ideality factors and isolate the internal loss mechanisms in P3HT:PCBM bulk heterojunction solar cells. We compare two different structures using OCVD transients over more than six orders in timescale. The equivalent circuit parameters of diodes can be reliably extracted from such decays. Specifically, the numerical solution of the transient allows the determination of the diode ideality factor, and the saturation leakage current. In addition, this technique makes it possible to determine the diode current in the presence of excess carriers under photo irradiance, and hence, the light induced recombination current and shunt resistance can be separately extracted. We compare the decay transients of an efficient device with a leaky device and demonstrate that the diode current changes in the same manner in both the cases. We study in detail the intensity power-law dependence of the recombination current that controls the decay transient and observe that it increases significantly faster in leaky devices with light intensity.

  17. Characteristics of SnO2:Sb Films as Transparent Conductive Electrodes of Flexible Inverted Organic Solar Cells.

    PubMed

    Lee, Jaehyeong; Kim, Nam-Hoon; Park, Yong Seob

    2016-05-01

    Antimony-doped tin oxide (ATO) films were deposited on polyethersulfone (PES) substrates by means of a radio frequency (RF) magnetron sputtering method, using a SnO2 target mixed with 6 wt% Sb at room temperature and using various RF powers; these films were used as transparent electrodes in inverted organic solar cells (IOSC). We investigated the structural, optical, and electrical properties of the resulting films by means of various analyses, including X-ray diffraction (XRD), UV-visible spectroscopy, and Hall effect measurements. The crystallinity and conductivity of the ATO films were increased by increasing the RF power used. Based on the experimental data acquired, we fabricated IOSCs based on ATO electrodes deposited by using various conditions. Each IOSC device was composed of an ATO electrode, a ZnO buffer layer, a photoactive layer (P3HT:PCBM), and an Al cathode. The IOSC based on an ATO electrode fabricated at the RF power of 160 W exhibited good device performance due to the electrode's high conductivity and crystallinity.

  18. Improvement of Charge Collection and Performance Reproducibility in Inverted Organic Solar Cells by Suppression of ZnO Subgap States.

    PubMed

    Wu, Bo; Wu, Zhenghui; Yang, Qingyi; Zhu, Furong; Ng, Tsz-Wai; Lee, Chun-Sing; Cheung, Sin-Hang; So, Shu-Kong

    2016-06-15

    Organic solar cells (OSCs) with inverted structure usually exhibit higher power conversion efficiency (PCE) and are more stable than corresponding devices with regular configuration. Indium tin oxide (ITO) surface is often modified with solution-processed low work function metal oxides, such as ZnO, serving as the transparent cathode. However, the defect-induced subgap states in the ZnO interlayer hamper the efficient charge collection and the performance reproducibility of the OSCs. In this work, we demonstrate that suppression of the ZnO subgap states by modification of its surface with an ultrathin Al layer significantly improves the charge extraction and performance reproducibility, achieving PCE of 8.0%, which is ∼15% higher than that of a structurally identical control cell made with a pristine ZnO interlayer. Light intensity-dependent current density-voltage characteristic, photothermal deflection spectroscopy, and X-ray photoelectron spectroscopy measurements point out the enhancement of charge collection efficiency at the organic/cathode interface, due to the suppression of the subgap states in the ZnO interlayer.

  19. Correlating high power conversion efficiency of PTB7:PC71BM inverted organic solar cells with nanoscale structures.

    PubMed

    Das, Sanjib; Keum, Jong K; Browning, James F; Gu, Gong; Yang, Bin; Dyck, Ondrej; Do, Changwoo; Chen, Wei; Chen, Jihua; Ivanov, Ilia N; Hong, Kunlun; Rondinone, Adam J; Joshi, Pooran C; Geohegan, David B; Duscher, Gerd; Xiao, Kai

    2015-10-14

    Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their "conventional" counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.

  20. Correlating high power conversion efficiency of PTB7:PC 71 BM inverted organic solar cells with nanoscale structures

    DOE PAGES

    Das, Sanjib; Keum, Jong K.; Browning, James F.; ...

    2015-06-16

    Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their “conventional” counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a wellestablished bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3’-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifyinglayer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that themore » high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.« less

  1. Electrospun ZnO nanowire plantations in the electron transport layer for high-efficiency inverted organic solar cells.

    PubMed

    Elumalai, Naveen Kumar; Jin, Tan Mein; Chellappan, Vijila; Jose, Rajan; Palaniswamy, Suresh Kumar; Jayaraman, Sundaramurthy; Raut, Hemant Kumar; Ramakrishna, Seeram

    2013-10-09

    Inverted bulk heterojunction organic solar cells having device structure ITO/ZnO/poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61 butyric acid methyl ester (PCBM) /MoO3/Ag were fabricated with high photoelectric conversion efficiency and stability. Three types of devices were developed with varying electron transporting layer (ETL) ZnO architecture. The ETL in the first type was a sol-gel-derived particulate film of ZnO, which in the second and third type contained additional ZnO nanowires of varying concentrations. The length of the ZnO nanowires, which were developed by the electrospinning technique, extended up to the bulk of the photoactive layer in the device. The devices those employed a higher loading of ZnO nanowires showed 20% higher photoelectric conversion efficiency (PCE), which mainly resulted from an enhancement in its fill factor (FF). Charge transport characteristic of the device were studied by transient photovoltage decay and charge extraction by linearly increasing voltage techniques. Results show that higher PCE and FF in the devices employed ZnO nanowire plantations resulted from improved charge collection efficiency and reduced recombination rate.

  2. Electrolytes as Cathode Interlayers in Inverted Organic Solar Cells: Influence of the Cations on Bias-Dependent Performance.

    PubMed

    Li, Yaru; Liu, Xiaohui; Li, Xiaodong; Zhang, Wenjun; Xing, Feifei; Fang, Junfeng

    2017-03-08

    The performance of organic solar cells (OSCs) with edetate electrolytes depends on external bias, and ions are speculated to be responsible for this phenomenon. To clarify the detailed relationship between the ions of electrolytes and the bias-dependent behaviors of devices, this work introduces four edetate cathode interlayers (EDTA-X, X = nH(4-n)Na, n = 0, 1, 2, and 4) containing different kinds and number of cations into inverted OSCs. The results show that the devices initial and saturated (after external bias treatment) power conversion efficiencies (PCEs) both decrease with the increase in the number of H(+). Moreover, the bias-dependent degrees increase with the increase in H(+) number; with that, the PCE increment of EDTA-4H device is 53.4%, while that of the EDTA-4Na device is almost unchanged. The electrical impedance spectroscopy and capacitance-voltage tests reveal that the interfacial recombination is greatly suppressed by external bias treatment, which is not a result of the decreased density of defect states. The results indicate that the ion's motion, specifically the H(+) motion, under external electrical field is responsible for the bias-dependent behavior, which is conducive to the design of new efficient electrolytic interlayers without bias-dependent performance.

  3. Correlating high power conversion efficiency of PTB7:PC 71 BM inverted organic solar cells with nanoscale structures

    SciTech Connect

    Das, Sanjib; Keum, Jong K.; Browning, James F.; Gu, Gong; Yang, Bin; Dyck, Ondrej; Do, Changwoo; Chen, Wei; Chen, Jihua; Ivanov, Ilia N.; Hong, Kunlun; Rondinone, Adam J.; Joshi, Pooran C.; Geohegan, David B.; Duscher, Gerd; Xiao, Kai

    2015-06-16

    Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their “conventional” counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a wellestablished bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3’-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifyinglayer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.

  4. Optimization of an Electron Transport Layer to Enhance the Power Conversion Efficiency of Flexible Inverted Organic Solar Cells.

    PubMed

    Lee, Kang Hyuck; Kumar, Brijesh; Park, Hye-Jeong; Kim, Sang-Woo

    2010-08-31

    The photovoltaic (PV) performance of flexible inverted organic solar cells (IOSCs) with an active layer consisting of a blend of poly(3-hexylthiophene) and [6, 6]-phenyl C(61)-butlyric acid methyl ester was investigated by varying the thicknesses of ZnO seed layers and introducing ZnO nanorods (NRs). A ZnO seed layer or ZnO NRs grown on the seed layer were used as an electron transport layer and pathway to optimize PV performance. ZnO seed layers were deposited using spin coating at 3,000 rpm for 30 s onto indium tin oxide (ITO)-coated polyethersulphone (PES) substrates. The ZnO NRs were grown using an aqueous solution method at a low temperature (90°C). The optimized device with ZnO NRs exhibited a threefold increase in PV performance compared with that of a device consisting of a ZnO seed layer without ZnO NRs. Flexible IOSCs fabricated using ZnO NRs with improved PV performance may pave the way for the development of PV devices with larger interface areas for effective exciton dissociation and continuous carrier transport paths.

  5. Thermodynamically self-organized hole transport layers for high-efficiency inverted-planar perovskite solar cells.

    PubMed

    Kim, Wanjung; Kim, Soyeon; Chai, Sung Uk; Jung, Myung Sun; Nam, Jae Keun; Kim, Jung-Hyun; Park, Jong Hyeok

    2017-08-31

    Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a popular and promising hole transport material for making efficient inverted-planar perovskite solar cells (IP-PSCs). However, the mismatch between the work function of conventional PEDOT:PSS and the valence band maximum of perovskite materials is still a challenge for efficient hole extraction. Here, we report systematic studies on the work-function modification and thermodynamic morphological evolution of PEDOT:PSS films by tuning the PSS/PEDOT ratio, along with its effects on the photovoltaic responses of IP-PSCs. We found that the open-circuit voltage (VOC) of an IP-PSC could be enhanced by controlling the work function of PEDOT:PSS. Furthermore, the optical transmittance of the PEDOT:PSS film could be maximized by controlling the morphological evolution, which will further increase the short-circuit current density (JSC) of the IP-PSC. The VOC and JSC of the IP-PSC with the optimized PEDOT:PSS composition increased from 0.88 to 0.93 V and from 17.11 to 20.77 mA cm(-2), respectively, compared with an IP-PSC containing commercial PEDOT:PSS, which results in a power conversion energy that is greatly improved from 12.39 to 15.24%.

  6. Highly efficient organic solar cells with improved vertical donor-acceptor compositional gradient via an inverted off-center spinning method

    SciTech Connect

    Huang, Jiang; Carpenter, Joshua H.; Li, Chang -Zhi; Yu, Jun -Sheng; Ade, Harald; Jen, Alex K. -Y.

    2015-12-02

    A novel, yet simple solution fabrication technique to address the trade-off between photocurrent and fill factor in thick bulk heterojunction organic solar cells is described. Lastly, the inverted off-center spinning technique promotes a vertical gradient of the donor–acceptor phase-separated morphology, enabling devices with near 100% internal quantum efficiency and a high power conversion efficiency of 10.95%.

  7. Highly Efficient Organic Solar Cells with Improved Vertical Donor-Acceptor Compositional Gradient Via an Inverted Off-Center Spinning Method.

    PubMed

    Huang, Jiang; Carpenter, Joshua H; Li, Chang-Zhi; Yu, Jun-Sheng; Ade, Harald; Jen, Alex K-Y

    2016-02-03

    A novel, yet simple solution fabrication technique to address the trade-off between photocurrent and fill factor in thick bulk heterojunction organic solar cells is described. The inverted off-center spinning technique promotes a vertical gradient of the donor-acceptor phase-separated morphology, enabling devices with near 100% internal quantum efficiency and a high power conversion efficiency of 10.95%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Magnetron Sputtered Molybdenum Oxide for Application in Polymers Solar Cells

    NASA Astrophysics Data System (ADS)

    Sendova-Vassileva, M.; Dikov, Hr; Vitanov, P.; Popkirov, G.; Gergova, R.; Grancharov, G.; Gancheva, V.

    2016-10-01

    Thin films of molybdenum oxide were deposited by radio frequency (RF) magnetron sputtering in Ar from a MoO3 target at different deposition power on glass and silicon substrates. The thickness of the films was determined by profilometer measurements and by ellipsometry. The films were annealed in air at temperatures between 200 and 400°C in air. The optical transmission and reflection spectra were measured. The conductivity of the as deposited and annealed films was determined. The crystal structure was probed by Raman spectroscopy. The oxidation state of the surface was studied by X-ray photoelectron spectroscopy (XPS) spectroscopy. The deposition technique described above was used to experiment with MoOx as a hole transport layer (HTL) in polymer solar cells with bulk hetrojunction active layer, deposited by spin coating. The performance of these layers was compared with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), which is the standard material used in this role. The measured current-voltage characteristics of solar cells with the structure glass/ITO/HTL/Poly(3-hexyl)thiophene (P3HT):[6,6]-phenyl-C61- butyric acid methyl ester (PCBM)/Al demonstrate that the studied MoOx layer is a good HTL and leads to comparable characteristics to those with PEDOT:PSS. On the other hand the deposition by magnetron sputtering guarantees reliable and repeatable HTLs.

  9. One-Step Interface Engineering for All-Inkjet-Printed, All-Organic Components in Transparent, Flexible Transistors and Inverters: Polymer Binding.

    PubMed

    Ha, Jewook; Chung, Seungjun; Pei, Mingyuan; Cho, Kilwon; Yang, Hoichang; Hong, Yongtaek

    2017-03-15

    We report a one-step interface engineering methodology which can be used on both polymer electrodes and gate dielectric for all-inkjet-printed, flexible, transparent organic thin-film transistors (OTFTs) and inverters. Dimethylchlorosilane-terminated polystyrene (PS) was introduced as a surface modifier to cured poly(4-vinylphenol) dielectric and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) electrodes without any pretreatment. On the untreated and PS interlayer-treated dielectric and electrode surfaces, 6,13-bis(triisopropylsilylethynyl)pentacene was printed to fabricate OTFTs and inverters. With the benefit of the PS interlayer, the electrical properties of the OTFTs on a flexible plastic substrate were significantly improved, as shown by a field-effect mobility (μFET) of 0.27 cm(2) V(-1) s(-1) and an on/off current ratio (Ion/Ioff) of greater than 10(6). In contrast, the untreated systems showed a low μFET of less than 0.02 cm(2) V(-1) s(-1) and Ion/Ioff ∼ 10(4). Additionally, the all-inkjet-printed inverters based on the PS-modified surfaces exhibited a voltage gain of 7.17 V V(-1). The all-organic-based TFTs and inverters, including deformable and transparent PEDOT:PSS electrodes with a sheet resistance of 160-250 Ω sq(-1), exhibited a light transmittance of higher than 70% (at wavelength of 550 nm). Specifically, there was no significant degradation in the electrical performance of the interface engineering-assisted system after 1000 bending cycles at a radius of 5 mm.

  10. A Metal-Free, Nonconjugated Polymer for Solar Photocatalysis.

    PubMed

    Irigoyen-Campuzano, Rafael; González-Béjar, María; Pino, Eduardo; Proal-Nájera, Jose B; Pérez-Prieto, Julia

    2017-02-24

    Heterogeneous catalysts that can absorb light over the solar range are ideal for green photocatalysis. Recently, attention has been directed towards the generation of novel solar-light photocatalysts, in particular, metal-free polymers. Herein, it is demonstrated that a metal-free, nonconjugated, anthraquinone-based copolymer (poly[1,4-diamine-9,10-dioxoanthracene-alt-(benzene-1,4-dioic acid)] (COP)) with a strong absorption in the visible region is effective as a sunlight heterogeneous photocatalyst. As a proof of concept, it has been used to mineralize 2,5-dichlorophenol (2,5-DCP) in water under air and sunlight irradiation. The photocatalytic efficiency of COP compares well with that of TiO2 -P25 when the reaction is carried out in a solar photoreactor in acid medium. Steady-state and time-resolved (absorption and emission) studies performed on COP suspended in 6:4 DMF/H2 O have provided valuable information about the COP species generated under different pH conditions. Steady-state absorption and fluorescence data are consistent with the existence of a tautomeric equilibrium between the 9,10-keto and 1,10-iminoketo quinoid forms for the anthraquinone in the ground state. Moreover, in basic media, transient absorption measurements showed the presence of two bands ascribed to the tautomeric triplet excited states, whereas only one of the triplets was observed in acid medium. A mechanism for the photocatalyzed degradation of 2,5-DCP by COP is proposed on the basis of these observations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Solar Energy Grid Integration Systems. Final Report of the Princeton Power Systems Development of the 100kW Demand Response Inverter.

    SciTech Connect

    Bower, Ward Isaac; Heavener, Paul; Sena-Henderson, Lisa; Hammell, Darren; Holveck, Mark; David, Carolyn; Akhil, Abbas Ali; Gonzalez, Sigifredo

    2012-01-01

    Initiated in 2008, the Solar Energy Grid Integration (SEGIS) program is a partnership involving the U.S. Department of Energy, Sandia National Laboratories, electric utilities, academic institutions and the private sector. Recognizing the need to diversify the nation's energy portfolio, the SEGIS effort focuses on specific technologies needed to facilitate the integration of large-scale solar power generation into the nation's power grid Sandia National Laboratories (SNL) awarded a contract to Princeton Power Systems, Inc., (PPS) to develop a 100kW Advanced AC-link SEGIS inverter prototype under the Department of Energy Solar Energy Technologies Program for near-term commercial applications. This SEGIS initiative emphasizes the development of advanced inverters, controllers, communications and other balance-of-system components for photovoltaic (PV) distributed power applications. The SEGIS Stage 3 Contract was awarded to PPS on July 28, 2010. PPS developed and implemented a Demand Response Inverter (DRI) during this three-stage program. PPS prepared a 'Site Demonstration Conference' that was held on September 28, 2011, to showcase the cumulative advancements. This demo of the commercial product will be followed by Underwriters Laboratories, Inc., certification by the fourth quarter of 2011, and simultaneously the customer launch and commercial production sometime in late 2011 or early 2012. This final report provides an overview of all three stages and a full-length reporting of activities and accomplishments in Stage 3.

  12. Diketopyrrolopyrrole Polymers with Thienyl and Thiazolyl Linkers for Application in Field-Effect Transistors and Polymer Solar Cells.

    PubMed

    Yu, Yaping; Wu, Yang; Zhang, Andong; Li, Cheng; Tang, Zheng; Ma, Wei; Wu, Yonggang; Li, Weiwei

    2016-11-09

    Conjugated polymers consisting of diketopyrrolopyrrole (DPP) units have been successfully applied in field-effect transistors (FETs) and polymer solar cells (PSCs), while most of the DPP polymers were designed as symmetric structures containing identical aromatic linkers. In this manuscript, we design a new asymmetric DPP polymer with varied aromatic linkers in the backbone for application in FETs and PSCs. The designation provides the chance to finely adjust the energy levels of conjugated polymers so as to influence the device performance. The asymmetric polymer exhibits highly crystalline properties, high hole mobilities of 3.05 cm(2) V(-1) s(-1) in FETs, and a high efficiency of 5.9% in PSCs with spectra response from 300 to 850 nm. Morphology investigation demonstrates that the asymmetric polymer has a large crystal domain in blended thin films, indicating that the solar cell performance can be further enhanced by optimizing the microphase separation. The study reveals that the asymmetric design via adjusting the aromatic linkers in DPP polymers is a useful route toward flexible electronic devices.

  13. The role of Ag nanoparticles in inverted polymer solar cells: Surface plasmon resonance and backscattering centers

    NASA Astrophysics Data System (ADS)

    Xu, Peng; Shen, Liang; Meng, Fanxu; Zhang, Jiaqi; Xie, Wenfa; Yu, Wenjuan; Guo, Wenbin; Jia, Xu; Ruan, Shengping

    2013-03-01

    Here, we demonstrate silver (Ag) nanoparticles (NPs) existing in molybdenum trioxide (MoO3) buffer layers can improve the photocurrent by surface plasmon resonance (SPR) and backscattering enhancement. The device structure is glass/indium tin oxides/titanium dioxide (TiO2)/regioregular poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester/MoO3/Ag NPs/MoO3/Ag. Compared to the device without Ag NPs, the short current density (Jsc) is improved from 7.76 ± 0.14 mA/cm2 to 8.89 ± 0.12 mA/cm2, and the power conversion efficiency is also enhanced from 2.70% ± 0.11% to 3.35% ± 0.08%. The transmittance spectra show that the device with Ag NPs has weaker transmittance than the device without, which could be attributed to the photons absorption of Ag NPs and light scattering by Ag NPs. The absorption profile of the devices with or without Ag NPs is simulated using finite-difference time-domain methods. It is approved that the Ag NPs result in the absorption improvement by SPR and backscattering enhancement.

  14. Interface Engineering of Metal Oxides using Ammonium Anthracene in Inverted Organic Solar Cells.

    PubMed

    Jeon, Il; Zeljkovic, Sasa; Kondo, Kei; Yoshizawa, Michito; Matsuo, Yutaka

    2016-11-09

    In this work, by casting water-soluble ammonium anthracene on metal oxides, the organic surface modifier re-engineered the interface of the metal oxide to improve charge transport. The energy level of ammonium anthracene increased the work function of indium tin oxide (ITO), functioning as a hole-blocker (electron-transporter). Solar cells in which ITO was treated by the ammonium anthracene produced an average power conversion efficiency (PCE) of 5.8% without ZnO, the electron-transporting layer. When the ammonium anthracene was applied to ZnO, an average PCE of 8.1% was achieved, which is higher than the average PCE of 7.5% for nontreated ZnO-based devices.

  15. Polymer-Polymer Förster Resonance Energy Transfer Significantly Boosts the Power Conversion Efficiency of Bulk-Heterojunction Solar Cells.

    PubMed

    Gupta, Vinay; Bharti, Vishal; Kumar, Mahesh; Chand, Suresh; Heeger, Alan J

    2015-06-24

    Optically resonant donor polymers can exploit a wider range of the solar spectrum effectively without a complicated tandem design in an organic solar cell. Ultrafast Förster resonance energy transfer (FRET) in a polymer-polymer system that significantly improves the power conversion efficiency in bulk heterojunction polymer solar cells from 6.8% to 8.9% is demonstrated, thus paving the way to achieving 15% efficient solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer.

    PubMed

    Chen, Hong-Yan; Lu, Hong-Liang; Ren, Qing-Hua; Zhang, Yuan; Yang, Xiao-Feng; Ding, Shi-Jin; Zhang, David Wei

    2015-10-07

    Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.

  17. High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer

    NASA Astrophysics Data System (ADS)

    Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

    2016-05-01

    During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid (PEDOT:PSS) as the hole transport material (HTM), the hydrophilicity of the PEDOT:PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm-2 and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PEDOT:PSS layer, indicating that CuOx could be a promising HTM for replacing PEDOT:PSS in inverted planar heterojunction perovskite solar cells.During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid (PEDOT:PSS) as the hole transport material (HTM), the hydrophilicity of the PEDOT:PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a

  18. Optimization of molecular organization and nanoscale morphology for high performance low bandgap polymer solar cells

    NASA Astrophysics Data System (ADS)

    He, Ming; Wang, Mengye; Lin, Changjian; Lin, Zhiqun

    2014-03-01

    Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor-acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells.

  19. Optimization of molecular organization and nanoscale morphology for high performance low bandgap polymer solar cells.

    PubMed

    He, Ming; Wang, Mengye; Lin, Changjian; Lin, Zhiqun

    2014-04-21

    Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor-acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells.

  20. Correlating highpower conversion efficiency of PTB7:PC71BM inverted organic solar cells with nanoscale structures [Unraveling the correlation between the structural aspects and power conversion efficiency in PTB7:PC71BM inverted organic solar cells

    DOE PAGES

    Das, Sanjib; Browning, Jim; Gu, Gong; ...

    2015-07-16

    Advances in materials design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) to their conventional counterparts, in addition to the well-known better ambient stability. Despite the significant progress, however, it has so far been unclear how the morphologies of the photoactive layer and its interface with the cathode modifying layer impact device performance. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with the well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3 -(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. Wemore » have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using a variety of characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the smearing (diffusion) of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The PC71BM diffusion occurs after spin-casting the active layer onto the PFN layer, when residual solvent molecules act as a plasticizer. Furthermore, the DIO additive, with a higher boiling point than the host solvent, has a longer residence time in the spin-cast active layer, resulting in more PC71BM smearing and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.« less

  1. Thin polymer film collectors as a contribution to the solar industry

    SciTech Connect

    Wilhelm, W.G.

    1984-06-01

    Achievements made in research on thin polymer film solar flat-plate collectors using monocoque construction techniques are briefly discussed. The significance of these achievements for cost reduction of flat-plate collectors without compromising performance is briefly discussed.

  2. Mapping Polymer Donors toward High-Efficiency Fullerene Free Organic Solar Cells.

    PubMed

    Lin, Yuze; Zhao, Fuwen; Wu, Yang; Chen, Kai; Xia, Yuxin; Li, Guangwu; Prasad, Shyamal K K; Zhu, Jingshuai; Huo, Lijun; Bin, Haijun; Zhang, Zhi-Guo; Guo, Xia; Zhang, Maojie; Sun, Yanming; Gao, Feng; Wei, Zhixiang; Ma, Wei; Wang, Chunru; Hodgkiss, Justin; Bo, Zhishan; Inganäs, Olle; Li, Yongfang; Zhan, Xiaowei

    2017-01-01

    Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.

  3. Critical role of domain crystallinity, domain purity and domain interface sharpness for reduced bimolecular recombination in polymer solar cells

    DOE PAGES

    Venkatesan, Swaminathan; Chen, Jihua; Ngo, Evan C.; ...

    2014-12-31

    In this study, inverted bulk heterojunction solar cells were fabricated using poly(3-hexylthiophene) (P3HT) blended with two different fullerene derivatives namely phenyl-C61-butyric acid methyl ester (PC60BM) and indene-C60 bis-adduct (IC60BA). The effects of annealing temperatures on the morphology, optical and structural properties were studied and correlated to differences in photovoltaic device performance. It was observed that annealing temperature significantly improved the performance of P3HT:IC60BA solar cells while P3HT:PC60BM cells showed relatively less improvement. The performance improvement is attributed to the extent of fullerene mixing with polymer domains. Energy filtered transmission electron microscopy (EFTEM) and x-ray diffraction (XRD) results showed that ICBAmore » mixes with disordered P3HT much more readily than PC60BM which leads to lower short circuit current density and fill factor for P3HT:IC60BA cells annealed below 120°C. Annealing above 120°C improves the crystallinity of P3HT in case of P3HT:IC60BA whereas in P3HT:PC60BM films, annealing above 80°C leads to negligible change in crystallinity. Crystallization of P3HT also leads to higher domain purity as seen EFTEM. Further it is seen that cells processed with additive nitrobenzene (NB) showed enhanced short circuit current density and power conversion efficiency regardless of the fullerene derivative used. Addition of NB led to nanoscale phase separation between purer polymer and fullerene domains. Kelvin probe force microscopy (KPFM) images showed that enhanced domain purity in additive casted films led to a sharper interface between polymer and fullerene. Lastly, enhanced domain purity and interfacial sharpness led to lower bimolecular recombination and higher mobility and charge carrier lifetime in NB modified devices.« less

  4. Graphene oxide nanoribbon as hole extraction layer to enhance efficiency and stability of polymer solar cells.

    PubMed

    Liu, Jun; Kim, Gi-Hwan; Xue, Yuhua; Kim, Jin Young; Baek, Jong-Beom; Durstock, Michael; Dai, Liming

    2014-02-01

    Graphene oxide nanoribbons for efficient and stable polymer solar cells are discussed. With controllable bandgap, good solubility and film forming property, graphene oxide nanoribbons serve as a new class of excellent hole extraction materials for efficient and stable polymer solar cells outperforming their counterparts based on conventional hole extraction materials, including PEDOT:PSS. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Enhancing the photocurrent in diketopyrrolopyrrole-based polymer solar cells via energy level control.

    PubMed

    Li, Weiwei; Roelofs, W S Christian; Wienk, Martijn M; Janssen, René A J

    2012-08-22

    A series of diketopyrrolopyrrole (DPP)-based small band gap polymers has been designed and synthesized by Suzuki or Stille polymerization for use in polymer solar cells. The new polymers contain extended aromatic π-conjugated segments alternating with the DPP units and are designed to increase the free energy for charge generation to overcome current limitations in photocurrent generation of DPP-based polymers. In optimized solar cells with [6,6]phenyl-C(71)-butyric acid methyl ester ([70]PCBM) as acceptor, the new DPP-polymers provide significantly enhanced external and internal quantum efficiencies for conversion of photons into collected electrons. This provides short-circuit current densities in excess of 16 mA cm(-2), higher than obtained so far, with power conversion efficiencies of 5.8% in simulated solar light. We analyze external and internal photon to collected electron quantum efficiencies for the new polymers as a function of the photon energy loss, defined as the offset between optical band gap and open circuit voltage, and compare the results to those of some of the best DPP-based polymers solar cells reported in the literature. We find that for the best solar cells there is an empirical relation between quantum efficiency and photon energy loss that presently limits the power conversion efficiency in these devices.

  6. Correlating high power conversion efficiency of PTB7:PC71BM inverted organic solar cells with nanoscale structures

    NASA Astrophysics Data System (ADS)

    Das, Sanjib; Keum, Jong K.; Browning, James F.; Gu, Gong; Yang, Bin; Dyck, Ondrej; Do, Changwoo; Chen, Wei; Chen, Jihua; Ivanov, Ilia N.; Hong, Kunlun; Rondinone, Adam J.; Joshi, Pooran C.; Geohegan, David B.; Duscher, Gerd; Xiao, Kai

    2015-09-01

    Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their ``conventional'' counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their ``conventional'' counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active

  7. Preliminary study of application of Moringa oleifera resin as polymer electrolyte in DSSC solar cells

    NASA Astrophysics Data System (ADS)

    Saehana, Sahrul; Darsikin, Muslimin

    2016-04-01

    This study reports the preliminary study of application of Moringa oleifera resin as polymer electrolyte in dye-sensitized solar cell (DSSC). We found that polymer electrolyte membrane was formed by using solution casting methods. It is observed that polymer electrolyte was in elastic form and it is very potential to application as DSSC component. Performance of DSSC which employing Moringa oleifera resin was also observed and photovoltaic effect was found.

  8. Co-functionalized organic/inorganic hybrid ZnO nanorods as electron transporting layers for inverted organic solar cells.

    PubMed

    Ambade, Swapnil B; Ambade, Rohan B; Eom, Seung Hun; Baek, Myung-Jin; Bagde, Sushil S; Mane, Rajaram S; Lee, Soo-Hyoung

    2016-03-07

    In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM-ZnO NRs) leads to higher aggregation owing to the weaker solubility of SMs in solutions of ZnO NRs dispersed in chlorobenzene (CB). A prior addition of organic 2-(2-methoxyethoxy)acetic acid (MEA) over ZnO NRs not only inhibits aggregation of SMs over ZnO NRs, but also provides enough sites for the SM to strongly couple with the ZnO NRs to yield transparent SM-MEA-ZnO NRs hybrids that exhibited excellent capability as electron transporting layers (ETLs) in inverted organic solar cells (iOSCs) of P3HT:PC60BM bulk-heterojunction (BHJ) photoactive layers. A strongly coupled SM-MEA-ZnO NR hybrid reduces the series resistance by enhancing the interfacial area and tunes the energy level alignment at the interface between the (indium-doped tin oxide, ITO) cathode and BHJ photoactive layers. A significant enhancement in power conversion efficiency (PCE) was achieved for iOSCs comprising ETLs of SM-MEA-ZnO NRs (3.64%) advancing from 0.9% for pristine ZnO NRs, while the iOSCs of aggregated SM-ZnO NRs ETL exhibited a much lower PCE of 2.6%, thus demonstrating the potential of the co-functionalization approach. The superiority of the co-functionalized SM-MEA-ZnO NRs ETL is also evident from the highest PCE of 7.38% obtained for the iOSCs comprising BHJ of PTB7-Th:PC60BM compared with extremely poor 0.05% for non-functionalized ZnO NRs.

  9. Correlating High Power Conversion Efficiency of PTB7:PC71BM Inverted Organic Solar Cells with Nanoscale Structures

    DOE PAGES

    Das, Sanjib; Keum, Jong Kahk; Browning, Jim; ...

    2015-01-01

    Advances in materials design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) to their conventional counterparts, in addition to the well-known better ambient stability. Despite the significant progress, however, it has so far been unclear how the morphologies of the photoactive layer and its interface with the cathode modifying layer impact device performance. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with the well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3 -(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. Wemore » have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using a variety of characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the smearing (diffusion) of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The PC71BM diffusion occurs after spin-casting the active layer onto the PFN layer, when residual solvent molecules act as a plasticizer. The DIO additive, with a higher boiling point than the host solvent, has a longer residence time in the spin-cast active layer, resulting in more PC71BM smearing and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.« less

  10. Solution-Processed One-Dimensional ZnO@CdS Heterojunction toward Efficient Cu2ZnSnS4 Solar Cell with Inverted Structure.

    PubMed

    Chen, Rongrong; Fan, Jiandong; Liu, Chong; Zhang, Xing; Shen, Yanjiao; Mai, Yaohua

    2016-10-13

    Kesterite Cu2ZnSnS4 (CZTS) semiconductor has been demonstrated to be a promising alternative absorber in thin film solar cell in virtue of its earth-abundant, non-toxic element, suitable optical and electrical properties. Herein, a low-cost and non-toxic method that based on the thermal decomposition and reaction of metal-thiourea-oxygen sol-gel complexes to synthesize CZTS thin film was developed. The low-dimensional ZnO@CdS heterojunction nano-arrays coupling with the as-prepared CZTS thin film were employed to fabricate a novel solar cell with inverted structure. The vertically aligned nanowires (NWs) allow facilitating the charge carrier collection/separation/transfer with large interface areas. By optimizing the parameters including the annealing temperature of CZTS absorber, the thickness of CdS buffer layer and the morphology of ZnO NWs, an open-circuit voltage (VOC) as high as 589 mV was obtained by such solar cell with inverted structure. The all-solution-processed technic allows the realization of CZTS solar cell with extremely low cost.

  11. Solution-Processed One-Dimensional ZnO@CdS Heterojunction toward Efficient Cu2ZnSnS4 Solar Cell with Inverted Structure

    NASA Astrophysics Data System (ADS)

    Chen, Rongrong; Fan, Jiandong; Liu, Chong; Zhang, Xing; Shen, Yanjiao; Mai, Yaohua

    2016-10-01

    Kesterite Cu2ZnSnS4 (CZTS) semiconductor has been demonstrated to be a promising alternative absorber in thin film solar cell in virtue of its earth-abundant, non-toxic element, suitable optical and electrical properties. Herein, a low-cost and non-toxic method that based on the thermal decomposition and reaction of metal-thiourea-oxygen sol-gel complexes to synthesize CZTS thin film was developed. The low-dimensional ZnO@CdS heterojunction nano-arrays coupling with the as-prepared CZTS thin film were employed to fabricate a novel solar cell with inverted structure. The vertically aligned nanowires (NWs) allow facilitating the charge carrier collection/separation/transfer with large interface areas. By optimizing the parameters including the annealing temperature of CZTS absorber, the thickness of CdS buffer layer and the morphology of ZnO NWs, an open-circuit voltage (VOC) as high as 589 mV was obtained by such solar cell with inverted structure. The all-solution-processed technic allows the realization of CZTS solar cell with extremely low cost.

  12. Solution-Processed One-Dimensional ZnO@CdS Heterojunction toward Efficient Cu2ZnSnS4 Solar Cell with Inverted Structure

    PubMed Central

    Chen, Rongrong; Fan, Jiandong; Liu, Chong; Zhang, Xing; Shen, Yanjiao; Mai, Yaohua

    2016-01-01

    Kesterite Cu2ZnSnS4 (CZTS) semiconductor has been demonstrated to be a promising alternative absorber in thin film solar cell in virtue of its earth-abundant, non-toxic element, suitable optical and electrical properties. Herein, a low-cost and non-toxic method that based on the thermal decomposition and reaction of metal-thiourea-oxygen sol-gel complexes to synthesize CZTS thin film was developed. The low-dimensional ZnO@CdS heterojunction nano-arrays coupling with the as-prepared CZTS thin film were employed to fabricate a novel solar cell with inverted structure. The vertically aligned nanowires (NWs) allow facilitating the charge carrier collection/separation/transfer with large interface areas. By optimizing the parameters including the annealing temperature of CZTS absorber, the thickness of CdS buffer layer and the morphology of ZnO NWs, an open-circuit voltage (VOC) as high as 589 mV was obtained by such solar cell with inverted structure. The all-solution-processed technic allows the realization of CZTS solar cell with extremely low cost. PMID:27734971

  13. Donor polymer design enables efficient non-fullerene organic solar cells

    PubMed Central

    Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

    2016-01-01

    To achieve efficient organic solar cells, the design of suitable donor–acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells. PMID:27782112

  14. Donor polymer design enables efficient non-fullerene organic solar cells.

    PubMed

    Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

    2016-10-26

    To achieve efficient organic solar cells, the design of suitable donor-acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells.

  15. Improved performance of polymer solar cells using PBDTT-F-TT:PC71BM blend film as active layer

    NASA Astrophysics Data System (ADS)

    Zang, Yue; Gao, Xiumin; Lu, Xinmiao; Xin, Qing; Lin, Jun; Zhao, Jufeng

    2016-07-01

    A detailed study of high-efficiency polymer solar cells (PSCs) based on a low bandgap polymer PBDTT-F-TT and PC71BM as the bulk heterojunction (BHJ) layer is carried out. By using 1,8-diiodooctane (DIO) as solvent additive to control the morphology of active layer and comparing different device architecture to optimize the optical field distribution, the power conversion efficiency (PCE) of the resulted devices can be reached as high as 9.34%. Comprehensive characterization and optical modeling of the resulting devices is performed to understand the effect of DIO and device geometry on photovoltaic performance. It was found that the addition of DIO can significantly improve the nanoscale morphology and increased electron mobility in the BHJ layer. The inverted device architecture was chosen because the results from optical modeling shows that it offers better optical field distribution and exciton generation profile. Based on these results, a low-temperature processed ZnO was finally introduced as an electron transport layer to facility the fabrication on flexible substrates and showed comparable performance with the device based on conventional ZnO interlayer prepared by sol-gel process.

  16. On the importance of morphology control in polymer solar cells.

    PubMed

    van Bavel, Svetlana; Veenstra, Sjoerd; Loos, Joachim

    2010-11-01

    Nanostructured polymer-based solar cells (PSCs) have emerged as a promising low-cost alternative to conventional inorganic photovoltaic devices and are now a subject of intensive research both in academia and industry. For PSCs to become practical efficient devices, several issues should still be addressed, including further understanding of their operation and stability, which in turn are largely determined by the morphological organisation in the photoactive layer. The latter is typically a few hundred nanometres thick film and is a blend composed of two materials: the bulk heterojunction consisting of the electron donor and the electron acceptor. The main requirements for the morphology of efficient photoactive layers are nanoscale phase segregation for a high donor/acceptor interface area and hence efficient exciton dissociation, short and continuous percolation pathways of both components leading through the layer thickness to the corresponding electrodes for efficient charge transport and collection, and high crystallinity of both donor and acceptor materials for high charge mobility. In this paper, we review recent progress of our understanding on how the efficiency of a bulk heterojunction PSC largely depends on the local nanoscale volume organisation of the photoactive layer. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Induced Infiltration of Hole-Transporting Polymer into Photocatalyst for Staunch Polymer-Metal Oxide Hybrid Solar Cells.

    PubMed

    Park, Jong Hwan; Jung, Youngsuk; Yang, Yooseong; Shin, Hyun Suk; Kwon, Soonchul

    2016-10-05

    For efficient solar cells based on organic semiconductors, a good mixture of photoactive materials in the bulk heterojunction on the length scale of several tens of nanometers is an important requirement to prevent exciton recombination. Herein, we demonstrate that nanoporous titanium dioxide inverse opal structures fabricated using a self-assembled monolayer method and with enhanced infiltration of electron-donating polymers is an efficient electron-extracting layer, which enhances the photovoltaic performance. A calcination process generates an inverse opal structure of titanium dioxide (<70 nm of pore diameters) providing three-dimensional (3D) electron transport pathways. Hole-transporting polymers was successfully infiltrated into the pores of the surface-modified titanium dioxide under vacuum conditions at 200 °C. The resulting geometry expands the interfacial area between hole- and electron-transport materials, increasing the thickness of the active layer. The controlled polymer-coating process over titanium dioxide materials enhanced photocurrent of the solar cell device. Density functional theory calculations show improved interfacial adhesion between the self-assembled monolayer-modified surface and polymer molecules, supporting the experimental result of enhanced polymer infiltration into the voids. These results suggest that the 3D inverse opal structure of the surface-modified titanium dioxide can serve as a favorable electron-extracting layer in further enhancing optoelectronic performance based on organic or organic-inorganic hybrid solar cell.

  18. Tuning the properties of polymer bulk heterojunction solar cells by adjusting fullerene size to control intercalation

    SciTech Connect

    Cates, N.C.

    2010-02-24

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

  19. Tuning the properties of polymer bulk heterojunction solar cells by adjusting fullerene size to control intercalation.

    PubMed

    Cates, Nichole C; Gysel, Roman; Beiley, Zach; Miller, Chad E; Toney, Michael F; Heeney, Martin; McCulloch, Iain; McGehee, Michael D

    2009-12-01

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

  20. Grid-connected polymer solar panels: initial considerations of cost, lifetime, and practicality.

    PubMed

    Medford, Andrew J; Lilliedal, Mathilde R; Jørgensen, Mikkel; Aarø, Dennis; Pakalski, Heinz; Fyenbo, Jan; Krebs, Frederik C

    2010-09-13

    Large solar panels were constructed from polymer solar cell modules prepared using full roll-to-roll (R2R) manufacture based on the previously published ProcessOne. The individual flexible polymer solar modules comprising multiple serially connected single cell stripes were joined electrically and laminated between a 4 mm tempered glass window and black Tetlar foil using two sheets of 0.5 mm thick ethylene vinyl acetate (EVA). The panels produced up to 8 W with solar irradiance of ~960 Wm⁻², and had outer dimensions of 1 m x 1.7 m with active areas up to 9180 cm². Panels were mounted on a tracking station and their output was grid connected between testing. Several generations of polymer solar cells and panel constructions were tested in this context to optimize the production of polymer solar panels. Cells lacking a R2R barrier layer were found to degrade due to diffusion of oxygen after less than a month, while R2R encapsulated cells showed around 50% degradation after 6 months but suffered from poor performance due to de-lamination during panel production. A third generation of panels with various barrier layers was produced to optimize the choice of barrier foil and it was found that the inclusion of a thin protective foil between the cell and the barrier foil is critical. The findings provide a preliminary foundation for the production and optimization of large-area polymer solar panels and also enabled a cost analysis of solar panels based on polymer solar cells.

  1. Solution-Processed CuS NPs as an Inorganic Hole-Selective Contact Material for Inverted Planar Perovskite Solar Cells.

    PubMed

    Rao, Haixia; Sun, Weihai; Ye, Senyun; Yan, Weibo; Li, Yunlong; Peng, Haitao; Liu, Zhiwei; Bian, Zuqiang; Huang, Chunhui

    2016-03-01

    Organic-inorganic hybrid perovskite solar cells (PSCs) have drawn worldwide intense research in recent years. Herein, we have first applied another p-type inorganic hole-selective contact material, CuS nanoparticles (CuS NPs), in an inverted planar heterojunction (PHJ) perovskite solar cell. The CuS NP-modification of indium tin oxide (ITO) has successfully tuned the surface work function from 4.9 to 5.1 eV but not affect the surface roughness and transmittance, which can effectively reduce the interfacial carrier injection barrier and facilitate high hole extraction efficiency between the perovskite and ITO layers. After optimization, the maximum power conversion efficiency (PCE) has been over 16% with low J-V hysteresis and excellent stability. Therefore, the low-cost solution-processed and stable CuS NPs would be an alternative interfacial modification material for industrial production in perovskite solar cells.

  2. `Inorganics-in-Organics': recent developments and outlook for 4G polymer solar cells

    NASA Astrophysics Data System (ADS)

    Jayawardena, K. D. G. Imalka; Rozanski, Lynn J.; Mills, Chris A.; Beliatis, Michail J.; Nismy, N. Aamina; Silva, S. Ravi P.

    2013-08-01

    Recent developments in solution processable single junction polymer solar cells have led to a significant improvement in power conversion efficiencies from ~5% to beyond 9%. While much of the initial efficiency improvements were driven through judicious design of donor polymers, it is the engineering of device architectures through the incorporation of inorganic nanostructures and better processing that has continued the efficiency gains. Inorganic nano-components such as carbon nanotubes, graphene and its derivatives, metal nanoparticles and metal oxides have played a central role in improving device performance and longevity beyond those achieved by conventional 3G polymer solar cells. The present work aims to summarise the diverse roles played by the nanosystems and features in state of the art next generation (4G) polymer solar cells. The challenges associated with the engineering of such devices for future deployment are also discussed.

  3. High performance all polymer solar cells fabricated via non-halogenated solvents (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Bao, Zhenan

    2015-10-01

    The performance of organic solar cells consisting of a donor/acceptor bulk heterojunction (BHJ) has rapidly improved over the past few years.1. Major efforts have been focused on developing a variety of donor materials to gain access to different regions of the solar spectrum as well as to improve carrier transport properties.2 On the other hand, the most utilized acceptors are still restricted to the fullerene family, which includes PC61BM, PC71BM and ICBA.2b, 3 All-polymer solar cells, consisting of polymers for both the donor and acceptor, gained significantly increased interests recently, because of their ease of solution processing, potentially low cost, versatility in molecular design, and their potential for good chemical and morphological stability due to entanglement of polymers. Unlike small molecular fullerene acceptors, polymer acceptors can benefit from the high mobility of intra-chain charge transport and exciton generation by both donor and acceptor. Despite extensive efforts on all-polymer solar cells in the past decade, the fundamental understanding of all-polymer solar cells is still in its inceptive stage regarding both the materials chemistry and structure physics.4 Thus, rational design rules must be utilized to enable fundamental materials understanding of the all polymer solar cells. We report high performance all-polymer solar cells employing polymeric donors based on isoindigo and acceptor based on perylenedicarboximide. The phase separation domain length scale correlates well with the JSC and is found to be highly sensitive to the aromatic co-monomer structures used in the crystalline donor polymers. With the PS polymer side chain engineering, the phase separation domain length scale decreased by more than 45%. The PCE and JSC of the devices increased accordingly by more than 20%. A JSC as high as 10.0 mA cm-2 is obtained with the donor-acceptor pair despite of a low LUMO-LUMO energy offset of less than 0.1 eV. All the factors such as

  4. Panchromatic polymer-polymer ternary solar cells enhanced by Forster resonance energy transfer and solvent vapor annealing

    SciTech Connect

    Goh, Tenghooi; Sfeir, Matthew Y.; Huang, Jing -Shun; Bartolome, Benjamin; Vaisman, Michelle; Lee, Minjoo L.; Taylor, Andre D.

    2015-08-04

    Thanks to the bulk-heterojunction (BHJ) feature of polymer solar cells (PSC), additional light active components can be added with ease to form ternary solar cells. This strategy has achieved great success largely due to expanded spectral response range and improved power conversion efficiency (PCE) without incurring excessive processing costs. Here, we report ternary blend polymer–polymer solar cells comprised of PTB7, P3HT, and PC71BM with PCE as high as 8.2%. Analyses of femtosecond time resolved photoluminescence and transient absorption spectroscopy data confirm that P3HT is effective in transferring energy non-radiatively by inducing excitons and prolonging their overall lifetime in PTB7. As a result, solvent vapor annealing (SVA) treatment was employed to rectify the overly-coarse morphology, thus enhancing the fill factor, reducing interfacial recombination, and boosting the PCE to 8.7%.

  5. Panchromatic polymer-polymer ternary solar cells enhanced by Forster resonance energy transfer and solvent vapor annealing

    DOE PAGES

    Goh, Tenghooi; Sfeir, Matthew Y.; Huang, Jing -Shun; ...

    2015-08-04

    Thanks to the bulk-heterojunction (BHJ) feature of polymer solar cells (PSC), additional light active components can be added with ease to form ternary solar cells. This strategy has achieved great success largely due to expanded spectral response range and improved power conversion efficiency (PCE) without incurring excessive processing costs. Here, we report ternary blend polymer–polymer solar cells comprised of PTB7, P3HT, and PC71BM with PCE as high as 8.2%. Analyses of femtosecond time resolved photoluminescence and transient absorption spectroscopy data confirm that P3HT is effective in transferring energy non-radiatively by inducing excitons and prolonging their overall lifetime in PTB7. Asmore » a result, solvent vapor annealing (SVA) treatment was employed to rectify the overly-coarse morphology, thus enhancing the fill factor, reducing interfacial recombination, and boosting the PCE to 8.7%.« less

  6. Comparison of the Morphology Development of Polymer-Fullerene and Polymer-Polymer Solar Cells during Solution-Shearing Blade Coating

    SciTech Connect

    Gu, Xiaodan; Yan, Hongping; Kurosawa, Tadanori; Schroeder, Bob C.; Gu, Kevin L.; Zhou, Yan; To, John W. F.; Oosterhout, Stefan D.; Savikhin, Victoria; Molina-Lopez, Francisco; Tassone, Christopher J.; Mannsfeld, Stefan C. B.; Wang, Cheng; Toney, Michael F.; Bao, Zhenan

    2016-08-22

    Here in this work, the detailed morphology studies of polymer poly(3-hexylthiophene-2,5-diyl) (P3HT):fullerene(PCBM) and polymer(P3HT):polymer naphthalene diimide thiophene (PNDIT) solar cell are presented to understand the challenge for getting high performance all-polymer solar cells. The in situ X-ray scattering and optical interferometry and ex situ hard and soft X-ray scattering and imaging techniques are used to characterize the bulk heterojunction (BHJ) ink during drying and in dried state. The crystallization of P3HT polymers in P3HT:PCBM bulk heterojunction shows very different behavior compared to that of P3HT:PNDIT BHJ due to different mobilities of P3HT in the donor:acceptor glass. Supplemented by the ex situ grazing incidence X-ray diffraction and soft X-ray scattering, PNDIT has a lower tendency to form a mixed phase with P3HT than PCBM, which may be the key to inhibit the donor polymer crystallization process, thus creating preferred small phase separation between the donor and acceptor polymer.

  7. Comparison of the Morphology Development of Polymer-Fullerene and Polymer-Polymer Solar Cells during Solution-Shearing Blade Coating

    DOE PAGES

    Gu, Xiaodan; Yan, Hongping; Kurosawa, Tadanori; ...

    2016-08-22

    Here in this work, the detailed morphology studies of polymer poly(3-hexylthiophene-2,5-diyl) (P3HT):fullerene(PCBM) and polymer(P3HT):polymer naphthalene diimide thiophene (PNDIT) solar cell are presented to understand the challenge for getting high performance all-polymer solar cells. The in situ X-ray scattering and optical interferometry and ex situ hard and soft X-ray scattering and imaging techniques are used to characterize the bulk heterojunction (BHJ) ink during drying and in dried state. The crystallization of P3HT polymers in P3HT:PCBM bulk heterojunction shows very different behavior compared to that of P3HT:PNDIT BHJ due to different mobilities of P3HT in the donor:acceptor glass. Supplemented by the exmore » situ grazing incidence X-ray diffraction and soft X-ray scattering, PNDIT has a lower tendency to form a mixed phase with P3HT than PCBM, which may be the key to inhibit the donor polymer crystallization process, thus creating preferred small phase separation between the donor and acceptor polymer.« less

  8. Development and Characterization of New Donor-Acceptor Conjugated Polymers and Fullerene Nanoparticles for High Performance Bulk Heterojunction Solar Cells

    DTIC Science & Technology

    2011-01-14

    Nanoparticles for High Performance Bulk Heterojunction Solar Cells Jan. 14,2011 Name of Principal Investigators: Kung-Hwa Wei - e-mail address : khwei...donor-π-bridge-acceptor side chains for high efficiency polymer solar cells . Different from the commonly used linear D-A conjugated polymers, the...Development and Characterization of New Donor-Acceptor Conjugated Polymers and Fullerene Nanoparticles for High Performance Bulk Heterojunction Solar Cells

  9. Graphene Oxide Derivatives as Hole- and Electron-Extraction Layers for High-Performance Polymer Solar Cells

    DTIC Science & Technology

    2013-11-20

    Graphene oxide derivatives as hole- and electron- extraction layers for high-performance polymer solar cells Jun Liu,*a Michael Durstockb and Liming...oxide (GO) and its derivatives have been used as a new class of efficient hole- and electron-extraction materials in polymer solar cells (PSCs...new class of efficient hole- and electron-extraction materials in polymer solar cells (PSCs). Highly efficient and stable PSCs have been fabricated

  10. All-Polymer Solar Cells Based on Absorption-Complementary Polymer Donor and Acceptor with High Power Conversion Efficiency of 8.27%.

    PubMed

    Gao, Liang; Zhang, Zhi-Guo; Xue, Lingwei; Min, Jie; Zhang, Jianqi; Wei, Zhixiang; Li, Yongfang

    2016-03-02

    High-efficiency all-polymer solar cells with less thickness-dependent behavior are demonstrated by using a low bandgap n-type conjugated polymer N2200 as acceptor and an absorption-complementary difluorobenzotriazole-based medium-bandgap polymer J51 as donor.

  11. Fluoro-Substituted n-Type Conjugated Polymers for Additive-Free All-Polymer Bulk Heterojunction Solar Cells with High Power Conversion Efficiency of 6.71.

    PubMed

    Jung, Jae Woong; Jo, Jea Woong; Chueh, Chu-Chen; Liu, Feng; Jo, Won Ho; Russell, Thomas P; Jen, Alex K-Y

    2015-06-03

    Fluorinated n-type conjugated polymers are used as efficient electron acceptor to demonstrate high-performance all-polymer solar cells. The exciton generation, dissociation, and charge-transporting properties of blend films are improved by using these fluorinated n-type polymers to result in enhanced photocurrent and suppressed charge recombination.

  12. Over 11% Efficiency in Tandem Polymer Solar Cells Featured by a Low-Band-Gap Polymer with Fine-Tuned Properties.

    PubMed

    Zheng, Zhong; Zhang, Shaoqing; Zhang, Jianqi; Qin, Yunpeng; Li, Wanning; Yu, Runnan; Wei, Zhixiang; Hou, Jianhui

    2016-07-01

    Highly efficient polymer solar cells with tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion efficiencies over 11% can be realized featured by a low-band-gap polymer with fine-tuned properties.

  13. Polymer Acceptor Based on Double B←N Bridged Bipyridine (BNBP) Unit for High-Efficiency All-Polymer Solar Cells.

    PubMed

    Long, Xiaojing; Ding, Zicheng; Dou, Chuandong; Zhang, Jidong; Liu, Jun; Wang, Lixiang

    2016-08-01

    A novel polymer acceptor based on the double B←N bridged bipyridine building block is reported. All-polymer solar cells based on the new polymer acceptor show a power conversion efficiency of as high as 6.26% at a photon energy loss of only 0.51 eV.

  14. Flow-enhanced solution printing of all-polymer solar cells

    SciTech Connect

    Diao, Ying; Zhou, Yan; Kurosawa, Tadanori; Shaw, Leo; Wang, Cheng; Park, Steve; Guo, Yikun; Reinspach, Julia A.; Gu, Kevin; Gu, Xiaodan; Tee, Benjamin C. K.; Pang, Changhyun; Yan, Hongping; Zhao, Dahui; Toney, Michael F.; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2015-08-12

    Morphology control of solution coated solar cell materials presents a key challenge limiting their device performance and commercial viability. Here we present a new concept for controlling phase separation during solution printing using an all-polymer bulk heterojunction solar cell as a model system. The key aspect of our method lies in the design of fluid flow using a microstructured printing blade, on the basis of the hypothesis of flow-induced polymer crystallization. Our flow design resulted in a similar to 90% increase in the donor thin film crystallinity and reduced microphase separated donor and acceptor domain sizes. The improved morphology enhanced all metrics of solar cell device performance across various printing conditions, specifically leading to higher short-circuit current, fill factor, open circuit voltage and significantly reduced device-to-device variation. However, we expect our design concept to have broad applications beyond all-polymer solar cells because of its simplicity and versatility.

  15. Flow-enhanced solution printing of all-polymer solar cells

    PubMed Central

    Diao, Ying; Zhou, Yan; Kurosawa, Tadanori; Shaw, Leo; Wang, Cheng; Park, Steve; Guo, Yikun; Reinspach, Julia A.; Gu, Kevin; Gu, Xiaodan; Tee, Benjamin C. K.; Pang, Changhyun; Yan, Hongping; Zhao, Dahui; Toney, Michael F.; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2015-01-01

    Morphology control of solution coated solar cell materials presents a key challenge limiting their device performance and commercial viability. Here we present a new concept for controlling phase separation during solution printing using an all-polymer bulk heterojunction solar cell as a model system. The key aspect of our method lies in the design of fluid flow using a microstructured printing blade, on the basis of the hypothesis of flow-induced polymer crystallization. Our flow design resulted in a ∼90% increase in the donor thin film crystallinity and reduced microphase separated donor and acceptor domain sizes. The improved morphology enhanced all metrics of solar cell device performance across various printing conditions, specifically leading to higher short-circuit current, fill factor, open circuit voltage and significantly reduced device-to-device variation. We expect our design concept to have broad applications beyond all-polymer solar cells because of its simplicity and versatility. PMID:26264528

  16. Nanoparticle-doped Polymer Foils for Use in Solar Control Glazing

    NASA Astrophysics Data System (ADS)

    Smith, G. B.; Deller, C. A.; Swift, P. D.; Gentle, A.; Garrett, P. D.; Fisher, W. K.

    2002-04-01

    Since nanoparticles can provide spectrally selective absorption without scattering they can be used to dope polymers for use in windows, to provide a clear view while strongly attenuating both solar heat gain and UV, at lower cost than alternative technologies. The underlying physics and how it influences the choice and concentration of nanoparticle materials is outlined. Spectral data, visible and solar transmittance, and solar heat gain coefficient are measured for clear polymers and some laminated glass, in which the polymer layer is doped with conducting oxide nanoparticles. Simple models are shown to apply making general optical design straightforward. Use with clear glass and tinted glass is considered and performance shown to match existing solar control alternatives. A potential for widespread adoption in buildings and cars is clearly demonstrated, and scopes for further improvements are identified, so that ultimately both cost and performance are superior.

  17. Flow-enhanced solution printing of all-polymer solar cells.

    PubMed

    Diao, Ying; Zhou, Yan; Kurosawa, Tadanori; Shaw, Leo; Wang, Cheng; Park, Steve; Guo, Yikun; Reinspach, Julia A; Gu, Kevin; Gu, Xiaodan; Tee, Benjamin C K; Pang, Changhyun; Yan, Hongping; Zhao, Dahui; Toney, Michael F; Mannsfeld, Stefan C B; Bao, Zhenan

    2015-08-12

    Morphology control of solution coated solar cell materials presents a key challenge limiting their device performance and commercial viability. Here we present a new concept for controlling phase separation during solution printing using an all-polymer bulk heterojunction solar cell as a model system. The key aspect of our method lies in the design of fluid flow using a microstructured printing blade, on the basis of the hypothesis of flow-induced polymer crystallization. Our flow design resulted in a ∼90% increase in the donor thin film crystallinity and reduced microphase separated donor and acceptor domain sizes. The improved morphology enhanced all metrics of solar cell device performance across various printing conditions, specifically leading to higher short-circuit current, fill factor, open circuit voltage and significantly reduced device-to-device variation. We expect our design concept to have broad applications beyond all-polymer solar cells because of its simplicity and versatility.

  18. High-efficiency all-polymer solar cells based on a pair of crystalline low-bandgap polymers.

    PubMed

    Mu, Cheng; Liu, Peng; Ma, Wei; Jiang, Kui; Zhao, Jingbo; Zhang, Kai; Chen, Zhihua; Wei, Zhanhua; Yi, Ya; Wang, Jiannong; Yang, Shihe; Huang, Fei; Facchetti, Antonio; Ade, Harald; Yan, He

    2014-11-12

    All-polymer solar cells based on a pair of crystalline low-bandgap polymers (NT and N2200) are demonstrated to achieve a high short-circuit current density of 11.5 mA cm-2 and a power conversion efficiency of up to 5.0% under the standard AM1.5G spectrum with one sun intensity. The high performance of these NT:N2200-based cells can be attributed to the low optical bandgaps of the polymers and the reasonably high and balanced electron and hole mobilities of the NT:N2200 blends due to the crystalline nature of the two polymers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Efficient "light-soaking"-free inverted organic solar cells with aqueous solution processed low-temperature ZnO electron extraction layers.

    PubMed

    Wei, Wei; Zhang, Chunfu; Chen, Dazheng; Wang, Zhizhe; Zhu, Chunxiang; Zhang, Jincheng; Lu, Xiaoli; Hao, Yue

    2013-12-26

    Low-temperature processes are unremittingly pursued in the fabrication of organic solar cells. The paper reports that the highly efficient and "light-soaking"-free inverted organic solar cell can be achieved by using ZnO thin films processed from the aqueous solution method at a low temperature. The inverted organic solar with an aqueous-processed ZnO thin film annealed at 150 °C shows an efficiency of 3.79%. Even when annealed at a temperature as low as 80 °C, the device still shows an efficiency of 3.71%. With the proper annealing temperature of 80 °C, the flexible device, which shows an efficiency of 3.56%, is fabricated on PET. This flexible device still keeps the efficiency above 3.40% after bent for 1000 times with a curvature radius of 50 mm. In contrast, a low annealing temperature leads to an inferior device performance when the ZnO thin film is processed from the widely used sol-gel method. The device with sol-gel processed ZnO annealed at 150 °C only shows a PCE of 1.3%. Furthermore, the device shows a strong "light-soaking" effect, which is not observed in the device containing an aqueous-processed ZnO thin film. Our results suggest that the adopted aqueous solution method is a more efficient low temperature technique, compared with the sol-gel method.

  20. Microlens array induced light absorption enhancement in polymer solar cells

    SciTech Connect

    Chen, Yuqing; Elshobaki, Moneim; Ye, Zhuo; Park, Joong-Mok; Noack, Max A.; Ho, Kai-Ming; Chaudhary, Sumit

    2013-01-24

    Over the last decade, polymer solar cells (PSCs) have attracted a lot of attention and highest power conversion efficiencies (PCE) are now close to 10%. Here we employ an optical structure – the microlens array (MLA) – to increase light absorption inside the active layer, and PCE of PSCs increased even for optimized devices. Normal incident light rays are refracted at the MLA and travel longer optical paths inside the active layers. Two PSC systems – poly(3-hexylthiophene-2,5-diyl):(6,6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM) and poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]:(6,6)-phenyl C71 butyric acid methyl ester (PCDTBT:PC70BM) – were investigated. In the P3HT:PCBM system, MLA increased the absorption, absolute external quantum efficiency, and the PCE of an optimized device by [similar]4.3%. In the PCDTBT:PC70BM system, MLA increased the absorption, absolute external quantum efficiency, and PCE by more than 10%. In addition, simulations incorporating optical parameters of all structural layers were performed and they support the enhancement of absorption in the active layer with the assistance of MLA. Our results show that utilizing MLA is an effective strategy to further increase light absorption in PSCs, in which optical losses account for [similar]40% of total losses. MLA also does not pose materials processing challenges to the active layers since it is on the other side of the transparent substrate.

  1. Interfacial Engineering Importance of Bilayered ZnO Cathode Buffer on the Photovoltaic Performance of Inverted Organic Solar Cells.

    PubMed

    Ambade, Rohan B; Ambade, Swapnil B; Mane, Rajaram S; Lee, Soo-Hyoung

    2015-04-22

    The role of cathode buffer layer (CBL) is crucial in determining the power conversion efficiency (PCE) of inverted organic solar cells (IOSCs). The hallmarks of a promising CBL include high transparency, ideal energy levels, and tendency to offer good interfacial contact with the organic bulk-heterojunction (BHJ) layers. Zinc oxide (ZnO), with its ability to form numerous morphologies in juxtaposition to its excellent electron affinity, solution processability, and good transparency is an ideal CBL material for IOSCs. Technically, when CBL is sandwiched between the BHJ active layer and the indium-tin-oxide (ITO) cathode, it performs two functions, namely, electron collection from the photoactive layer that is effectively carried out by morphologies like nanoparticles or nanoridges obtained by ZnO sol-gel (ZnO SG) method through an accumulation of individual nanoparticles and, second, transport of collected electrons toward the cathode, which is more effectively manifested by one-dimensional (1D) nanostructures like ZnO nanorods (ZnO NRs). This work presents the use of bilayered ZnO CBL in IOSCs of poly(3-hexylthiophene) (P3HT)/[6, 6]-phenyl-C60-butyric acid methyl ester (PCBM) to overcome the limitations offered by a conventionally used single layer CBL. We found that the PCE of IOSCs with an appropriate bilayer CBL comprising of ZnO NRs/ZnO SG is ∼18.21% higher than those containing ZnO SG/ZnO NRs. We believe that, in bilayer ZnO NRs/ZnO SG, ZnO SG collects electrons effectively from photoactive layer while ZnO NRs transport them further to ITO resulting significant increase in the photocurrent to achieve highest PCE of 3.70%. The enhancement in performance was obtained through improved interfacial engineering, enhanced electrical properties, and reduced surface/bulk defects in bilayer ZnO NRs/ZnO SG. This study demonstrates that the novel bilayer ZnO CBL approach of electron collection/transport would overcome crucial interfacial recombination issues and

  2. Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells

    PubMed Central

    Liu, Yuhang; Zhao, Jingbo; Li, Zhengke; Mu, Cheng; Hu, Huawei; Jiang, Kui; Lin, Haoran; Ade, Harald; Yan, He

    2014-01-01

    Although the field of polymer solar cell has seen much progress in device performance in the past few years, several limitations are holding back its further development. For instance, current high-efficiency (>9.0%) cells are restricted to material combinations that are based on limited donor polymers and only one specific fullerene acceptor. Here we report the achievement of high-performance (efficiencies up to 10.8%, fill factors up to 77%) thick-film polymer solar cells for multiple polymer:fullerene combinations via the formation of a near-ideal polymer:fullerene morphology that contains highly crystalline yet reasonably small polymer domains. This morphology is controlled by the temperature-dependent aggregation behaviour of the donor polymers and is insensitive to the choice of fullerenes. The uncovered aggregation and design rules yield three high-efficiency (>10%) donor polymers and will allow further synthetic advances and matching of both the polymer and fullerene materials, potentially leading to significantly improved performance and increased design flexibility. PMID:25382026

  3. 11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor.

    PubMed

    Bin, Haijun; Gao, Liang; Zhang, Zhi-Guo; Yang, Yankang; Zhang, Yindong; Zhang, Chunfeng; Chen, Shanshan; Xue, Lingwei; Yang, Changduk; Xiao, Min; Li, Yongfang

    2016-12-01

    Simutaneously high open circuit voltage and high short circuit current density is a big challenge for achieving high efficiency polymer solar cells due to the excitonic nature of organic semdonductors. Herein, we developed a trialkylsilyl substituted 2D-conjugated polymer with the highest occupied molecular orbital level down-shifted by Si-C bond interaction. The polymer solar cells obtained by pairing this polymer with a non-fullerene acceptor demonstrated a high power conversion efficiency of 11.41% with both high open circuit voltage of 0.94 V and high short circuit current density of 17.32 mA cm(-2) benefitted from the complementary absorption of the donor and acceptor, and the high hole transfer efficiency from acceptor to donor although the highest occupied molecular orbital level difference between the donor and acceptor is only 0.11 eV. The results indicate that the alkylsilyl substitution is an effective way in designing high performance conjugated polymer photovoltaic materials.

  4. 11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor

    PubMed Central

    Bin, Haijun; Gao, Liang; Zhang, Zhi-Guo; Yang, Yankang; Zhang, Yindong; Zhang, Chunfeng; Chen, Shanshan; Xue, Lingwei; Yang, Changduk; Xiao, Min; Li, Yongfang

    2016-01-01

    Simutaneously high open circuit voltage and high short circuit current density is a big challenge for achieving high efficiency polymer solar cells due to the excitonic nature of organic semdonductors. Herein, we developed a trialkylsilyl substituted 2D-conjugated polymer with the highest occupied molecular orbital level down-shifted by Si–C bond interaction. The polymer solar cells obtained by pairing this polymer with a non-fullerene acceptor demonstrated a high power conversion efficiency of 11.41% with both high open circuit voltage of 0.94 V and high short circuit current density of 17.32 mA cm−2 benefitted from the complementary absorption of the donor and acceptor, and the high hole transfer efficiency from acceptor to donor although the highest occupied molecular orbital level difference between the donor and acceptor is only 0.11 eV. The results indicate that the alkylsilyl substitution is an effective way in designing high performance conjugated polymer photovoltaic materials. PMID:27905397

  5. 11.4% Efficiency non-fullerene polymer solar cells with trialkylsilyl substituted 2D-conjugated polymer as donor

    NASA Astrophysics Data System (ADS)

    Bin, Haijun; Gao, Liang; Zhang, Zhi-Guo; Yang, Yankang; Zhang, Yindong; Zhang, Chunfeng; Chen, Shanshan; Xue, Lingwei; Yang, Changduk; Xiao, Min; Li, Yongfang

    2016-12-01

    Simutaneously high open circuit voltage and high short circuit current density is a big challenge for achieving high efficiency polymer solar cells due to the excitonic nature of organic semdonductors. Herein, we developed a trialkylsilyl substituted 2D-conjugated polymer with the highest occupied molecular orbital level down-shifted by Si-C bond interaction. The polymer solar cells obtained by pairing this polymer with a non-fullerene acceptor demonstrated a high power conversion efficiency of 11.41% with both high open circuit voltage of 0.94 V and high short circuit current density of 17.32 mA cm-2 benefitted from the complementary absorption of the donor and acceptor, and the high hole transfer efficiency from acceptor to donor although the highest occupied molecular orbital level difference between the donor and acceptor is only 0.11 eV. The results indicate that the alkylsilyl substitution is an effective way in designing high performance conjugated polymer photovoltaic materials.

  6. A polymer tandem solar cell with 10.6% power conversion efficiency.

    PubMed

    You, Jingbi; Dou, Letian; Yoshimura, Ken; Kato, Takehito; Ohya, Kenichiro; Moriarty, Tom; Emery, Keith; Chen, Chun-Chao; Gao, Jing; Li, Gang; Yang, Yang

    2013-01-01

    An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4 eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2',3'-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm(-2), IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%.

  7. A polymer tandem solar cell with 10.6% power conversion efficiency

    PubMed Central

    You, Jingbi; Dou, Letian; Yoshimura, Ken; Kato, Takehito; Ohya, Kenichiro; Moriarty, Tom; Emery, Keith; Chen, Chun-Chao; Gao, Jing; Li, Gang; Yang, Yang

    2013-01-01

    An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4 eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2′,3′-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm−2, IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%. PMID:23385590

  8. Ultraviolet-ozone surface modification for non-wetting hole transport materials based inverted planar perovskite solar cells with efficiency exceeding 18%

    NASA Astrophysics Data System (ADS)

    Xu, Xiuwen; Ma, Chunqing; Cheng, Yuanhang; Xie, Yue-Min; Yi, Xueping; Gautam, Bhoj; Chen, Shengmei; Li, Ho-Wa; Lee, Chun-Sing; So, Franky; Tsang, Sai-Wing

    2017-08-01

    Non-wetting hole transport materials (HTMs) have great potential in facilitating large-sized perovskite crystal growth and enhancing device stability by opposing moisture ingress, However, the severe non-wetting issue limits the wide application of these materials in low-temperature solution-processed inverted planar perovskite solar cells (PVSCs), and corresponding devices are rarely reported. Here, a facile ultraviolet-ozone (UVO) modification method is demonstrated to overcome this issue. By carefully controlling the UVO modification time, the surface wettability of poly-TPD can be tuned without affecting the bulk properties of the film, hence perovskite films with desired grain size and excellent coverage can be deposited via a one-step spin-coating method. Benefiting from the high-quality perovskite, well-matched energy level alignment and hydrophobic property of poly-TPD, the resulting PVSCs show a champion power conversion efficiency of 18.19% with significantly enhanced stability as compared to the PEDOT:PSS counterparts. Moreover, the UVO modification approach also demonstrates its validity when being extended to other hydrophobic HTMs. This work not only provides a general strategy to broaden the selection pool of HTMs for solution-processed inverted planar PVSCs, but also may triggers the exploration of more advanced strategies to make non-wetting HTMs applicable in solution-processed inverted planar PVSCs.

  9. All-Polymer Solar Cell Performance Optimized via Systematic Molecular Weight Tuning of Both Donor and Acceptor Polymers.

    PubMed

    Zhou, Nanjia; Dudnik, Alexander S; Li, Ting I N G; Manley, Eric F; Aldrich, Thomas J; Guo, Peijun; Liao, Hsueh-Chung; Chen, Zhihua; Chen, Lin X; Chang, Robert P H; Facchetti, Antonio; Olvera de la Cruz, Monica; Marks, Tobin J

    2016-02-03

    The influence of the number-average molecular weight (Mn) on the blend film morphology and photovoltaic performance of all-polymer solar cells (APSCs) fabricated with the donor polymer poly[5-(2-hexyldodecyl)-1,3-thieno[3,4-c]pyrrole-4,6-dione-alt-5,5-(2,5-bis(3-dodecylthiophen-2-yl)thiophene)] (PTPD3T) and acceptor polymer poly{[N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2); N2200) is systematically investigated. The Mn effect analysis of both PTPD3T and N2200 is enabled by implementing a polymerization strategy which produces conjugated polymers with tunable Mns. Experimental and coarse-grain modeling results reveal that systematic Mn variation greatly influences both intrachain and interchain interactions and ultimately the degree of phase separation and morphology evolution. Specifically, increasing Mn for both polymers shrinks blend film domain sizes and enhances donor-acceptor polymer-polymer interfacial areas, affording increased short-circuit current densities (Jsc). However, the greater disorder and intermixed feature proliferation accompanying increasing Mn promotes charge carrier recombination, reducing cell fill factors (FF). The optimized photoactive layers exhibit well-balanced exciton dissociation and charge transport characteristics, ultimately providing solar cells with a 2-fold PCE enhancement versus devices with nonoptimal Mns. Overall, it is shown that proper and precise tuning of both donor and acceptor polymer Mns is critical for optimizing APSC performance. In contrast to reports where maximum power conversion efficiencies (PCEs) are achieved for the highest Mns, the present two-dimensional Mn optimization matrix strategy locates a PCE "sweet spot" at intermediate Mns of both donor and acceptor polymers. This study provides synthetic methodologies to predictably access conjugated polymers with desired Mn and highlights the importance of optimizing Mn for both polymer

  10. Co-functionalized organic/inorganic hybrid ZnO nanorods as electron transporting layers for inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Ambade, Swapnil B.; Ambade, Rohan B.; Eom, Seung Hun; Baek, Myung-Jin; Bagde, Sushil S.; Mane, Rajaram S.; Lee, Soo-Hyoung

    2016-02-01

    In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM-ZnO NRs) leads to higher aggregation owing to the weaker solubility of SMs in solutions of ZnO NRs dispersed in chlorobenzene (CB). A prior addition of organic 2-(2-methoxyethoxy)acetic acid (MEA) over ZnO NRs not only inhibits aggregation of SMs over ZnO NRs, but also provides enough sites for the SM to strongly couple with the ZnO NRs to yield transparent SM-MEA-ZnO NRs hybrids that exhibited excellent capability as electron transporting layers (ETLs) in inverted organic solar cells (iOSCs) of P3HT:PC60BM bulk-heterojunction (BHJ) photoactive layers. A strongly coupled SM-MEA-ZnO NR hybrid reduces the series resistance by enhancing the interfacial area and tunes the energy level alignment at the interface between the (indium-doped tin oxide, ITO) cathode and BHJ photoactive layers. A significant enhancement in power conversion efficiency (PCE) was achieved for iOSCs comprising ETLs of SM-MEA-ZnO NRs (3.64%) advancing from 0.9% for pristine ZnO NRs, while the iOSCs of aggregated SM-ZnO NRs ETL exhibited a much lower PCE of 2.6%, thus demonstrating the potential of the co-functionalization approach. The superiority of the co-functionalized SM-MEA-ZnO NRs ETL is also evident from the highest PCE of 7.38% obtained for the iOSCs comprising BHJ of PTB7-Th:PC60BM compared with extremely poor 0.05% for non-functionalized ZnO NRs.In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM

  11. Systematic investigation of benzodithiophene- and diketopyrrolopyrrole-based low-bandgap polymers designed for single junction and tandem polymer solar cells.

    PubMed

    Dou, Letian; Gao, Jing; Richard, Eric; You, Jingbi; Chen, Chun-Chao; Cha, Kitty C; He, Youjun; Li, Gang; Yang, Yang

    2012-06-20

    The tandem solar cell architecture is an effective way to harvest a broader part of the solar spectrum and make better use of the photonic energy than the single junction cell. Here, we present the design, synthesis, and characterization of a series of new low bandgap polymers specifically for tandem polymer solar cells. These polymers have a backbone based on the benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) units. Alkylthienyl and alkylphenyl moieties were incorporated onto the BDT unit to form BDTT and BDTP units, respectively; a furan moiety was incorporated onto the DPP unit in place of thiophene to form the FDPP unit. Low bandgap polymers (bandgap = 1.4-1.5 eV) were prepared using BDTT, BDTP, FDPP, and DPP units via Stille-coupling polymerization. These structural modifications lead to polymers with different optical, electrochemical, and electronic properties. Single junction solar cells were fabricated, and the polymer:PC(71)BM active layer morphology was optimized by adding 1,8-diiodooctane (DIO) as an additive. In the single-layer photovoltaic device, they showed power conversion efficiencies (PCEs) of 3-6%. When the polymers were applied in tandem solar cells, PCEs over 8% were reached, demonstrating their great potential for high efficiency tandem polymer solar cells.

  12. A New Strategy to Construct Low Bandgap Polymer Acceptor for High Performance All-Polymer Solar Cells.

    PubMed

    Li, Yongfang; Zhang, Zhi-Guo; Yang, Yankang; Yao, Jia; Xue, Lingwei; Chen, Shanshan; Li, Xiaojun; Morrison, William; Yang, Changduk

    2017-08-29

    All polymer solar cells (all-PSCs) offer unique morphology stability for the application as flexible devices, but the lack of high performance polymer acceptors limits their power conversion efficiency (PCE) lower than the PSCs based on fullerene derivative or organic small molecule acceptors. We herein demonstrate a strategy to synthesize a high performance polymer acceptor PZ1 by embedding an acceptor-donor-acceptor building block into the polymer main chain. PZ1 possesses broad absorption with a low bandgap of 1.55 eV and high absorption coefficient (1.3 × 105 cm-1). The all-PSCs with a wide bandgap polymer PBDT-T as donor and PT1 as acceptor demonstrated a record high PCE of 9.19% for the all-PSCs. The success of our polymerization strategy can provide a new way to develop efficient polymer acceptors for all-PSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Pyramid shape of polymer solar cells: a simple solution to triple efficiency

    NASA Astrophysics Data System (ADS)

    Xia, Yuxin; Hou, Lintao; Ma, Kaijie; Wang, Biao; Xiong, Kang; Liu, Pengyi; Liao, Jihai; Wen, Shangsheng; Wang, Ergang

    2013-07-01

    Pyramid-shaped polymer solar cells fabricated on flexible substrates were investigated. Effective light trapping can be realized due to light reflection in all 360° directions, and 100% space utilization is achieved when assembled into arrays. The power conversion efficiency is enhanced by 200% ([60]PCBM as the acceptor) and 260% ([70]PCBM as the acceptor) with a dihedral angle of 30° between the opposite sides of the pyramid compared with a planar device, and a high Voc of 3.5 V in series connection is obtained. Considering the material utilization, an angle of 90° for pyramid-shaped polymer solar cells is proposed. Pyramid-shaped polymer solar cells are particularly suitable for installation on roof of vehicles and houses, which have limited surface area.

  14. Photocurrent enhancement from diketopyrrolopyrrole polymer solar cells through alkyl-chain branching point manipulation.

    PubMed

    Meager, Iain; Ashraf, Raja Shahid; Mollinger, Sonya; Schroeder, Bob C; Bronstein, Hugo; Beatrup, Daniel; Vezie, Michelle S; Kirchartz, Thomas; Salleo, Alberto; Nelson, Jenny; McCulloch, Iain

    2013-08-07

    Systematically moving the alkyl-chain branching position away from the polymer backbone afforded two new thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT-T) polymers. When used as donor materials in polymer:fullerene solar cells, efficiencies exceeding 7% were achieved without the use of processing additives. The effect of the position of the alkyl-chain branching point on the thin-film morphology was investigated using X-ray scattering techniques and the effects on the photovoltaic and charge-transport properties were also studied. For both solar cell and transistor devices, moving the branching point further from the backbone was beneficial. This is the first time that this effect has been shown to improve solar cell performance. Strong evidence is presented for changes in microstructure across the series, which is most likely the cause for the photocurrent enhancement.

  15. Evolved phase separation toward balanced charge transport and high efficiency in polymer solar cells.

    PubMed

    Fan, Haijun; Zhang, Maojie; Guo, Xia; Li, Yongfang; Zhan, Xiaowei

    2011-09-01

    Understanding effect of morphology on charge carrier transport within polymer/fullerene bulk heterojunction is necessary to develop high-performance polymer solar cells. In this work, we synthesized a new benzodithiophene-based polymer with good self-organization behavior as well as favorable morphology evolution of its blend films with PC(71)BM under improved processing conditions. Charge carrier transport behavior of blend films was characterized by space charge limited current method. Evolved blend film morphology by controlling blend composition and additive content gradually reaches an optimized state, featured with nanoscale fibrilla polymer phase in moderate size and balanced mobility ratio close to 1:1 for hole and electron. This optimized morphology toward more balanced charge carrier transport accounts for the best power conversion efficiency of 3.2%, measured under simulated AM 1.5 solar irradiation 100 mW/cm(2), through enhancing short circuit current and reducing geminate recombination loss.

  16. All-Polymer Solar Cell Performance Optimized via Systematic Molecular Weight Tuning of Both Donor and Acceptor Polymers

    SciTech Connect

    Zhou, Nanjia; Dudnik, Alexander S.; Li, Ting I. N. G.; Manley, Eric F.; Aldrich, Thomas J.; Guo, Peijun; Liao, Hsueh-Chung; Chen, Zhihua; Chen, Lin X.; Chang, Robert P. H.; Facchetti, A; Olvera de la Cruz, Monica; Marks, Tobin J.

    2016-02-03

    ABSTRACT: The influence of the number-average molecular weight (Mn) on the blend film morphology and photovoltaic performance of all-polymer solar cells (APSCs) fabricated with the donor polymer poly[5-(2-hexyldodecyl)-1,3-thieno[3,4- c]pyrrole-4,6-dione-alt-5,5-(2,5-bis(3-dodecylthiophen-2-yl)- thiophene)] (PTPD3T) and acceptor polymer poly{[N,N′- bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)- 2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2); N2200) is systematically investigated. The Mn effect analysis of both PTPD3T and N2200 is enabled by implementing a polymerization strategy which produces conjugated polymers with tunable Mns. Experimental and coarse-grain modeling results reveal that systematic Mn variation greatly influences both intrachain and interchain interactions and ultimately the degree of phase separation and morphology evolution. Specifically, increasing Mn for both polymers shrinks blend film domain sizes and enhances donor−acceptor polymer−polymer interfacial areas, affording increased short-circuit current densities (Jsc). However, the greater disorder and intermixed feature proliferation accompanying increasing Mn promotes charge carrier recombination, reducing cell fill factors (FF). The optimized photoactive layers exhibit well-balanced exciton dissociation and charge transport characteristics, ultimately providing solar cells with a 2-fold PCE enhancement versus devices with nonoptimal Mns. Overall, it is shown that proper and precise tuning of both donor and acceptor polymer Mns is critical for optimizing APSC performance. In contrast to reports where maximum power conversion efficiencies (PCEs) are achieved for the highest Mns, the present two-dimensional Mn optimization matrix strategy locates a PCE “sweet spot” at intermediate Mns of both donor and acceptor polymers. This study provides synthetic methodologies to predictably access conjugated polymers with desired Mn and highlights the importance of

  17. Inverted Ultrathin Organic Solar Cells with a Quasi-Grating Structure for Efficient Carrier Collection and Dip-less Visible Optical Absorption

    PubMed Central

    In, Sungjun; Park, Namkyoo

    2016-01-01

    We propose a metallic-particle-based two-dimensional quasi-grating structure for application to an organic solar cell. With the use of oblate spheroidal nanoparticles in contact with an anode of inverted, ultrathin organic solar cells (OSCs), the quasi-grating structure offers strong hybridization between localized surface plasmons and plasmonic gap modes leading to broadband (300~800 nm) and uniform (average ~90%) optical absorption spectra. Both strong optical enhancement in extreme confinement within the active layer (90 nm) and improved hole collection are thus realized. A coupled optical-electrical multi-physics optimization shows a large (~33%) enhancement in the optical absorption (corresponding to an absorption efficiency of ~47%, AM1.5G weighted, visible) when compared to a control OSC without the quasi-grating structure. That translates into a significant electrical performance gain of ~22% in short circuit current and ~15% in the power conversion efficiency (PCE), leading to an energy conversion efficiency (~6%) which is comparable to that of optically-thick inverted OSCs (3–7%). Detailed analysis on the influences of mode hybridization to optical field distributions, exciton generation rate, charge carrier collection efficiency and electrical conversion efficiency is provided, to offer an integrated understanding on the coupled optical-electrical optimization of ultrathin OSCs. PMID:26902974

  18. Inverted Ultrathin Organic Solar Cells with a Quasi-Grating Structure for Efficient Carrier Collection and Dip-less Visible Optical Absorption.

    PubMed

    In, Sungjun; Park, Namkyoo

    2016-02-23

    We propose a metallic-particle-based two-dimensional quasi-grating structure for application to an organic solar cell. With the use of oblate spheroidal nanoparticles in contact with an anode of inverted, ultrathin organic solar cells (OSCs), the quasi-grating structure offers strong hybridization between localized surface plasmons and plasmonic gap modes leading to broadband (300~800 nm) and uniform (average ~90%) optical absorption spectra. Both strong optical enhancement in extreme confinement within the active layer (90 nm) and improved hole collection are thus realized. A coupled optical-electrical multi-physics optimization shows a large (~33%) enhancement in the optical absorption (corresponding to an absorption efficiency of ~47%, AM1.5G weighted, visible) when compared to a control OSC without the quasi-grating structure. That translates into a significant electrical performance gain of ~22% in short circuit current and ~15% in the power conversion efficiency (PCE), leading to an energy conversion efficiency (~6%) which is comparable to that of optically-thick inverted OSCs (3-7%). Detailed analysis on the influences of mode hybridization to optical field distributions, exciton generation rate, charge carrier collection efficiency and electrical conversion efficiency is provided, to offer an integrated understanding on the coupled optical-electrical optimization of ultrathin OSCs.

  19. Inverted Ultrathin Organic Solar Cells with a Quasi-Grating Structure for Efficient Carrier Collection and Dip-less Visible Optical Absorption

    NASA Astrophysics Data System (ADS)

    in, Sungjun; Park, Namkyoo

    2016-02-01

    We propose a metallic-particle-based two-dimensional quasi-grating structure for application to an organic solar cell. With the use of oblate spheroidal nanoparticles in contact with an anode of inverted, ultrathin organic solar cells (OSCs), the quasi-grating structure offers strong hybridization between localized surface plasmons and plasmonic gap modes leading to broadband (300~800 nm) and uniform (average ~90%) optical absorption spectra. Both strong optical enhancement in extreme confinement within the active layer (90 nm) and improved hole collection are thus realized. A coupled optical-electrical multi-physics optimization shows a large (~33%) enhancement in the optical absorption (corresponding to an absorption efficiency of ~47%, AM1.5G weighted, visible) when compared to a control OSC without the quasi-grating structure. That translates into a significant electrical performance gain of ~22% in short circuit current and ~15% in the power conversion efficiency (PCE), leading to an energy conversion efficiency (~6%) which is comparable to that of optically-thick inverted OSCs (3–7%). Detailed analysis on the influences of mode hybridization to optical field distributions, exciton generation rate, charge carrier collection efficiency and electrical conversion efficiency is provided, to offer an integrated understanding on the coupled optical-electrical optimization of ultrathin OSCs.

  20. Enhanced interfacial electron transfer of inverted perovskite solar cells by introduction of CoSe into the electron-transporting-layer

    NASA Astrophysics Data System (ADS)

    Chen, Shanshan; Yang, Songwang; Sun, Hong; Zhang, Lu; Peng, Jiajun; Liang, Ziqi; Wang, Zhong-Sheng

    2017-06-01

    To improve the electron transfer at the interface between the perovskite film and the electron-transporting-material (ETM) layer, CoSe doped [6,6]-phenyl C61-butyric acid methyl ester (PCBM) is employed as the ETM layer for the inverted planar perovskite solar cell with NiO as the hole-transporting-material layer. Introduction of CoSe (5.8 wt%) into the PCBM layer improves the conductivity of the ETM layer and decreases the photoluminescence intensity, thus enhancing the interfacial electron extraction and reducing the electron transfer resistance at the perovskite/ETM interface. As a consequence, the power conversion efficiency is enhanced from 11.43% to 14.91% by 30% due to the noted increases in short-circuit current density from 17.95 mA cm-2 to 19.85 mA cm-2 and fill factor from 0.60 to 0.70. This work provides a new strategy to improve the performance of inverted perovskite solar cells.

  1. Morphology evolution in high-performance polymer solar cells processed from nonhalogenated solvent

    SciTech Connect

    Cai, Wanzhu; Liu, Peng; Jin, Yaocheng; Xue, Qifan; Liu, Feng; Russell, Thomas P.; Huang, Fei; Yip, Hin -Lap; Cao, Yong

    2015-05-26

    A new processing protocol based on non-halogenated solvent and additive is developed to produce polymer solar cells with power conversion efficiencies better than those processed from commonly used halogenated solvent-additive pair. Morphology studies show that good performance correlates with a finely distributed nanomorphology with a well-defined polymer fibril network structure, which leads to balanced charge transport in device operation.

  2. Interface engineering for ternary blend polymer solar cells with a heterostructured near-IR dye.

    PubMed

    Xu, Huajun; Ohkita, Hideo; Tamai, Yasunari; Benten, Hiroaki; Ito, Shinzaburo

    2015-10-21

    Ternary-blend polymer solar cells can be effectively improved by incorporating a heterostructured near-IR dye, which has a hexyl group compatible with the polymer and a benzyl group compatible with the fullerene. Because of the compatibility with both materials, the heterostructured dye can be loaded up to 15 wt% and hence can boost the photocurrent generation by 30%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Efficient, Air-Stable Bulk Heterojunction Polymer Solar Cells Using MoOx as the Anode Interfacial Layer

    SciTech Connect

    Sun, Yanming; Takacs, Christopher J.; Cowan, Sarah R.; Seo, Jung Hwa; Gong, Xiong; Roy, Anshuman; Heeger, Alan J.

    2011-04-05

    The use of molybdenum oxide as the anode interfacial layer in conventional bulk heterojunction polymer solar cells leads to an improved power conversion efficiency and also dramatically increases the device stability. This indicates that the engineering of improved anode interface materials is an important method by which to fabricate efficient and stable polymer solar cells.

  4. Tandem Solar Cells from Accessible Low Band-Gap Polymers Using an Efficient Interconnecting Layer.

    PubMed

    Bag, Santanu; Patel, Romesh J; Bunha, Ajaykumar; Grand, Caroline; Berrigan, J Daniel; Dalton, Matthew J; Leever, Benjamin J; Reynolds, John R; Durstock, Michael F

    2016-01-13

    Tandem solar cell architectures are designed to improve device photoresponse by enabling the capture of wider range of solar spectrum as compared to single-junction device. However, the practical realization of this concept in bulk-heterojunction polymer systems requires the judicious design of a transparent interconnecting layer compatible with both polymers. Moreover, the polymers selected should be readily synthesized at large scale (>1 kg) and high performance. In this work, we demonstrate a novel tandem polymer solar cell that combines low band gap poly isoindigo [P(T3-iI)-2], which is easily synthesized in kilogram quantities, with a novel Cr/MoO3 interconnecting layer. Cr/MoO3 is shown to be greater than 80% transparent above 375 nm and an efficient interconnecting layer for P(T3-iI)-2 and PCDTBT, leading to 6% power conversion efficiencies under AM 1.5G illumination. These results serve to extend the range of interconnecting layer materials for tandem cell fabrication by establishing, for the first time, that a thin, evaporated layer of Cr/MoO3 can work as an effective interconnecting layer in a tandem polymer solar cells made with scalable photoactive materials.

  5. Anthracene-containing wide-band-gap conjugated polymers for high-open-circuit-voltage polymer solar cells.

    PubMed

    Gong, Xue; Li, Cuihong; Lu, Zhen; Li, Guangwu; Mei, Qiang; Fang, Tao; Bo, Zhishan

    2013-07-25

    The synthesis, characterization, and photophysical and photovoltaic properties of two anthracene-containing wide-band-gap donor and acceptor (D-A) alternating conjugated polymers (P1 and P2) are described. These two polymers absorb in the range of 300-600 nm with a band gap of about 2.12 eV. Polymer solar cells with P1:PC71 BM as the active layer demonstrate a power conversion efficiency (PCE) of 2.23% with a high Voc of 0.96 V, a Jsc of 4.4 mA cm(-2) , and a comparable fill factor (FF) of 0.53 under simulated solar illumination of AM 1.5 G (100 mW cm(-2) ). In addition, P2:PC71 BM blend-based solar cells exhibit a PCE of 1.42% with a comparable Voc of 0.89 V, a Jsc of 3.0 mA cm(-2) , and an FF of 0.53.

  6. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    PubMed Central

    Heckler, Ilona M.; Kesters, Jurgen; Defour, Maxime; Madsen, Morten V.; Penxten, Huguette; D’Haen, Jan; Van Mele, Bruno; Maes, Wouter; Bundgaard, Eva

    2016-01-01

    The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT) or thiazolo[5,4-d]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs’ lifetime. PMID:28773308

  7. High-efficiency polymer solar cells with small photon energy loss

    PubMed Central

    Kawashima, Kazuaki; Tamai, Yasunari; Ohkita, Hideo; Osaka, Itaru; Takimiya, Kazuo

    2015-01-01

    A crucial issue facing polymer-based solar cells is how to manage the energetics of the polymer/fullerene blends to maximize short-circuit current density and open-circuit voltage at the same time and thus the power conversion efficiency. Here we demonstrate that the use of a naphthobisoxadiazole-based polymer with a narrow bandgap of 1.52 eV leads to high open-circuit voltages of approximately 1 V and high-power conversion efficiencies of ∼9% in solar cells, resulting in photon energy loss as small as ∼0.5 eV, which is much smaller than that of typical polymer systems (0.7–1.0 eV). This is ascribed to the high external quantum efficiency for the systems with a very small energy offset for charge separation. These unconventional features of the present polymer system will inspire the field of polymer-based solar cells towards further improvement of power conversion efficiencies with both high short-circuit current density and open-circuit voltage. PMID:26626042

  8. High-efficiency polymer solar cells with small photon energy loss.

    PubMed

    Kawashima, Kazuaki; Tamai, Yasunari; Ohkita, Hideo; Osaka, Itaru; Takimiya, Kazuo

    2015-12-02

    A crucial issue facing polymer-based solar cells is how to manage the energetics of the polymer/fullerene blends to maximize short-circuit current density and open-circuit voltage at the same time and thus the power conversion efficiency. Here we demonstrate that the use of a naphthobisoxadiazole-based polymer with a narrow bandgap of 1.52 eV leads to high open-circuit voltages of approximately 1 V and high-power conversion efficiencies of ∼9% in solar cells, resulting in photon energy loss as small as ∼0.5 eV, which is much smaller than that of typical polymer systems (0.7-1.0 eV). This is ascribed to the high external quantum efficiency for the systems with a very small energy offset for charge separation. These unconventional features of the present polymer system will inspire the field of polymer-based solar cells towards further improvement of power conversion efficiencies with both high short-circuit current density and open-circuit voltage.

  9. Inverted tetrahedron-pyramidal micropatterned polymer films for boosting light output power in flip-chip light-emitting diodes.

    PubMed

    Leem, Jung Woo; Lee, Soo Hyun; Guan, Xiang-Yu; Yu, Jae Su

    2015-04-20

    We report the improved light output power in gallium nitride-based green flip-chip light-emitting diodes (FCLEDs) employed with inverted tetrahedron-pyramidal micropatterned polydimethylsiloxane (ITPM PDMS) films as an encapsulation and protection layer. The micropatterns are transferred into the surface of PDMS films from the sapphire substrate master molds with two-dimensional periodic hexagonal TPM arrays by a soft imprint lithography method. The ITPM PDMS film laminated on the sapphire dramatically enhances the diffuse transmittance (T(D)) in a wavelength (λ) range of 400-650 nm, exhibiting the larger T(D) value of ~53% at λ = 525 nm, (cf., T(D) ~1% for planar sapphire). By introducing the ITPM PDMS film on the outer surface of sapphire in FCLEDs, the light output power is enhanced, indicating the increment percentage of ~11.1% at 500 mA of injection current compared to the reference FCLED without the ITPM PDMS film, together with better electroluminescence intensity and far-field radiation pattern.

  10. Constructing Post-Permeation Method to Fabricate Polymer/Nanocrystals Hybrid Solar Cells with PCE Exceeding 6.

    PubMed

    Du, Xiaohang; Zeng, Qingsen; Jin, Gan; Liu, Fangyuan; Ji, Tianjiao; Yue, Yuanyuan; Yang, Yi; Zhang, Hao; Yang, Bai

    2017-03-01

    A post-permeation method is constructed for fabricating bulk-heterojunction hybrid solar cells. Porous CdTe film is prepared by annealing the mixture solution of aqueous CdTe nanocrystals and cetyltrimethyl ammonium bromide, after which the post-permeation of polymer is employed. By this method, kinds of polymers can be applied regardless of the intermiscibility with the nanoparticles. The inorganic nanocrystals and the polymer can be treated under respective optimized annealing temperatures, which can facilitate the growth of nanocrystals without damaging the polymers. A high power conversion efficiency of 6.36% in the polymer/nanocrystals hybrid solar cells is obtained via systematical optimization.

  11. Tandem solar cells made from amorphous silicon and polymer bulk heterojunction sub-cells.

    PubMed

    Park, Sung Heum; Shin, Insoo; Kim, Kwang Ho; Street, Robert; Roy, Anshuman; Heeger, Alan J

    2015-01-14

    A tandem solar cell based on a combination of an amorphous silicon (a-Si) and polymer solar cell (PSC) is demonstrated. As these tandem devices can be readily fabricated by low-cost methods, they require only a minor increase in the total manufacturing cost. Therefore, a combination of a-Si and PSC provides a compelling solution to reduce the cost of electricity produced by photovoltaics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Very High Performance Polymer Solar Cells -- A step closer to reality

    NASA Astrophysics Data System (ADS)

    Yang, Yang

    2010-03-01

    Recently, together with our research partners, we have demonstrated polymer solar cell with a power conversion efficiency (PCE) of close to 8%. This is achieved by several technical and scientific approaches. A new series of photovoltaic polymers based on a low bandgap polymer, poly[4,8-bis-substituted-benzo [1,2-b:4,5-b' ]dithiophene-2,6-diyl-alt-4-substituted-thieno[3,4-b]thio- phene-2,6-diyl] (PBDTTT), were designed and synthesized by chemists from University of Chicago and Solarmer Energy Inc., a start-up from UCLA. By adding different electron-withdrawing functional groups, the open circuit voltage (Voc) of polymers based on PBDTTT can be systematically increased, step by step. It was found that in this polymer system, the bandgap of the polymer can be maintained when the functional groups are added. As a result, the molecular energy levels of PBDTTT can be tuned without sacrificing the light harvesting. Together with the increased Voc, a polymer solar cell with efficiency as high as 7.7% PCE was realized, bringing them one step closer to reality for practical application.

  13. Pyrazine-fused isoindigo: a new building block for polymer solar cells with high open circuit voltage.

    PubMed

    Li, Jiu-Long; Chai, Yun-Fei; Wang, Wei Vanessa; Shi, Zi-Fa; Xu, Zhu-Guo; Zhang, Hao-Li

    2017-05-30

    Pyrazine-fused isoindigo (PzIIG) was designed and synthesized as a novel electron acceptor to construct two D-A conjugated polymers, PzIIG-BDT2TC8 and PzIIG-BTT2TC10. Both the polymers were successfully applied in polymer solar cells, and the PzIIG-BDT2TC8 based solar cell device exhibited a PCE of 5.26% with a high Voc over 1.0 V.

  14. One-Pot Large-Scale Synthesis of Carbon Quantum Dots: Efficient Cathode Interlayers for Polymer Solar Cells.

    PubMed

    Yang, Yuzhao; Lin, Xiaofeng; Li, Wenlang; Ou, Jiemei; Yuan, Zhongke; Xie, Fangyan; Hong, Wei; Yu, Dingshan; Ma, Yuguang; Chi, Zhenguo; Chen, Xudong

    2017-05-03

    Cathode interlayers (CILs) with low-cost, low-toxicity, and excellent cathode modification ability are necessary for the large-scale industrialization of polymer solar cells (PSCs). In this contribution, we demonstrated one-pot synthesized carbon quantum dots (C-dots) with high production to serve as efficient CIL for inverted PSCs. The C-dots were synthesized by a facile, economical microwave pyrolysis in a household microwave oven within 7 min. Ultraviolet photoelectron spectroscopy (UPS) studies showed that the C-dots possessed the ability to form a dipole at the interface, resulting in the decrease of the work function (WF) of cathode. External quantum efficiency (EQE) measurements and 2D excitation-emission topographical maps revealed that the C-dots down-shifted the high energy near-ultraviolet light to low energy visible light to generate more photocurrent. Remarkably improvement of power conversion efficiency (PCE) was attained by incorporation of C-dots as CIL. The PCE was boosted up from 4.14% to 8.13% with C-dots as CIL, which is one of the best efficiency for i-PSCs used carbon based materials as interlayers. These results demonstrated that C-dots can be a potential candidate for future low cost and large area PSCs producing.

  15. Critical role of domain crystallinity, domain purity and domain interface sharpness for reduced bimolecular recombination in polymer solar cells

    SciTech Connect

    Venkatesan, Swaminathan; Chen, Jihua; Ngo, Evan C.; Dubey, Ashish; Khatiwada, Devendra; Zhang, Cheng; Qiao, Qiquan

    2014-12-31

    In this study, inverted bulk heterojunction solar cells were fabricated using poly(3-hexylthiophene) (P3HT) blended with two different fullerene derivatives namely phenyl-C61-butyric acid methyl ester (PC60BM) and indene-C60 bis-adduct (IC60BA). The effects of annealing temperatures on the morphology, optical and structural properties were studied and correlated to differences in photovoltaic device performance. It was observed that annealing temperature significantly improved the performance of P3HT:IC60BA solar cells while P3HT:PC60BM cells showed relatively less improvement. The performance improvement is attributed to the extent of fullerene mixing with polymer domains. Energy filtered transmission electron microscopy (EFTEM) and x-ray diffraction (XRD) results showed that ICBA mixes with disordered P3HT much more readily than PC60BM which leads to lower short circuit current density and fill factor for P3HT:IC60BA cells annealed below 120°C. Annealing above 120°C improves the crystallinity of P3HT in case of P3HT:IC60BA whereas in P3HT:PC60BM films, annealing above 80°C leads to negligible change in crystallinity. Crystallization of P3HT also leads to higher domain purity as seen EFTEM. Further it is seen that cells processed with additive nitrobenzene (NB) showed enhanced short circuit current density and power conversion efficiency regardless of the fullerene derivative used. Addition of NB led to nanoscale phase separation between purer polymer and fullerene domains. Kelvin probe force microscopy (KPFM) images showed that enhanced domain purity in additive casted films led to a sharper interface between polymer and fullerene. Lastly, enhanced domain purity and interfacial sharpness led to lower bimolecular recombination and higher mobility and charge carrier lifetime in NB modified devices.

  16. Novel benzodithiophene-based polymer acceptors for efficient organic solar cells.

    PubMed

    Wang, Yan-Ling; Li, Quan-Song; Li, Ze-Sheng

    2017-08-30

    All polymer organic solar cells afford unique potentials due to the tunable chemical and electronic properties of both polymer donors and polymer acceptors. Compared with the rapid development of polymer donors, the development of polymer acceptors lags far behind. To seek high-performance polymer acceptors used in organic solar cells, based on the experimentally reported D-A polymer acceptor (NDI2OD-T2)n (P1), a series of novel acceptors, designated as (BDTNDI2OD-T2)n(P2), (BDTNDTI)n(P3), (BDTNDI2OD-Tz2)n(P4), and (BDTNDTzI)n(P5), were designed by introduction of a benzodithiophene (BDT) unit and the nitrogen atom in the bridged thiophene ring. The density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods were applied to study the effect of the BDT unit and the nitrogen atom on the geometrical, optical, electronic, and charge transport properties. The obtained results show that incorporation of the electron-donating BDT unit into P1 and the replacement of a carbon atom by the nitrogen atom in the bridged thiophene ring are effective strategies to lower the lowest unoccupied molecular orbital (LUMO) energy and exciton binding energy, and enhance light-absorbing capacity and electron mobility. Moreover, among the investigated molecules, P2 and P5 exhibit stronger and broader light absorption, higher light absorption efficiency and exciton separation ability as well as electron mobility; therefore they are recommended as promising polymer acceptors for future high-efficiency organic solar cells.

  17. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell

    SciTech Connect

    Venkatasubramanian, R. )

    1993-01-01

    This report describes work to develop inverted-grown Al[sub 0.34]Ga[sub 0.66]As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al[sub 0.34]Ga[sub 0.66]As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The cycled'' organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al[sub 0.34]Ga[sub 0.66]As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  18. A summary report on the Flat-Plate Solar Array Project Workshop on Transparent Conducting Polymers

    NASA Technical Reports Server (NTRS)

    Kachare, R.; Moacanin, J.

    1985-01-01

    The proceedings and technical discussions of a workshop on Transparent Conducting Polymers (TCP) for solar cell applications are reported. This is in support of the Device Research Task of the Flat-Flate Solar Array Project. The workshop took place on January 11 and 12, 1985, in Santa Barbara, California. Participants included university and industry researchers. The discussions focused on the electronic and optical properties of TCP, and on experimental issues and problems that should be addressed for high-efficiency solar cell application.

  19. Correlation between charge transfer exciton recombination and photocurrent in polymer/fullerene solar cells

    SciTech Connect

    Hallermann, Markus; Da Como, Enrico; Feldmann, Jochen; Izquierdo, Marta; Filippone, Salvatore; Martin, Nazario; Juechter, Sabrina; Hauff, Elizabeth von

    2010-07-12

    We correlate carrier recombination via charge transfer excitons (CTEs) with the short circuit current, J{sub sc}, in polymer/fullerene solar cells. Near infrared photoluminescence spectroscopy of CTE in three blends differing for the fullerene acceptor, gives unique insights into solar cell characteristics. The energetic position of the CTE is directly correlated with the open-circuit voltage, V{sub oc}, and more important J{sub sc} decreases with increasing CTE emission intensity. CTE emission intensity is discussed from the perspective of blend morphology. The work points out the fundamental role of CTE recombination and how optical spectroscopy can be used to derive information on solar cell performances.

  20. A (001) dominated conjugated polymer with high-performance of hydrogen evolution under solar light irradiation.

    PubMed

    Zhou, Jun; Lei, Yanhua; Ma, Chenghai; Lv, Wenhua; Li, Na; Wang, Ying; Xu, Hu; Zou, Zhigang

    2017-09-21

    A two-dimensional imide-based conjugated polymer with a preferred (001) orientation was constructed by solvent-induced assembly. A high performance of 1640 μmol h(-1) g(-1) for solar-driven photocatalytic hydrogen evolution and an excellent stability were achieved due to tunnelling charge transport between the neighbouring molecular sheets.

  1. The mechanism of burn-in loss in a high efficiency polymer solar cell.

    PubMed

    Peters, Craig H; Sachs-Quintana, I T; Mateker, William R; Heumueller, Thomas; Rivnay, Jonathan; Noriega, Rodigo; Beiley, Zach M; Hoke, Eric T; Salleo, Alberto; McGehee, Michael D

    2012-02-02

    Degradation in a high efficiency polymer solar cell is caused by the formation of states in the bandgap. These states increase the energetic disorder in the system. The power conversion efficiency loss does not occur when current is run through the device in the dark but occurs when the active layer is photo-excited.

  2. Light concentration and redistribution in polymer solar cells by plasmonic nanoparticles.

    PubMed

    Zhu, Jinfeng; Xue, Mei; Hoekstra, Ryan; Xiu, Faxian; Zeng, Baoqing; Wang, Kang L

    2012-03-21

    We propose an optoelectronic model to investigate polymer solar cells with plasmonic nanoparticles. The optical properties of the plasmonic active layers, approximated by the effective medium theory, are combined with the organic semiconductor model. The simulation suggests the enhancement on short-circuit photocurrent is due to light concentration and redistribution by particle plasmons.

  3. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated.

  4. Control of miscibility and aggregation via the material design and coating process for high-performance polymer blend solar cells.

    PubMed

    Zhou, Erjun; Cong, Junzi; Hashimoto, Kazuhito; Tajima, Keisuke

    2013-12-23

    A power conversion efficiency of 3.6% for an all-polymer solar cell, which is the highest ever reported, is achieved by introducing a conjugated side chain into a p-type polymer to improve the miscibility of the polymer blend and by adding small amounts of 1,8-diiodooctane to increase the aggregation of n-type polymer. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The Effect of Fluorine Substitution on the Molecular Interactions and Performance in Polymer Solar Cells.

    PubMed

    Kim, In-Bok; Jang, Soo-Young; Kim, Yeong-A; Kang, Rira; Kim, In-Sik; Ko, Do-Kyeong; Kim, Dong-Yu

    2017-07-19

    Fluorine (F) substitution on conjugated polymers in polymer solar cells (PSCs) has a diverse effect on molecular properties and device performance. We present a series of three D-A type conjugated polymers (PBT, PFBT, and PDFBT) based on dithienothiophene and benzothiadiazole units with different numbers of F atoms to explain the influence of F substitution by comparing the molecular interactions of the polymers and the recombination kinetics in PSCs. The preaggregation behavior of PFBT and PDFBT in o-DCB at the UV-vis absorption spectra proves that both polymers have strong intermolecular interactions. Besides, more closely packed structures and change into face-on orientation of fluorinated polymers are observed in polymer:PC71BM blends by GIXD which is beneficial for charge transport and, ultimately, for current density in PSCs (4.3, 13.0, and 14.5 mA cm(-2) for PBT, PFBT, and PDFBT, respectively). Also, the introduction of F atoms on conjugated backbones affects the recombination kinetics by suppressing bimolecular recombination, thereby improving the fill factor (0.41, 0.68, and 0.69 for PBT, PFBT, and PDFBT, respectively). Consequently, the PCE of PSCs reached 7.3% without any additional treatment (annealing, solvent additive, etc.) in the polymer containing difluorinated BT (PDFBT) that is much higher than nonfluorinated BT (PBT ∼ 1%) and monofluorinated BT (PFBT ∼ 6%).

  6. Optical properties of a conjugated-polymer-sensitised solar cell: the effect of interfacial structure.

    PubMed

    Drumm, Daniel W; Bilic, A; Tachibana, Y; Miller, A; Russo, S P

    2015-06-14

    Dye-sensitised solar cells (DSSCs) have sparked considerable interest over two decades. Recently, a method of polymer-wire sensitisation was demonstrated; the polymer is suggested to form a hole transport pathway (wire) following initial charge separation. We predict the optical properties of this polymer in various interfacial configurations, including the effects of chain length and attachment to {100} or {101} TiO2 facets. Contrary to most DSSCs, the {100} facet model best describes the experimental spectrum, predicting a relative thickness of 5.7 ± 0.2 μm, although {101} attachment, if implemented, may improve collection efficiency. Long chains are optimal, and stable attachment sites show minimal differences to absorbance in the major solar emission (visible) band. Combinations of {100}, {101}, and pseudo-bulk TiO2 models in three-parameter fits to experiment confirm the relative importance of the {100} facet.

  7. Tuning the thermal conductivity of solar cell polymers through side chain engineering.

    PubMed

    Guo, Zhi; Lee, Doyun; Liu, Yi; Sun, Fangyuan; Sliwinski, Anna; Gao, Haifeng; Burns, Peter C; Huang, Libai; Luo, Tengfei

    2014-05-07

    Thermal transport is critical to the performance and reliability of polymer-based energy devices, ranging from solar cells to thermoelectrics. This work shows that the thermal conductivity of a low band gap conjugated polymer, poly(4,8-bis-alkyloxybenzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-(alkylthieno[3,4-b]thiophene-2-carboxylate)-2,6-diyl) (PBDTTT), for photovoltaic applications can be actively tuned through side chain engineering. Compared to the original polymer modified with short branched side chains, the engineered polymer using all linear and long side chains shows a 160% increase in thermal conductivity. The thermal conductivity of the polymer exhibits a good correlation with the side chain lengths as well as the crystallinity of the polymer characterized using small-angle X-ray scattering (SAXS) experiments. Molecular dynamics simulations and atomic force microscopy are used to further probe the molecular level local order of different polymers. It is found that the linear side chain modified polymer can facilitate the formation of more ordered structures, as compared to the branched side chain modified ones. The effective medium theory modelling also reveals that the long linear side chain enables a larger heat carrier propagation length and the crystalline phase in the bulk polymer increases the overall thermal conductivity. It is concluded that both the length of the side chains and the induced polymer crystallization are important for thermal transport. These results offer important guidance for actively tuning the thermal conductivity of conjugated polymers through molecular level design.

  8. Breaking the barriers of all-polymer solar cells: Solving electron transporter and morphology problems

    NASA Astrophysics Data System (ADS)

    Gavvalapalli, Nagarjuna

    All-polymer solar cells (APSC) are a class of organic solar cells in which hole and electron transporting phases are made of conjugated polymers. Unlike polymer/fullerene solar cell, photoactive material of APSC can be designed to have hole and electron transporting polymers with complementary absorption range and proper frontier energy level offset. However, the highest reported PCE of APSC is 5 times less than that of polymer/fullerene solar cell. The low PCE of APSC is mainly due to: i) low charge separation efficiency; and ii) lack of optimal morphology to facilitate charge transfer and transport; and iii) lack of control over the exciton and charge transport in each phase. My research work is focused towards addressing these issues. The charge separation efficiency of APSC can be enhanced by designing novel electron transporting polymers with: i) broad absorption range; ii) high electron mobility; and iii) high dielectric constant. In addition to with the above parameters chemical and electronic structure of the repeating unit of conjugated polymer also plays a role in charge separation efficiency. So far only three classes of electron transporting polymers, CN substituted PPV, 2,1,3-benzothiadiazole derived polymers and rylene diimide derived polymers, are used in APSC. Thus to enhance the charge separation efficiency new classes of electron transporting polymers with the above characteristics need to be synthesized. I have developed a new straightforward synthetic strategy to rapidly generate new classes of electron transporting polymers with different chemical and electronic structure, broad absorption range, and high electron mobility from readily available electron deficient monomers. In APSCs due to low entropy of mixing, polymers tend to micro-phase segregate rather than forming the more useful nano-phase segregation. Optimizing the polymer blend morphology to obtain nano-phase segregation is specific to the system under study, time consuming, and not

  9. Nafion-modified MoOx as effective room-temperature hole injection layer for stable, high-performance inverted organic solar cells.

    PubMed

    Qiu, Weiming; Müller, Robert; Voroshazi, Eszter; Conings, Bert; Carleer, Robert; Boyen, Hans-Gerd; Turbiez, Mathieu; Froyen, Ludo; Heremans, Paul; Hadipour, Afshin

    2015-02-18

    We present a hole injection layer processed from solution at room temperature for inverted organic solar cells. Bis(2,4-pentanedionato) molybdenum(VI) dioxide (MoO2(acac)2) is used as the precursor for MoOx. Small amounts of Nafion in the precursor solution allow it to form continuous films with good wetting onto the active layers. The hydrolysis of MoO2(acac)2 and the effects of adding Nafion to the precursor solution are studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The devices with solution-processed MoOx including Nafion exhibited comparable performance to the reference devices based on the commonly used hole injection layers such as poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) or evaporated MoO3. Inverted poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester devices with Nafion-modified MoOx maintain 80% of their initial power conversion efficiency upon exposure to ambient air for ∼5000 h, outperforming devices with PEDOT:PSS or with evaporated MoO3.

  10. Platinum-acetylide polymers with higher dimensionality for organic solar cells.

    PubMed

    Wang, Qiwei; He, Zhicai; Wild, Andreas; Wu, Hongbin; Cao, Yong; S Schubert, Ulrich; Chui, Chung-Hin; Wong, Wai-Yeung

    2011-07-04

    A new series of platinum(II)-acetylide polymers P1-P3 containing thiophene-triarylamine chromophores of different dimensions were synthesized and their electronic band structures, field-effect charge transport, and application in bulk heterojunction solar cells were evaluated. These materials are soluble in polar organic solvents and show strong absorptions in the solar spectra (with the highest absorption coefficient of 1.59×10(5)  cm(-1) from thin films), thus rendering them excellent candidates for bulk heterojunction polymer solar cells. The spin-coated polymer thin films showed p-channel field-effect charge transport with hole mobilities of 1.90×10(-5) to 7.86×10(-5)  cm(2)  V(-1)  s(-1) for P1-P3 and an improved charge carrier transport was found for P2 with higher molecular dimensionality than P1. The dependence of their photovoltaic properties and dimensionality was also investigated. Even if the polymers possess relatively high bandgaps and narrow absorption bandwidths, the highest power conversion efficiency of 2.24 % can be obtained based on blends of P3 with [6,6]phenyl-C(61)-butyric acid methyl ester (PCBM) (1:5, w/w) under AM1.5 simulated solar illumination. The present work indicates that multidimensional polymers exhibit a better photovoltaic performance over the linear polymers under the same measurement conditions and can provide an attractive approach to developing highly efficient conjugated metallopolymers for efficient power generation.

  11. Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films.

    PubMed

    Chirilă, Adrian; Buecheler, Stephan; Pianezzi, Fabian; Bloesch, Patrick; Gretener, Christina; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Perrenoud, Julian; Seyrling, Sieghard; Verma, Rajneesh; Nishiwaki, Shiro; Romanyuk, Yaroslav E; Bilger, Gerhard; Tiwari, Ayodhya N

    2011-09-18

    Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.

  12. Cooperative plasmonic effect of Ag and Au nanoparticles on enhancing performance of polymer solar cells.

    PubMed

    Lu, Luyao; Luo, Zhiqiang; Xu, Tao; Yu, Luping

    2013-01-09

    This article describes a cooperative plasmonic effect on improving the performance of polymer bulk heterojunction solar cells. When mixed Ag and Au nanoparticles are incorporated into the anode buffer layer, dual nanoparticles show superior behavior on enhancing light absorption in comparison with single nanoparticles, which led to the realization of a polymer solar cell with a power conversion efficiency of 8.67%, accounting for a 20% enhancement. The cooperative plasmonic effect aroused from dual resonance enhancement of two different nanoparticles. The idea was further unraveled by comparing Au nanorods with Au nanoparticles for solar cell application. Detailed studies shed light into the influence of plasmonic nanostructures on exciton generation, dissociation, and charge recombination and transport inside thin film devices.

  13. High-performance hole-extraction layer of sol-gel-processed NiO nanocrystals for inverted planar perovskite solar cells.

    PubMed

    Zhu, Zonglong; Bai, Yang; Zhang, Teng; Liu, Zhike; Long, Xia; Wei, Zhanhua; Wang, Zilong; Zhang, Lixia; Wang, Jiannong; Yan, Feng; Yang, Shihe

    2014-11-10

    Hybrid organic/inorganic perovskite solar cells have been rapidly evolving with spectacular successes in both nanostructured and thin-film versions. Herein, we report the use of a simple sol-gel-processed NiO nanocrystal (NC) layer as the hole-transport layer in an inverted perovskite solar cell. The thin NiO NC film with a faceted and corrugated surface enabled the formation of a continuous and compact layer of well-crystallized CH3 NH3 PbI3 in a two-step solution process. The hole-extraction and -transport capabilities of this film interfaced with the CH3 NH3 PbI3 film were higher than those of organic PEDOT:PSS layers. The cell with a NiO NC film with a thickness of 30-40 nm exhibited the best performance, as a thinner layer led to a higher leakage current, whereas a thicker layer resulted in a higher series resistance. With the NiO film, we observed a cell efficiency of 9.11 %, which is by far the highest reported for planar perovskite solar cells based on an inorganic hole-extracting layer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Engineering polymer-fullerene thin films and solar cells with external fields

    NASA Astrophysics Data System (ADS)

    Cabral, Joao

    2014-03-01

    Trace amounts of nanoparticles, including fullerenes, can impart stability to thin polymer films against dewetting by the combined effects of pinning the contact lines of dewetting holes and by effectively altering the polymer-substrate interaction. Polymer nanocomposite (meta)stable thin films can yield well-defined morphologies from uniform to spinodal-like, via spontaneous polymer-nanoparticle phase separation and crystallization. Confinement breaks the structural isotropy and generally causes (partial) segregation of components orthogonally to the film surface. Surface energy patterning can thus modulate composition and morphology, both in plane and normal to the surface. Further, UV-visible, and even background, light exposure, in both solutions and melts, is shown to tune the solution stucture and morphology of dewetting and phase separating polymer-fullerene thin films. Neutron reflectivity allows us to locate the various constituents within the film. We find a coupling of fullerene photo-sensitivity and both self-assembly processes which results in controlled pattern formation, and we illustrate the potential with a model polymer-fullerene circuit pattern. We then translate this approach into the directed assembly of energy harvesting bulk heterojunctions thin films. Indeed, a key challenge to the commercialization of organic solar cells remains the achievement of morphological stability, particularly under thermal stress conditions. The directed assembly a blend polymer:PC60BM solar cells via a simple light processing step results in a 10-100 fold increase in device thermal stability and, under certain conditions, enhanced device performance. The enhanced stability is linked to the light-induced oligomerisation of PC60BM that effectively hinders diffusion and crystallization in blends. This effect appears to be general and promises to be an effective and cost-effective strategy to optimize fullerene-based solar cell performance.

  15. Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells

    PubMed Central

    2011-01-01

    Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes. PMID:21970654

  16. Inverted GaInP/(In)GaAs/InGaAs Triple-Junction Solar Cells with Low-Stress Metamorphic Bottom Junctions: Preprint

    SciTech Connect

    Geisz, J. F.; Kurtz, S. R.; Wanlass, M. W.; Ward, J. S.; Duda, A.; Friedman, D. J.; Olson, J. M.; McMahon, W. E.; Moriarty, T. E.; Kiehl, J. T.; Romero, M. J.; Norman, A. G.; Jones, K. M.

    2008-05-01

    We demonstrate high efficiency performance in two ultra-thin, Ge-free III-V semiconductor triple-junction solar cell device designs grown in an inverted configuration. Low-stress metamorphic junctions were engineered to achieve excellent photovoltaic performance with less than 3 x 106 cm-2 threading dislocations. The first design with band gaps of 1.83/1.40/1.00 eV, containing a single metamorphic junction, achieved 33.8% and 39.2% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 131 suns, respectively. The second design with band gaps of 1.83/1.34/0.89 eV, containing two metamorphic junctions achieved 33.2% and 40.1% efficiencies under the standard one-sun global spectrum and concentrated direct spectrum at 143 suns, respectively.

  17. Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells.

    PubMed

    Fan, Xi; Fang, Guojia; Guo, Shishang; Liu, Nishuang; Gao, Huimin; Qin, Pingli; Li, Songzhan; Long, Hao; Zheng, Qiao; Zhao, Xingzhong

    2011-10-04

    Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes.

  18. Modelling of polymer photodegradation for solar cell modules

    NASA Technical Reports Server (NTRS)

    Guillet, J. E.

    1982-01-01

    A computer program which simulates the complex processes of photooxidation which take place in a polymer upon prolonged exposure outdoors causing it to fail in photovoltaic and other applications. The method calculates from an input data set of elementary reactions and rates the concentration profiles of all species over time.

  19. Low-voltage organic field-effect transistors and inverters enabled by ultrathin cross-linked polymers as gate dielectrics.

    PubMed

    Yoon, Myung-Han; Yan, He; Facchetti, Antonio; Marks, Tobin J

    2005-07-27

    The quest for high-performance organic thin-film transistor (OTFT) gate dielectrics is of intense current interest. Beyond having excellent insulating properties, such materials must meet other stringent requirements for optimum OTFT function: efficient low-temperature solution fabrication, mechanical flexibility, and compatibility with diverse gate materials and organic semiconductors. The OTFTs should function at low biases to minimize power consumption, hence the dielectric must exhibit large gate capacitance. We report the realization of new spin-coatable, ultrathin (<20 nm) cross-linked polymer blends exhibiting excellent insulating properties (leakage current densities approximately 10(-)(8) Acm(-)(2)), large capacitances (up to approximately 300 nF cm(-)(2)), and enabling low-voltage OTFT functions. These dielectrics exhibit good uniformity over areas approximately 150 cm(2), are insoluble in common solvents, can be patterned using standard microelectronic etching methodologies, and adhere to/are compatible with n(+)-Si, ITO, and Al gates, and with a wide range of p- and n-type semiconductors. Using these dielectrics, complementary invertors have been fabricated which function at 2 V.

  20. Design and synthesis of chlorinated benzothiadiazole-based polymers for efficient solar energy conversion

    DOE PAGES

    Hu, Zhiming; Chen, Hui; Qu, Jianfei; ...

    2017-03-10

    Here, chlorinated benzothiadiazide based polymers with multiple chlorine atoms has been designed and synthesized for polymer solar cells with enhanced open circuit voltage up to 0.85 V. The chlorine substitution is found to significantly adjust the band gap of the polymers, and change polymer’s orientation from random morphology of chlorine free PBT4T-2OD, to mixed face-on packing of one chlorine substituted PCBT4T-2OD, and finally to edge-on of two chlorine substituted PCCBT4T-2OD. The optimized chlorinated polymer, PCBT4T-2OD with only one chlorine atom substituted on BT moiety, has been founded to achieve the highest power conversion efficiency up to 8.20% with PC71BM, whichmore » is about 68% higher than that of its non-chlorine analogues.« less