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Sample records for polyaniline films conducting

  1. Nanoscale electrical and mechanical characteristics of conductive polyaniline network in polymer composite films.

    PubMed

    Jafarzadeh, Shadi; Claesson, Per M; Sundell, Per-Erik; Pan, Jinshan; Thormann, Esben

    2014-11-12

    The presence and characteristics of a connected network of polyaniline (PANI) within a composite coating based on polyester acrylate (PEA) has been investigated. The bulk electrical conductivity of the composite was measured by impedance spectroscopy. It was found that the composite films containing PANI have an electrical conductivity level in the range of semiconductors (order of 10(-3) S cm(-1)), which suggests the presence of a connected network of the conductive phase. The nanoscopic distribution of such a network within the cured film was characterized by PeakForce tunneling atomic force microscopy (AFM). This method simultaneously provides local information about surface topography and nanomechanical properties, together with electrical conductivity arising from conductive paths connecting the metallic substrate to the surface of the coating. The data demonstrates that a PEA-rich layer exists at the composite-air interface, which hinders the conductive phase to be fully detected at the surface layer. However, by exposing the internal structure of the composites using a microtome, a much higher population of a conductive network of PANI, with higher elastic modulus than the PEA matrix, was observed and characterized. Local current-voltage (I-V) spectroscopy was utilized to investigate the conduction mechanism within the nanocomposite films, and revealed non-Ohmic characteristics of the conductive network.

  2. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    NASA Astrophysics Data System (ADS)

    Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

    2016-04-01

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  3. Effect of nanosilica on optical, electric modulus and AC conductivity of polyvinyl alcohol/polyaniline films

    NASA Astrophysics Data System (ADS)

    El-Sayed, Somyia; Abel-Baset, Tarob; Elfadl, Azza Abou; Hassen, Arafa

    2015-05-01

    Nanosilica (NS) was synthesized by a sol-gel method and mixed with 0.98 polyvinyl alcohol (PVA)/0.02 polyaniline (PANI) in different amounts to produce nanocomposite films. High-resolution transmission electron microscopy (HR-TEM) revealed the average particle size of the NS to be ca. 15 nm. Scanning electron microscopy (SEM) showed that the NS was well-dispersed on the surface of the PVA/PNAI films. The Fourier transform infrared (FTIR) spectra of the samples showed a significant change in the intensity of the characteristic peak of the functional groups in the composite films with the amount of NS added. The absorbance and refractive index (n) of the composites were studied in the UV-vis range, and the optical energy band gap, Eg, and different optical parameters were calculated. The dielectric loss modulus, M″ and ac conductivity, σac, of the samples were studied within 300-425 K and 0.1 kHz-5 MHz, respectively. Two relaxation peaks were observed in the frequency dependence of the dielectric loss modulus, M″. The behavior of σac(f) for the composite films indicated that the conduction mechanism was correlated barrier hopping (CBH). The results of this work are discussed and compared with those of previous studies of similar composites.

  4. Transparent conducting films of hierarchically nanostructured polyaniline networks on flexible substrates for high-performance gas sensors.

    PubMed

    Bai, Shouli; Sun, Chaozheng; Wan, Pengbo; Wang, Cheng; Luo, Ruixian; Li, Yaping; Liu, Junfeng; Sun, Xiaoming

    2015-01-21

    Transparent chemical gas sensors are assembled from a transparent conducting film of hierarchically nanostructured polyaniline (PANI) networks fabricated on a flexible PET substrate, by coating silver nanowires (Ag NWs) followed by the in situ polymerization of aniline near the sacrificial Ag NW template. The sensor exhibits enhanced gas sensing performance at room temperature in both sensitivity and selectivity to NH3 compared to pure PANI film.

  5. Conducting polyaniline nanowire electrode junction

    NASA Astrophysics Data System (ADS)

    Gaikwad, Sumedh; Bodkhe, Gajanan; Deshmukh, Megha; Patil, Harshada; Rushi, Arti; Shirsat, Mahendra D.; Koinkar, Pankaj; Kim, Yun-Hae; Mulchandani, Ashok

    2015-03-01

    In this paper, a synthesis of conducting polyaniline nanowires electrode junction (CPNEJ) has been reported. Conducting polyaniline nanowires electrode junction on Si/SiO2 substrate (having 3 μm gap between two gold microelectrodes) is prepared. Polyaniline nanowires with diameter (ca. 140 nm to 160 nm) were synthesized by one step electrochemical polymerization using galvanostatic (constant current) technique to bridge this gap. The surface morphology of CPNEJ was studied by scanning electron microscope (SEM). The synthesized CPNEJ is an excellent platform for biosensor applications.

  6. Heat conduction in conducting polyaniline nanofibers

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, A.; Syu, K.-Z.; Kuo, Y.-K.

    2013-09-01

    Thermal conductivity and specific heat of conducting polyaniline nanofibers are measured to identify the nature of heat carrying modes combined with their inhomogeneous structure. The low temperature thermal conductivity results reveal crystalline nature while the high temperature data confirm the amorphous nature of the material suggesting heterogeneous model for conducting polyaniline. Extended acoustic phonons dominate the low temperature (<100 K) heat conduction, while localized optical phonons hopping, assisted by the extended acoustic modes, account for the high temperature (>100 K) heat conduction.

  7. Polyaniline Based Conductive Textiles

    NASA Astrophysics Data System (ADS)

    Teli, M.; Dash, S.; Desai, P.

    2014-12-01

    The conductive polymers were mixed with binder and coated on cotton, polyester and wool fabric, keeping conductive polymer concentration at 5 %. Conductive woven fabrics were obtained by pad-dry-cure coating technique. The surface and bulk conductivity behaviour of the coating paste with respect to temperature were studied using four probe and two probe technique. The conductivity studies show that the coated fabrics have good electrical conductivity in the range of 33.2 μS/cm-3281 μS/cm and there was an increase in conductivity with rise in temperature.

  8. Humidity-independent conducting polyaniline films synthesized using advanced atmospheric pressure plasma polymerization with in-situ iodine doping

    NASA Astrophysics Data System (ADS)

    Park, Choon-Sang; Kim, Do Yeob; Kim, Dong Ha; Lee, Hyung-Kun; Shin, Bhum Jae; Tae, Heung-Sik

    2017-01-01

    This study reports on the synthesis and characterization of conducting polyaniline (PANI) thin films when using advanced atmospheric pressure plasma jets (APPJs). A simple method for synthesizing conducting polymers (CPs) with humidity-independent characteristics is introduced using advanced APPJs and an in-situ iodine doping method. In the case of ex-situ I2 doping, a humidity effect study showed that increasing the relative humidity produced significant changes in the electrical resistance (R) of the PANI, indicating strong humidity-dependent characteristics similar to conventional CPs. In contrast, in the case of in-situ I2 doping, the R and sensitivity of the PANI remained essentially unchanged when increasing the relative humidity, except for a very low sensitivity of 0.5% under 94% relative humidity. In addition, the R for the PANI with in-situ I2 doping showed no aging effect, while the R for the ex-situ-doped PANI increased dramatically over time. Thus, it is anticipated that the use of in-situ doping during plasma polymerization can be widely used to design stable and high-performance CPs with humidity-independent characteristics for a variety of applications.

  9. Polyaniline nanofibers: broadening applications for conducting polymers.

    PubMed

    Baker, Christina O; Huang, Xinwei; Nelson, Wyatt; Kaner, Richard B

    2017-01-18

    Polyaniline is a conducting polymer with incredible promise, but it has had limited use due to poor reaction control and processability associated with conventional morphologies. Polyaniline nanofibers, on the other hand, have demonstrated, through manufacturing techniques discovered during the past decade, increased processability, higher surface area, and improved consistency and stability in aqueous dispersions, which are finally allowing for expanded commercial development of this promising polymer. This review explores some intriguing applications of polyaniline nanofibers, as well as the advantages and remaining challenges in developing better products using polyaniline in this new morphology.

  10. Electronic thermal conductivity, thermoelectric properties and supercapacitive behaviour of conjugated polymer nanocomposite (polyaniline-WO3) thin film

    NASA Astrophysics Data System (ADS)

    Chinedu Amaechi, Ifeanyichukwu; Nwanya, Assumpta C.; Ekwealor, Azubike B. C.; Asogwa, Paul U.; Osuji, Rose U.; Maaza, Malik; Ezema, Fabian I.

    2015-03-01

    A facile two-step, binder-free, chemical bath deposition (CBD) method was successfully employed in the synthesis of WO3 nanograins onto the matrix of conjugated polymer (polyaniline). The X-ray diffraction (XRD) results showed that the nanocomposite retained monoclinic phase of WO3 even when dispersed in polyaniline matrix. Owing to the synergistic effect offered by both the nanocomposite and structured metal oxide which may enhance the surface area, polyaniline-WO3 nanocomposite exhibited good specific capacitance. Polyaniline-WO3 yielded maximum specific capacitance ~96 F/g at scan rate of 5 mV/s in 0.5 M H2SO4 electrolyte. With the electronic thermal conductivity showing strong dependence on temperature, the estimated dimensionless figure of merit zT ~ 10-3 shows that the polymer nanocomposite (PNC) is promising as a new type of thermoelectric material. The electrochemical impedance spectroscopy showed that the PNC exhibited both pseudocapacitive and electric double layer capacitance behaviour.

  11. Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

    NASA Astrophysics Data System (ADS)

    Deb, K.; Bhowmik, K. L.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

    2016-05-01

    Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

  12. Intra-grain conduction of self-doped polyaniline

    NASA Astrophysics Data System (ADS)

    Usami, Yuki; Imamura, Kentaro; Akai, Tomoki; Che, Dock-Chil; Ohoyama, Hiroshi; Kobayashi, Hikaru; Matsumoto, Takuya

    2016-08-01

    The conduction behavior of ultrathin films (about 10 nm thick) composed of self-doped water-soluble polyaniline sulfonate (SPAN) was investigated using nano-gap electrodes under vacuum conditions. The conductance was found to be ohmic even in the high field regime up to 105 V cm-1 over a temperature range of 10-300 K. The temperature dependence of the conductance indicated that SPAN gave the extremely high value of localization length ( L ) = 300 nm without secondary doping, in comparison with conventional polyaniline. We propose that SPAN forms long-range highly crystalline metallic grains, and we observed intra-grain conduction due to some grains directly bridging the two nano-gap electrodes at low temperature. We conclude that inter-grain conduction becomes dominant as the temperature increases.

  13. Conducting Polyaniline Nanowire and Its Applications in Chemiresistive Sensing

    PubMed Central

    Song, Edward; Choi, Jin-Woo

    2013-01-01

    One dimensional polyaniline nanowire is an electrically conducting polymer that can be used as an active layer for sensors whose conductivity change can be used to detect chemical or biological species. In this review, the basic properties of polyaniline nanowires including chemical structures, redox chemistry, and method of synthesis are discussed. A comprehensive literature survey on chemiresistive/conductometric sensors based on polyaniline nanowires is presented and recent developments in polyaniline nanowire-based sensors are summarized. Finally, the current limitations and the future prospect of polyaniline nanowires are discussed. PMID:28348347

  14. Advanced Synthesis of Conductive Polyaniline Using Laccase as Biocatalyst.

    PubMed

    de Salas, Felipe; Pardo, Isabel; Salavagione, Horacio J; Aza, Pablo; Amougi, Eleni; Vind, Jesper; Martínez, Angel T; Camarero, Susana

    2016-01-01

    Polyaniline is a conductive polymer with distinctive optical and electrical properties. Its enzymatic synthesis is an environmentally friendly alternative to the use of harsh oxidants and extremely acidic conditions. 7D5L, a high-redox potential laccase developed in our lab, is the biocatalyst of choice for the synthesis of green polyaniline (emeraldine salt) due to its superior ability to oxidize aniline and kinetic stability at the required polymerization conditions (pH 3 and presence of anionic surfactants) as compared with other fungal laccases. Doses as low as 7.6 nM of 7D5L catalyze the polymerization of 15 mM aniline (in 24 h, room temperature, 7% yield) in the presence of different anionic surfactants used as doping templates to provide linear and water-soluble polymers. Aniline polymerization was monitored by the increase of the polaron absorption band at 800 nm (typical for emeraldine salt). Best polymerization results were obtained with 5 mM sodium dodecylbenzenesulfonate (SDBS) as template. At fixed conditions (15 mM aniline and 5mM SDBS), polymerization rates obtained with 7D5L were 2.5-fold the rates obtained with commercial Trametes villosa laccase. Moreover, polyaniline yield was notably boosted to 75% by rising 7D5L amount to 0.15 μM, obtaining 1g of green polyaniline in 1L-reaction volume. The green polymer obtained with the selected system (7D5L/SDBS) holds excellent electrochemical and electro-conductive properties displayed in water-dispersible nanofibers, which is advantageous for the nanomaterial to be readily cast into uniform films for different applications.

  15. Advanced Synthesis of Conductive Polyaniline Using Laccase as Biocatalyst

    PubMed Central

    de Salas, Felipe; Pardo, Isabel; Salavagione, Horacio J.; Aza, Pablo; Amougi, Eleni; Vind, Jesper; Martínez, Angel T.; Camarero, Susana

    2016-01-01

    Polyaniline is a conductive polymer with distinctive optical and electrical properties. Its enzymatic synthesis is an environmentally friendly alternative to the use of harsh oxidants and extremely acidic conditions. 7D5L, a high-redox potential laccase developed in our lab, is the biocatalyst of choice for the synthesis of green polyaniline (emeraldine salt) due to its superior ability to oxidize aniline and kinetic stability at the required polymerization conditions (pH 3 and presence of anionic surfactants) as compared with other fungal laccases. Doses as low as 7.6 nM of 7D5L catalyze the polymerization of 15 mM aniline (in 24 h, room temperature, 7% yield) in the presence of different anionic surfactants used as doping templates to provide linear and water-soluble polymers. Aniline polymerization was monitored by the increase of the polaron absorption band at 800 nm (typical for emeraldine salt). Best polymerization results were obtained with 5 mM sodium dodecylbenzenesulfonate (SDBS) as template. At fixed conditions (15 mM aniline and 5mM SDBS), polymerization rates obtained with 7D5L were 2.5-fold the rates obtained with commercial Trametes villosa laccase. Moreover, polyaniline yield was notably boosted to 75% by rising 7D5L amount to 0.15 μM, obtaining 1g of green polyaniline in 1L-reaction volume. The green polymer obtained with the selected system (7D5L/SDBS) holds excellent electrochemical and electro-conductive properties displayed in water-dispersible nanofibers, which is advantageous for the nanomaterial to be readily cast into uniform films for different applications. PMID:27741301

  16. Molecular dynamics in plastic conducting compounds of polyaniline

    NASA Astrophysics Data System (ADS)

    Djurado, D.; Bée, M.; Gonzalez, M.; Mondelli, C.; Dufour, B.; Rannou, P.; Pron, A.; Travers, J. P.

    2003-08-01

    Polyaniline (PANI) has been protonated (doped) with phthalosulfonic acid and sulfosuccinic acid diesters. Freestanding films exhibiting high electrical conductivity and good plasticity were obtained. The dynamics of protons attached to the alkyl chains of these "plastdopants" has been studied by using quasielastic neutron scattering techniques. A glass transition was thus detected at a temperature corresponding to that measured by DSC. This dynamical transition occurred in the temperature range, in which both a thermochromism and an insulator-metal electrical transitions (IMT) were also observed. The local diffusive motions of these protons are described in terms of diffusion within spheres whose temperature dependent radii are distributed in size along the alkyl chains.

  17. Synthesis, Characterization, and Electrochemical Properties of Polyaniline Thin Films

    NASA Astrophysics Data System (ADS)

    Rami, Soukaina

    Conjugated polymers have been used in various applications (battery, supercapacitor, electromagnetic shielding, chemical sensor, biosensor, nanocomposite, light-emitting-diode, electrochromic display etc.) due to their excellent conductivity, electrochemical and optical properties, and low cost. Polyaniline has attracted the researchers from all disciplines of science, engineering, and industry due to its redox properties, environmental stability, conductivity, and optical properties. Moreover, it is a polymer with fast electroactive switching and reversible properties displayed at low potential, which is an important feature in many applications. The thin oriented polyaniline films have been fabricated using self-assembly, Langmuir-Blodgett, in-situ self-assembly, layer-by-layer, and electrochemical technique. The focus of this thesis is to synthesize and characterize polyaniline thin films with and without dyes. Also, the purpose of this thesis is to find the fastest electroactive switching PANI electrode in different electrolytic medium by studying their electrochemical properties. These films were fabricated using two deposition techniques: in-situ self-assembly and electrochemical deposition. The characterization of these films was done using techniques such as Fourier Transform Infrared Spectroscopy (FTIR), UV-spectroscopy, Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD). FTIR and UV-spectroscopy showed similar results in the structure of the polyaniline films. However, for the dye incorporated films, since there was an addition in the synthesis of the material, peak locations shifted, and new peaks corresponding to these materials appeared. The 1 layer PANI showed compact film morphology, comparing to other PANI films, which displayed a fiber-like structure. Finally, the electrochemical properties of these thin films were studied using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in

  18. Chiral electrodes of magneto- electropolymerized polyaniline films

    NASA Astrophysics Data System (ADS)

    Mogi, I.; Watanabe, K.

    2006-12-01

    Polyaniline films were prepared by electropolymerization under a magnetic field of 5 T parallel (+5 T) or antiparallel (-5 T) to the faradaic currents. They were used as a modified electrode and their chiral properties were examined for L-ascorbic acid (L-AA), D-isoascorbic acid (D-AA) and L-3-(3,4-dihydroxyphenyl)alanine (L-DOPA) by cyclic voltammetry. The +5T-film electrode showed different oxidation currents between L- and D-AA, and the -5T-film electrode showed opposite chirality. The redox currents of L-DOPA on the +5T-film electrode were smaller than those on the -5T-film electrode, and the results for racemic mixture of L- and D-DOPA were the same on the two electrodes. These results indicate that the Lorentz force in the electropolymerization process under magnetic fields introduces chirality to the polyaniline films and such film electrodes have the ability of chiral recognition. Figs 8, Refs 14.

  19. Anisotropy and Crystalline Structure in Polyaniline Films

    NASA Astrophysics Data System (ADS)

    Minto, C. D. G.; Vaughan, A. S.

    1996-03-01

    Films of polyaniline -- camphor sulphonic acid cast from m-cresol exhibit transport properties characteristic of a material stradelling the metal/insulator transition. This improvement in properties over traditional methods of polyaniline production has been suggested as being caused by the macromolecule adopting an expanded coil configuration in this solvent. Such films have been shown to be semi--crystalline and are presumed to be completely isotropic. We present here new results which demonstrate that such films are in fact appreciably aligned. X-ray scattering is utilised to expose the presence of molecular anisotropy within such films, the polymers forming a stacked structure with the molecules preferentially oriented parallel to the plane of the film. Similar measurements confirm that the molecules are randomly oriented within this plane. Such alignment considerably improves the transport properties. Anisotropy and the crystalline structure within these films, those cast from chloroform and those using the isolated enantiomeric counter ion are quantified and discussed. The results demonstrate that improved transport properties have arisen as a result of both polymer--solvent interactions and as a result of improved chain alignment.

  20. Synthesis and characterization of porous polyaniline conductive polymers

    NASA Astrophysics Data System (ADS)

    Price, Aaron D.; Naguib, Hani E.

    2007-04-01

    Polyaniline conductive polymers exhibit great potential for linear actuator applications. Many recent studies report methods to develop polyaniline-based materials with increased mechanical properties, electrical conductivity, and faster response time during actuation. In this study, porous blends of poly(methylmethacrylate) and polyaniline are processed using a two phase batch foaming setup. The effect of materials, processing, and system parameters on the physical properties of the resulting cellular structure are investigated. Hence, the effect of density and cell morphology on the electrical conductivity is elucidated.

  1. Modification And Designing Of Electrodeposited Polyaniline Films For Potential Applications

    NASA Astrophysics Data System (ADS)

    Sharma, I. D.; Dhawan, S. K.; Srivastav, Ritu; Sharma, V. K.

    2011-12-01

    Conducting polymers have been widely investigated for both academic and industrial purposes over three decades. Thin film of polyaniline(PANI) upon ITO coated glass was electrodeposited using direct power supply method. In this method stainless steel electrode was used as cathode and ITO coated glass as anode. 0.1 M aniline monomer and 0.5 M H2SO4 solution in distilled water was used as electrolyte. The electric current in the electrolite was supplied at fixed voltage 1.5 volt upto the required time to obtained the desired thickness of the polymer film. An attempt has been made to estimate various electronic perameters such as barrier height through I/V measurements of the polyaniline film upon ITO coated glass. The surface morphology of the film material was studied by scanning electron microscopy. The film material was also characterised by X-Ray Difractometer & FTIR The value of potential barrier O/b &constant factor ß was obtained using Schottky equations. Bandgap calculations were carried out by using U.V. Visible spectroscopy method. The results has been explained for potential applications.

  2. Modification of conductive polyaniline with carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Sedaghat, Sajjad; Alavijeh, Mahdi Soleimani

    2014-08-01

    The synthesis of polyaniline/single-wall nanotube, polyaniline/multi-wall nanotube and polyaniline/single-wall nanotube/graphen nanosheets nanocomposites by in situ polymerization are reported in this study. The substrates were treated with a mixture of concentrated sulfuric acid and concentrated nitric acid before usage to functionalize with carboxylic and hydroxyl groups. Aniline monomers are adsorbed and polymerized on the surface of these fillers. Structural analysis using scanning electron microscopy showed that nanomaterials dispersed into polymer matrix and made tubular structures with diameters several tens to hundreds nanometers depending on the polyaniline content. These nanocomposites can be used for production of excellent electrode materials applications in high-performance supercapacitors.

  3. Impressive electromagnetic shielding effects exhibited by highly ordered, micrometer thick polyaniline films

    NASA Astrophysics Data System (ADS)

    Mohan, Ranjini R.; Varma, Sreekanth J.; Sankaran, Jayalekshmi

    2016-04-01

    The present work highlights the remarkably high shielding effectiveness of about 68 dB, exhibited by highly ordered and doped polyaniline films, in the microwave frequency range 4-12 GHz, obtained by self-stabilized dispersion polymerization as the synthesis route. The observed shielding effectiveness is found to depend quite sensitively on the electrical conducting properties, which are predominantly controlled by the nature and concentration of the dopants. The structural and morphological characterization of the films using XRD and TEM techniques reveals surprisingly high extent of crystallinity, which contributes significantly towards enhancing the electrical conductivity of the films. Most of the available reports on the microwave response of conducting polymer film samples deal with much thicker films, compared to the micrometer thick films of the present studies. The shielding effectiveness of acid doped, micrometer thick polyaniline films reported in the present work far exceeds most of the previously reported values and meets the commercial requirements.

  4. Electrochemical preparation of Photosystem I-polyaniline composite films for biohybrid solar energy conversion.

    PubMed

    Gizzie, Evan A; LeBlanc, Gabriel; Jennings, G Kane; Cliffel, David E

    2015-05-13

    In this work, we report for the first time the entrapment of the biomolecular supercomplex Photosystem I (PSI) within a conductive polymer network of polyaniline via electrochemical copolymerization. Composite polymer-protein films were prepared on gold electrodes through potentiostatic electropolymerization from a single aqueous solution containing both aniline and PSI. This study demonstrates the controllable integration of large membrane proteins into rapidly prepared composite films, the entrapment of such proteins was observed through photoelectrochemical analysis. PSI's unique function as a highly efficient biomolecular photodiode generated a significant enhancement in photocurrent generation for the PSI-loaded polyaniline films, compared to pristine polyaniline films, and dropcast PSI films. A comprehensive study was then performed to separately evaluate film thickness and PSI concentration in the initial polymerization solution and their effects on the net photocurrent of this novel material. The best performing composite films were prepared with 0.1 μM PSI in the polymerization solution and deposited to a film thickness of 185 nm, resulting in an average photocurrent density of 5.7 μA cm(-2) with an efficiency of 0.005%. This photocurrent output represents an enhancement greater than 2-fold over bare polyaniline films and 200-fold over a traditional PSI multilayer film of comparable thickness.

  5. Surface area and conductivity of polyaniline synthesized under UV irradiation

    NASA Astrophysics Data System (ADS)

    Budi, S.; Fitri, E.; Paristiowati, M.; Cahyana, U.; Pusparini, E.; Nasbey, H.; Imaddudin, A.

    2017-02-01

    This paper reports our study on the synthesis of high electrical conductivity and surface area polyaniline using oxidative polymerization under UV light irradiation. The formation of emeraldine structures of polyaniline was revealed by major absorption bands of FTIR (Fourier transform infrared spectroscopy) spectra attributed to C-N stretching, C=C stretching in the benzenoid ring, C=C stretching in the quinoid ring and QNH+B stretching. XRD (X-ray diffractometer) measurements confirmed typical diffraction patterns with a crystallinity of 13% and 16% for polyaniline prepared under non-stirred and stirred reaction, respectively. SEM (Scanning electron microscope) studies showed more uniform morphology of polyaniline was obtained with stirring reaction process compare to those prepared without stirring. Surface analysis using SAA (surface area analyzer) showed that pure polyaniline with the relatively high surface area of ca.28 m2/g was successfully prepared in this work. Based on four point probe measurement, the prepared polyaniline possesses high conductivity which is important in electrode application.

  6. Electrical characterization of gold and platinum thin film electrodes with polyaniline modified surfaces

    NASA Astrophysics Data System (ADS)

    Aggas, John Richard

    Recent studies into soft organic electronics have burgeoned as a result of discoveries of conducting polymers such as polyaniline, polythiophene, and polypyrrole. However, in order to make these conducting polymers suitable for in vivo soft organic electronics, they must be developed so that they can be biocompatible and provide accurate sensing. Chitosan, a naturally occurring polymer structure found in exoskeletons of crustaceans, has been studied for its biocompatible properties. Composites of polyaniline (PAn), an intrinsically conductive polymer (ICP) and chitosan (Chi), a biopolymer, were developed and applied to gold and platinum Thin Film Electrode (TFE) devices. Electropolymerization and drop cast deposition were utilized to modify TFEs with a thin film of PAn or PAn-Chi composite. The impedance response over a spectrum of frequencies was studied for blank control TFEs, platinized TFEs, and platinized TFEs with various polyaniline coatings. Impedance measurements were taken in dry environments, DI Water, and in buffers such as PBS, and HEPES. Current-Voltage (I-V) characterization was used to study the current response and SEM imaging was used to study the surface topography. Resistance was measured for PAn modified unplatinized gold TFEs with varying amounts of incorporated chitosan. Impedance measurements of control and platinized TFEs yielded results similar to a low pass filter. Due to the conductive nature of polyaniline, the impedance of TFEs decreased substantially after poylaniline deposition. Measured resistance values for polyaniline and chitosan composites on TFEs revealed a window of concentrations of incorporated chitosan to lower resistance.

  7. Redox-Switchable Surface Wrinkling on Polyaniline Film.

    PubMed

    Xie, Jixun; Zong, Chuanyong; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Yang, Xiu; Lu, Conghua

    2016-04-01

    Here the redox-driven switch between the wrinkled and dewrinkled states on poly-aniline (PANI) film is reported. This switch is derived from the reversible transition in different intrinsic redox states of polyaniline (e.g., between emeraldine salt (ES) and leucoemeraldine base (LEB) or between ES and pernigraniline base (PB)) that are involved in the redox reaction, coupled with the corresponding volume expansion/shrinkage. Interestingly, the as-wrinkled ES film becomes deswollen and dewrinkled when reduced to the LEB state or oxidized to the PB state. Conversely, oxidation of the LEB film or reduction of the PB film into the swollen ES film leads to the reoccurrence of surface wrinkling. Furthermore, the reducibility of the dewrinkled LEB film and the oxidizability of the dewrinkled PB film are well utilized respectively to yield various wrinkled PANI-based composite films.

  8. Cysteine modified polyaniline films improve biocompatibility for two cell lines.

    PubMed

    Yslas, Edith I; Cavallo, Pablo; Acevedo, Diego F; Barbero, César A; Rivarola, Viviana A

    2015-06-01

    This work focuses on one of the most exciting application areas of conjugated conducting polymers, which is cell culture and tissue engineering. To improve the biocompatibility of conducting polymers we present an easy method that involves the modification of the polymer backbone using l-cysteine. In this publication, we show the synthesis of polyaniline (PANI) films supported onto Polyethylene terephthalate (PET) films, and modified using cysteine (PANI-Cys) in order to generate a biocompatible substrate for cell culture. The PANI-Cys films are characterized by Fourier Transform infrared and UV-visible spectroscopy. The changes in the hydrophilicity of the polymer films after and before the modification were tested using contact angle measurements. After modification the contact angle changes from 86°±1 to 90°±1, suggesting a more hydrophylic surface. The adhesion properties of LM2 and HaCaT cell lines on the surface of PANI-Cys films in comparison with tissue culture plastic (TCP) are studied. The PANI-Cys film shows better biocompatibility than PANI film for both cell lines. The cell morphologies on the TCP and PANI-Cys film were examined by florescence and Atomic Force Microscopy (AFM). Microscopic observations show normal cellular behavior when PANI-Cys is used as a substrate of both cell lines (HaCaT and LM2) as when they are cultured on TCP. The ability of these PANI-Cys films to support cell attachment and growth indicates their potential use as biocompatible surfaces and in tissue engineering.

  9. Electrodeposited conductive polypyrrole/polyaniline composite film for the corrosion protection of copper bipolar plates in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Pan, T. J.; Zuo, X. W.; Wang, T.; Hu, J.; Chen, Z. D.; Ren, Y. J.

    2016-01-01

    A conductive composite coating consisting of an inner polypyrrole (PPY) layer and an outer polyaniline (PANI) layer is prepared on a copper substrate by an electrochemical synthesis. Potential application of these composite coatings in a proton exchange membrane fuel cell (PEMFC) is evaluated. The corrosion performance of the copper substrate without and with the polymer coatings in the acidic solutions containing H2SO4 (0.2 M), HCl (0.1 M) and HF (3 ppm) is investigated by electrochemical impedance spectroscopy, polarization and open-circuit potential measurements. The results indicate that both the bilayered PPY/PANI and the single PPY coating can increase the corrosion potential of copper substrate by more than 250 mV (SCE), and effectively decrease the corrosion current density by an order of magnitude in comparison with the uncoated copper substrate. Long-term test further confirms that the bilayered PPY/PANI coating with acceptable contact resistance provides better protection for the substrate than the single PPY coating. The bilayered structure with different ion-permselective nature may serve as an effective physical barrier to the inward penetration of corrosive species.

  10. Porous conductive polyblends of polyaniline in poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Price, Aaron D.; Naguib, Hani E.

    2008-03-01

    The conductive polymer polyaniline is typically blended with conventional industrial thermoplastics in order to obtain an electrically conductive polymer blend with adequate mechanical properties. Processing these polyblends into foams yields a porous conductive material that exhibits immense application potential such as dynamic separation media and low-density electrostatic discharge protection. In the current study, the morphology of a thermally-processable blend consisting of an electrically conductive polyaniline-dodecylbenzene sulfonic acid complex and poly(methyl methacrylate) is explored using a two-phase batch foaming setup. The effect of blend composition and processing parameters on the resulting cellular morphology is investigated. Finally, the impact of the underlying microstructure on the frequency dependent electrical conductivity is elucidated.

  11. Conductivity and structure of DBSA-protonated polyaniline

    NASA Astrophysics Data System (ADS)

    Taka, T.; Laakso, J.; Levon, K.

    1994-11-01

    The discovery of a processable and conducting polyaniline complexes including functionalized sulphonic acids is an important discovery in the field of conjugated polymers. The conductivity, electronic and crystalline structure properties of polyaniline protonated with dodecylbenzenesulphonic acid are proportional to the molar concentration of the acid. The protonation leads to a layer structure evident in X-ray diffraction patterns and the crystallinity follows a growth as a function of the acid concentration similar to the conductivity increase. The electronic structure measured by UV-VIS spectroscopy shows an increase in the polaron concentration up to an acid concentration of 0.35 after which a broadening of the peak indicates the formation of a polaron band.

  12. Improved surface properties of polyaniline films by blending with Pluronic polymers without the modification of the other characteristics.

    PubMed

    Li, Z F; Ruckenstein, E

    2003-08-15

    Films of conductive polyaniline and amphiphilic Pluronic (P105) copolymer blends were prepared by dissolving the two polymers in N-methylpyrrolidinone (NMP) followed by a slow solvent evaporation at 55 degrees C. The characteristics of both doped and undoped films were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water droplet contact angles, differential scanning calorimetry (DSC), thermal gravimetry analysis (TG), wide-angle X-ray diffraction (WAXD), and tensile strength measurements. The surface of the blends became more hydrophilic than that of the hydrophobic PANI film, but the other properties of the blends did not change appreciably for Pluronic content lower than 50 wt%. Compared to PANI films, the more hydrophilic surfaces decreased the amount of bovine serum albumin protein adsorbed. By preventing biofouling, the polyaniline-Pluronic blends can become more useful as biosensors than the polyaniline films.

  13. Synthesis and characterization thin films of conductive polymer (PANI) for optoelectronic device application

    NASA Astrophysics Data System (ADS)

    Jarad, Amer N.; Ibrahim, Kamarulazizi; Ahmed, Nasser M.

    2016-07-01

    In this work we report preparation and investigation of structural and optical properties of polyaniline conducting polymer. By using sol-gel in spin coating technique to synthesize thin films of conducting polymer polyaniline (PANI). Conducting polymer polyaniline was synthesized by the chemical oxidative polymerization of aniline monomers. The thin films were characterized by technique: Hall effect, High Resolution X-ray diffraction (HR-XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FE-SEM), and UV-vis spectroscopy. Polyaniline conductive polymer exhibit amorphous nature as confirmed by HR-XRD. The presence of characteristic bonds of polyaniline was observed from FTIR spectroscopy technique. Electrical and optical properties revealed that (p-type) conductivity PANI with room temperature, the conductivity was 6.289×10-5 (Ω.cm)-1, with tow of absorption peak at 426,805 nm has been attributed due to quantized size of polyaniline conducting polymer.

  14. Processable Conducting Polyaniline, Carbon Nanotubes, Graphene and Their Composites

    NASA Astrophysics Data System (ADS)

    Wang, Kan

    Good processability is often required for applications of conducting materials like polyaniline (PANI), carbon nanotubes (CNTs) and graphene. This can be achieved by either physical stabilization or chemical functionalization. Functionalization usually expands the possible applications for the conducting materials depending on the properties of the functional groups. Processable conducting materials can also be combined with other co-dissolving materials to prepare composites with desired chemical and physical properties. Polyanilines (PANI) doped with dodecylbenzenesulfonic acid (DBSA) are soluble in many organic solvents such as chloroform and toluene. Single wall carbon nanotubes (SWCNTs) can be dispersed into PANI/DBSA to form homogeneous solutions. PANI/DBSA functions as a conducting surfactant for SWCNTs. The mixture can be combined with two-parts polyurethanes that co-dissolve in the organic solvent to produce conducting polymer composites. The composite mixtures can be applied onto various substrates by simple spray-on methods to obtain transparent and conducting coatings. Graphene, a single layer of graphite, has drawn intense interest for its unique properties. Processable graphene has been produced in N-methyl-2-pyrrolidone (NMP) by a one-step solvothermal reduction of graphite oxide without the aid of any reducing reagent and/or surfactant. The as-synthesized graphene disperses well in a variety of organic solvents such as dimethylsulfoxide (DMSO), ethanol and tetrahydrogenfuran (THF). The conductivity of solvothermal reduced graphite oxide is comparable to hydrazine reduced graphite oxide. Attempts were made to create intrinsically conducting glue comparable to mussel adhesive protiens using polyaniline and graphene. Mussels can attach to a variety of substrates under water. Catechol residue in 3,4-dihydroxyphenylalanine (L-DOPA) is the key to the wet adhesion. Tyrosine and phosphoserine with primary alkyl amine groups also participate in adhesion. A

  15. Synthesis and characterization of conducting polyaniline-copper composites.

    PubMed

    Liu, Aijie; Bac, Luong Huu; Kim, Ji-Soon; Kim, Byoung-Kee; Kim, Jin-Chun

    2013-11-01

    Conducting polymer composites have many interesting physical properties and important application potentials. Suitable combinations of metal nanoparticles with conductive polymers can result in composite materials having unique physical and chemical properties that can have wide application potential in diverse areas. In this work, copper nanoparticles were fabricated by electrical explosion of wire (EEW) in solution of polyacrylic acid (PAA) and ethanol. Conductive polyaniline-copper (PANI-Cu) composites have been synthesized by in-situ polymerization of aniline in the fabricated copper suspension. Optical absorption in the UV-visible region of these suspensions was measured in the range of 200-900 nm. Morphology and structure of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR). Pure copper nanoparticles were uniformly dispersed into the polymer matrix. Thermal stability of the composites was characterized by thermogravimetric analysis (TGA). Electrical conductivity measurements indicated that the conductivity of the composites was higher than that of pure polyaniline and increased with increasing content of copper.

  16. Morphology in electrochemically grown conducting polymer films

    DOEpatents

    Rubinstein, I.; Gottesfeld, S.; Sabatani, E.

    1992-04-28

    A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventionally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol. 2 figs.

  17. Morphology in electrochemically grown conducting polymer films

    DOEpatents

    Rubinstein, Israel; Gottesfeld, Shimshon; Sabatani, Eyal

    1992-01-01

    A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventioonally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol.

  18. NMR evidence for the metallic nature of highly conducting polyaniline

    NASA Astrophysics Data System (ADS)

    Kolbert, A. C.; Caldarelli, S.; Thier, K. F.; Sariciftci, N. S.; Cao, Y.; Heeger, A. J.

    1995-01-01

    Polyaniline doped with camphor sulphonic acid (PANI-CSA) has been shown to yield a material that, after casting from solution in meta-cresol, exhibits a temperature-independent magnetic susceptibility [Y. Cao, P. Smith, and A. J. Heeger, Synth. Met. 48, 91 (1992); N. S. Sariciftici, A. J. Heeger, and Y. Cao, Phys. Rev. B 49, 5988 (1994)]. We report recent 13C NMR experiments on uniformly 13enriched PANI-CSA in which the 13C spin-lattice relaxation rates are shown to obey a modified Korringa relation for relaxation via the hyperfine coupling to conduction electrons. This observation of Korringa relaxation in polyaniline provides strong evidence for a metallic state in this material. An estimate is made of the Korringa enhancement factor that provides a measure of the degree of electron-electron correlations present. Two-dimensional spin-exchange experiments are also reported, which show that the 13C NMR signal results from a heterogeneity in the sample over at least a 30-Å distance scale. These results are discussed in terms of the spatial extent of the doping-induced defect.

  19. Elaboration of m-cresol polyamide12/ polyaniline composite films for antistatic applications

    SciTech Connect

    Mezdour, D.; Tabellout, M.; Bardeau, J.-F; Sahli, S.

    2013-12-16

    The present work deals with the preparation of transparent antistatic films from an extreme dilution of an intrinsically conducting polymer (ICP) with not coloured polymers. Our approach is based on the chemical polymerization of a very thin layer of Polyaniline (PANI) around particles of an insulating polymer (PA12). Films were obtained by dissolving the synthesized core-shell particles in m-Cresol. The electric property and structure relationships were investigated by using dielectric relaxation spectroscopy, X-ray diffraction and micro-Raman spectroscopy. Composite films exhibited a well established dc conductivity over all the frequency range for 10 wt. % of PANI concentration related to the conductive properties of the PANI clusters. X-ray diffraction data show broader and lower intensity of PA12 peaks when increasing PANI content, probably due to the additional doping effect of m- cresol. The doping of PA12/PANI films with Dodecyl benzene sulfonic acid (DBSA) was unequivocally verified by Raman spectroscopy.

  20. Doping level dependent space charge limited conduction in polyaniline nanoparticles

    NASA Astrophysics Data System (ADS)

    Nath, Chandrani; Kumar, A.

    2012-11-01

    Spherical shaped polyaniline nanoparticles of average diameter ˜4 nm were doped with different concentration of hydrochloric acid. The x-ray diffraction studies reveal an increase in crystallinity with doping. Temperature dependent current-voltage measurements on the different nanoparticle samples indicate the prevalence of bulk-controlled space charge limited conduction (SCLC) mechanism in the high voltage (>1 V) region while the ohmic conduction dominates at the lower voltage (<1 V) region. With increasing doping the nature of SCLC changes from trap-free SCLC to Child-Langmuir type SCLC via exponential trap-limited SCLC. Moreover, the field and temperature dependence of mobility exhibits the universal Poole-Frenkel behavior. The energetic disorder parameter, spatial disorder parameter, inter-site distance, and localization length have been extracted employing the uncorrelated and the correlated Gaussian disorder model.

  1. Effect of polyaniline to enhance lithium iron phosphate conductivity

    NASA Astrophysics Data System (ADS)

    Wijayati, Anissa; Susanti, Susan; Rahayu, Iman; Hidayat, Sahrul

    2016-02-01

    Lithium cobalt oxide is commonly used as secondary battery. One of the disadvantages of lithium cobalt oxide is highly toxicity waste. One of the promising cathode is lithium iron phosphate (LiFePO4). But it has poor conductivity (10-9 S/cm), so conductive material must be added to improve its conductivity. The present paper aims to study the effect of Polyaniline (PANI) and PVDF to enhance lithium iron phosphate conductivity. PANI was prepared through interfacial polymerization. Hydrochloric acid, ammonium persulfate, and toluene were used as dopant, oxidant, and organic solvent respectively. Their morphology was confirmed by scanning electron microscopy (SEM), molecular structure was investigated by Infrared Spectroscopy, and conductivity was confirmed by four point probes method. The composite products have conductivities in the range 9.14 × 10-3 - 6.2×10-1 S/cm. This result is expected to provide an alternative conductive material that can improve the conductivity of lithium iron phosphate, as well as the alternative cathode which is environmental friendly, and no harmful waste.

  2. Coating of zinc ferrite particles with a conducting polymer, polyaniline.

    PubMed

    Stejskal, Jaroslav; Trchová, Miroslava; Brodinová, Jitka; Kalenda, Petr; Fedorova, Svetlana V; Prokes, Jan; Zemek, Josef

    2006-06-01

    Particles of zinc ferrite, ZnOFe2O3, were coated with polyaniline (PANI) phosphate during the in situ polymerization of aniline in an aqueous solution of phosphoric acid. The PANI-ferrite composites were characterized by FTIR spectroscopy. X-ray photoelectron spectroscopy was used to determine the degree of coating with a conducting polymer. Even a low content of PANI, 1.4 wt%, resulted in the 45% coating of the particles' surface. On the other hand, even at high PANI content, the coating of ferrite surface did not exceeded 90%. This is explained by the clustering of hydrophobic aniline oligomers at the hydrophilic ferrite surface and the consequent irregular PANI coating. The conductivity increased from 2 x 10(-9) to 6.5 S cm(-1) with increasing fraction of PANI phosphate in the composite. The percolation threshold was located at 3-4 vol% of the conducting component. In the absence of any acid, a conducting product, 1.4 x 10(-2) Scm(-1), was also obtained. As the concentration of phosphoric acid increased to 3 M, the conductivity of the composites reached 1.8 S cm(-1) at 10-14 wt% of PANI. The ferrite alone can act as an oxidant for aniline; a product having a conductivity 0.11 S cm(-1) was obtained after a one-month immersion of ferrite in an acidic solution of aniline.

  3. On the Efect of the Oxidative Reagents on the Conductivity of Polyaniline/MMT Nanocomposites

    NASA Astrophysics Data System (ADS)

    Garcia-Bernabé, A.; Gil-Agustí, M.; Ortega, G.; Llovera, P.; Almarza, A.; Vázquez, S.; Amantia, D.; Aubouy, L.

    2010-06-01

    The synthesis of polyaniline has been reported using three different oxidative reagents: ammonium persulfate, potassium iodate and potassium iodate+sodium hypochlorite. This polyaniline has been used to prepare several nanocomposites with different percentage of Montmorillonite. The DC conductivity of the nanocomposites was determined by impedance spectroscopy. The oxidative reagent that gives higher conductivity is ammonium persulfate. The temperature dependence of the conductivity was studied.

  4. Effect of HCl doping on optoelectrical and LPG sensing properties of nanostructured polyaniline thin films

    NASA Astrophysics Data System (ADS)

    Upadhye, Deepak S.; Huse, Nanasaheb P.; Sharma, Ramphal

    2016-05-01

    Nanostructure Polyaniline thin films doped with 0.5 M, 0.7 M, and 1 M of HCL were synthesized by simple and inexpensive chemical oxidative polymerization technique at room temperature. All prepared thin films of Polyaniline were characterized by optical absorbance study by UV-visible spectroscopy. The absorbance spectrum of Polyaniline shows three fundamental peaks at 356, 419 and 820 nm with increase in absorption intensity. The electrical study shows magnitude of resistance of HCL doped Polyaniline is dependent on doping level. Furthermore, the thin film of Polyaniline was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents irregular granular morphology. In order to investigate LPG sensing properties, I-V characteristics of the Polyaniline films doped with 0.5 M, 0.7 M, and 1 M of HCL were recorded at room temperature in presence of air and 100 ppm of LPG. The observed values of sensitivity found to be 7.21%, 9.85% and 17.46 % for 0.5 M, 0.75 M, and 1.0 M of HCL doped Polyaniline thin films respectively

  5. Electrochemical supercapacitors from conducting polyaniline-graphene platforms.

    PubMed

    Ashok Kumar, Nanjundan; Baek, Jong-Beom

    2014-06-18

    Energy storage devices such as electrochemical supercapacitors, with high power and energy densities are required to address the colossal energy requirements against the backdrop of global warming and the looming energy crisis. Nanocarbon, particularly two-dimensional graphene and graphene-based conducting polymer composites are promising electrode materials for such energy storage devices. Owing to their environmental stability, the low cost of polymers with high electroactivity and pseudocapacitance, such composite hybrids are expected to have wide implications in next generation clean and efficient energy systems. In this feature article, an overview of current research and important advances over the past four years on the development of conducting polyaniline (PANI)-graphene based composite electrodes for electrochemical supercapacitors are highlighted. Particular emphasis is made on the design, fabrication and assembly of nanostructured electrode architectures comprising PANI and graphene along with metal oxides/hydroxides and carbon nanotubes. Comments on the challenges and perspectives towards rational design and synthesis of graphene-based conducting polymer composites for energy storage are discussed.

  6. Development and characterization of multilayer films of polyaniline, titanium dioxide and CTAB for potential antimicrobial applications.

    PubMed

    Farias, Emanuel Airton O; Dionisio, Natália A; Quelemes, Patrick V; Leal, Sergio Henrique; Matos, José Milton E; Silva Filho, Edson C; Bechtold, Ivan H; Leite, José Roberto S A; Eiras, Carla

    2014-02-01

    Composites prepared from polyaniline (PANI) and the ceramic technology of titanium dioxide (TiO2) have been proposed, however, the interaction of these materials with greater control of molecular arrangement becomes attractive in order to achieve properties not previously described or yet the optimization of those already reported. Therefore, in this study, thin hybrid films made of polyaniline (PANI), a conductive polymer, and the technological ceramic, titanium dioxide (TiO2), were prepared by the layer-by-layer (LbL) self-assembly technique. The films were characterized by cyclic voltammetry (CV), UV-VIS spectroscopy and atomic force microscopy (AFM). Aiming to improve the dispersion of the ceramic in the polymer matrix, the commercial surfactant, cetyl trimethylammonium bromide (CTAB), was used in the formation of the films. The best condition of deposition was found showing synergic interactions between the conjugated materials. The antibacterial activity of the PANI(TiO2)/CTAB films was studied and the obtained results suggest their use as antimicrobial coatings.

  7. Optical and electronic properties of layer-by-layer and composite polyaniline-cadmium selenide quantum dot films

    NASA Astrophysics Data System (ADS)

    Ayub, Ambreen; Shakoor, Abdul; Elahi, Asmat; Rizvi, Tasneem Zahra

    2015-08-01

    Two organic-inorganic hybrid films of intrinsically conducting polymer; polyaniline and cadmium selenide quantum dots were prepared. One by layer-by-layer deposition of polyaniline and cadmium selenide films on PEDOT-PSS/ITO coated glass substrate (ITO/PEDOT-PSS/PANI/CdSe) and other by depositing polyaniline-cadmium selenide quantum dots composite film on the same substrate (ITO/PEDOT-PSS/PANI-CdSe) using spin coating technique. Pure polyaniline, cadmium selenide quantum dots and their composites thus obtained were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV/VIS/NIR absorption spectroscopy. The surface morphologies were studied by Scanning Electron Microscopy (SEM). The diode performance parameters were compared and contrasted for the two devices obtained by different deposition routes. J-V characteristics of these devices showed a rectifying contact with Al metal, however with variation in performance parameters like barrier height, ideality factor and reverse saturation current the ITO/PEDOT-PSS/PANI-CdSe/Al device exhibited better diode performance as compared to ITO/PEDOT-PSS/PANI/CdSe/Al device.

  8. Lightweight polyaniline-cobalt coated fly ash cenosphere composite film for electromagnetic interference shielding

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Vinoy, K. J.; Ramamurthy, Praveen C.; Kishore; Madras, Giridhar

    2016-09-01

    Thermal power plant's solid environmental waste fly ash cenosphere (FAC) is cobalt coated chemically and functionalized by in situ synthesis of polyaniline (PANI) under nitrogen atmosphere at -30 ± 2 °C and characterized by various techniques. The electromagnetic interference shielding effectiveness (EMI SE) of free standing PANI/Co-FAC (PCC) films prepared by solution casting indicates an appreciable shielding. The most effective average EMI SE of ~ 30 dB was obtained for 89 ± 3 μm thicker flexible film over the frequency range of 12.4-18 GHz (Ku-band). Mechanistically, EMI shielding due to absorption was found to be dominant. The obtained shielding effectiveness due to absorbance ( SE A ) of PCC film is nearly two times higher than PC film. The microwave conductivity (σ) of PCC film (157-184 Sm-1) is much higher than PC film (118-142 Sm-1). Moreover, the high EM attenuation constant ( α) value of PCC film indicates excellent suitability of EMI shielding due to absorption.

  9. EFFECTS OF TRITIUM GAS EXPOSURE ON THE GLASS TRANSITION TEMPERATURE OF EPDM ELASTOMER AND ON THE CONDUCTIVITY OF POLYANILINE

    SciTech Connect

    Clark, E; Marie Kane, M

    2008-12-12

    Four formulations of EPDM (ethylene-propylene diene monomer) elastomer were exposed to tritium gas initially at one atmosphere and ambient temperature for between three and four months in closed containers. Material properties that were characterized include density, volume, mass, appearance, flexibility, and dynamic mechanical properties. The glass transition temperature was determined by analysis of the dynamic mechanical property data per ASTM standards. EPDM samples released significant amounts of gas when exposed to tritium, and the glass transition temperature increased by about 3 C. during the exposure. Effects of ultraviolet and gamma irradiation on the surface electrical conductivity of two types of polyaniline films are also documented as complementary results to planned tritium exposures. Future work will determine the effects of tritium gas exposure on the electrical conductivity of polyaniline films, to demonstrate whether such films can be used as a sensor to detect tritium. Surface conductivity was significantly reduced by irradiation with both gamma rays and ultraviolet light. The results of the gamma and UV experiments will be correlated with the tritium exposure results.

  10. Effect of Polyaniline additions on structural and gas sensing behaviour of metal oxides thin films

    NASA Astrophysics Data System (ADS)

    Hj. Jumali, Mohammad H.; Izzuddin, Izura; Ramli, Norhashimah; Mat Salleh, Muhamad; Yahaya, Muhammad

    2009-07-01

    The structural and gas sensing behaviour of metal oxides namely TiO2 and ZnO thin films were investigated. In this paper, commercial Polyaniline (PANi) powder were added into two different metal oxides sol gel solutions with PANi : metal oxides weight ratios of 1wt.%, 2wt.% and 3wt.%. The thin films were fabricated using spin coating technique. Structural investigation using XRD presented that all films exhibited amorphous structure. Typical films surface morphology consists of agglomerated round shaped particles with the particles size varies between 57nm to 200nm. Addition of PANi formed network chains between the particles. Ethanol vapor detection test conducted at room temperature showed that both TiO2 and ZnO based films were capable to sense the vapor. The optimum ratio in sensing ethanol vapour for both PANi-TiO2 and PANi-ZnO films was 3:1. However, other issues such as reliability, selectability and repeatability remain as the major problems.

  11. Robotic extrusion processes for direct ink writing of 3D conductive polyaniline structures

    NASA Astrophysics Data System (ADS)

    Holness, F. Benjamin; Price, Aaron D.

    2016-04-01

    The intractable nature of intrinsically conductive polymers (ICP) leads to practical limitations in the fabrication of ICP-based transducers having complex three-dimensional geometries. Conventional ICP device fabrication processes have focused primarily on thin-film deposition techniques; therefore this study explores novel additive manufacturing processes specifically developed for ICP with the ultimate goal of increasing the functionality of ICP sensors and actuators. Herein we employ automated polymer paste extrusion processes for the direct ink writing of 3D conductive polyaniline (PANI) structures. Realization of these structures is enabled through a modified fused filament fabrication delta robot equipped with an integrated polymer paste extruder. This unique robot-controlled additive manufacturing platform is capable of fabricating high-resolution 3D conductive PANI and has been utilized to produce structures with a minimum feature size of 1.5 mm. The required processability of PANI is achieved by means of a counter-ion induced thermal doping method. Using this method, a viscous paste is formulated as the extrudate and a thermo-chemical treatment is applied post extrusion to finalize the complexation.

  12. Synthesis, characterization and low temperature electrical conductivity of Polyaniline/NiFe2O4 nanocomposites

    NASA Astrophysics Data System (ADS)

    Prasanna, G. D.; Prasad, V. B.; Jayanna, H. S.

    2015-02-01

    Conducting polymer/ferrite nanocomposites with an organized structure provide a new functional hybrid between organic and inorganic materials. The most popular among the conductive polymers is the polyaniline (PANI) due to its wide application in different fields. In the present work nickel ferrite (NiFe2O4) nanoparticles were prepared by sol-gel citrate-nitrate method with an average size of 21.6nm. PANI/NiFe2O4 nanoparticles were synthesized by a simple general and inexpensive in-situ polymerization in the presence of NiFe2O4 nanoparticles. The effects of NiFe2O4 nanoparticles on the dc-electrical properties of polyaniline were investigated. The structural components in the nanocomposites were identified from Fourier Transform Infrared (FTIR) spectroscopy. The crystalline phase of nanocomposites was characterized by X-Ray Diffraction (XRD). The Scanning Electron Micrograph (SEM) reveals that there was some interaction between the NiFe2O4 particles and polyaniline and the nanocomposites are composed of polycrystalline ferrite nanoparticles and PANI. The dc conductivity of polyaniline/NiFe2O4 nanocomposites have been measured as a function of temperature in the range of 80K to 300K. It is observed that the room temperature conductivity cRT decreases with increase in the relative content of NiFe2O4. The experimental data reveals that the resistivity increases for all composites with decrease of temperature exhibiting semiconductor behaviour.

  13. Chemical Oxidative Polymerization of Polyaniline: A Practical Approach for Preparation of Smart Conductive Textiles

    ERIC Educational Resources Information Center

    Abu-Thabit, Nedal Y.

    2016-01-01

    Electrically conducting polymers are one of the promising alternative materials for technological applications in many interdisciplinary areas, including chemistry, material sciences, and engineering. This experiment was designed for providing undergraduate students with a quick and practical approach for preparation of a polyaniline-conducting…

  14. Electromagnetic interference shielding efficiency of MnO2 nanorod doped polyaniline film

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Vinoy, K. J.; Ramamurthy, Praveen C.; Madras, Giridhar

    2017-02-01

    The polymer nanocomposite thin film is of interest due to many advantages for electromagnetic interference (EMI) shielding. In this work, low temperature (‑30  ±  2 °C) in situ synthesized polyaniline (PANI)–MnO2 nanorod composite (PMN) were solution processed, followed by acid vapor treatment for preparing free standing films and EMI shielding effectiveness (SE) were investigated in the frequency range i.e. X-band (8.2–12.4 GHz) and Ku-band (12.4–18 GHz). As prepared PMN film (169  ±  2 µm) shows most effective EMI SE ~ 35 dB (EMI shielding due to absorption, SEA ~ 24 dB and EMI shielding due to reflection SER ~ 11 dB) in the X-band which was observed to be ~39 dB (SEA ~ 29 dB and SER ~ 10 dB) in the Ku-band. The variations of conductivity, penetration depth, EM attenuation constant of the PMN film in the X-band and Ku-band were also investigated along with dielectric study.

  15. Electromechanical behavior of polyaniline/poly (vinyl alcohol) blend films under static, dynamic and time-dependent strains

    NASA Astrophysics Data System (ADS)

    Akhilesan, S.; Lakshmana Rao, C.; Varughese, S.

    2014-07-01

    We report on the experimentally observed electrical conductivity enhancement in polyaniline/poly (vinyl alcohol) blend films under uniaxial tensile loading. Polyaniline (PANI) is an intrinsically conducting polymer, which does not form stretchable free-standing films easily and hence its electromechanical characterization is a challenge. Blending of PANI with other insulating polymers is a good choice to overcome the processability problem. We report the electromechanical response of solution blended and HCl doped PANI/PVA blends subjected to uniaxial, static, dynamic and time-dependent tensile loading. The demonstrated viscoelastic and morphological contributions of the component polymers to the electrical conductivity behavior in these blends could lead to interesting applications in strain sensors and flexible electronics. The reversibility of the electromechanical response under dynamic strain is found to increase in blends with higher PANI content. Time-dependent conductivity studies during mechanical stress relaxation reveal that variations in the micro-domain ordering and the relative relaxation rate of the individual polymer phases can give rise to interesting electrical conductivity changes in PANI blends. From morphological and electrical conductivity studies, we show that PANI undergoes primary and secondary agglomeration behavior in these blends that contributes to the changes in conductivity behavior during the deformation. A 3D variable range hopping (VRH) process, which uses a deformable core and shell concept based on blend morphology analysis, is used to explain the experimentally observed electromechanical behavior.

  16. Dielectric and conduction behaviour of H2SO4 doped conducting Polyaniline

    NASA Astrophysics Data System (ADS)

    Mohanty, J.; Behera, P.; Mishra, S. R.; Badapanda, T.; Anwar, S.

    2017-02-01

    We report the effect of H2SO4 doping on the dielectric and conduction behaviour of Polyaniline (PANI) samples. The PANI salt prepared by oxidising aniline hydrochloride in distilled water with the oxidant ammonium persulphate with continuous stirring at room temperature and PANI base is produced by subjecting PANI salt to a reaction with 0.5M NaOH. H2SO4 doped PANI is prepared by subjecting PANI base to reaction with 1M H2SO4 at room temperature under constant stirring for 1h. The synthesied PANI along with the doped samples were further washed with acetone to study the effect of acetone washing on the electrical behaviour. It is observed that the dielectric constant as well as the dielectric loss decreases with frequency in the entire studied sample. The frequency dependent AC conductivity at room temperature obeys the power law and the DC conductivity was obtained from the fitting parameter. It is found that the non acetone washed PANI doped in 1M H2SO4 shows highest dielectric constant and conductivity.

  17. Potential Dependence of the Conductivity of Highly Oxidized Polythiophenes, Polypyrroles, and Polyaniline: Finite Windows of High Conductivity

    DTIC Science & Technology

    1990-05-16

    protonation/deprotonation mechanism . Conductivity increases by at least 108 upon oxidizing polyani-ine from neutral to maximally conducting, and decreases...reversible, potential dependent changes in conductivity in liquid S02/electrolyte in the apparent absence of a protonation/deprotonation mechanism ...polyaniline is similar in 0.5 M H2SO4 ,1 liquid S02 /electrolyte, and poly(vinyl alchohol )/H 3PO4.nH20.8 However, the positive potential limit in aqueous

  18. Fabrication of graphene/polyaniline composite multilayer films by electrostatic layer-by-layer assembly

    SciTech Connect

    Cong, Jiaojiao; Chen, Yuze; Luo, Jing Liu, Xiaoya

    2014-10-15

    A novel graphene/polyaniline composite multilayer film was fabricated by electrostatic interactions induced layer-by-layer self-assembly technique, using water dispersible and negatively charged chemically converted graphene (CCG) and positively charged polyaniline (PANI) as building blocks. CCG was achieved through partly reduced graphene oxide, which remained carboxyl group on its surface. The remaining carboxyl groups not only retain the dispersibility of CCG, but also allow the growth of the multilayer films via electrostatic interactions between graphene and PANI. The structure and morphology of the obtained CCG/PANI multilayer film are characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Ultraviolet–visible absorption spectrum (UV–vis), scanning electron microscopy (SEM), Raman spectroscopy and X-Ray Diffraction (XRD). The electrochemical properties of the resulting film are studied using cyclic voltammetry (CV), which showed that the resulting CCG/PANI multilayer film kept electroactivity in neutral solution and showed outstanding cyclic stability up to 100 cycles. Furthermore, the composite film exhibited good electrocatalytic ability toward ascorbic acid (AA) with a linear response from 1×10{sup −4} to 1.2×10{sup −3} M with the detect limit of 5×10{sup −6} M. This study provides a facile and effective strategy to fabricate graphene/PANI nanocomposite film with good electrochemical property, which may find potential applications in electronic devices such as electrochemical sensor. - Graphical abstract: A novel graphene/polyaniline (CCG/PANI) film was prepared by layer-by-layer assembly. - Highlights: • A novel graphene/polyaniline (CCG/PANI) film was prepared by layer-by-layer assembly. • The water dispersible and negatively charged graphene (CCG) was used as building block. • CCG was achieved through partly reduced graphene oxide with carboxyl group on its surface. • CCG/PANI film kept

  19. Influence of external voltage on the reprotonated polyaniline films by Fourier Transform Infrared spectroscopy.

    PubMed

    Zhou, Tieli; Xing, Shuangxi; Zhang, Chuanzhou; Wu, Yan; Zhao, Chun

    2009-07-01

    In this paper, we reported the electrical fourier transform infrared (FT-IR) spectra measurements on the reprotonated polyaniline (PANI) thin films. Application of external voltage reduced the intensity in FT-IR spectra and resulted in the shift of band situation. The FT-IR spectra as a function of temperature were also conducted in order to investigate the effect of Joule heating. We found that the influence of CC of phenyl units and the CC of quinoid were quite different as a function of external voltage and temperature. The current-voltage (I-V) curves of the PANI film measured in the range of 0-175 V showed that the resistance kept constant at 0-75 V while it increased from 75 to 175 V. The I-V curves confirmed the presence of Joule heating effect during 75-175 V. According to the experiment results, we concluded that external voltage could produce large average hopping energy, which allowed the charge transfer by hopping between the conducting domains during 0-75 V. The deprotonation of PANI was caused by Joule heating effect, resulting in the decreasing conductivity from 75 to 175 V.

  20. Prevention of corrosion with polyaniline

    NASA Technical Reports Server (NTRS)

    MacDiarmid, Alan G. (Inventor); Ahmad, Naseer (Inventor)

    1997-01-01

    Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating.

  1. Positive temperature coefficient of resistivity of polyaniline films in the framework of phonon-assisted tunnelling model

    NASA Astrophysics Data System (ADS)

    Pipinys, P.; Kiveris, A.

    2005-12-01

    In the present paper it is shown that a change from semiconducting behaviour of conductivity to metallic behaviour observed in polyaniline (PANI) films [Long et al., Physica B 325 (2003) 208; 344 (2004) 82] and fibres [Adams et al., Synth. Met. 101 (1999) 685] at higher temperatures could be explained on the basis of phonon-assisted tunnelling model. A transition from negative temperature coefficient of resistivity (TCR) to positive TCR in the framework of this model occurs at the temperatures, at which the phonon emission dominates in the process of tunnelling.

  2. Polyaniline modified flexible conducting paper for cancer detection

    NASA Astrophysics Data System (ADS)

    Kumar, Saurabh; Sen, Anindita; Kumar, Suveen; Augustine, Shine; Yadav, Birendra K.; Mishra, Sandeep; Malhotra, Bansi D.

    2016-05-01

    We report results of studies relating to the fabrication of a flexible, disposable, and label free biosensing platform for detection of the cancer biomarker (carcinoembryonic antigen, CEA). Polyaniline (PANI) has been electrochemically deposited over gold sputtered paper (Au@paper) for covalent immobilization of monoclonal carcinoembryonic antibodies (anti-CEA). The bovine serum albumin (BSA) has been used for blocking nonspecific binding sites at the anti-CEA conjugated PANI/Au@Paper. The PANI/Au@Paper, anti-CEA/PANI/Au@Paper, and BSA/anti-CEA/PANI/Au@Paper platforms have been characterized using scanning electron microscopy, X-ray diffraction, Fourier transmission infrared spectroscopy, chronoamperometry, and electrochemical impedance techniques. The results of the electrochemical response studies indicate that this BSA/anti-CEA/PANI/Au@paper electrode has sensitivity of 13.9 μA ng-1 ml cm2, shelf life of 22 days, and can be used to estimate CEA in the range of 2-20 ng ml-1. This paper sensor has been validated by detection of CEA in serum samples of cancer patients via immunoassay technique.

  3. Photoelectrical properties of polyaniline/polyimide complex thin film

    NASA Astrophysics Data System (ADS)

    Zheng, Jianbang; Hou, Chaoqi; Liu, Jia; Ren, Ju; Zhao, Jianlin

    2006-02-01

    Using pyromellitic dianhydride (PMDA) and bis(4-aminophenyl) ether (ODA) as monomer materials, the polyamic acid (PAA), a precursor of polyimide (PI), was synthesized. PAn was doped and modified with the polyamic acid by solution mixing method, and the modified PAn/PAA blend with good solubility and forming-film was obtained. Then uniform PAn/PI complex thin film with good forming-film and thermo-stability can be prepared by solvent casting and followed by thermal imidization process at the temperature of 150 °C-250 °C for 60 min. Conductance experiments showed the surface conductivity of PAn/PI thin films can raise to 10 -5S from 10 -10S and change with the increase of the content of PAA. IR and UV-vis spectra showed that it has a chemical doping reaction between PAn and PAA during mixing, and the absorption of PAn/PI complex films in UV-vis region appears red shift and the peak shape becomes broad. The degenerate four-wave mixing experimental results showed that the third-order optical nonlinear susceptibility χ (3) of PAn/PI thin films can be markedly enhanced and the maximum χ (3) can reach 8.85×10 -10esu, which presents good third-order nonlinear property.

  4. Antimicrobial activity and cytotoxicity of cotton fabric coated with conducting polymers, polyaniline or polypyrrole, and with deposited silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Maráková, Nela; Humpolíček, Petr; Kašpárková, Věra; Capáková, Zdenka; Martinková, Lenka; Bober, Patrycja; Trchová, Miroslava; Stejskal, Jaroslav

    2017-02-01

    Cotton fabric was coated with conducting polymers, polyaniline or polypyrrole, in situ during the oxidation of respective monomers. Raman and FTIR spectra proved the complete coating of substrates. Polypyrrole content was 19.3 wt.% and that of polyaniline 6.0 wt.%. Silver nanoparticles were deposited from silver nitrate solutions of various concentrations by exploiting the reduction ability of conducting polymers. The content of silver was up to 11 wt.% on polypyrrole and 4 wt.% on polyaniline. The sheet resistivity of fabrics was determined. The conductivity was reduced after deposition of silver. The chemical cleaning reduced the conductivity by less than one order of magnitude for polypyrrole coating, while for polyaniline the decrease was more pronounced. The good antibacterial activity against S. aureus and E. coli and low cytotoxicity of polypyrrole-coated cotton, both with and without deposited silver nanoparticles

  5. Dielectric spectroscopy of polyaniline

    SciTech Connect

    Calleja, R.D.; Matveeva, E.M.

    1993-12-31

    Polyaniline films (PANI) are being considered as attractive new galvanic sources, electrochromic displays, chemical sensors, etc. So far much work has been done to study their optical, electrochemical and electrical properties. However, there are still doubts about the basic electric conductivity mechanisms of PANI. The aim of this paper is to study the influence of water molecules and acid anions on the properties of PANI films by dielectric spectroscopy.

  6. Highly anisotropic conductivity of tablets pressed from polyaniline-montmorillonite nanocomposite

    SciTech Connect

    Tokarský, Jonáš

    2016-03-15

    Highlights: • Montmorillonite (MMT) can be intercalated with polyaniline (PANI) chains. • Tablets pressed from PANI/MMT exhibit high anisotropy in electrical conductivity. • Pressure 28MPa is sufficient to reach the anisotropy. • Tablets pressed from pure PANI also exhibit anisotropy in electrical conductivity. - Abstract: Polyaniline-montmorillonite nanocomposite was prepared from anilinium sulfate (precursor) and ammonium peroxodisulfate (oxidizing agent) using simple one-step method. The resulting nanocomposite obtained in powder form has been pressed into tablets using various compression pressures (28–400 MPa). Electrical conductivities of tablets in two perpendicular directions, i.e. direction parallel with the main surface of tablet (σ=) and in orthogonal direction (σ⊥), and corresponding anisotropy factors (i.e., the ratio σ=/σ⊥) have been studied in dependence on compression pressure used during the preparation. Polyaniline-montmorillonite nanocomposite was characterized using X-ray diffraction analysis, raman spectroscopy, transmission electron microscopy, thermogravimetric analysis and molecular modeling which led to the understanding of the internal structure. Measurement of hardness performed on pressed tablets has been also involved. Taking into account the highest value of anisotropy factor reached (σ=/σ⊥ = 490), present study shows a chance to design conductors with nearly two-dimensional conductivity.

  7. Effects of temperature and humidity on electrospun conductive nanofibers based on polyaniline blends

    NASA Astrophysics Data System (ADS)

    Zampetti, E.; Muzyczuk, A.; Macagnano, A.; Pantalei, S.; Scalese, S.; Spinella, C.; Bearzotti, A.

    2011-11-01

    This study focuses and discusses the effects of temperature and humidity on electrospun conductive nanofibers, made with different polymer blends, deposited directly on interdigitated electrodes. The selected conductive polymers were based on blends of polyaniline emeraldine salt form and three different carrier hosting polymers: polyvinilpyrrolidone, polystyrene, and polyethylene oxide respectively. The obtained fibrous layers were investigated by the electrical measurements and morphological analysis (scanning electron microscopy). The study was made on the correlation between the electrical changes and morphological discrepancies due to temperature treatment. Moreover, this article reports the effects of relative humidity variations on electrical parameters. Since polyaniline is a well-known sensing material for different gases and volatile organic compounds, this study could be considered a supportive study for employing of the mentioned polymer blends as chemical interactive materials in gas sensor applications.

  8. Preparation and characterization of graphene nano-platelets integrated polyaniline based conducting nanocomposites

    NASA Astrophysics Data System (ADS)

    Tokala, Mamata Reddy; Padya, Balaji; Jain, P. K.; Shilpa Chakra, C. H.

    2015-06-01

    Natural graphite flakes were intercalated with strong oxidizing agents and were converted into thermally expanded graphite (TEG) through thermal exfoliation. Thermally expanded graphite was delaminated and transformed into graphene nanoplatelets (GNP) by using ultrasonic irradiation. GNP integrated polyaniline (PANi) nanocomposites were synthesized via in-situ polymerization of aniline monomers in the presence of GNP. The structure and morphology of composite was evidenced by scanning electron microscopy, Transmission electron microscopy (TEM), X-ray diffraction and Raman spectroscopy. TEM micrographs revealed that GNP consists of 20-25 graphene layers and PANi was uniformly coated on GNP. From Raman analysis it was showed significant interactions between GNP and polyaniline. Electrical conductivity was measured by using 4-point probe device, enhanced conductivity was obtained for composite.

  9. Stable two-dimensional conductance switch of polyaniline molecule connecting to graphene nanoribbons.

    PubMed

    Fan, Zhi-Qiang; Chen, Ke-Qiu

    2014-08-07

    Incorporating the characteristics of the single-layer graphene nanoribbon and the polyaniline molecule, we theoretically design a two-dimensional molecular device and investigate its transport properties by applying nonequilibrium Green's functions in combination with density-functional theory. The calculated results reveal that the arrangements of frontier molecular orbitals and the energy gap between the HOMO and the LUMO of an isolated polyaniline molecule are different between its two isolable states: full reduced leucoemeraldine base and full oxidized pernigraniline base. When a polyaniline molecule connects to two graphene nanoribbons as a two-dimensional molecular device, the conductance of its full oxidized pernigraniline base is much higher than the conductance of its full reduced leucoemeraldine base. The switch ratios of two bases' currents almost maintain a constant value before 0.8 V. In other word, the conductance switch behavior in our device is stable in a big bias region which makes it have a broader application in future logic and memory devices.

  10. Electrochemical synthesis of a microporous conductive polymer based on a metal-organic framework thin film.

    PubMed

    Lu, Chunjing; Ben, Teng; Xu, Shixian; Qiu, Shilun

    2014-06-16

    A new approach to preparing 3D microporous conductive polymer has been demonstrated in the electrochemical synthesis of a porous polyaniline network with the utilization of a MOF thin film supported on a conducting substrate. The prepared porous polyaniline with well-defined uniform micropores of 0.84 nm exhibits a high BET surface area of 986 m(2) g(-1) and a high electric conductivity of 0.125 S cm(-1) when doped with I2, which is superior to existing porous conducting materials of porous MOFs, CMPs, and COFs.

  11. Polyaniline nanofibers: a unique polymer nanostructure for versatile applications.

    PubMed

    Li, Dan; Huang, Jiaxing; Kaner, Richard B

    2009-01-20

    Known for more than 150 years, polyaniline is the oldest and potentially one of the most useful conducting polymers because of its facile synthesis, environmental stability, and simple acid/base doping/dedoping chemistry. Because a nanoform of this polymer could offer new properties or enhanced performance, nanostructured polyaniline has attracted a great deal of interest during the past few years. This Account summarizes our recent research on the syntheses, processing, properties, and applications of polyaniline nanofibers. By monitoring the nucleation behavior of polyaniline, we demonstrate that high-quality nanofibers can be readily produced in bulk quantity using the conventional chemical oxidative polymerization of aniline. The polyaniline nanostructures formed using this simple method have led to a number of exciting discoveries. For example, we can readily prepare aqueous polyaniline colloids by purifying polyaniline nanofibers and controlling the pH. The colloids formed are self-stabilized via electrostatic repulsions without the need for any chemical modification or steric stabilizer, thus providing a simple and environmentally friendly way to process this polymer. An unusual nanoscale photothermal effect called "flash welding", which we discovered with polyaniline nanofibers, has led to the development of new techniques for making asymmetric polymer membranes and patterned nanofiber films and creating polymer-based nanocomposites. We also demonstrate the use of flash-welded polyaniline films for monolithic actuators. Taking advantage of the unique reduction/oxidation chemistry of polyaniline, we can decorate polyaniline nanofibers with metal nanoparticles through in situ reduction of selected metal salts. The resulting polyaniline/metal nanoparticle composites show promise for use in ultrafast nonvolatile memory devices and for chemical catalysis. In addition, the use of polyaniline nanofibers or their composites can significantly enhance the sensitivity

  12. Layer-by-layer nanostructured hybrid films of polyaniline and vanadium oxide.

    PubMed

    Ferreira, Marystela; Zucolotto, Valtencir; Huguenin, Fritz; Torresi, Roberto M; Oliveira, Osvaldo N

    2002-02-01

    Supramolecular structures of polyaniline (PANI) and vanadium oxide (V2O5) have been assembled via the electrostatic layer-by-layer (ELBL) technique. Strong ionic interactions and H-bonding impart unique features to the ELBL films, which are distinct from cast films obtained with the same materials. The interactions were manifested in UV-vis and Fourier transform infrared spectroscopy data. They are enhanced by the intimate contact between the components, as the films are molecularly thin, with 25 A per PANI/V2O5 bilayer.

  13. Gas sensors based on polyaniline/zinc oxide hybrid film for ammonia detection at room temperature

    NASA Astrophysics Data System (ADS)

    Zhu, Guotao; Zhang, Qiuping; Xie, Guangzhong; Su, Yuanjie; Zhao, Kang; Du, Hongfei; Jiang, Yadong

    2016-11-01

    Polyaniline/zinc oxide (PANI/ZnO) hybrid film based sensors have been developed for ammonia (NH3) detection at room temperature (RT). Results shows that hybrid film sensor exhibits a p-type semiconductor behavior and larger response than that of pure PANI film sensor. In the system, ZnO nanorod arrays can not only create nanoscale gap for gas diffusion but also provide abundant adsorption sites, thus leading to enhancement of response. Besides, hydrothermal time is proportional to the length of nanorods, Longer nanorods will provide efficient gap for gas diffusion, which leads to better sensitivity. This work offers a promising way to optimize sensor performance.

  14. Impact of low-pressure glow-discharge-pulsed plasma polymerization on properties of polyaniline thin films

    NASA Astrophysics Data System (ADS)

    Jatratkar, Aviraj A.; Yadav, Jyotiprakash B.; Deshmukh, R. R.; Barshilia, Harish C.; Puri, Vijaya; Puri, R. K.

    2016-12-01

    This study reports on polyaniline thin films deposited on a glass substrate using a low-pressure glow-discharge-pulsed plasma polymerization method. The polyaniline thin film obtained by pulsed plasma polymerization has been successfully demonstrated as an optical waveguide with a transmission loss of 3.93 dB cm-1, and has the potential to be employed in integrated optics. An attempt has been made to investigate the effect of plasma OFF-time on the structural, optical as well as surface properties of polyaniline thin film. The plasma ON-time has been kept constant and the plasma OFF-time has been varied throughout the work. The plasma OFF-time strongly influenced the properties of the polyaniline thin film, and a nanostructured and compact surface was revealed in the morphological studies. The plasma OFF-time was found to enhance film thickness, roughness, refractive index and optical transmission loss, whereas it reduced the optical band gap of the polyaniline thin films. Retention in the aromatic structure was confirmed by FTIR results. Optical studies revealed a π-π* electronic transition at about 317 nm as well as the formation of a branched structure. As compared with continuous wave plasma, pulsed plasma polymerization shows better properties. Pulsed plasma polymerization reduced the roughness of the film from 1.2 nm to 0.42 nm and the optical transmission loss from 6.56 dB cm-1 to 3.39 dB cm-1.

  15. Graphene/polyaniline woven fabric composite films as flexible supercapacitor electrodes.

    PubMed

    Zang, Xiaobei; Li, Xiao; Zhu, Miao; Li, Xinming; Zhen, Zhen; He, Yijia; Wang, Kunlin; Wei, Jinquan; Kang, Feiyu; Zhu, Hongwei

    2015-04-28

    We report the design and preparation of graphene and polyaniline (PANI) woven-fabric composite films by in situ electropolymerization. The introduction of PANI greatly improves the electrochemical properties of solid-state supercapacitors which possess capacitances as high as 23 mF cm(-2), and exhibit excellent cycling stability with ∼ 100% capacitance retention after 2000 cycles. The devices have displayed superior flexibility with improved areal specific capacitances to 118% during deformation.

  16. Realization of an ultra-sensitive hydrogen peroxide sensor with conductance change of horseradish peroxidase-immobilized polyaniline and investigation of the sensing mechanism.

    PubMed

    Fang, Kuan-Chung; Hsu, Chen-Pin; Kang, Yen-Wen; Fang, Jung-Ying; Huang, Chih-Cheng; Hsu, Chia-Hsien; Huang, Yu-Fen; Chen, Chih-Chen; Li, Sheng-Shian; Andrew Yeh, J; Yao, Da-Jeng; Wang, Yu-Lin

    2014-05-15

    In this study, we fabricate an ultra-sensitive hydrogen peroxide sensor by using horseradish peroxidase (HRP)-immobilized conducting polymer, polyaniline (PANI). With the proposed detection mechanism, hydrogen peroxide first oxidizes HRP, which then oxidizes polyaniline, thus resulting in decreased conductivity of the polyaniline thin film. The reduced HRP can be further oxidized by hydrogen peroxide and the cycle of the oxidation/reduction would continue until all hydrogen peroxide are reacted, leading to the high sensitivity of the sensor due to the signal contributed from all hydrogen peroxide molecule. The detection limit of this sensor is only 0.7 nM. The detectable concentration of H2O2 is from 0.7 nM to 1 μM. Beyond 1 μM, the sensor gradually saturates and some H2O2 remains, indicating the inhibition of HRP activity at high concentration of H2O2. There is no response to hydrogen peroxide once the PANI is standalone without HRP immobilized, showing the enzymatic reaction is required in the process of hydrogen peroxide detection. The simple process for the sensor fabrication allows the sensor to be cost-effective and disposable. This electronic hydrogen peroxide sensor is promising in applications for low concentration hydrogen peroxide detections, such as the reactive oxygen species (ROS) in oxidative stress studies.

  17. Ferromagnetic Conducting Lignosulfonic Acid-doped Polyaniline Nanocomposites

    NASA Technical Reports Server (NTRS)

    Viswansthan, Tito (Inventor); Berry, Brian (Inventor)

    2004-01-01

    A conductive ferromagnetic composition of matter comprising sulfonated lignin or a sulfonated polyflavonoid, or derivatives thereof, and ferromagnetic iron oxide particles is disclosed. Among the uses of the composition is to shield electromagnetic radiation. The ferromagnetic iron oxide particles of the composition are surprisingly stable to acid, and are easily and inexpensively formed from iron cations in solution.

  18. Conducting Properties of Polyaniline in the THz Region: Investigations of Various Processing Conditions

    NASA Astrophysics Data System (ADS)

    Tapia, Alvin Karlo G.; Tominaga, Keisuke

    2017-02-01

    The conduction properties of polyaniline (PAni) with various processing conditions were demonstrated using terahertz time-domain spectroscopy. The effects of protonation were observed by varying the doping time and annealing time. The measurements agreed with the Mott-Davis hopping model with the exponent varying inversely with the protonation conditions. Also, the density of the samples increased with compression pressure thereby increasing the inter-chain and inter-particle charge transport. Lastly, the THz response on PAni-polyethylene pellets showed dominant contribution of PAni network.

  19. Electrically Conductive Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, Anne K.; Ezzel, Stephen A.; Taylor, Larry T.; Boston, Harold G.

    1993-01-01

    Semiconducting surfaces of SnO2 formed by curing polyamic acids containing tin complexes. Polyimide films made semiconductive via incorporation of semiconductive surface layers of SnO2. If SnO2-surfaced polyimide film used as free-standing film, then semiconductive layer protected by top coat of polyimide, deposited as film from solution directly onto SnO2. Resultant films flexible and resistant to both weather and high temperature. Used on aircraft to provide resistance to lightning strikes, and in microelectronics and flexible circuitry.

  20. Electrodynamics of the conducting polymer polyaniline on the insulating side of the metal-insulator transition

    NASA Astrophysics Data System (ADS)

    Helgren, Erik; Penney, Keith; Diefenbach, Matt; Longnickel, Maryna; Wainwright, Mark; Walker, Eldridge; Al-Azzawi, Sarah; Erhahon, Hendrix; Singley, Jason

    2017-03-01

    Conducting polymer samples of polyaniline (PANI) exhibit a dramatic change in their conductivity as a function of protonation level, analogous with the changes in the transport properties of semiconductors upon doping. In this paper, PANI samples were prepared by protonating with varying concentrations of hydrochloric acid. The complex terahertz frequency-dependent conductivity and the dc conductivity of these samples were measured and analyzed in the framework of the disorder-driven, metal-insulator quantum phase transition. The samples were determined to all fall in the insulating phase of this phase transition. The frequency dependence of both the real and imaginary terahertz conductivity are found to be consistent with theories that include electronic correlation effects.

  1. Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering.

    PubMed

    Zhao, Xin; Li, Peng; Guo, Baolin; Ma, Peter X

    2015-10-01

    Biomaterials with injectability, conductivity and antibacterial effect simultaneously have been rarely reported. Herein, we developed a new series of in situ forming antibacterial conductive degradable hydrogels using quaternized chitosan (QCS) grafted polyaniline with oxidized dextran as crosslinker. The chemical structures, morphologies, electrochemical property, conductivity, swelling ratio, rheological property, in vitro biodegradation and gelation time of hydrogels were characterized. Injectability was verified by in vivo subcutaneous injection on a Sprague Dawley rat. The antibacterial activity of the hydrogels was firstly evaluated employing antibacterial assay using Escherichia coli and Staphylococcus aureus in vitro. The hydrogels containing polyaniline showed enhanced antibacterial activity compared to QCS hydrogel, especially for hydrogels with 3 wt% polyaniline showing 95 kill% and 90kill% for E. coli and S. aureus, respectively. Compared with QCS hydrogel, the hydrogels with 3 wt% polyaniline still showed enhanced antibacterial activity for E. coli in vivo. The adipose-derived mesenchymal stem cells (ADMSCs) were used to evaluate the cytotoxicity of the hydrogels and hydrogels with polyaniline showed better cytocompatibility than QCS hydrogel. The electroactive hydrogels could significantly enhance the proliferation of C2C12 myoblasts compared to QCS hydrogel. This work opens the way to fabricate in situ forming antibacterial and electroactive degradable hydrogels as a new class of bioactive scaffolds for tissue regeneration applications.

  2. Temperature characterization of dielectric permittivity and AC conductivity of nano copper oxide-doped polyaniline composite

    NASA Astrophysics Data System (ADS)

    Shubha, L. N.; Madhusudana Rao, P.

    2016-06-01

    The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UV-visible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 102-106Hz using LCR meter. Dielectric permittivity ɛ‧(w) and dielectric loss factor ɛ‧‧(w) were investigated. It was observed that ɛ‧(w) and ɛ‧‧(w) decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both ɛ‧(w) and ɛ‧‧(w) increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

  3. Styrene-Butadiene Co-Polymer Based Highly Conducting and Flexible Polymer Composite Film with Low Percolation Threshold

    NASA Astrophysics Data System (ADS)

    Mathew, Anisha Mary; Neena, P.

    2011-10-01

    Conducting polymer composites are finding novel applications in various fields especially in device technology. In this work an effort has been made to synthesize polyaniline-synthetic rubber (Styrene-butadiene rubber) composite via ex-situ technique and its electrochemical properties are investigated. Highly conducting emeraldine form of polyaniline (20 S/cm) is prepared by the oxidative polymerization of aniline in aqueous acidic (CSA) media using ammonium peroxydisulfate as oxidizing agent. These composite films are characterized by UV-Visible spectroscopy to investigate their optical properties. The dc conductivity studies indicate that these composite films show extremely low percolation threshold.

  4. Efficient photocatalytic decolorization of some textile dyes using Fe ions doped polyaniline film on ITO coated glass substrate.

    PubMed

    Haspulat, Bircan; Gülce, Ahmet; Gülce, Handan

    2013-09-15

    In this study, the photocatalytic decolorization of four commercial textile dyes with different structures has been investigated using electrochemically synthesized polyaniline and Fe ions doped polyaniline on ITO coated glass substrate as photocatalyst in aqueous solution under UV irradiation for the first time. Scanning electron microscopy, atomic force microscopy, FT-IR spectra, UV-vis spectroscopy measurements were used to characterize the electrochemically synthesized polymer film photocatalyst. Film hydrophilicity was assessed from contact angle measurements. The results show that both of the polymer films exhibit good photocatalytic performance. Surprisingly, it was determined that by using Fe(II) ions during polymerization, it is possible to modify the surface roughness and wettability of the produced polyaniline films which favors their photocatalytic activity in water-based solutions. All four of the used dyes (methylene blue, malachite green, methyl orange and methyl red) were completely decolorizated in 90 min of irradiation under UV light by using Fe ions doped polyaniline at the dye concentration of 1.5 × 10(-5)M, while the decolorization of those dyes were between 43% and 83% by using polyaniline as photocatalyst. Hence, it may be a viable technique for the safe disposal of textile wastewater into waste streams.

  5. Novel poly (vinyl butyral) (PVB)/polyaniline-cenosphere composite film for EMI shielding

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Shahidsha, N.; Madras, Giridhar; Kishore, Ramamurthy, Praveen C.

    2016-05-01

    in-situ synthesis of polyaniline (PANI)/fly ash cenosphere (hollow microspheres) composite was carried out under nitrogen atmosphere at -30±2 °C. Investigated electromagnetic shielding effectiveness (EMI SE) of free standing PVB/PANI-cenosphere (PVBPC) composite films prepared by solution casting indicates an ap preciable shielding. The most effective EMI SE of 30.3 dB was obtained for 197±3 µm thicker flexible film over the frequency range 8.2-12.4 GHz. Mechanistically, absorption was found to be dominant. The obtained shielding effectiveness due to absorbance (SEA) of PVBPC film is more than two times higher than PVB/PANI composite film. In the presence of hollow PANI-cenospheres in PVB matrix the time average power of incident electromagnetic wave decreases resulting in an increase of absorbance.

  6. Electrical conductivity and spectroscopic characterization of Blends of poly(2-chloroaniline)/polyaniline P(2ClANI)/PANI copolymer with PVC exposed to gamma-rays

    NASA Astrophysics Data System (ADS)

    Sevil, Uğur Adnan; Coşkun, Emel; Güven, Olgun

    2014-01-01

    Poly(2-chloroaniline)/polyaniline P(2ClANI)/PANI) random copolymer was synthesized in the form of nanoparticles by chemical routes. Incorporation of P(2ClANI) into PANI backbone significantly increased the solubility of copolymer in THF. Thin PVC/P(2ClANI)/PANI blend films were prepared by solvent casting and subsequently exposed to gamma-rays. Conductivity measurements on the irradiated blend films of PVC/P(2ClANI)/PANI showed that conductivity was increased from 10-8 S/cm to 10-5 S/cm when irradiated to radiation dose of up to 200 kGy. The increase in conductivity was also revealed by FTIR and UV-vis spectra.

  7. Electrical conductivity of hollow polyaniline microspheres synthesized by a self-assembly method

    NASA Astrophysics Data System (ADS)

    Long, Yunze; Chen, Zhaojia; Ma, Yongjun; Zhang, Ze; Jin, Aizi; Gu, Changzhi; Zhang, Lijuan; Wei, Zhixiang; Wan, Meixiang

    2004-03-01

    In this letter, we report the electrical properties of hollow polyaniline (PANI) microspheres. β-naphthalene sulfonic acid (NSA) and salicylic acid (SA) doped PANI microspheres were synthesized by a self-assembly method. The room-temperature conductivity is 8.6×10-2 S/cm for PANI-NSA microspheres (0.8-2 μm in outer diameter) and 5.6×10-4 S/cm for PANI-SA microspheres (3-7 μm in outer diameter). The conductivity of an individual PANI-SA microsphere is measured directly by a two-probe technique, about 8×10-2 S/cm (which is two orders of magnitude higher than that of a PANI-SA microsphere's pellet). The measurements of conductivity, I-V curve, and magnetoresistance demonstrate that the electrical properties of PANI microspheres are dominated by the intersphere contacts due to the sample's microscopic inhomogeneity.

  8. Electrically conductive polyaniline-coated electrospun poly(vinylidene fluoride) mats

    NASA Astrophysics Data System (ADS)

    Merlini, Claudia; Barra, Guilherme; Ramoa, Sílvia; Contri, Giseli; Almeida, Rosemeire; D´Ávila, Marcos; Soares, Bluma

    2015-02-01

    Electrically conductive polyaniline (PANI)-coated electrospun poly(vinylidene fluoride) (PVDF) mats were fabricated through aniline (ANI) oxidative polymerization on electrospun PVDF mats. The effect of polymerization condition on structure and property of PVDF/PANI mats was investigated. The electrical conductivity and PANI content enhanced significantly with increasing ANI concentration due to the formation of a conducting polymer layer that completely coated the PVDF fibers surface. The PANI deposition on the PVDF fibers surface increased the Young Modulus and the elongation at break reduced significantly. Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) revealed that the electrospun PVDF and PVDF/PANI mats display a polymorph crystalline structure, with absorption bands associated to the β, α and γ phases.

  9. Conducting polyaniline nanoparticles and their dispersion for waterborne corrosion protection coatings.

    PubMed

    Chen, Fei; Liu, Peng

    2011-07-01

    A novel approach for preparing waterborne corrosion protection polyaniline (PANI)-containing coatings was developed. First, conducting polyaniline/partially phosphorylated poly(vinyl alcohol) (PANI/P-PVA) spherical nanoparticles with significant dispersibility in aqueous media were prepared by the chemical oxidative dispersion polymerization in presence of partially phosphorylated poly(vinyl alcohol) (P-PVA). The PANI/P-PVA-containing coatings with different PANI/P-PVA contents were then prepared, employing waterborne epoxy resin as the matrix. The corrosion protection property of PANI/P-PVA-containing coatings on mild steel was investigated by salt spray test and electrochemical impedance spectroscopy (EIS) technique in 3.0 wt % NaCl aqueous solution. The results indicated that the waterborne PANI/P-PVA-containing coatings (PANI/P-PVA content, 2.5 wt %) could offer high protection because the impedance values remained at higher than 1 × 10(7) Ω cm(2) after 30 days of salt spray tests. All the results were compared with these of the waterborne coatings containing PANI nanoparticles in the emeraldine salt form (PANI ES), and the protection mechanism was also proposed with the evidence of scanning electron microscope (SEM) and X-ray photoelectron spectrometry (XPS).

  10. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  11. Fabrication of polyaniline/polyimide composite fibers with electrically conductive properties

    NASA Astrophysics Data System (ADS)

    Lv, Pengxia; Zhao, Yong; Liu, Fangfang; Li, Guomin; Dai, Xuemin; Ji, Xiangling; Dong, Zhixin; Qiu, Xuepeng

    2016-03-01

    A series of polyaniline/polyimide (PANi/PI) composite fibers was prepared via dry-jet wet spinning followed by in situ polymerization growth. The resultant composite fibers showed good mechanical properties with a tensile strength of 0.90 GPa, a tensile modulus of 6.79 GPa, and an elongation at break of 14.63%. Thermogravimetric and thermal mechanical analyses revealed that the composite fibers had considerably good thermal stabilities in air and nitrogen atmospheres, as well as good size stabilities at 50-150 °C. Current-voltage curves indicated the transformation from electric insulation to electrical conductivity along the fiber axial direction. The composite fibers exhibited a sensitive response to immersion in solutions with different pH values. This work provides a simple approach to fabricate PANi/PI composite fibers that could be applied in the antistatic textile and military industries.

  12. Electrical conductivity, optical property and ammonia sensing studies on HCl Doped Au@polyaniline nanocomposites

    NASA Astrophysics Data System (ADS)

    Hasan, Mudassir; Ansari, Mohd Omaish; Cho, Moo Hwan; Lee, Moonyong

    2015-01-01

    This paper reports the synthesis of HCl-doped Au@polyaniline (Pani) nanocomposite fibers by the in situ oxidative polymerization of aniline in the presence of gold nanoparticles. Thus prepared nanocomposite fibers were characterized by SEM, TEM, XRD, Raman spectroscopy, XPS, UV-visible diffused reflectance spectroscopy, TGA, and DSC. The Au@Pani nanocomposite fibers showed superior DC electrical conductivity to HCl-doped Pani, which might be due to the increased mobility of the charge carriers after the incorporation of gold nanoparticle in Pani. Au@Pani also exhibited a better ammonia sensing and recovery response than Pani, which might be due to the increase in the surface area of Pani after the incorporation of gold nanoparticles.

  13. Mercaptoethane sulfonate protected, water-soluble gold and silver nanoparticles: Syntheses, characterization and their building multilayer films with polyaniline via ion-dipole interactions.

    PubMed

    Zou, Xiangqin; Bao, Haifeng; Guo, Hongwei; Zhang, Lei; Qi, Li; Jiang, Junguang; Niu, Li; Dong, Shaojun

    2006-03-15

    Mercaptoethane sulfonate protected, water-soluble gold and silver nanoparticles (Au-MES and Ag-MES) are synthesized by one-phase method and characterized by TEM, TGA and XPS techniques, UV-vis and FTIR spectra. Both Au-MES and Ag-MES nanoparticles are soluble in the water up to 2.0 mg/ml and the stability of Au-MES is much better than that of Ag-MES. When dissolved in the water, they behave like a polyanion and can be used to build multilayer films with polyaniline (PANI) by way of layer-by-layer. A new approach is presented to fabricate the multilayer films of Au-MES/PANI and Ag-MES/PANI. The assembly mechanism of these multilayer films is also discussed. We anticipate highly conducting PANI films can be obtained by doping with these nanoparticles.

  14. Electric properties of carbon nano-onion/polyaniline composites: a combined electric modulus and ac conductivity study

    NASA Astrophysics Data System (ADS)

    Papathanassiou, Anthony N.; Mykhailiv, Olena; Echegoyen, Luis; Sakellis, Ilias; Plonska-Brzezinska, Marta E.

    2016-07-01

    The complex electric modulus and the ac conductivity of carbon nano-onion/polyaniline composites were studied from 1 mHz to 1 MHz at isothermal conditions ranging from 15 K to room temperature. The temperature dependence of the electric modulus and the dc conductivity analyses indicate a couple of hopping mechanisms. The distinction between thermally activated processes and the determination of cross-over temperature were achieved by exploring the temperature dependence of the fractional exponent of the dispersive ac conductivity and the bifurcation of the scaled ac conductivity isotherms. The results are analyzed by combining the granular metal model (inter-grain charge tunneling of extended electron states located within mesoscopic highly conducting polyaniline grains) and a 3D Mott variable range hopping model (phonon assisted tunneling within the carbon nano-onions and clusters).

  15. Preparation, characterization and electrochromic properties of composite thin films incorporation of polyaniline

    NASA Astrophysics Data System (ADS)

    Farasat, Mahshid; Golzan, M. Maqsood; Farhadi, Khalil; Shojaei, S. H. Reza; Gheisvandi, Sorayya

    2016-05-01

    Two different electrochromic composite films consisting of aniline/sodium molybdate (S1) and aniline/ferric nitrate (S2) were obtained by electrochemical polymerization method on indium tin oxide (ITO) coated glass substrates in oxalic acid (H2C2O4ṡ2H2O) aqueous solution. The electrochromic properties of the resulting thin films were investigated by spectroelectrochemical measurement and cyclic voltammetry (CV). Under a square electrical potential, they show capacitive current characteristic and represent electrochromic performance, with maximum optical attenuations (ΔT%) of 30.8% at 355nm and 28.3% at 400nm for aniline/ferric nitrate and aniline/sodium molybdate thin films, respectively. Optical behavior of thin films was examined by UV-Vis spectrophotometry technique. The doped films indicated multiple color changes (yellow; green; and bluish green). The spectra also showed that produced layers have high absorption of UV radiation with respect to pure polyaniline (PANI) films. The optical band gap energy of PANI film decreased by dopant injection. Due to their decent transparency and electrochromic behavior, they are promising materials for electrochromic devices.

  16. Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzhi; Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin; Hu, Chenglong

    2016-03-01

    Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV-vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C4H9)4N+ under the positive and negative potentials as comparison with the small Li+ ion.

  17. Development of Conducting Polyaniline/ Poly(Lactic Acid) Nanofibers by Electrospinning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultrafine fibers consisting of blends of polyaniline doped with p-toluene sulfonic acid and poly(L-lactic acid) were prepared by electrospinning. The presence of polyaniline resulted in fibers with diameters as thin as 100– 200 nm and a significant reduction of bead formation. These fibers were visu...

  18. Small Angle Neutron Scattering (SANS) Characterization of Electrically Conducting Polyaniline Nanofiber/Polyimide Nanocomposites

    DTIC Science & Technology

    2011-10-25

    range, neither the D-B nor the IPL model could be used to characterize the size and shape of all PANI-0.5-CSA (polyaniline camphor sulfonic acid doped...be used to characterize the size and shape of all PANI-0.5-CSA (polyaniline camphor sulfonic acid doped polymer)/polyimide blend systems. At 1 and 2

  19. Cost-effective and highly sensitive cholesterol microsensors with fast response based on the enzyme-induced conductivity change of polyaniline

    SciTech Connect

    Fang, Kuan-Chung; Chu, Chia-Ho; Hsu, Chen-Pin; Kang, Yen-Wen; Fang, Jung-Ying; Chen, Chih-Chen; Li, Sheng-Shian; Andrew Yeh, J.; Yao, Da-Jeng; Wang, Yu-Lin; Hsu, Chia-Hsien; Huang, Yu-Fen

    2014-09-15

    In this study, a cost-effective and highly sensitive cholesterol microsensor, which is consisted of cholesterol oxidase (ChOx), horseradish peroxidase (HRP), and polyaniline (PANI), was developed based on the enzyme-induced conductivity change of PANI with fast response. Hydrogen peroxide is produced via the reaction between cholesterol and ChOx, which was immobilized in a dialysis membrane. The produced hydrogen peroxide can oxidize HRP, which can be reduced by oxidizing PANI, thus resulting in decreased conductivity of the polyaniline thin film. The reduced HRP can be oxidized again by hydrogen peroxide and the cycle of the oxidation/reduction continues until all hydrogen peroxide are reacted, leading to the high sensitivity of the sensor due to the signal contributed from all hydrogen peroxide molecules. Cholesterol was detected near the physiological concentrations ranging from 100 mg/dl to 400 mg/dl with the cholesterol microsensors. The results show linear relation between cholesterol concentration and the conductivity change of the PANI. The microsensor showed no response to cholesterol when the PANI was standalone without cholesterol oxidase immobilized, indicating that the enzymatic reaction is required for cholesterol detection. The simple process of the sensor fabrication allows the sensor to be cost-effective and disposable usage. This electronic cholesterol microsensor is promising for point-of-care health monitoring in cholesterol level with low cost and fast response.

  20. Cost-effective and highly sensitive cholesterol microsensors with fast response based on the enzyme-induced conductivity change of polyaniline

    NASA Astrophysics Data System (ADS)

    Fang, Kuan-Chung; Chu, Chia-Ho; Hsu, Chen-Pin; Kang, Yen-Wen; Fang, Jung-Ying; Hsu, Chia-Hsien; Huang, Yu-Fen; Chen, Chih-Chen; Li, Sheng-Shian; Andrew Yeh, J.; Yao, Da-Jeng; Wang, Yu-Lin

    2014-09-01

    In this study, a cost-effective and highly sensitive cholesterol microsensor, which is consisted of cholesterol oxidase (ChOx), horseradish peroxidase (HRP), and polyaniline (PANI), was developed based on the enzyme-induced conductivity change of PANI with fast response. Hydrogen peroxide is produced via the reaction between cholesterol and ChOx, which was immobilized in a dialysis membrane. The produced hydrogen peroxide can oxidize HRP, which can be reduced by oxidizing PANI, thus resulting in decreased conductivity of the polyaniline thin film. The reduced HRP can be oxidized again by hydrogen peroxide and the cycle of the oxidation/reduction continues until all hydrogen peroxide are reacted, leading to the high sensitivity of the sensor due to the signal contributed from all hydrogen peroxide molecules. Cholesterol was detected near the physiological concentrations ranging from 100 mg/dl to 400 mg/dl with the cholesterol microsensors. The results show linear relation between cholesterol concentration and the conductivity change of the PANI. The microsensor showed no response to cholesterol when the PANI was standalone without cholesterol oxidase immobilized, indicating that the enzymatic reaction is required for cholesterol detection. The simple process of the sensor fabrication allows the sensor to be cost-effective and disposable usage. This electronic cholesterol microsensor is promising for point-of-care health monitoring in cholesterol level with low cost and fast response.

  1. Thin nanocomposite films of polyaniline/Au nanoparticles by the Langmuir-Blodgett technique.

    PubMed

    Tanami, Golan; Gutkin, Vitaly; Mandler, Daniel

    2010-03-16

    The Langmuir-Blodgett (LB) method was used to deposit multilayers of polyaniline (PANI)- and mercaptoethanesulfonate (MES)-stabilized Au nanoparticles. The electrostatic interaction between the negatively charged nanoparticles in the subphase and the positively charged PANI at the air-water interface assisted the deposition of the nanocomposite film onto a solid support. These PANI/Au-NPs films were characterized using cyclic voltammetry, copper under potential deposition, scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. We found that the nanocomposite layers were uniform and reproducible. The density of Au-NPs in the monolayer depended on the acidity of the subphase as well as on the nanoparticles concentration. Moreover, the Au-NPs extrude above the PANI and therefore could be used as nanoelectrodes for the underpotential deposition (UPD) of copper.

  2. Alcohol vapours sensor based on thin polyaniline salt film and quartz crystal microbalance.

    PubMed

    Ayad, Mohamad M; Torad, Nagy L

    2009-06-15

    A sensor based on the quartz crystal microbalance (QCM) technique was developed for detection of a number of primary aliphatic alcohols such as ethanol, methanol, 1-propanol, and 2-propanol vapours. Detection was based on a sensitive and a thin film of polyaniline, emeraldine salt (ES), coated the QCM electrode. The frequency shifts (Delta f) of the QCM were increased due to the vapour absorption into the ES film. The values of Delta f were found to be linearly correlated with the concentrations of alcohols vapour in mg L(-1). The changes in frequency are due to the hydrophilic character of the ES and the electrostatic interaction as well as the type of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusion and diffusion coefficient (D) of different alcohols vapour were determined. It was found that the sensor follows Fickian kinetics.

  3. Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High-Performance Gas Sensing.

    PubMed

    Wan, Pengbo; Wen, Xuemei; Sun, Chaozheng; Chandran, Bevita K; Zhang, Han; Sun, Xiaoming; Chen, Xiaodong

    2015-10-28

    A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices.

  4. Immobilization of biomolecules on cysteamine-modified polyaniline film for highly sensitive biosensing.

    PubMed

    Cai, Qi; Xu, Baojian; Ye, Lin; Di, Zengfeng; Zhang, Jishen; Jin, Qinghui; Zhao, Jianlong; Xue, Jian; Chen, Xianfeng

    2014-03-01

    We present a new cysteamine (CS)-modified polyaniline (PANI) film for highly efficient immobilization of biomolecules in biosensing technology. This electrochemical deposited PANI film treated with CS and glutaraldehyde could be employed as an excellent substrate for biomolecules immobilization. The parameters of PANI growth were optimized to obtain suitable surface morphology of films for biomolecules combination with the help of electron and atomic force microscopy. Cyclic voltammetry (CV) was utilized to illustrate the different electrochemical activities of each modified electrode. Due to the existence of sulfydryl group and amino group in CS, surface modification with CS was proven to reduce oxidized units on PANI film remarkably, as evidenced by both ATR-FTIR and Raman spectroscopy characterizations. Furthermore, bovine serum albumin (BSA) was used as the model protein to investigate the immobilization efficiency of biomolecules on the PANI film, comparative study using quartz crystal microbalance (QCM) showed that BSA immobilized on CS-modified PANI could be increased by at least 20% than that without CS-modified PANI in BSA solution with the concentration of 0.1-1mg/mL. The CS-modified PANI film would be significant for the immobilization and detection of biomolecules and especially promising in the application of immunosensor for ultrasensitive detection.

  5. Conducting Electronic Polymers by Non-Redox Processes

    DTIC Science & Technology

    1987-12-31

    polyacrylic acid , polyvinylsulfonic acid , polystyrene sulfonic acid . Our electron microscopy study indicated that polyaniline morphology is strongly... Polyaniline derivatized with very stable and nonvolatile acids still seems to yield the most thermally stable conductive polyaniline . A paper concerning...be the optimum acid precursor, the use of a photosynthesized acid to derivatize polyaniline emeraldine free-base films may prove to be an easy method

  6. Conducting Electronic Polymers by Non-Redox Processes

    DTIC Science & Technology

    1988-12-31

    systematic detailed observation of competing crystalline phases in a doped polymer. The multiple structures of the erneraldine form of polyaniline , together...states and other properties has been determined. Class I of the emeraldine form of polyaniline consists of materials prepared in the conducting, doped ...tosylic acid doped polyaniline ad polyethyleneoxide. We found that a 50:50 blend of tosylic acid doped polyaniline:PEO could form a homogeneous film

  7. Thermally conductive of nanofluid from surfactant doped polyaniline nanoparticle and deep eutectic ionic liquid

    NASA Astrophysics Data System (ADS)

    Siong, Chew Tze; Daik, Rusli; Hamid, Muhammad Azmi Abdul

    2014-09-01

    Nanofluid is a colloidal suspension of nano-size particles in a fluid. Spherical shape dodecylbenzenesulfonic acid doped polyaniline (DBSA-PANI) nanoparticles were synthesized via reverse micellar polymerization in isooctane with average size of 50 nm- 60 nm. The aim of study is to explore the possibility of using deep eutectic ionic liquid (DES) as a new base fluid in heat transfer application. DES was prepared by heating up choline chloride and urea with stirring. DES based nanofluids containing DBSA-PANI nanoparticles were prepared using two-step method. Thermal conductivity of nanofluids was measured using KD2 Pro Thermal Properties Analyzer. When incorporated with DBSA-PANI nanoparticles, DES with water was found to exhibit a bigger increase in thermal conductivity compared to that of the pure DES. The thermal conductivity of DES with water was increased by 4.67% when incorporated with 0.2 wt% of DBSA-PANI nanoparticles at 50°C. The enhancement in thermal conductivity of DES based nanofluids is possibly related to Brownian motion of nanoparticles as well as micro-convection of base fluids and also interaction between dopants and DES ions.

  8. Electrical conducting behavior of hybrid nanocomposites containing polyaniline, carbon nanotube, and carbon black

    NASA Astrophysics Data System (ADS)

    Veena, M. G.; Renukappa, N. M.; Siddaramaiah, M.; Sudhakersamuel, R. D.

    2008-12-01

    Nanocomposites of high density polyethylene (HDPE) reinforced with hybrid fillers of polyaniline coated multiwalled carbon nanotube (MWNT), and carbon black (CB) were developed aiming at enhancing the electrical conductivity of the composites. The electrical properties such as volume resistivity, impedance, and conductance have been measured as a function of filler volume concentration (%), frequency and voltage. The electrical property such as volume resistivity depends on the concentration of fillers. This is due to the formation of a continuous conducting network throughout the polymer matrix with increase in the conducting filler. This kind of variation is referred as Maxwell-Wagner effect. The resistance of the prepared PANI/c-MWNT/CB/HDPE nanocomposites is found to be ohmic. It was shown that adding CB in PANI/c-MWCNTs composites can enhance the electrical properties of the nanocomposites: a low percolation threshold was achieved with 0.25 wt% CNTs and 20 wt% of CB/HDPE. CB enhanced the ductility of the nanocomposites, confirming the synergic effect of CB as effective multi-functional filler.

  9. Novel ammonia sensor based on polyaniline/polylactic acid composite films

    NASA Astrophysics Data System (ADS)

    Sotirov, S.; Bodurov, I.; Marudova, M.

    2017-01-01

    We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al2O3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected.

  10. Enhancement of photoelectric catalytic activity of TiO 2 film via Polyaniline hybridization

    NASA Astrophysics Data System (ADS)

    Wang, Yajun; Xu, Jing; Zong, Weizheng; Zhu, Yongfa

    2011-06-01

    A Polyaniline (PANI)/TiO 2 film coated on titanium foil was successfully prepared using the sol-gel method followed by a facile chemisorption. Compared with pristine TiO 2, the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation rates of 2,4-dichlorophenol (2,4-DCP) with the PANI/TiO 2 film were enhanced by 22.2% and 57.5%, respectively. 2,4-DCP can be mineralized more effectively in the presence of PANI/TiO 2 film. The best PEC degradation efficiency of 2,4-DCP with the PANI/TiO 2 film was acquired at an external potential of 1.5 V with a layer of 1 nm thick PANI. The PANI/TiO 2 film was characterized by Raman spectra, Fourier transform infrared spectra (FT-IR), Auger electron spectroscopy (AES), and electrochemical analysis. These results indicated that there was a chemical interaction on the interface of PANI and TiO 2. This interaction may be of significance to promote the migration efficiency of carriers and induce a synergetic effect to enhance the PC and PEC activities.

  11. Hierarchical graphene-polyaniline nanocomposite films for high-performance flexible electronic gas sensors.

    PubMed

    Guo, Yunlong; Wang, Ting; Chen, Fanhong; Sun, Xiaoming; Li, Xiaofeng; Yu, Zhongzhen; Wan, Pengbo; Chen, Xiaodong

    2016-06-09

    A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully interconnected and deposited onto flexible PET substrates to form hierarchical nanocomposite (PPANI/rGO-FPANI) network films. The assembled flexible, transparent electronic gas sensor exhibits high sensing performance towards NH3 gas concentrations ranging from 100 ppb to 100 ppm, reliable transparency (90.3% at 550 nm) for the PPANI/rGO-FPANI film (6 h sample), fast response/recovery time (36 s/18 s), and robust flexibility without an obvious performance decrease after 1000 bending/extending cycles. The excellent sensing performance could probably be ascribed to the synergetic effects and the relatively high surface area (47.896 m(2) g(-1)) of the PPANI/rGO-FPANI network films, the efficient artificial neural network sensing channels, and the effectively exposed active surfaces. It is expected to hold great promise for developing flexible, cost-effective, and highly sensitive electronic sensors with real-time analysis to be potentially integrated into wearable flexible electronics.

  12. Fabrication and characterization of polyaniline-znO hybrid nanocomposite thin films.

    PubMed

    Kaushik, Ajeet; Kumar, Jitendra; Tiwari, M K; Khan, R; Malhotra, B D; Gupta, Vinay; Singh, S P

    2008-04-01

    Polyaniline (PANI)-ZnO nanocomposite thin film has been successfully fabricated on glass substrates by using vacuum deposition technique. The as-grown PANI-ZnO nanocomposite thin films have been characterized using X-ray diffraction, Scanning Electron Microscopy, Atomic Force Microscopy, UV-visible spectrophotometer and Fourier Transform Infrared (FTIR) spectroscopy, respectively. X-ray diffraction of as-grown film shows the reflection of ZnO nanoparticles along with a broad peak of PANI. The surface morphology of nanocomposite films has been investigated using scanning electron microscopy and atomic force microscopy. The hypsochromic shift of the UV absorption band corresponding to pi-pi* transition in polymeric chain of PANI and a band at 504 cm(-1) due to ZnO nanoparticles has been observed in the FTIR spectra. The hydrogen bonding between the imine group of PANI and ZnO nanoparticle has been confirmed from the presence of the absorbance band at 1151 cm(-1) in the FTIR spectra of the nanocomposite thin films.

  13. A polyaniline based intrinsically conducting coating for corrosion protection of structural steels.

    PubMed

    Pan, Tongyan; Wang, Zhaoyang

    2013-11-01

    Among the various corrosion protection strategies for structural steels, coating techniques provide the most cost-effective protection and have been used as the primary mode of corrosion protection. Existing coating techniques however have been used mainly for their barrier capability and therefore all have a limited service life due to oxidation aging, electrolytic degradation, or various inadvertent defects and flaws occurred in and after coating applications. This work investigated the anti-corrosion potential of a π-conjugated polymer-polyaniline (PANi), which was doped into an intrinsically conducting polymer and then included in a two-layer coating system as a primer layer. To achieve a long service life, the primer layer was made by mixing the conductive PANi in a waterborne poly-vinyl butyral solution to provide strong adhesion to steel surface, and then topcoated with a layer of elastomer-modified polyethylene to obtain extra mechanical and barrier protections. Two ASTM standard tests were conducted to evaluate the corrosion durability and tensile adhesion of the two-layer system, in which the system demonstrated superior performance. The Scanning Kelvin Probe Force Microscopy (SKPFM) was used to provide the microscopic evidences for the outstanding performance.

  14. Oxidation and sensing of ascorbic acid and dopamine on self-assembled gold nanoparticles incorporated within polyaniline film

    NASA Astrophysics Data System (ADS)

    Chu, Wenya; Zhou, Qun; Li, Shuangshuang; Zhao, Wei; Li, Na; Zheng, Junwei

    2015-10-01

    Electrochemical biosensors based on conducting polymers incorporated with metallic nanoparticles can greatly enhance sensitivity and selectivity. Herein, we report a facile fabrication approach for polyaniline (PAN) incorporated with a gold nanoparticle (AuNP) composite electrode by electrodeposition of PAN on a self-assembled AuNP layer on the surface of an indium tin oxide electrode. The resulting AuNP/PAN composite electrode exhibits a remarkable synergistic effect on the electrocatalytic oxidation of ascorbic acid (AA) and dopamine (DA). It is demonstrated that the oxidation reaction of AA mainly occurs at AuNPs inside the PAN film as the ascorbate anions are doped into the polymer during the oxidation of the PAN film. Conversely, the oxidation of positively charged DA may only take place at the PAN/solution interface. The different mechanisms of the electrode reactions result in the oxidation of AA and DA occurring at different potentials. As a result, the AuNP/PAN composite electrode can be employed to simultaneously detect AA and DA with a good linear range, high sensitivity, and low detection limit.

  15. Enzyme entrapment in polyaniline films observed via fluorescence anisotropy and antiquenching

    NASA Astrophysics Data System (ADS)

    Nemzer, Louis R.; McCaffrey, Marisa; Epstein, Arthur J.

    2014-05-01

    The facile entrapment of oxidoreductase enzymes within polyaniline polymer films by inducing hydrophobic collapse using phosphate buffered saline (PBS) has been shown to be a cost-effective method for fabricating organic biosensors. Here, we use fluorescence anisotropy measurements to verify enzyme immobilization and subsequent electron donation to the polymer matrix, both prerequisites for an effective biosensor. Specifically, we measure a three order of magnitude decrease in the ratio of the fluorescence to rotational lifetimes. In addition, the observed fluorescence antiquenching supports the previously proposed model that the polymer chain assumes a severely coiled conformation when exposed to PBS. These results help to empirically reinforce the theoretical basis previously laid out for this biosensing platform.

  16. Application of polyaniline/sol-gel derived tetraethylorthosilicate films to an amperometric lactate biosensor.

    PubMed

    Chaubey, Asha; Pande, K K; Malhotra, B D

    2003-11-01

    The electrochemical entrapment of polyaniline (PANI) onto sol-gel derived tetraethylorthosilicate (TEOS) films deposited onto indium-tin-oxide (ITO) coated glass has been utilized for immobilization of lactate dehydrogenase (LDH). The performance of these sol-gel/PANI/LDH electrodes has been investigated as a function of the lactate concentration, applied potential, pH of the medium and interferents. The amperometric response of the electrodes under optimum conditions exhibited a linear relationship from 1 mM to 4 mM. An attempt has been made to extend the linearity up to 10 mM for lactate by coating an external layer of polyvinyl chloride (PVC) over the sol-gel/PANI/LDH electrodes with a correlation coefficient of 0.89. These sol-gel/PANI/LDH electrodes have a response time of about 60 s, a shelf life of about 8 weeks at 0-4 degrees C and have implications in a lactate biosensor.

  17. A facile method for synthesis of polyaniline nanospheres and effect of doping on their electrical conductivity

    PubMed Central

    Neelgund, Gururaj M.; Oki, Aderemi

    2011-01-01

    The synthesis of polyaniline (PANI) nanospheres by a simple template-free method has been described. The polymerization of aniline in aqueous medium was accomplished using ammonium persulfate without any protonic acid. The UV-vis spectrum of PANI nanospheres displayed the characteristic absorption peak of π-π* transition of the benzenoid ring at 355 nm. The oxidation state of PANI nanospheres was identified with FT-IR spectroscopy by comparing the two bands at 1582 (ring stretching in quinoid unit) and 1498 cm−1 (ring stretching in bezenoid unit). The X-ray diffraction patterns demonstrated the low crystalline nature of PANI nanospheres. The morphology of PANI nanospheres was spherical and the mean diameter of nanospheres was found in the range of 3-12 nm. The thermal behavior of PANI nanospheres was studied by thermogravimetric analysis. The effect of doping of HCl and H2SO4 on PANI nanospheres was studied by measuring the current as a function of time of exposure. The high electrical conductivity of 6×10−2 S cm−1 was obtained for PANI nanospheres at their optimum doping state by 100 ppm HCl. PMID:21966097

  18. Synthesis of highly conductive cotton fiber/nanostructured silver/polyaniline composite membranes for water sterilization application

    NASA Astrophysics Data System (ADS)

    Abu-Thabit, Nedal Y.; Basheer, Rafil A.

    2014-09-01

    Electrically conductive composite membranes (ECCMs) composed of cotton fibers, conductive polyaniline and silver nanostructures were prepared and utilized as electrifying filter membranes for water sterilization. Silver metal and polyaniline were formed in situ during the oxidative polymerization of aniline monomers in the presence of silver nitrate as weak oxidizing agent. The reaction was characterized by long induction period and the morphology of the obtained ECCMs contained silver nanoparticles and silver flakes of 500-1000 nm size giving a membrane electrical resistance in the range of 10-30 Ohm sq-1. However, when dimethylformamide (DMF) was employed as an auxiliary reducing agent to trigger and speed up the polymerization reaction, silver nanostructures such as wires, ribbons, plates were formed and were found to be embedded between polyaniline coating and cotton fibers. These ECCMs exhibited a slightly lower resistance in the range of 2-10 Ohm sq.-1 and, therefore, were utilized for the fabrication of a bacteria inactivation device. When water samples containing 107-108 CFU mL-1 E. coli bacteria were passed through the prepared ECCMs by gravity force, with a filtration rate of 0.8 L h-1 and at an electric potential of 20 V, the fabricated device showed 92% bacterial inactivation efficiency. When the treated solution was passed through the membrane for a second time under the same conditions, no E. coli bacteria was detected.

  19. Hierarchical graphene-polyaniline nanocomposite films for high-performance flexible electronic gas sensors

    NASA Astrophysics Data System (ADS)

    Guo, Yunlong; Wang, Ting; Chen, Fanhong; Sun, Xiaoming; Li, Xiaofeng; Yu, Zhongzhen; Wan, Pengbo; Chen, Xiaodong

    2016-06-01

    A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully interconnected and deposited onto flexible PET substrates to form hierarchical nanocomposite (PPANI/rGO-FPANI) network films. The assembled flexible, transparent electronic gas sensor exhibits high sensing performance towards NH3 gas concentrations ranging from 100 ppb to 100 ppm, reliable transparency (90.3% at 550 nm) for the PPANI/rGO-FPANI film (6 h sample), fast response/recovery time (36 s/18 s), and robust flexibility without an obvious performance decrease after 1000 bending/extending cycles. The excellent sensing performance could probably be ascribed to the synergetic effects and the relatively high surface area (47.896 m2 g-1) of the PPANI/rGO-FPANI network films, the efficient artificial neural network sensing channels, and the effectively exposed active surfaces. It is expected to hold great promise for developing flexible, cost-effective, and highly sensitive electronic sensors with real-time analysis to be potentially integrated into wearable flexible electronics.A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully

  20. Electrical and structural characterization of plasma polymerized polyaniline/TiO2 heterostructure diode: a comparative study of single and bilayer TiO2 thin film electrode.

    PubMed

    Ameen, Sadia; Akhtar, M Shaheer; Kimi, Young Soon; Yang, O-Bong; Shin, Hyung-Shik

    2011-04-01

    A heterostructure was fabricated using p-type plasma polymerized polyaniline (PANI) and n-type (single and bilayer) titanium dioxide (TiO2) thin film on FTO glass. The deposition of single and bilayer TiO2 thin film on FTO substrate was achieved through doctor blade followed by dip coating technique before subjected to plasma enhanced polymerization. To fabricate p-n heterostructure, a plasma polymerization of aniline was conducted using RF plasma at 13.5 MHz and at the power of 120 W on the single and bilayer TiO2 thin film electrodes. The morphological, optical and the structural characterizations revealed the formation of p-n heterostructures between PANI and TiO2 thin film. The PANI/bilayer TiO2 heterostructure showed the improved current-voltage (I-V) characteristics due to the substantial deposition of PANI molecules into the bilayer TiO2 thin film which provided good conducting pathway and reduced the degree of excitons recombination. The change of linear I-V behavior of PANI/TiO2 heterostructure to non linear behavior with top Pt contact layer confirmed the formation of Schottky contact at the interfaces of Pt layer and PANI/TiO2 thin film layers.

  1. Correlation between Raman spectroscopy and electrical conductivity of graphite/polyaniline composites reacted with hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Aymen, Mannai; Sami, Saidi; Ahmed, Souissi; Fethi, Gmati; Abdellatif, Belhadj Mohamed

    2013-08-01

    The aim of this work is to correlate the Raman spectroscopic studies to the electrical properties of graphite/polyaniline composites (G/PANI) reacted with hydrogen peroxide. Raman spectroscopic studies have been performed for G/PANI composites with different graphite weight concentrations (y% = 0, 10, 20, 50). As expected, Raman bands situated at 1350 and 1580 cm-1 coming from graphite lattice appear, and their intensity increases with increasing graphite concentrations. The measured Raman region (1170-1800 cm-1) of PANI reacted with hydrogen peroxide was convoluted and fitted with seven Lorentzian curves. Three Lorentzian curves centred at 1609, 1578 and 1336 cm-1 are investigated. We find that the band at 1578 cm-1 attributed to the C=C stretching vibration in the quinonoid ring (Q) is slightly shifted to 1584 cm-1 and its intensity increases during the reaction with hydrogen peroxide. However, the peaks at 1609 and 1336 cm-1 attributed respectively to the C-C stretching of the benzenoid ring (B) and C-N+. vibration of delocalized polaronic structures (protonation band—PB), keep the same position and their intensities decrease. This could be interpreted as a deprotonation of imines nitrogen atoms in PANI. These results were correlated with the electrical percolation behaviour which occurs in the composite. Indeed, the electrical conductivity of G/PANI composites treated with H2O2 increases with increasing G weight concentration, only when this later becomes higher than a critical concentration yc known as the percolation threshold. We find that the percolation behaviour is linked to the intensity decrease of B and PB bands and to the intensity increase of Q band.

  2. DC electrical conductivity retention and electrical compensation of polyaniline by TiO2 at higher loading percentages in polyaniline@TiO2 nanocomposites

    NASA Astrophysics Data System (ADS)

    Ansari, Mohd Omaish; Khan, Mohammad Mansoob; Ansari, Sajid Ali; Cho, Moo Hwan

    2015-07-01

    Electrically conductive HCl-doped polyaniline (Pani)@titanium dioxide (TiO2) nanocomposites were prepared by the in-situ oxidative polymerization of aniline in the presence of different amounts of TiO2 nanoparticles. The synthesized Pani@TiO2 nanocomposites were characterized by transmission electron microscopy, X-ray diffraction, UV-visible spectroscopy, and thermogravimetric analysis. The stability of the Pani@TiO2 nanocomposites in terms of their electrical conductivity retention was examined under isothermal and cyclic aging conditions, and compared with that of pure Pani. The Pani@TiO2 nanocomposites showed higher thermal stability than pure Pani. The effect of competitive doping/de-doping by TiO2 was examined at different Pani to TiO2 weight ratios. TiO2 at a higher weight percentage was found to be involved in the de-doping type of interaction with Pani, leading to its neutralization, which was found to be similar to the dedoping phenomenon, as in the case of neutralization in basic media. The novel mechanism for this de-doping type of interaction of TiO2 with Pani has also been proposed. [Figure not available: see fulltext.

  3. Flame-retardant electrical conductive nanopolymers based on bisphenol F epoxy resin reinforced with nano polyanilines.

    PubMed

    Zhang, Xi; He, Qingliang; Gu, Hongbo; Colorado, Henry A; Wei, Suying; Guo, Zhanhu

    2013-02-01

    Both fibril and spherical polyaniline (PANI) nanostructures have successfully served as nanofillers for obtaining epoxy resin polymer nanocomposites (PNCs). The effects of nanofiller morphology and loading level on the mechanical properties, rheological behaviors, thermal stability, flame retardancy, electrical conductivity, and dielectric properties were systematically studied. The introduction of the PANI nanofillers was found to reduce the heat-release rate and to increase the char residue of epoxy resin. A reduced viscosity was observed in both types of PANI-epoxy resin liquid nanosuspension samples at lower loadings (1.0 wt % for PANI nanospheres; 1.0 and 3.0 wt % for PANI nanofibers), the viscosity was increased with further increases in the PANI loading for both morphologies. The dynamic storage and loss modulii were studied, together with the glass-transition temperature (T(g)) being obtained from the peak of tan δ. The critical PANI nanofiller loading for the modulus and T(g) was different, i.e., 1.0 wt % for the nanofibers and 5.0 wt % for the nanospheres. The percolation thresholds of the PANI nanostructures were identified with the dynamic mechanical property and electrical conductivity, and, because of the higher aspect ratio, nanofibers reached the percolation threshold at a lower loading (3.0 wt %) than the PANI nanospheres (5.0 wt %). The PANI nanofillers could increase the electrical conductivity, and, at the same loading, the epoxy nanocomposites with the PANI nanofibers showed lower volume resistivity than the nanocomposites with the PANI nanospheres, which were discussed with the contact resistance and percolation threshold. The tensile test indicated an improved tensile strength of the epoxy matrix with the introduction of the PANI nanospheres at a lower loading (1.0 wt %). Compared with pure epoxy, the elasticity modulus was increased for all the PNC samples. Moreover, further studies on the fracture surface revealed an enhanced

  4. Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

    NASA Astrophysics Data System (ADS)

    de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

    2014-08-01

    The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

  5. Modification of inner surface of photonic crystal fibers with self-assembled polyaniline films

    NASA Astrophysics Data System (ADS)

    Pidenko, Sergei A.; Pidenko, Pavel S.; Bondarenko, Sergei D.; Shuvalov, Andrei A.; Burmistrova, Natalia A.; Goryacheva, Irina Y.

    2016-04-01

    Photonic crystal fibers (PCFs) with a hollow core are one of the most promising solid support of fiber-optic sensors. The main advantages of PCF as sensor elements in clinical analysis are minimization of optical interactions from the sample and the ability to analyze small volume of samples. At the same time, low sorption capacity of glass which is the basic material for the fabrication of the PCF, limits their use in the development of biosensors. Modification of the inner surface of the PCF can be the solution of the problem. In this work the synthesis of self-assembled films of polyaniline (PANI) on the inner surface of the PCFs was carried out. The modified PCFs were studied by spectroscopy and electron microscopy. It was found that the covering of the inner surface of the PCFs with PANI leads to a shift of the local maximums of the transmission spectrum PCFs up to 25 nm. These makes possible to design the method of varying of photonic bandgaps location.

  6. Fabrication of Composite Films by Controlling Molecular Doping Processes between Polyaniline and Soluble Multiwalled Nanotubes and Their Optical Characteristics

    NASA Astrophysics Data System (ADS)

    Feng, Wei; Zhou, Feng; Wang, Xiaogong; Bai, Xiaodong; Liang, Ji; Yoshino, Katsumi

    2003-09-01

    An efficient approach to composite film fabrication that involves the control of doping processes between soluble multiwalled nanotubes (s-MWNTs) and polyaniline (PAN) molecules has been developed in this work. The s-MWNTs were prepared by introducing carboxylic acid and sulfonic acid groups to the surfaces of nanotubes. The s-MWNT was used as a dopant to react with the imine nitrogens of emeraldine PAN via the protonation doping process in a layer-by-layer manner. The resultant composite films on the quartz substrates were characterized by UV/Vis spectroscopy, photoluminescence, Fourier-transform infrared spectroscopy, scanning electron micrograph and X-ray diffraction. Results showed that s-MWNTs were doped into polyaniline layers, which caused changes in the composite film characteristics such as electrical properties, spectroscopic features and morphology. Unlike the already-used layer-by-layer process based on electrostatic attraction, our process is based on the acid-base reaction between emeraldine and s-MWNT. Owing to the protonation doping, the bond between the carboxyl group and the imine nitrogen group becomes covalent, which enhances the stability of the film.

  7. Dielectric Properties of Aligned Conducting Polymers

    DTIC Science & Technology

    1991-10-01

    It has been demonstrated that aligned polyacetylene and polyaniline possess remarkably enhanced conductivities. The increase in crystallinity and...and thermal stability compared to other CPs such as polyacetylenes, polythiophenes, and polyaniline . These favorable properties and the commercial...stretch-orientation of BF4- doped PPy films electrochemically deposited at -30,C, 7 pyrrole electropolymerization at a xylene/water interface, 8 and

  8. Electrically Conductive Polyimide Films Containing Gold Surface

    NASA Technical Reports Server (NTRS)

    Caplan, Maggie L.; Stoakley, Diane M.; St. Clair, Anne K.

    1994-01-01

    Polyimide films exhibiting high thermo-oxidative stability and including electrically conductive surface layers containing gold made by casting process. Many variations of basic process conditions, ingredients, and sequence of operations possible, and not all resulting versions of process yield electrically conductive films. Gold-containing layer formed on film surface during cure. These metallic gold-containing polyimides used in film and coating applications requiring electrical conductivity, high reflectivity, exceptional thermal stability, and/or mechanical integrity. They also find commercial potential in areas ranging from thin films for satellite antennas to decorative coatings and packaging.

  9. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces

    PubMed Central

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-01-01

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is. PMID:27649159

  10. Organic conductive films for semiconductor electrodes

    DOEpatents

    Frank, Arthur J.

    1984-01-01

    According to the present invention, improved electrodes overcoated with conductive polymer films and preselected catalysts are provided. The electrodes typically comprise an inorganic semiconductor overcoated with a charge conductive polymer film comprising a charge conductive polymer in or on which is a catalyst or charge-relaying agent.

  11. Organic conductive films for semiconductor electrodes

    DOEpatents

    Frank, A.J.

    1984-01-01

    According to the present invention, improved electrodes overcoated with conductive polymer films and preselected catalysts are provided. The electrodes typically comprise an inorganic semiconductor over-coated with a charge conductive polymer film comprising a charge conductive polymer in or on which is a catalyst or charge-relaying agent.

  12. Stabilization of polyaniline solutions through additives

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.

    1996-01-01

    A stabilized non-conductive polyaniline solution comprising from about 1 to bout 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution.

  13. Stabilization of polyaniline solutions through additives

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.

    1996-12-10

    A stabilized non-conductive polyaniline solution comprising from about 1 to about 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution. 4 figs.

  14. Immunosensing of Atrazine with Antibody-Functionalized Cu-MOF Conducting Thin Films.

    PubMed

    Bhardwaj, Sanjeev K; Bhardwaj, Neha; Mohanta, Girish C; Kumar, Pawan; Sharma, Amit L; Kim, Ki-Hyun; Deep, Akash

    2015-12-02

    This work reports the assembly of thin films of a silica (SiO2)-modified copper-metal organic framework, Cu3(BTC)2 [Cu3(BTC)2@SiO2, BTC = benzene-1,3,5-tricarboxylic acid] on a conducting substrate of NH2-BDC [NH2-BDC = 2-aminobenzene-1,4-dicarboxylic acid] doped polyaniline (PANI). Assembled Cu3(BTC)2@SiO2/BDC-PANI thin films displayed electrical conductivity in the range of 35 μA. These thin films were conjugated with antiatrazine antibodies to create a novel immunosensing platform. Various structural and spectral characteristics of the synthesized material and its bioconjugate were investigated. The developed immunosensor was used for the conductometric sensing of atrazine. The detection of atrazine was achieved with a high sensor sensitivity (limit of detection = 0.01 nM) and specificity in the presence of diverse pesticides (e.g., endosulfan, parathion, paraoxon, malathion, and monochrotophos).

  15. Synthesis of nanostructured polyaniline

    NASA Astrophysics Data System (ADS)

    Surwade, Sumedh P.

    The organization of my thesis is as follows: (a) Chapter III describes the synthesis of bulk quantities of polyaniline nanofibers in one step using a simple and versatile high ionic strength aqueous system (HCl/NaCl) that permits the use of pure H2O2 as a mild oxidant without any added metal or enzyme catalyst. Polyaniline nanofibers obtained are highly conducting, sigma˜1--5 S/cm, and spectroscopically similar to conventional polyaniline synthesized using stronger oxidants. The synthesis method is further extended to the synthesis of oligoanilines of controlled molecular weight, e.g., aniline tetramer, octamer, and hexadecamer. Microns long tetramer nanofibers are synthesized using this method. (b) Chapter IV describes the mechanism of nanofiber formation in polyaniline. It is proposed that the surfaces such as the walls of the reaction vessel and/or intentionally added surfaces play a dramatic role in the evolution of nanofibrillar morphology. Nucleation sites on surfaces promote the accumulation of aniline dimer that reacts further to yield aniline tetramer, which (surprisingly) is entirely in form of nanofibers and whose morphology is transcribed to the bulk by a double heterogeneous nucleation mechanism. This unexpected phenomenon could form the basis of nanofiber formation in all classes of precipitation polymerization systems. (c) Chapter V is the mechanistic study on the formation of oligoanilines during the chemical oxidation of aniline in weakly acidic, neutral or basic media using peroxydisulfate oxidant. It is proposed that the reaction proceeds via the intermediacy of benzoquinone monoimine that is formed as a result of a Boyland-Sims rearrangement of aniline. The initial role of peroxydisulfate is to provide a pathway for the formation of benzoquinone monoimine intermediate that is followed by a conjugate Michael-type addition reaction with aniline or sulfated anilines. The products isolated in pH 2.5--10.0 buffers are intermediate species at various

  16. Thermal conductivity of sputtered amorphous Ge films

    SciTech Connect

    Zhan, Tianzhuo; Xu, Yibin; Goto, Masahiro; Tanaka, Yoshihisa; Kato, Ryozo; Sasaki, Michiko; Kagawa, Yutaka

    2014-02-15

    We measured the thermal conductivity of amorphous Ge films prepared by magnetron sputtering. The thermal conductivity was significantly higher than the value predicted by the minimum thermal conductivity model and increased with deposition temperature. We found that variations in sound velocity and Ge film density were not the main factors in the high thermal conductivity. Fast Fourier transform patterns of transmission electron micrographs revealed that short-range order in the Ge films was responsible for their high thermal conductivity. The results provide experimental evidences to understand the underlying nature of the variation of phonon mean free path in amorphous solids.

  17. Three-dimensional structures of graphene/polyaniline hybrid films constructed by steamed water for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhang, Liling; Huang, Da; Hu, Nantao; Yang, Chao; Li, Ming; Wei, Hao; Yang, Zhi; Su, Yanjie; Zhang, Yafei

    2017-02-01

    A novel three-dimensional (3D) structure of reduced graphene oxide/polyaniline (rGO/PANI) hybrid films has been demonstrated for high-performance supercapacitors. Steamed water in closed vessels with high pressure and moderately high temperature is applied to facilely construct this structure. The as-designed rGO/PANI hybrid films exhibit a highest gravimetric specific capacitance of 1182 F g-1 at 1 A g-1 in the three-electrode test. The assembled symmetric device based on this structure shows both a high capacitance of 808 F g-1 at 1 A g-1 and a high gravimetric energy density (28.06 Wh kg-1 at a power density of 0.25 kW kg-1). Above all, this novel 3D structure constructed by steamed water regulation techniques shows excellent capacitance performance and holds a great promise for high-performance energy storage applications.

  18. Effect of diameter of cellulosic nano-fiber on conductivity of poly(aniline sulfonic acid) composites

    NASA Astrophysics Data System (ADS)

    Konagaya, S.; Shimizu, K.; Terada, M.; Yamada, T.; Sanada, K.; Numata, O.; Sugino, G.

    2014-05-01

    The authors have been studying the effect of cellulosic nano-fiber (CeNF) with the diameter of less than 30 nm and the length of a few micrometers on the conductivity of the conductive polymer composites (PAS/PEs/CeNF) prepared from poly(aniline sulfonic acid) (PAS), a water dispersible polyester (PEs) and CeNF and confirmed that CeNF was effective for the enhancement of their conductivity, and that the conductivity enhancement was attributable to the strong adsorbing ability of CeNF to PAS molecules. Thiner CeNF has so larger surface area that it is expected to adsorb more PAS molecules on its surface, which possibly lead to further conductivity enhancement of the composites. The authors prepared thinner CeNF with the size of 16 nm by the use of ultrasonic dispersing machine. It was clarified that the thinner CeNF had a higher adsorbing ability to PAS molecules and a larger effect on the conductivity enhancement of PAS/PEs/CeNF composites.

  19. Hydrogen film/conductive cooling

    NASA Technical Reports Server (NTRS)

    Ewen, R. L.

    1972-01-01

    Small scale nozzle tests using heated nitrogen were run to obtain effectiveness and wall heat transfer data with hydrogen film cooling. Effectiveness data are compared with an entrainment model developed from planar, unaccelerated flow data. Results indicate significant effects due to flow turning and acceleration. With injection velocity effects accounted for explicitly, heat transfer correlation coefficients were found to be the same with and without film cooling when properties are evaluated at an appropriate reference temperature for the local gas composition defined by the coolant effectiveness. A design study for an O2/H2 application with 300 psia (207 N/sq cm) chamber pressure and 1500 lbs (6670 N) thrust indicates an adiabatic wall design requires 4 to 5 percent of the total flow as hydrogen film cooling. Internal regenerative cooling designs were found to offer no reduction in coolant requirements.

  20. A Simple Visual Ethanol Biosensor Based on Alcohol Oxidase Immobilized onto Polyaniline Film for Halal Verification of Fermented Beverage Samples

    PubMed Central

    Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

    2014-01-01

    A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%–0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification. PMID:24473284

  1. A simple visual ethanol biosensor based on alcohol oxidase immobilized onto polyaniline film for halal verification of fermented beverage samples.

    PubMed

    Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

    2014-01-27

    A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%-0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification.

  2. Anisotropic conducting films for electromagnetic radiation applications

    DOEpatents

    Cavallo, Francesca; Lagally, Max G.; Rojas-Delgado, Richard

    2015-06-16

    Electronic devices for the generation of electromagnetic radiation are provided. Also provided are methods for using the devices to generate electromagnetic radiation. The radiation sources include an anisotropic electrically conducting thin film that is characterized by a periodically varying charge carrier mobility in the plane of the film. The periodic variation in carrier mobility gives rise to a spatially varying electric field, which produces electromagnetic radiation as charged particles pass through the film.

  3. Experiments On Transparent Conductive Films For Spacecraft

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Rutledge, Sharon K.; De Groh, Kim K.; Hung, Ching-Cheh; Malave-Sanabria, Tania; Hambourger, Paul; Roig, David

    1995-01-01

    Report describes experiments on thin, transparent, electrically conductive films made, variously, of indium tin oxide covered by magnesium fluoride (ITO/MgF2), aluminum-doped zinc oxide (AZO), or pure zinc oxide (ZnO). Films are candidates for application to such spacecraft components, including various optoelectronic devices and window surfaces that must be protected against buildup of static electric charge. On Earth, such films useful on heat mirrors, optoelectronic devices, gas sensors, and automotive and aircraft windows.

  4. Layered conductive polymer on nylon membrane templates for high performance, thin-film supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Shi, HaoTian Harvey; Naguib, Hani E.

    2016-04-01

    Flexible Thin-film Electrochemical Capacitors (ECs) are emerging technology that plays an important role as energy supply for various electronics system for both present era and the future. Intrinsically conductive polymers (ICPs) are promising pseudo-capacitive materials as they feature both good electrical conductivity and high specific capacitance. This study focuses on the construction and characterization of ultra-high surface area porous electrodes based on coating of nano-sized conductive polymer materials on nylon membrane templates. Herein, a novel nano-engineered electrode material based on nylon membranes was presented, which allows the creation of super-capacitor devices that is capable of delivering competitive performance, while maintaining desirable mechanical characteristics. With the formation of a highly conductive network with the polyaniline nano-layer, the electrical conductivity was also increased dramatically to facilitate the charge transfer process. Cyclic voltammetry and specific capacitance results showed promising application of this type of composite materials for future smart textile applications.

  5. Self-Supported Crack-Free Conducting Polymer Films with Stabilized Wrinkling Patterns and Their Applications

    PubMed Central

    Xie, Jixun; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Zhao, Jingxin; Lu, Conghua

    2016-01-01

    Self-supported conducting polymer films with controlled microarchitectures are highly attractive from fundamental and applied points of view. Here a versatile strategy is demonstrated to fabricate thin free-standing crack-free polyaniline (PANI)-based films with stable wrinkling patterns. It is based on oxidization polymerization of pyrrole inside a pre-wrinkled PANI film, in which the wrinkled PANI film is used both as a template and oxidizing agent for the first time. The subsequently grown polypyrrole (PPy) and the formation of interpenetrated PANI/PPy networks play a decisive role in enhancing the film integrity and the stability of wrinkles. This enhancing effect is attributed to the modification of internal stresses by the interpenetrated PANI/PPy microstructures. Consequently, a crack-free film with stable controlled wrinkles such as the wavelength, orientation and spatial location has been achieved. Moreover, the wrinkling PANI/PPy film can be removed from the initially deposited substrate to become free-standing. It can be further transferred onto target substrates to fabricate hierarchical patterns and functional devices such as flexible electrodes, gas sensors, and surface-enhanced Raman scattering substrates. This simple universal enhancing strategy has been extended to fabrication of other PANI-based composite systems with crack-free film integrity and stabilized surface patterns, irrespective of pattern types and film geometries. PMID:27827459

  6. Self-Supported Crack-Free Conducting Polymer Films with Stabilized Wrinkling Patterns and Their Applications

    NASA Astrophysics Data System (ADS)

    Xie, Jixun; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Zhao, Jingxin; Lu, Conghua

    2016-11-01

    Self-supported conducting polymer films with controlled microarchitectures are highly attractive from fundamental and applied points of view. Here a versatile strategy is demonstrated to fabricate thin free-standing crack-free polyaniline (PANI)-based films with stable wrinkling patterns. It is based on oxidization polymerization of pyrrole inside a pre-wrinkled PANI film, in which the wrinkled PANI film is used both as a template and oxidizing agent for the first time. The subsequently grown polypyrrole (PPy) and the formation of interpenetrated PANI/PPy networks play a decisive role in enhancing the film integrity and the stability of wrinkles. This enhancing effect is attributed to the modification of internal stresses by the interpenetrated PANI/PPy microstructures. Consequently, a crack-free film with stable controlled wrinkles such as the wavelength, orientation and spatial location has been achieved. Moreover, the wrinkling PANI/PPy film can be removed from the initially deposited substrate to become free-standing. It can be further transferred onto target substrates to fabricate hierarchical patterns and functional devices such as flexible electrodes, gas sensors, and surface-enhanced Raman scattering substrates. This simple universal enhancing strategy has been extended to fabrication of other PANI-based composite systems with crack-free film integrity and stabilized surface patterns, irrespective of pattern types and film geometries.

  7. Synthesis of a new electrically conducting nanosized Ag-polyaniline-silica complex using γ-radiolysis and its biosensing application

    NASA Astrophysics Data System (ADS)

    Kim, Hwa-Jung; Park, Sang Hyun; Park, Hae-Jun

    2010-08-01

    In this study, a new electrically conducting nanosized Ag-PANI-silica complex, in which nano-silver is bound to silica and polyaniline (PANI), has been synthesized by using γ-irradiation at room temperature and not by using polyvinylpyrrolidone (PVP) as a colloidal stabilizer. The conductivity of nanosized Ag-PANI-silica complex was determined by using the Van der PauW method, and the complex turned out to have a high semi-conductivity (200 S/cm). The optical property and morphology were characterized by using a UV-vis spectrophotometer, field emission-scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The optical absorption bands of UV-vis analysis revealed a peak at 262, 368, and a slowly decreasing band at 600-800 nm originating from the a nanosized Ag-PANI-silica complex. FE-SEM and TEM showed that the nanosized Ag-PANI-silica complex has a particle size ranging from 10 to 30 nm and high stability. The nano-complex prepared by γ-irradiation can be applicable to be used as biosensor materials.

  8. Exploding conducting film laser pumping apparatus

    DOEpatents

    Ware, Kenneth D.; Jones, Claude R.

    1986-01-01

    Exploding conducting film laser optical pumping apparatus. The 342-nm molecular iodine and the 1.315-.mu.m atomic iodine lasers have been optically pumped by intense light from exploding-metal-film discharges. Brightness temperatures for the exploding-film discharges were approximately 25,000 K. Although lower output energies were achieved for such discharges when compared to exploding-wire techniques, the larger surface area and smaller inductance inherent in the exploding-film should lead to improved efficiency for optically-pumped gas lasers.

  9. Fabrication of multiwalled carbon nanotube-polyaniline/platinum nanocomposite films toward improved performance for a cholesterol amperometric biosensor.

    PubMed

    Xu, ZeHong; Cheng, XiaoDan; Tan, JianHong; Gan, Xianxue

    2016-11-01

    A simple and high sensitive cholesterol amperometric biosensor, which is based on in situ electropolymerization of multi-walled carbon nanotube-polyaniline (MWCNT-PANI) nanocomposite and electrodeposition of platinum nanoparticle (nano-Pt) films onto the glassy carbon electrode surface for cholesterol oxidase immobilization, was constructed in this study. The preparation process of the modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and chronoamperometry. Because of the synergistic electrocatalytic activity between MWCNT-PANI nanocomposites and nano-Pt, the cholesterol biosensor exhibited an excellent performance with a linear range of 2.0-510.0 µM, a detection limit of 0.8 µM (signal-to-noise ratio = 3), a high sensitivity of 109.9 µA mM(-1) , and a short response time within 5 Sec. Moreover, the reproducibility, stability, and selectivity of the biosensor were also investigated.

  10. Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band

    NASA Astrophysics Data System (ADS)

    Singh, Avanish Pratap; Anoop Kumar, S.; Chandra, Amita; Dhawan, S. K.

    2011-06-01

    β-Naphthalene sulphonic acid (β-NSA) doped polyaniline (PANI)-flyash (FA) composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37-21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D-VRH model. SEM images demonstrate that β-NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ'- iɛ″) and permeability (μ*=μ'- iμ″) of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21) using theoretical calculations given in Nicholson-Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 - 12.4 GHz) & Ku-Band (12.4 - 18 GHz) frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.

  11. Polyaniline supercapacitors

    NASA Astrophysics Data System (ADS)

    Eftekhari, Ali; Li, Lei; Yang, Yang

    2017-04-01

    Polyaniline (PANI) has been widely used for the energy storage applications either as a conducting agent or directly as an electroactive material due to the tunable pseudocapacitive performance owing to its various oxidation states. Although PANI supercapacitors are known for over three decades, immediate attention has been paid just over the past few years due to the potential practical applications. Here, we extensively review recent works on PANI-based supercapacitors using nanocomposites of PANI with other electrochemically active materials including carbonaceous materials and metal oxides. Recent works on developing new electrolytes for PANI supercapacitors including utilization of additional redox systems within the electrolyte, neutral electrolytes, and solid-state electrolytes are discussed. Some other interesting applications of PANI in energy-related applications are also covered in this review.

  12. Terahertz Conductivity of Single Walled Nanotube Films

    NASA Astrophysics Data System (ADS)

    Han, Jia-Guang; Zhu, Zhi-Yuan; He, Feng; Liao, Yi; Wang, Zhen-Xia; Zhang, Wei; Yu, Li-Ping; Sun, Li-Tao; Wang, Ting-Tai

    2003-09-01

    The conductivity of single walled nanotube films is investigated with a combination of the Maxwell-Garnett (MG) model and the Drude-Lorentzian (DL) model in the Terahertz region. A theoretical fit for Jeon's experiment is given and a decrease of the real conductivity with increasing frequency is predicted. Meanwhile, the MG and DL models are also discussed for different samples.

  13. Multilevel conductance switching in polymer films

    NASA Astrophysics Data System (ADS)

    Lauters, M.; McCarthy, B.; Sarid, D.; Jabbour, G. E.

    2006-07-01

    Multilevel conductance switching in poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) films is demonstrated. A thin-film structure, ITO-coated glass/MEH-PPV/Al, has shown the ability to store a continuum of conductance states. These states are nonvolatile and can be switched reproducibly by applying appropriate programing biases above a certain threshold voltage. The electrical conductivity of the highest and lowest states can differ by five orders of magnitude. Furthermore, these devices exhibit good cyclic switching characteristics and retention times of several weeks.

  14. Simultaneously improving electrical conductivity and thermopower of polyaniline composites by utilizing carbon nanotubes as high mobility conduits.

    PubMed

    Wang, Hong; Yi, Su-in; Pu, Xiong; Yu, Choongho

    2015-05-13

    Electrical conductivity and thermopower of isotropic materials typically have inversely proportional correlation because both are strongly affected in the opposite way by the electronic carrier concentration. This behavior has been one of the major hurdles in developing high-performance thermoelectrics whose figure-of-merit enhances with large thermopower and high electrical conductivity. Here we report a promising method of simultaneously improving both properties with polyaniline (PANI) composites filled by carbon nanotubes (CNTs). With addition of double-wall CNTs (DWCNTs), the electronic mobility of PANI doped with camphorsulfonic acid (PANI-CSA) was raised from ∼0.15 to ∼7.3 cm(2)/(V s) (∼50 time improvement) while the carrier concentration was decreased from ∼2.1 × 10(21) to ∼5.6 × 10(20) cm(-3) (∼4 time reduction). The larger increase of mobility increased electrical conductivity despite the carrier concentration reduction that enlarges thermopower. The improvement in the carrier mobility could be attributed to the band alignment that attracts hole carriers to CNTs whose mobility is much higher than that of PANI-CSA. The electrical conductivity of the PANI-CSA composites with 30-wt % DWCNTs was measured to be ∼610 S/cm with a thermopower value of ∼61 μV/K at room temperature, resulting in a power factor value of ∼220 μW/(m K(2)), which is more than two orders higher than that of PANI-CSA as well as the highest among those of the previously reported PANI composites. Further study may result in high performance thermoelectric organic composites uniquely offering mechanical flexibility, light weight, low toxicity, and easy manufacturing. unlike conventional inorganic semiconductors.

  15. Influence of n-type nickel ferrite in enhancing the AC conductivity of optimized polyaniline-nickel ferrite nanocomposite

    NASA Astrophysics Data System (ADS)

    Megha, R.; Ravikiran, Y. T.; Vijaya Kumari, S. C.; Thomas, S.

    2017-04-01

    In the present work, n-type nickel ferrite (NF) particles prepared by sol gel autocombustion method were used to synthesize optimized polyaniline-nickel ferrite (PANI-NF) nanocomposite by in situ polymerization method. Then, NF, PANI and the composite were structurally characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Improved π-electron delocalization in PANI-NF composite as compared to that in PANI was confirmed from FTIR analysis. Interfacial interaction between PANI and NF was confirmed from XRD studies. Highly agglomerated, more densely packed particles of the composite facilitating easier charge transport were confirmed from SEM image. Transmission electron microscopy (TEM) image was analysed to calculate accurate average particle size of the composite by fitting the data to log-normal distribution function. Crystalline nature of the composite was confirmed from selected area electron diffraction (SAED) analysis. Remarkable increase in AC conductivity of the PANI-NF composite as compared to that of PANI due mainly to the formation of interfacial heterojunction barrier between p-type PANI and n-type NF was confirmed experimentally and well supported theoretically by calculating binding energy, hopping distance and density of states at Fermi level as per correlated barrier hopping (CBH) model.

  16. Electrically conducting polyimide film containing tin complexes

    NASA Technical Reports Server (NTRS)

    St. Clair, Anne K. (Inventor); Ezzell, Stephen A. (Inventor); Taylor, Larry T. (Inventor); Boston, Harold G. (Inventor)

    1996-01-01

    Disclosed is a thermally-stable SnO.sub.2 -surfaced polyimide film wherein the electrical conductivity of the SnO.sub.2 surface is within the range of about 3.0.times.10.sup.-3 to about 1.times.10.sup.-2 ohms.sup.-1,. Also disclosed is a method of preparing this film from a solution containing a polyamic acid and SnCl.sub.4 (DMSO).sub.2.

  17. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H₂S and SO₂.

    PubMed

    Dong, Xingchen; Zhang, Xiaoxing; Wu, Xiaoqing; Cui, Hao; Chen, Dachang

    2016-11-10

    Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF₆, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H₂S and SO₂, two decomposed products of SF₆ under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H₂S and SO₂ when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H₂S and SO₂ in gas-insulated switchgears at room temperature.

  18. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H2S and SO2

    PubMed Central

    Dong, Xingchen; Zhang, Xiaoxing; Wu, Xiaoqing; Cui, Hao; Chen, Dachang

    2016-01-01

    Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF6, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H2S and SO2, two decomposed products of SF6 under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H2S and SO2 when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H2S and SO2 in gas-insulated switchgears at room temperature. PMID:27834895

  19. Efficient spin transport through polyaniline

    NASA Astrophysics Data System (ADS)

    Mendes, J. B. S.; Alves Santos, O.; Gomes, J. P.; Assis, H. S.; Felix, J. F.; Rodríguez-Suárez, R. L.; Rezende, S. M.; Azevedo, A.

    2017-01-01

    By using the spin pumping process, we show that it is possible to transport a pure spin current across layers of conducting polyaniline (PANI) with several hundred nanometers sandwiched between a film of the ferrimagnetic insulator yttrium iron garnet (YIG) and a thin layer of platinum. The spin current generated by microwave-driven ferromagnetic resonance of the YIG film, injected through the YIG/PANI interface, crosses the whole PANI layer and then is injected into the Pt layer. By means of the inverse spin Hall effect in the Pt, the spin current is converted into charge current and electrically detected as a dc voltage. We measured a spin diffusion length in PANI of 590 ± 40 nm, which is very large compared with normal metals, demonstrating that PANI can be used as an efficient spin current conductor and poor charge current conductor, opening the path towards spintronics applications based in this very attractive material.

  20. Thermal conductivities of thin, sputtered optical films

    SciTech Connect

    Henager, C.H. Jr.; Pawlewicz, W.T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO{sub 2}/Si{sub 3}N{sub 4}){sup n} and Al(Al{sub 2}O{sub 3}/AIN){sup n}. Sputtered films of more conventional materials like SiO{sub 2}, Al{sub 2}O{sub 3}, Ta{sub 2}O{sub 5}, Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented.

  1. A novel microextractor stick (polyaniline/zinc film/stainless steel) for polycyclic aromatic hydrocarbons in water.

    PubMed

    Chaiphet, Thitiphan; Bunkoed, Opas; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

    2014-01-01

    A novel microextractor stick (MES) has been developed for the determination of trace amounts of polycyclic aromatic hydrocarbons (PAHs) in water samples. The proposed MES was prepared by electrodepositing a Zn-film onto a stainless steel stick followed by a coating with polyaniline (PANI) sorptive layers. This PANI/Zn-film/stainless steel stick produced a large surface area, provided a high extraction efficiency (82.0 ± 6.2% to 111.0 ± 7.5% recovery) of spiked chrysene (Chry) and benzo(a)pyrene (BaP). This MES is cost-effective, easy to prepare, robust and provides a good stick-to-stick reproducibility (n = 10) with a relative standard deviation of less than 10%. The effect of various parameters on the efficiency of extraction of PAHs were optimized, including the extraction time, extraction and desorption stirring speeds, volume of desorption solvent and desorption time. Under the optimum conditions, the limit of detection (S/N ≥ 3) and limit of quantification (S/N ≥ 10) of both Chry and BaP were 0.05 and 0.12 μg L(-1), respectively. The developed MES was successfully applied to determine PAHs in real water samples.

  2. Electrically conductive palladium containing polyimide films

    NASA Technical Reports Server (NTRS)

    Taylor, L. T.; St.clair, A. K.; Carver, V. C.; Furtsch, T. A. (Inventor)

    1982-01-01

    Lightweight, high temperature resistant, electrically conductive, palladium containing polyimide films and methods for their preparation are described. A palladium (II) ion-containing polyamic acid solution is prepared by reacting an aromatic dianhydride with an equimolar quantity of a palladium II ion-containing salt or complex and the reactant product is cast as a thin film onto a surface and cured at approximately 300 C to produce a flexible electrically conductive cyclic palladium containing polyimide. The source of palladium ions is selected from the group of palladium II compounds consisting of LiPdCl4, PdS(CH3)2Cl2Na2PdCl4, and PdCl2. The films have application to aerodynamic and space structures and in particular to the relieving of space charging effects.

  3. Thermal Conductivity in Nanocrystalline Ceria Thin Films

    SciTech Connect

    Marat Khafizov; In-Wook Park; Aleksandr Chernatynskiy; Lingfeng He; Jianliang Lin; John J. Moore; David Swank; Thomas Lillo; Simon R. Phillpot; Anter El-Azab; David H. Hurley

    2014-02-01

    The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser-based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries.

  4. A highly porous NiO/polyaniline composite film prepared by combining chemical bath deposition and electro-polymerization and its electrochromic performance

    NASA Astrophysics Data System (ADS)

    Xia, X. H.; Tu, J. P.; Zhang, J.; Wang, X. L.; Zhang, W. K.; Huang, H.

    2008-11-01

    A highly porous NiO/polyaniline (PANI) composite film was prepared on ITO glass by combining the chemical bath deposition and electro-polymerization methods, successively. The porous NiO film acts as a template for the preferential growth of PANI along NiO flakes, and the NiO/PANI composite film has an intercrossing net-like morphology. The electrochromic performance of the NiO/PANI composite film was investigated in 1 M LiClO4+1 mM HClO4/propylene carbonate (PC) by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The NiO/PANI thin film exhibits a noticeable electrochromism with reversible color changes from transparent yellow to purple and presents quite good transmittance modulation with a variation of transmittance up to 56% at 550 nm. The porous NiO/polyaniline (PANI) composite film also shows good reaction kinetics with fast switching speed, and the response time for oxidation and reduction is 90 and 110 ms, respectively.

  5. Workshop on thin film thermal conductivity measurements

    NASA Astrophysics Data System (ADS)

    Feldman, Albert; Balzaretti, Naira M.; Guenther, Arthur H.

    1998-04-01

    On a subject of considerable import to the laser-induced damage community, a two day workshop on the topic, Thin Film Thermal Conductivity Measurement was held as part of the 13th Symposium on Thermophysical Properties at the University of Colorado in Boulder CO, June 25 and 26, 1997. The Workshop consisted of 4 sessions of 17 oral presentations and two discussion sessions. Two related subjects of interest were covered; 1) methods and problems associated with measuring thermal conductivity ((kappa) ) of thin films, and 2) measuring and (kappa) of chemical vapor deposited (CVD) diamond. On the subject of thin film (kappa) measurement, several recently developed imaginative techniques were reviewed. However, several authors disagreed on how much (kappa) in a film differs from (kappa) in a bulk material of the same nominal composition. A subject of controversy was the definition of an interface. In the first discussion session, several questions were addressed, a principal one being, how do we know that the values of (kappa) we obtain are correct and is there a role for standards in thin film (kappa) measurement. The second discussion session was devoted to a round-robin interlaboratory comparison of (kappa) measurements on a set of CVD diamond specimens and several other specimens of lower thermal conductivity. Large interlaboratory differences obtained in an earlier round robin had been attributed to specimen inhomogeneity. Unfortunately, large differences were also observed in the second round robin even though the specimens were more homogenous. There was good consistency among the DC measurements, however, the AC measurements showed much greater variability. There was positive feedback from most of the attenders regarding the Workshop with nearly all respondents recommending another Workshop in three or fewer years. There was general recognition that thin film thermal conductivity measurements are important for predicting the resistance of optical coating

  6. High quality transparent conducting oxide thin films

    DOEpatents

    Gessert, Timothy A.; Duenow, Joel N.; Barnes, Teresa; Coutts, Timothy J.

    2012-08-28

    A transparent conducting oxide (TCO) film comprising: a TCO layer, and dopants selected from the elements consisting of Vanadium, Molybdenum, Tantalum, Niobium, Antimony, Titanium, Zirconium, and Hafnium, wherein the elements are n-type dopants; and wherein the transparent conducting oxide is characterized by an improved electron mobility of about 42 cm.sup.2/V-sec while simultaneously maintaining a high carrier density of .about.4.4e.times.10.sup.20 cm.sup.-3.

  7. Structural modeling of amorphous conducting carbon film

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Somnath; Pati, Swapan K.; Subramanyam, S. V.

    1998-04-01

    Amorphous conducting carbon films are prepared using plasma assisted polymerization process. SEM and TEM shows random aggregate of globular clusters of micron size inside the samples. Electrical measurements indicate a near metallic nature. A tendency of saturation of resistivity at low temperature is observed. From spectroscopic analysis we find some unusual features. Based on these observations a structural model of this carbon is proposed.

  8. Anionically-Conductive Ultrathin Film Composite Membranes

    DTIC Science & Technology

    1994-08-19

    these polymers in pervaporation separations. The interfacial polymerizations we have developed are used to prepare ultrathin films of conductive... pervaporation -separations, etc. We are continuing this research effort by exploring in particular sensor and pervaporation applications of these coated...particular emphasis are in novel biosensors and novel membranes for pervaporation separations. IV. Research Articles. 1. Lei, J.; Menon, V. P.; Martin, C. R

  9. Charge Transport in Polyaniline and Vapour Induced Structural Changes

    NASA Astrophysics Data System (ADS)

    Minto, C. D. G.; Vaughan, A. S.

    1996-03-01

    Camphor sulphonic acid protonation renders polyaniline soluble in both m-cresol and chloroform. Films cast from these solvents exhibit vastly differing transport properties. m-cresol cast films are metallic or lie on the metal/insulator transition, whereas those cast from chloroform are insulators. Similarly pellets of pressed doped polyaniline powder exhibit insulating characteristics. We present an investigation of such effects in polyaniline obtained from both insulating conditions (films and powders). We find that m-cresol -- vapour treatment of these materials causes a rapid increase both in the conductivity and the type of conduction, changing from an insulator to a material approaching the metal/insulator transition. Chloroform films actually take on characteristics of those cast from m-cresol, including a positive temperature coefficient of resistivity. Both starting materials exhibit similar X-ray scattering patterns, after exposure to vapour, the pattern becomes more similar to that which is found in m-cresol cast films. Conformational changes resulting from a strong polymer--interaction are discussed as the motivation for the improvements in transport properties.

  10. Thermal Conductivity of Carbon Nanotube Composite Films

    NASA Technical Reports Server (NTRS)

    Ngo, Quoc; Cruden, Brett A.; Cassell, Alan M.; Walker, Megan D.; Koehne, Jessica E.; Meyyappan, M.; Li, Jun; Yang, Cary Y.

    2004-01-01

    State-of-the-art ICs for microprocessors routinely dissipate power densities on the order of 50 W/sq cm. This large power is due to the localized heating of ICs operating at high frequencies, and must be managed for future high-frequency microelectronic applications. Our approach involves finding new and efficient thermally conductive materials. Exploiting carbon nanotube (CNT) films and composites for their superior axial thermal conductance properties has the potential for such an application requiring efficient heat transfer. In this work, we present thermal contact resistance measurement results for CNT and CNT-Cu composite films. It is shown that Cu-filled CNT arrays enhance thermal conductance when compared to as-grown CNT arrays. Furthermore, the CNT-Cu composite material provides a mechanically robust alternative to current IC packaging technology.

  11. Synthesis, pervaporation and gas separation studies of polyaniline blends

    SciTech Connect

    Huang, S.C.; Conklin, J.A.; Su, T.M.

    1995-12-01

    Membranes have been successfully produced from blends of polyaniline/polyacrylic acid and polyaniline/polyimide. The uniqueness of these membranes is the incorporation of {open_quotes}polymer dopants{close_quotes} in polyaniline. Conductivity measurements show that polyacrylic acid dopes the polyaniline. Pervaporation of water and water/acetic acid mixtures were performed using polyaniline and its polyacrylic acid blend. An improved flux over the polyaniline base form is observed. Polyaniline/polyimide blends were synthesized for gas permeability studies. These blends combine improved thermal stability relative to polyaniline with greater gas selectivity relative to polyimide. The blend shows an increase in permeability for all gases studied over both, polyaniline base and polyimide, while maintaining comparable separation factors.

  12. Titanium dioxide dye-sensitized polyaniline solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hooi-Sung

    2005-11-01

    A novel form of a dye-sensitized solar cell was investigated with in situ photopolymerization of aniline. Tris(4-carboxyphenyl)mono(4-aminophenyl) porphyrin (TC3APP) was successfully synthesized and used as a sensitizer. Nanoparticulate TiO2 electrodes were prepared from 25 nm size TiO 2 particles (P25); in addition, commercial TiO2 electrodes from Solaronix and INAP were used. Electrochemically polymerized polyaniline films were used as a counterelectrode. Aniline gel as an electrolyte solution was composed of (1S)-(+)-10-camphorsulfonic acid (CSA), lithium perchlorate (LiClO4), polyethylene oxide (PEO), and aniline as solvent. Morphology study of TiO2 electrodes and electropolymerized polyaniline films proceeded with atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results showed that TiO2 electrodes have a highly porous and well connected structure and polyaniline film is composed of a waxy surface and bush-like structure. The conductive emeraldine salt form of polyaniline was confirmed with UV absorption spectroscopy. Adsorption study of TC3APP on TiO2 electrode suggested that most of the adsorption proceeded in 6 hours after the immersion of TiO 2 electrode in TC3APP solution. Greater amounts of TC 3APP were adsorbed on TiO2 electrode in the presence of deoxycholic acid as coadsorber. Photopolymerization proceeded in a sandwiched solar cell with TC 3APP-adsorbed TiO2 electrode and polyaniline counterelectrode including aniline gel. Photocurrent was observed with zero bias voltage. Photocurrent as a function of time was composed of two stages: (1) photoelectropolymerization of polyaniline and (2) conduction of photoelectrons as in a typical solar cell. The current-voltage measurement produced Voc = 0.6 V, J sc = 0.23 mA/cm2, FF = 0.78, and eta = 0.74% under 14.6 mW/cm2 of light intensity. Spectral study and action spectrum confirm that TC3APP is responsible for the photocurrent upon absorption of visible light, and some absorption by

  13. Method for preparing polyaniline fibers

    DOEpatents

    Mattes, Benjamin R.; Wang, Hsing-Lin

    2000-01-01

    Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (>15% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.

  14. Cyclic voltammetry of fast conducting electrocatalytic films.

    PubMed

    Costentin, Cyrille; Savéant, Jean-Michel

    2015-07-15

    In the framework of contemporary energy challenges, cyclic voltammetry is a particularly useful tool for deciphering the kinetics of catalytic films. The case of fast conducting films is analyzed, whether conduction is of the ohmic type or proceeds through rapid electron hopping. The rate-limiting factors are then the diffusion of the substrate in solution and through the film as well as the catalytic reaction itself. The dimensionless combination of the characteristics of these factors allows reducing the number of actual parameters to a maximum of two. The kinetics of the system may then be fully analyzed with the help of a kinetic zone diagram. Observing the variations of the current-potential responses with operational parameters such as film thickness, the potential scan rate and substrate concentration allows a precise assessment of the interplay between these factors and of the values of the rate controlling factors. A series of thought experiments is described in order to render the kinetic analysis more palpable.

  15. 3D polyaniline porous layer anchored pillared graphene sheets: enhanced interface joined with high conductivity for better charge storage applications.

    PubMed

    Sekar, Pandiaraj; Anothumakkool, Bihag; Kurungot, Sreekumar

    2015-04-15

    Here, we report synthesis of a 3-dimensional (3D) porous polyaniline (PANI) anchored on pillared graphene (G-PANI-PA) as an efficient charge storage material for supercapacitor applications. Benzoic acid (BA) anchored graphene, having spatially separated graphene layers (G-Bz-COOH), was used as a structure controlling support whereas 3D PANI growth has been achieved by a simple chemical oxidation of aniline in the presence of phytic acid (PA). The BA groups on G-Bz-COOH play a critical role in preventing the restacking of graphene to achieve a high surface area of 472 m(2)/g compared to reduced graphene oxide (RGO, 290 m(2)/g). The carboxylic acid (-COOH) group controls the rate of polymerization to achieve a compact polymer structure with micropores whereas the chelating nature of PA plays a crucial role to achieve the 3D growth pattern of PANI. This type of controlled interplay helps G-PANI-PA to achieve a high conductivity of 3.74 S/cm all the while maintaining a high surface area of 330 m(2)/g compared to PANI-PA (0.4 S/cm and 60 m(2)/g). G-PANI-PA thus conceives the characteristics required for facile charge mobility during fast charge-discharge cycles, which results in a high specific capacitance of 652 F/g for the composite. Owing to the high surface area along with high conductivity, G-PANI-PA displays a stable specific capacitance of 547 F/g even with a high mass loading of 3 mg/cm(2), an enhanced areal capacitance of 1.52 F/cm(2), and a volumetric capacitance of 122 F/cm(3). The reduced charge-transfer resistance (RCT) of 0.67 Ω displayed by G-PANI-PA compared to pure PANI (0.79 Ω) stands out as valid evidence of the improved charge mobility achieved by the system by growing the 3D PANI layer along the spatially separated layers of the graphene sheets. The low RCT helps the system to display capacitance retention as high as 65% even under a high current dragging condition of 10 A/g. High charge/discharge rates and good cycling stability are the other

  16. Oriented ZnO nanorods grown on a porous polyaniline film as a novel coating for solid-phase microextraction.

    PubMed

    Zeng, Jingbin; Zhao, Cuiying; Chong, Fayun; Cao, Yingying; Subhan, Fazle; Wang, Qianru; Yu, Jianfeng; Zhang, Maosheng; Luo, Liwen; Ren, Wei; Chen, Xi; Yan, Zifeng

    2013-12-06

    In this work, oriented ZnO nanorods (ZNRs) were in situ hydrothermally grown on a porous polyaniline (PANI) film to function as a solid-phase microextraction (SPME) coating. Scanning electron microscopy (SEM) study revealed that the majority of oriented ZNRs grew from pores of PANI matrix, which protected the ZNRs from easily peeling off during operation. Furthermore, in this process, a thin layer of PANI was found to cover the ZNRs, which can enlarge the effective surface area of the composite coating. This ZNRs/PANI composite coating combined the merits of both ZNRs and PANI and, thus, has several advantages over that of sole PANI film and ZNRs coating such as improved extraction efficiency for benzene homologues, enhanced mechanical stability and longer service life (over 150 cycles of SPME-GC operation). Coupled with gas chromatography-flame ionization detector (GC-FID), the optimized SPME-GC-FID method was used for the analysis of six benzene homologues in water samples. The calibration curves were linear from 1 to 1000μgL(-1) for each analyte, and the limits of detection were between 0.001 and 0.024μgL(-1). Single fiber repeatability and fiber-to-fiber reproducibility were in the range of 1.3-6.8% and 5.3-11.2%, respectively. The spiked recoveries at 100 and 5μgL(-1) for three environmental water samples were in the range of 79.8-115.4% and 73.7-117.4%, respectively.

  17. Conduction mechanisms in undoped polycrystalline diamond films

    NASA Astrophysics Data System (ADS)

    Chou, Hsueh-Tao; Lee, Chia-Chang; Sun, Chia-Hsin

    2000-07-01

    The unadopted polycrystalline diamond films are deposited on p-type silicon substrates by a microwave plasma chemical vapor deposition (MPCVD) system. The deposition conditions are CH4?/H(subscript 2=0.5%, pressure equals 45 torr, power equals 2.2kW, and subtract temperature equals 885 degree(s)C. SEM was used to inspect the surface morphology, Raman Spectroscopy to determine the quality, and XPS to analyze the chemical composition. It in concluded that a cleaning procedure on diamond surfaces can eliminate the carbon phase but enhance the oxygenation on the films. The electrical characteristics were investigated by current-voltage-temperature measurements in a metal-insulator-semiconductor (MIS) structure with top metal contacts and back silicon substrates contacts. It can be found a transition electric field of 240 kV/cm, where Schottky emission (SE) mechanism is responsible for electric conduction below 240kV/cm, and Poole-Frenkel transport (PF) mechanism dominates beyond 240 kV/cm. By the extrapolations, the Schottky barrier height of silver and diamond film is 2.4 eV, and the tarp depth is 4.75 eV in the diamond film.

  18. Charge transport across the metal-polymer film boundary

    NASA Astrophysics Data System (ADS)

    Yumaguzin, Yu. M.; Salikhov, T. R.; Shayakhmetov, R. U.; Salikhov, R. B.

    2016-08-01

    Thin polyaniline films were fabricated by thermal vacuum evaporation from a Knudsen effusion cell. The conducting properties of films synthesized under different evaporation conditions were studied. The enhancement of the emission capacity of a wolfram tip coated with a polyaniline film of a nanometer thickness was demonstrated experimentally. A model of the discovered effect was proposed. The obtained Fowler-Nordheim current-voltage characteristics were used to estimate the change in the electronic work function occurring when a thin film is deposited on the tip surface. The effective temperature of electrons emitted from the polyaniline film was determined based on the results of analysis of energy distributions, and the specific features of charge transport in the metal-polyaniline-vacuum system were examined. A model of energy bands of the metal-polymer film contact was also constructed.

  19. Optimization of the thickness of a conducting polymer, polyaniline, deposited on the surface of poly(vinyl chloride) membranes: a new way to improve their potentiometric response.

    PubMed

    Shishkanova, T V; Matejka, P; Král, V; Sedenková, I; Trchová, M; Stejskal, J

    2008-08-29

    Repeated depositions of polyaniline (PANI) have been used to control the thickness of the polymeric film deposited on poly(vinyl chloride) (PVC) membrane surface. The oxidation of aniline was carried out in a dispersion mode, i.e. in the presence of poly(N-vinylpyrrolidone) (PVP). Two kinds of PVC were used for this purpose: a non-plasticized PVC for the study of PANI deposition and PVC, plasticized with nitrophenyl octyl ether (NPOE), as a prototype of a liquid membrane electrode. The results of UV-visible and FTIR spectroscopies and electron microscopy showed that (1) the film thickness increased by about equal increments of approximately 40 nm after each polymerization, and (2) the interface with PVC was constituted by PANI film and adhering PANI-PVP colloidal particles. The various thicknesses of the deposited PANI films affected the potentiometric response of the NPOE/PVC membrane with and without an anion-exchanger. The potentiometric anionic response was observed with a minimal thickness of PANI film on the blank NPOE/PVC membrane. Sensitivity of the PANI film to pH occurred only with a blank NPOE/PVC membrane coated with a thick polymeric film, while it was strongly suppressed by the presence of a lipophilic anion-exchanger, tridodecylmethylammonium chloride (TDDMACl), in the membrane, regardless of the thickness of the polymer film. The thickness of the PANI film did not affect the anionic selectivity pattern of TDDMACl-based membranes to any great extent, but its presence improved and stabilized their potentiometric characteristics (sensitivity, linear-response range).

  20. Properties of conductive thick-film inks

    NASA Technical Reports Server (NTRS)

    Holtze, R. F.

    1972-01-01

    Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

  1. Manufacturing conductive polyaniline/graphite nanocomposites with spent battery powder (SBP) for energy storage: A potential approach for sustainable waste management.

    PubMed

    Duan, Xiaojuan; Deng, Jinxing; Wang, Xue; Guo, Jinshan; Liu, Peng

    2016-07-15

    A potential approach for sustainable waste management of the spent battery material (SBM) is established for manufacturing conductive polyaniline (PANI) nanocomposites as electrode materials for supercapacitors, following the principle of "What comes from the power should be used for the power". The ternary nanocomposites (G/MnO2/PANI) containing PANI, graphite powder (G) and remanent MnO2 nanoparticles and the binary nanocomposites of polyaniline and graphite powder (G/PANI) are synthesized by the chemical oxidative polymerization of aniline in hydrochloric aqueous solution with the MnO2 nanoparticles in the spent battery powder (SBP) as oxidant. The G/PANI sample, which was prepared with MnO2/aniline mole ratio of 1:1 with 1.0mL aniline in 50mL of 1.0molL(-1) HCl, exhibits the electrical conductivity of 22.22Scm(-1), the highest specific capacitance up to 317Fg(-1) and the highest energy density of 31.0 Wh kg(-1), with retention of as high as 84.6% of its initial capacitance after 1000 cycles, indicating good cyclic stability.

  2. Latex-like water-borne polyaniline for coating applications

    SciTech Connect

    Liu, H.; Clark, R.; Yang, S.C.

    1998-07-01

    The authors report the synthesis of a polymeric complex of polyaniline that is dispersed in water as a stable suspension. The polymer, PAN:PVME-MLA, is a molecular complex of polyaniline and poly(vinylmethylether-co-maleic acid). The synthetic process leads to a stable latex-like suspension in water. The water-borne conducting polymer, once dried as a thin film on a substrate, is not dissolvable by water or other solvents. An example of piece-dyeing process is presented to show its potential for electrostatic dissipation of textile products. Another example illustrates that the material may be used as electroactive thin-films for electrochromic windows and for rechargeable battery applications.

  3. Transparent, Weakly Conductive Films for Space Applications

    NASA Astrophysics Data System (ADS)

    Griffin, John; Morgan, Ashraf; Hambourger, Paul

    2004-10-01

    Electrically insulating spacecraft surfaces are vulnerable to nonuniform charge buildup due to particles emitted by the sun. On Mars, insulating surfaces of exploration vehicles and structures will be affected by dust coatings possibly held in place by triboelectric surface charge. Application of a conductive film may be a solution to the charging problem, but the coating must be highly transparent if used on solar panels, lenses, etc. Sheet resistivity requirements depend on the application and are in the range 10^2-10^8 ohms/square. Co-deposited indium tin oxide (ITO) and MgF2 is promising, with high transparency, tailorable electrical properties, and durability to atomic oxygen.(Joyce A. Dever et al., NASA TM 1998-208499 (August 1998).) Due to ITO's relatively narrow bandgap ( ˜3.5 eV), the film might absorb enough ultraviolet to protect polymeric substrates. Recent work on dual-magnetron-sputtered ITO-MgF2 showed that a variety of polymeric substrates can be coated at room temperature.(Thomas Cashman et al., Vacuum Technology & Coating, September 2003, p. 38.) However, the sheet resistivity is very sensitive to composition, suggestive of a percolation transition. This could be a serious problem for large-scale coating production. We will report on attempts to control film composition by plasma emission monitoring of the ITO and MgF2 guns. Supported by NASA Glenn Research Center, Cooperative Agreements NCC3-1033 and NCC3-1065.

  4. DC Electrical Conductivity Retention, Optical Properties and Ammonia Sensing Analysis of Naturally Degraded CSA-Doped Graphene/polyaniline Composite Nanofibers Prepared with CTAB

    NASA Astrophysics Data System (ADS)

    Ghazali, Sayyed; Hossain, Muhammad M.; Khan, Abuzar; Khan, Mohd Y.; Hasan, Mudassir

    2017-01-01

    In this paper, we report surfactant-mediated synthesis of camphor sulfonic acid (CSA)-doped polyaniline/graphene (PANI/GN) composite nanofibers as an electrical conductor and excellent ammonia sensor. The synthesis was mediated by cetyltrimethylammonium bromide as surfactant. The as-synthesized composite nanofibers were characterized by Raman spectroscopy, scanning electron microscopy, tunneling electron microscopy, x-ray diffraction, diffused reflectance spectroscopy and differential scanning calorimetry. The electrical conductivity of the CSA-doped PANI/GN composite nanofibers was found to be remarkably enhanced as compared to the CSA-doped PANI. The boost in electronic conductivity could be attributed to an improved electronic interaction between CSA-doped PANI backbone and GN present in the composite system. The naturally degraded CSA-doped PANI/GN composite nanofibers showed a decrease in electrical conductivity but worked as a good ammonia sensor in open atmospheric conditions.

  5. Thermochromic effect in synthetic opal/polyaniline composite structures

    NASA Astrophysics Data System (ADS)

    Rahman, F.; Khokhar, A. Z.

    2009-02-01

    The design and construction of a novel storage/indicator bilayer system is described where ammonia gas stored in a porous material can be used to dope a colour-changing polyaniline film. Both reversible and irreversible colour change effects are possible. A thin synthetic opal film is coupled to a polyaniline film in a parallel plate glass cell with ammonia gas adsorbed on the silica balls that form the opal structure. When heated and cooled, ammonia reversibly exchanges between the opal and polyaniline films causing a very distinct change in the colour of the polyaniline film. This thermochromic effect is also electrically detectable because of the large concomitant change in the resistivity of the polyaniline film that accompanies its colour change.

  6. The electrical conductivity of polycrystalline metallic films

    NASA Astrophysics Data System (ADS)

    Moraga, Luis; Arenas, Claudio; Henriquez, Ricardo; Bravo, Sergio; Solis, Basilio

    2016-10-01

    We calculate the electrical conductivity of polycrystalline metallic films by means of a semi-numerical procedure that provides solutions of the Boltzmann transport equation, that are essentially exact, by summing over classical trajectories according to Chambers' method. Following Mayadas and Shatzkes (MS), grain boundaries are modeled as an array of parallel plane barriers situated perpendicularly to the direction of the current. Alternatively, according to Szczyrbowski and Schmalzbauer (SS), the model consists in a triple array of these barriers in mutual perpendicular directions. The effects of surface roughness are described by means of Fuchs' specularity parameters. Following SS, the scattering properties of grain boundaries are taken into account by means of another specularity parameter and a probability of coherent passage. The difference between the sum of these and one is the probability of diffuse scattering. When this formalism is compared with the approximate formula of Mayadas and Shatzkes (Phys. Rev. B 1, 103 (1986)) it is shown that the latter greatly overestimates the film resistivity over most values of the reflectivity of the grain boundaries. The dependence of the conductivity of thin films on the probability of coherent passage and grain diameters is examined. In accordance with MS we find that the effects of disorder in the distribution of grain diameters is quite small. Moreover, we find that it is not safe to neglect the effects of the scattering by the additional interfaces created by stacked grains. However, when compared with recent resitivity-thickness data, it is shown that all three formalisms can provide accurate fits to experiment. In addition, it is shown that, depending on the respective reflectivities and distance from a surface, some of these interfaces may increase or diminish considerably the conductivity of the sample. As an illustration of this effect, we show a tentative fit of resistivity data of gold films measured by

  7. Transparent conducting thin films for spacecraft applications

    SciTech Connect

    Perez-Davis, M.E.; Malave-Sanabria, T.; Hambourger, P.; Rutledge, S.K.; Roig, D.; Degroh, K.K.; Hung, C.

    1994-01-01

    Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and aluminum doped zinc oxide (AZO) at several dopant levels are investigated for electrical resistivity (sheet resistance), carrier concentration, optical properties, and atomic oxygen durability. The sheet resistance values of ITO-MgF2 range from 10[sup 2] to 10[sup 11] ohms/square, with transmittance of 75 to 86 percent. The AZO films sheet resistances range from 10[sup 7] to 10[sup 11] ohms/square with transmittances from 84 to 91 percent. It was found that in general, with respect to the optical properties, the zinc oxide (ZnO), AZO, and the high MgF2 content ITO-MgF2 samples, were all durable to atomic oxygen plasma, while the low MgF2 content of ITO-MgF2 samples were not durable to atomic oxygen plasma exposure.

  8. Transparent conducting thin films for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Malave-Sanabria, Tania; Hambourger, Paul; Rutledge, Sharon K.; Roig, David; Degroh, Kim K.; Hung, Ching-Cheh

    1994-01-01

    Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and aluminum doped zinc oxide (AZO) at several dopant levels are investigated for electrical resistivity (sheet resistance), carrier concentration, optical properties, and atomic oxygen durability. The sheet resistance values of ITO-MgF2 range from 10(exp 2) to 10(exp 11) ohms/square, with transmittance of 75 to 86 percent. The AZO films sheet resistances range from 10(exp 7) to 10(exp 11) ohms/square with transmittances from 84 to 91 percent. It was found that in general, with respect to the optical properties, the zinc oxide (ZnO), AZO, and the high MgF2 content ITO-MgF2 samples, were all durable to atomic oxygen plasma, while the low MgF2 content of ITO-MgF2 samples were not durable to atomic oxygen plasma exposure.

  9. Single-walled carbon nanotube/polyaniline/n-silicon solar cells: fabrication, characterization, and performance measurements.

    PubMed

    Tune, Daniel D; Flavel, Benjamin S; Quinton, Jamie S; Ellis, Amanda V; Shapter, Joseph G

    2013-02-01

    Carbon nanotube-silicon solar cells are a recently investigated photovoltaic architecture with demonstrated high efficiencies. Silicon solar-cell devices fabricated with a thin film of conductive polymer (polyaniline) have been reported, but these devices can suffer from poor performance due to the limited lateral current-carrying capacity of thin polymer films. Herein, hybrid solar-cell devices of a thin film of polyaniline deposited on silicon and covered by a single-walled carbon nanotube film are fabricated and characterized. These hybrid devices combine the conformal coverage given by the polymer and the excellent electrical properties of single-walled carbon nanotube films and significantly outperform either of their component counterparts. Treatment of the silicon base and carbon nanotubes with hydrofluoric acid and a strong oxidizer (thionyl chloride) leads to a significant improvement in performance.

  10. Electrically conductive palladium-containing polyimide films

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; Furtsch, T. A.; Taylor, L. T.

    1981-01-01

    Palladium addition makes light, flexible film with low resistivity to relieve space charging. Polyimide film is prepared in four steps: preparation of polyamic acid in polar solvent; addition of soluable palladium complex salt; fabrication of film of "palladium polyamic acid" solution; and thermal imidization of film to palladium-containing polyimide by 300 C heating. Lowered resistivities were achieved without loss in film flexibility or increase in film weight.

  11. Structural and optical study of spin-coated camphorsulfonic acid-doped polyaniline/titanium-di-oxide nanoparticles hybrid thin films

    NASA Astrophysics Data System (ADS)

    Geethalakshmi, D.; Muthukumarasamy, N.; Balasundaraprabhu, R.

    2015-06-01

    Polyaniline (PANI) doped with Camphorsulfonic acid (CSA) has been prepared by chemical oxidative polymerization and blend with titanium-di-oxide (TiO2) nanoparticles prepared by sol-gel method to form CSA-doped PANI/TiO2 hybrid thin films. The properties of as-deposited and heat-treated (100 °C) hybrid thin films having different PANI:TiO2 weight ratios (1:0.5, 1:1, and 1:2) have been compared. FTIR study indicated that chemical bonding between CSA-doped PANI and TiO2 has been formed. XRD studies reveal that the as-deposited hybrid thin films are of amorphous nature and heat-treatment of such films initiates crystallization. SEM study shows that as-deposited hybrid films are rough; increase in TiO2 ratio and heat-treatment increased the roughness due to coalescing and agglomeration. UV-visible absorbance of hybrid films shows its characteristic peak in the visible region along with a peak in UV range and its intensity increased with TiO2 ratio and heat-treatment due to agglomeration of TiO2 particles. Photoluminescence spectra revealed that emission occurs in visible region (495 nm) for as-deposited hybrid thin film and this emission increased with TiO2 ratio and heat-treatment of hybrid films.

  12. Synergy between polyaniline and OMt clay mineral in Langmuir-Blodgett films for the simultaneous detection of traces of metal ions.

    PubMed

    de Barros, Anerise; Ferreira, Mariselma; Constantino, Carlos José Leopoldo; Bortoleto, José Roberto Ribeiro; Ferreira, Marystela

    2015-04-01

    We report on Langmuir-Blodgett (LB) films made with emeraldine salt polyaniline (PAni-ES) and organophilic montmorillonite clay mineral (OMt), where synergy between the components was reached to yield an enhanced performance in detecting trace levels of cadmium (Cd(2+)), lead (Pb(2+)) and copper (Cu(2+)). Detection was carried out using square wave anodic stripping (SWAS) voltammetry with indium tin oxide (ITO) electrodes modified with LB films of PAni-ES/OMt nanocomposite, whose data were compared to those obtained with electrodes coated with neat PAni-ES and neat OMt LB films. The enhanced performance in the nanocomposite may be attributed to the stabilizing and ordering effect promoted by OMt in PAni-ES Langmuir films, which then led to more homogeneous LB films. According to X-ray diffraction data, the stacking of OMt layers was preserved in the LB films and therefore the PAni-ES chains did not cause clay mineral exfoliation. Instead, OMt affected the polaronic state of PAni-ES as indicated in UV-vis, Raman and FTIR spectra, also consistent with the changes observed for the Langmuir films. Taken together these results do indicate that semiconducting polymers and clay minerals may be combined for enhancing the electrical properties of nanostructures for sensing and related applications.

  13. Optical conductivity of amorphous Ta and beta-Ta films

    NASA Technical Reports Server (NTRS)

    Nestell, J. E., Jr.; Scoles, K. J.; Christy, R. W.

    1982-01-01

    Tantalum films evaporated in high vacuum onto liquid-nitrogen-cooled substrates had an amorphous structure that persisted even after warming to room temperature. The optical conductivity (as well as the dc conductivity) of the amorphous films differed significantly from that of the bcc films.

  14. Polycrystalline silicon conductivity modulated thin film transistors

    NASA Astrophysics Data System (ADS)

    Anish, Kumar K. P.

    1997-09-01

    Polycrystalline silicon (poly-Si) thin-film transistors (TFTs) on glass has received significant attention for use in large area microelectronic applications. These applications include both niche and large volume applications such as printer drivers, image scanners, active-matrix liquid crystal displays (AMLCDs), electro-luminescent displays, plasma assisted displays, etc. Currently, the leading technology for these applications is amorphous-Si (a-Si) TFT. However, as the information content increases, a-Si technology encounters severe challenges due to its inherent low mobility, high parasitic capacitance, low aperture ratio, and non-compatibility to CMOS process. On the other hand, poly-Si technology offers high mobility, low parasitic capacitance, small size, CMOS compatibility, good stability, and uses the infrastructure of silicon science and technology. Thus, a simple low temperature poly-Si technology which allows large area system integration on panel will be in great demand for future high definition displays. However, it was found that poly-Si material properties vary with its method of preparation, its grain size, its surface roughness, and the nature and distribution of the inter-granular and bulk defects. Therefore, extensive studies are needed to optimize the key parameters such as the off-current, on-current, and breakdown voltage of the devices. These parameters can be optimized by means of material preparation as well as innovative device designs. In this thesis, three TFT structures were invented and fabricated using a simple low temperature poly-Si technology. With these novel structures, pixels, pixel drivers, and analog and digital peripheral circuits can all be built on the same glass substrate. This allows the ultimate goal of display systems on glass to be much more closer to reality. First, a high voltage transistor called the Conductivity Modulated Thin Film Transistor (CMTFT) is presented. Using this structure, the fundamental current

  15. Optical conductivity of topological insulator thin films

    SciTech Connect

    Li, L. L.; Xu, W.; Peeters, F. M.

    2015-05-07

    We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k·p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi{sub 2}Se{sub 3}-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy ℏω<200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200<ℏω<300 meV), the optical absorption is induced mainly by interband electronic transitions from surface states in the valance band to surface states in the conduction band and an universal value σ{sub 0}=e{sup 2}/(8ℏ) for the optical conductivity can be obtained. (iii) In the high radiation frequency regime (ℏω>300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF.

  16. EDITORIAL: On display with transparent conducting films On display with transparent conducting films

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2012-03-01

    Transparent conducting films were already featuring in scientific literature over one hundred years ago. In 1894 Aryton and Mather described a conducting varnish for coating the screens of electric apparatus so they would not charge when accidentally brushed by a coat sleeve or other material [1]. Their method began with a similar approach to that used to make savoury jellies; by dissolving gelatine in vinegar, after which less palatable ingredients were incorporated including sulphuric acid and an antisulphuric enamel. While the search for transparent conducting films continued to attract other researchers, the same problem remained: the transparency would be compromised if the film was too thick, and the conductivity would be compromised if the film was too thin. In the early 1950s Gillham and Preston reported that thin gold films sputtered on bismuth oxide and heated resulted in a material that successfully combined the previously mutually exclusive properties of transparency and conductivity [2]. Other oxide films were also found to favourably combine these properties, including tin oxide, as reported by Ishiguro and colleagues in Japan in 1958 [3]. Today tin oxide doped with indium (ITO) has become the industry standard for transparent conducting films in a range of applications including photovoltaic technology and displays. It is perhaps the mounting ubiquity of electronic displays as a result of the increasingly digitised and computerised environment of the modern day world that has begun to underline the main drawback of ITO: expense. In this issue, a collaboration of researchers in Korea present an overview of graphene as a transparent conducting material with the potential to replace ITO in a range of electronic and optoelectronic applications [4]. One of the first innovations in optical microscopy was the use of dyes. This principle first came into practice with the use of ultraviolet light to reveal previously indistinguishable features. As explained

  17. Multilayer Films Electrodes Consisted of Cashew Gum and Polyaniline Assembled by the Layer-by-Layer Technique: Electrochemical Characterization and Its Use for Dopamine Determination.

    PubMed

    Barros, Sergio Bitencourt Araújo; Leite, Cleide Maria da Silva; de Brito, Ana Cristina Facundo; Dos Santos Júnior, José Ribeiro; Zucolotto, Valtencir; Eiras, Carla

    2012-01-01

    We take advantage of polyelectrolyte feature exhibited by natural cashew gum (Anacardium occidentale L.) (CG), found in northeast Brazil, to employ it in the formation of electroactive nanocomposites prepared by layer-by-layer (LbL) technique. We used polyaniline unmodified (PANI) or modified with phosphonic acid (PA), PANI-PA as cationic polyelectrolyte. On the other hand, the CG or polyvinyl sulfonic (PVS) acids were used as anionic polyelectrolytes. The films were prepared with PANI or PANI-PA intercalated with CG or with PVS alternately resulting in four films with different sequences: PANI/CG PANI-PA/CG, PANI/PVS and PANI-PA/PVS, respectively. Analysis by cyclic voltammetry (CV) of the films showed that the presence of gum increases the stability of the films in acidic medium. The performance of the modified electrode of PANI-PA/CG was evaluated in electro analytical determination of dopamine (DA). The tests showed great sensitivity of the film for this analyte that was detected at 10(-5) mol L(-1).

  18. Multilayer Films Electrodes Consisted of Cashew Gum and Polyaniline Assembled by the Layer-by-Layer Technique: Electrochemical Characterization and Its Use for Dopamine Determination

    PubMed Central

    Barros, Sergio Bitencourt Araújo; Leite, Cleide Maria da Silva; de Brito, Ana Cristina Facundo; Dos Santos Júnior, José Ribeiro; Zucolotto, Valtencir; Eiras, Carla

    2012-01-01

    We take advantage of polyelectrolyte feature exhibited by natural cashew gum (Anacardium occidentale L.) (CG), found in northeast Brazil, to employ it in the formation of electroactive nanocomposites prepared by layer-by-layer (LbL) technique. We used polyaniline unmodified (PANI) or modified with phosphonic acid (PA), PANI-PA as cationic polyelectrolyte. On the other hand, the CG or polyvinyl sulfonic (PVS) acids were used as anionic polyelectrolytes. The films were prepared with PANI or PANI-PA intercalated with CG or with PVS alternately resulting in four films with different sequences: PANI/CG PANI-PA/CG, PANI/PVS and PANI-PA/PVS, respectively. Analysis by cyclic voltammetry (CV) of the films showed that the presence of gum increases the stability of the films in acidic medium. The performance of the modified electrode of PANI-PA/CG was evaluated in electro analytical determination of dopamine (DA). The tests showed great sensitivity of the film for this analyte that was detected at 10−5 mol L−1. PMID:22505924

  19. Thin transparent conducting films of cadmium stannate

    DOEpatents

    Wu, Xuanzhi; Coutts, Timothy J.

    2001-01-01

    A process for preparing thin Cd.sub.2 SnO.sub.4 films. The process comprises the steps of RF sputter coating a Cd.sub.2 SnO.sub.4 layer onto a first substrate; coating a second substrate with a CdS layer; contacting the Cd.sub.2 SnO.sub.4 layer with the CdS layer in a water- and oxygen-free environment and heating the first and second substrates and the Cd.sub.2 SnO.sub.4 and CdS layers to a temperature sufficient to induce crystallization of the Cd.sub.2 SnO.sub.4 layer into a uniform single-phase spinel-type structure, for a time sufficient to allow full crystallization of the Cd.sub.2 SnO.sub.4 layer at that temperature; cooling the first and second substrates to room temperature; and separating the first and second substrates and layers from each other. The process can be conducted at temperatures less than 600.degree. C., allowing the use of inexpensive soda lime glass substrates.

  20. Exploding conducting film laser pumping apparatus

    DOEpatents

    Ware, K.D.; Jones, C.R.

    1984-04-27

    The 342-nm molecular iodine and the 1.315-..mu..m atomic iodine lasers have been optically pumped by intense light from exploding-metal-film discharges. Brightness temperatures for the exploding-film discharges were approximately 25,000 K. Although lower output energies were achieved for such discharges when compared to exploding-wire techniques, the larger surface area and smaller inductance inherent in the exploding-film should lead to improved efficiency for optically-pumped gas lasers.

  1. Preparation of Electrically Conductive Polymeric Membranes

    NASA Astrophysics Data System (ADS)

    Encinas, J. C.; Castillo-Ortega, M. M.; Rodríguez, F.; Castaño, V. M.

    2015-10-01

    Cellulose acetate porous membranes, coated with polyaniline, were chemically modified with polyelectrolytes to produce films of varying and controlled porosity and electrical conductivity. The highest electrical conductivity was obtained in membranes prepared with poly(styrene sulfonate) with large pore sizes. The electrical properties as well as scanning electron microscopy (SEM) images are discussed.

  2. Real-Time Deposition Monitor for Ultrathin Conductive Films

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline

    2011-01-01

    A device has been developed that can be used for the real-time monitoring of ultrathin (2 or more) conductive films. The device responds in less than two microseconds, and can be used to monitor film depositions up to about 60 thick. Actual thickness monitoring capability will vary based on properties of the film being deposited. This is a single-use device, which, due to the very low device cost, can be disposable. Conventional quartz/crystal microbalance devices have proven inadequate to monitor the thickness of Pd films during deposition of ultrathin films for hydrogen sensor devices. When the deposited film is less than 100 , the QCM measurements are inadequate to allow monitoring of the ultrathin films being developed. Thus, an improved, high-sensitivity, real-time deposition monitor was needed to continue Pd film deposition development. The new deposition monitor utilizes a surface acoustic wave (SAW) device in a differential delay-line configuration to produce both a reference response and a response for the portion of the device on which the film is being deposited. Both responses are monitored simultaneously during deposition. The reference response remains unchanged, while the attenuation of the sensing path (where the film is being deposited) varies as the film thickness increases. This device utilizes the fact that on high-coupling piezoelectric substrates, the attenuation of an SAW undergoes a transition from low to very high, and back to low as the conductivity of a film on the device surface goes from nonconductive to highly conductive. Thus, the sensing path response starts with a low insertion loss, and as a conductive film is deposited, the film conductivity increases, causing the device insertion loss to increase dramatically (by up to 80 dB or more), and then with continued film thickness increases (and the corresponding conductivity increases), the device insertion loss goes back down to the low level at which it started. This provides a

  3. Current-induced surface roughness reduction in conducting thin films

    NASA Astrophysics Data System (ADS)

    Du, Lin; Maroudas, Dimitrios

    2017-03-01

    Thin film surface roughness is responsible for various materials reliability problems in microelectronics and nanofabrication technologies, which requires the development of surface roughness reduction strategies. Toward this end, we report modeling results that establish the electrical surface treatment of conducting thin films as a physical processing strategy for surface roughness reduction. We develop a continuum model of surface morphological evolution that accounts for the residual stress in the film, surface diffusional anisotropy and film texture, film's wetting of the layer that is deposited on, and surface electromigration. Supported by linear stability theory, self-consistent dynamical simulations based on the model demonstrate that the action over several hours of a sufficiently strong and properly directed electric field on a conducting thin film can reduce its surface roughness and lead to a smooth planar film surface. The modeling predictions are in agreement with experimental measurements on copper thin films deposited on silicon nitride layers.

  4. Biotemplate synthesis of polyaniline@cellulose nanowhiskers/natural rubber nanocomposites with 3D hierarchical multiscale structure and improved electrical conductivity.

    PubMed

    Wu, Xiaodong; Lu, Canhui; Xu, Haoyu; Zhang, Xinxing; Zhou, Zehang

    2014-12-10

    Development of novel and versatile strategies to construct conductive polymer composites with low percolation thresholds and high mechanical properties is of great importance. In this work, we report a facile and effective strategy to prepare polyaniline@cellulose nanowhiskers (PANI@CNs)/natural rubber (NR) nanocomposites with 3D hierarchical multiscale structure. Specifically, PANI was synthesized in situ on the surface of CNs biotemplate to form PANI@CNs nanohybrids with high aspect ratio and good dispersity. Then NR latex was introduced into PANI@CNs nanohybrids suspension to enable the self-assembly of PANI@CNs nanohybrids onto NR latex microspheres. During cocoagulation process, PANI@CNs nanohybrids selectively located in the interstitial space between NR microspheres and organized into a 3D hierarchical multiscale conductive network structure in NR matrix. The combination of the biotemplate synthesis of PANI and latex cocoagulation method significantly enhanced the electrical conductivity and mechanical properties of the NR-based nanocomposites simultaneously. The electrical conductivity of PANI@CNs/NR nanocomposites containing 5 phr PANI showed 11 orders of magnitude higher than that of the PANI/NR composites at the same loading fraction,; meanwhile, the percolation threshold was drastically decreased from 8.0 to 3.6 vol %.

  5. Preparation of Electrically Conductive Polystyrene/Carbon Nanofiber Nanocomposite Films

    ERIC Educational Resources Information Center

    Sun, Luyi; O'Reilly, Jonathan Y.; Tien, Chi-Wei; Sue, Hung-Jue

    2008-01-01

    A simple and effective approach to prepare conductive polystyrene/carbon nanofiber (PS/CNF) nanocomposite films via a solution dispersion method is presented. Inexpensive CNF, which has a structure similar to multi-walled carbon nanotubes, is chosen as a nanofiller in this experiment to achieve conductivity in PS films. A good dispersion is…

  6. Development of Thin Conducting Film Fabrication Methods.

    DTIC Science & Technology

    1979-12-01

    mediate mandrels ( beeswax , polymeric resins such as PVA, PVC, PBS, Saran). Efforts to transfer the foils intact from formation on intermediate mandrels...methods Investigated for removing and transferring pyrolytic carbon films onto cylindrical electrodes consist of: (1) melted beeswax and other high...attempts at removing the carbon film from the quartz mandrel were made using melted beeswax , as in Figure 4. In the first few attempts, the entire

  7. Tuning carbon nanotube assembly for flexible, strong and conductive films.

    PubMed

    Wang, Yanjie; Li, Min; Gu, Yizhuo; Zhang, Xiaohua; Wang, Shaokai; Li, Qingwen; Zhang, Zuoguang

    2015-02-21

    Carbon nanotubes are ideal scaffolds for designing and architecting flexible graphite films with tunable mechanical, electrical and thermal properties. Herein, we demonstrate that the assembly of aligned carbon nanotubes with different aggregation density and morphology leads to different mechanical properties and anisotropic electrical conduction along the films. Using drying evaporation under tension treatment, the carbon nanotubes can be assembled into strong films with tensile strength and Young's modulus as high as 3.2 GPa and 124 GPa, respectively, leading to a remarkable toughness of 54.38 J g(-1), greatly outperforming conventional graphite films, spider webs and even Kevlar fiber films. Different types of solvents may result in the assembly of CNTs with different aggregation morphology and therefore different modulus. In addition, we reveal that the high density assembly of aligned CNTs correlates with better electric conduction along the axial direction, enabling these flexible graphite films to be both strong and conductive.

  8. Thermal conductivity and interface thermal conductance of thin films in Li ion batteries

    NASA Astrophysics Data System (ADS)

    Jagannadham, K.

    2016-09-01

    Laser physical vapor deposition is used to deposit thin films of lithium phosphorous oxynitride in nitrogen and lithium nickel manganese oxide in oxygen ambient on Si substrate. LIPON film is also deposited on LiNiMnO film that is deposited on Si. Graphene films consisting of graphene platelets are deposited on Si substrate from a suspension in isopropyl alcohol. Li-graphene films are obtained after Li adsorption by immersion in LiCl solution and further drying. Transient thermo reflectance signal is used to determine the cross-plane thermal conductivity of different layers and interface thermal conductance of the interfaces. The results show that LIPON film with lower thermal conductivity is a thermal barrier. The interface thermal conductance between LIPON and Au or Si is found to be very low. Thermal conductivity of LiNiMnO is found to be reasonably high so that it is not a barrier to thermal transport. Film with graphene platelets shows a higher value and Li adsorbed graphene film shows a much higher value of cross-plane thermal conductivity. The value of interface thermal conductance between graphene and Au or Si (100) substrate is also much lower. The implications of the results for the thermal transport in thin film Li batteries are discussed.

  9. Conductive layer for biaxially oriented semiconductor film growth

    DOEpatents

    Findikoglu, Alp T.; Matias, Vladimir

    2007-10-30

    A conductive layer for biaxially oriented semiconductor film growth and a thin film semiconductor structure such as, for example, a photodetector, a photovoltaic cell, or a light emitting diode (LED) that includes a crystallographically oriented semiconducting film disposed on the conductive layer. The thin film semiconductor structure includes: a substrate; a first electrode deposited on the substrate; and a semiconducting layer epitaxially deposited on the first electrode. The first electrode includes a template layer deposited on the substrate and a buffer layer epitaxially deposited on the template layer. The template layer includes a first metal nitride that is electrically conductive and has a rock salt crystal structure, and the buffer layer includes a second metal nitride that is electrically conductive. The semiconducting layer is epitaxially deposited on the buffer layer. A method of making such a thin film semiconductor structure is also described.

  10. Rapid synthesis of flexible conductive polymer nanocomposite films

    NASA Astrophysics Data System (ADS)

    Blattmann, C. O.; Sotiriou, G. A.; Pratsinis, S. E.

    2015-03-01

    Polymer nanocomposite films with nanoparticle-specific properties are sought out in novel functional materials and miniaturized devices for electronic and biomedical applications. Sensors, capacitors, actuators, displays, circuit boards, solar cells, electromagnetic shields and medical electrodes rely on flexible, electrically conductive layers or films. Scalable synthesis of such nanocomposite films, however, remains a challenge. Here, flame aerosol deposition of metallic nanosliver onto bare or polymer-coated glass substrates followed by polymer spin-coating on them leads to rapid synthesis of flexible, free-standing, electrically conductive nanocomposite films. Their electrical conductivity is determined during their preparation and depends on substrate composition and nanosilver deposition duration. Accordingly, thin (<500 nm) and flexible nanocomposite films are made having conductivity equivalent to metals (e.g. 5 × 104 S cm-1), even during repetitive bending.

  11. Synthesis of conducting polyelectrolyte complexes of polyaniline and poly(2-acrylamido-3-methyl-1-propanesulfonic acid) catalyzed by pH-stable palm tree peroxidase.

    PubMed

    Caramyshev, Alexei V; Evtushenko, Evgeny G; Ivanov, Viktor F; Barceló, Alfonso Ros; Roig, Manuel G; Shnyrov, Valery L; van Huystee, Robert B; Kurochkin, Iliya N; Vorobiev, Andrey Kh; Sakharov, Ivan Yu

    2005-01-01

    Comparison of the stability of five plant peroxidases (horseradish, royal palm tree leaf, soybean, and cationic and anionic peanut peroxidases) was carried out under acidic conditions favorable for synthesis of polyelectrolyte complexes of polyaniline (PANI). It demonstrates that palm tree peroxidase has the highest stability. Using this peroxidase as a catalyst, the enzymatic synthesis of polyelectrolyte complexes of PANI and poly(2-acrylamido-3-methyl-1-propanesulfonic acid) (PAMPS) was developed. The template polymerization of aniline was carried out in aqueous buffer at pH 2.8. Varying the concentrations of aniline, PAMPS, and hydrogen peroxide as reagents, favorable conditions for production of PANI were determined. UV-vis-NIR absorption and EPR demonstrated that PAMPS and PANI formed the electroactive complex similar to PANI doped traditionally using low molecular weight sulfonic acids. The effect of pH on conformational variability of the complex was evaluated by UV-vis spectroscopy. Atomic force microscopy showed that a size of the particles of the PANI-PAMPS complexes varied between 10 and 25 nm, depending on a concentration of PAMPS in the complex. The dc conductivity of the complexes depends also on the content of PAMPS, the higher conductivity being for the complexes containing the lower content of the polymeric template.

  12. Modifications vibrationnelles induites par différentes vapeurs acides sur les polyanilines

    NASA Astrophysics Data System (ADS)

    Cochet, M.; Quillard, S.; Buisson, J. P.; Lefrant, S.; Louarn, G.

    1998-06-01

    We present a comparative study of conductive form of polyaniline, i.e, polyemeraldine doped with HCl vapor or with HCSA upon m-cresol vapor. UV-Vis.-nir absorption measurements on polyaniline thin films, vs acid vapors time exposure, have been made. In the same way, Raman spectra have been recorded with different excitation lines from the blue and red ranges to the infrared region. Finally, an assignment of Raman bands observed, is proposed and confirmed by vibrational calculations based on valence-force-field. Nous présentons une étude comparative de la forme conductrice de la polyaniline, c'est-à-dire de la polyéméraldine dopée par des vapeurs d'HCl ou dopée par l'acide camphre sulfonique (HCSA) sous vapeurs de m-crésol. Des mesures d'absorption UV-Vis-proche infrarouge sur des films minces de polyaniline, en fonction du temps d'exposition aux vapeurs acides, ont été réalisées. Parallèlement, les spectres Raman ont été obtenus pour différentes longueurs d'onde d'excitation allant du visible jusqu'au proche infrarouge. Finalement, une attribution des bandes Raman observées est proposée et confirmée par des calculs vibrationnels basés sur des champs de force de valence.

  13. Structure, Order and the Metallic State in Polyaniline and its Derivatives.

    DTIC Science & Technology

    1991-03-18

    self-doped sulfonic acid substituted polyaniline , SPAN. Recent advances in the processing of the polyanilines enable the study of the orientation and...hydrochloride, and sulfonated polyaniline dlemonstraLe the importarnCe of interchain diffusion of charge in achieving high conductivities. These results are in...uidine) hydrochloride, and sulfonated polyaniline demonstrate the importance of interchain diffusion of charge in achieving high conductivities. These

  14. Silver Nanowire Networks as Flexible, Transparent, Conducting Films: Extremely High DC to Optical Conductivity Ratios.

    PubMed

    De, Sukanta; Higgins, Thomas M; Lyons, Philip E; Doherty, Evelyn M; Nirmalraj, Peter N; Blau, Werner J; Boland, John J; Coleman, Jonathan N

    2009-07-28

    We have used aqueous dispersions of silver nanowires to prepare thin, flexible, transparent, conducting films. The nanowires are of length and diameter close to 6.5 μm and 85 nm, respectively. At low thickness, the films consist of networks but appear to become bulk-like for mean film thicknesses above ∼160 nm. These films can be very transparent with optical transmittance reaching as high as 92% for low thickness. The transmittance (550 nm) decreases with increasing thickness, consistent with an optical conductivity of 6472 S/m. The films are also very uniform; the transmittance varies spatially by typically <2%. The sheet resistance decreases with increasing thickness, falling below 1 Ω/◻ for thicknesses above 300 nm. The DC conductivity increases from 2 × 10(5) S/m for very thin films before saturating at 5 × 10(6) S/m for thicker films. Similarly, the ratio of DC to optical conductivity increases with increasing thickness from 25 for the thinnest films, saturating at ∼500 for thicknesses above ∼160 nm. We believe this is the highest conductivity ratio ever observed for nanostructured films and is matched only by doped metal oxide films. These nanowire films are electromechanically very robust, with all but the thinnest films showing no change in sheet resistance when flexed over >1000 cycles. Such results make these films ideal as replacements for indium tin oxide as transparent electrodes. We have prepared films with optical transmittance and sheet resistance of 85% and 13 Ω/◻, respectively. This is very close to that displayed by commercially available indium tin oxide.

  15. UV and visible light controllable depletion zone of ZnO-polyaniline p-n junction and its application in a photoresponsive sensor.

    PubMed

    Gong, Jian; Li, Yinhua; Deng, Yulin

    2010-12-07

    In this communication, we report that the depletion zone thickness of the p-n junction between an n-type ZnO and a p-type polyaniline could be controlled by UV and visible light illumination. Based on this princile, photoresponsive sensors were constructed by combining polyaniline thin film and ZnO nanorods. Different from pure ZnO nanomaterials whose conductivity increases when they are exposed to UV illumination, the conductivity of the photoresponsive sensor studied in this communication decreased when the UV light was turned on. The surface modification of ZnO could switch the wavelength of the response light from UV to visible light.

  16. Enhancing the conductivity of transparent graphene films via doping.

    PubMed

    Kim, Ki Kang; Reina, Alfonso; Shi, Yumeng; Park, Hyesung; Li, Lain-Jong; Lee, Young Hee; Kong, Jing

    2010-07-16

    We report chemical doping (p-type) to reduce the sheet resistance of graphene films for the application of high-performance transparent conducting films. The graphene film synthesized by chemical vapor deposition was transferred to silicon oxide and quartz substrates using poly(methyl methacrylate). AuCl(3) in nitromethane was used to dope the graphene films and the sheet resistance was reduced by up to 77% depending on the doping concentration. The p-type doping behavior was confirmed by characterizing the Raman G-band of the doped graphene film. Atomic force microscope and scanning electron microscope images reveal the deposition of Au particles on the film. The sizes of the Au particles are 10-100 nm. The effect of doping was also investigated by transferring the graphene films onto quartz and poly(ethylene terephthalate) substrates. The sheet resistance reached 150 Omega/sq at 87% transmittance, which is comparable to those of indium tin oxide conducting film. The doping effect was manifested only with 1-2 layer graphene but not with multi-layer graphene. This approach advances the numerous applications of graphene films as transparent conducting electrodes.

  17. Chloride salt of conducting polyaniline synthesized in the presence of CeO2: Structural analysis of the core-shell nanocomposite

    NASA Astrophysics Data System (ADS)

    da Silva, J. S. M.; de Souza, S. M.; Trovati, G.; Sanches, E. A.

    2017-01-01

    Chloride salt of conducting Polyaniline (ES-PANI) was synthesized in the presence of cerium dioxide (CeO2) for structural and morphological evaluation of the resulting core-shell nanocomposite. X-ray Diffraction (XRD), estimative of crystallinity percentage, Le Bail Method, Scanning Electron Microscopy (SEM) and DC electrical conductivity were used for materials characterization. The resulting nanocomposite was constituted of three phases as identified by X-Ray Diffraction: ES-PANI, CeO2 and CeCl3(H2O)7, chloride hepta-hydrate cerium. Crystallinity of ES-PANI and nanocomposite were estimated around 40 and 85%, respectively. XRD patterns were also used to perform the Le Bail Method. This refinement allowed structural characterization of each phase, obtainment of cell parameters and crystallite size and shape. For ES-PANI and CeCl3(H2O)7, crystallites showed a prolate-like shape with an average size of 21 Å and 104 Å, respectively. CeO2 crystallites presented much larger size, as expected, with isotropic average size of 490 Å. SEM images showed that the nanocomposite has a core-shell morphology with both ES-PANI nanofibers and CeCl3(H2O)7 particles coating the CeO2 particles. The polymerization of ES-PANI over the CeO2 particles in order to form the nanocomposite affected the natural chain alignment of the polymer, resulting in better molecular rearrangement and larger crystallites. Finally, measurements of DC electrical conductivity of ES-PANI and nanocomposite have showed values of 1.11 × 10-4 and 2.22 × 10-4 S/cm, respectively. Nanocomposite has showed electrical conductivity 50 times greater than the pure ES-PANI. Thus, in this work we have reported a systematic structural and morphological investigation of PANI/CeO2/CeCl3(H2O)7 core-shell nanocomposite.

  18. Stretchable transistors with buckled carbon nanotube films as conducting channels

    DOEpatents

    Arnold, Michael S; Xu, Feng

    2015-03-24

    Thin-film transistors comprising buckled films comprising carbon nanotubes as the conductive channel are provided. Also provided are methods of fabricating the transistors. The transistors, which are highly stretchable and bendable, exhibit stable performance even when operated under high tensile strains.

  19. Polyaniline-iron oxide nanohybrid film as multi-functional label-free electrochemical and biomagnetic sensor for catechol.

    PubMed

    Chandra, Sudeshna; Lang, Heinrich; Bahadur, Dhirendra

    2013-09-17

    Polyaniline-iron oxide magnetic nanohybrid was synthesized and characterized using various spectroscopic, microstructural and electrochemical techniques. The smart integration of Fe3O4 nanoparticles within the polyaniline (PANI) matrix yielded a mesoporous nanohybrid (Fe3O4@PANI) with high surface area (94 m(2) g(-1)) and average pore width of 12.8 nm. Catechol is quasi-reversibly oxidized to o-quinone and reduced at the Fe3O4@PANI modified electrodes. The amperometric current response toward catechol was evaluated using the nanohybrid and the sensitivity and detection limit were found to be 312 μA μL(-1) and 0.2 nM, respectively. The results from electrochemical impedance spectroscopy (EIS) indicated that the increased solution resistance (Rs) was due to elevated adsorption of catechol on the modified electrodes. Photoluminescence spectra showed ligand-to-metal charge transfer (LMCT) between p-π orbitals of the phenolate oxygen in catechol and the d-σ* metal orbital of Fe3O4@PANI nanohybrid. Potential dependent spectroelectrochemical behavior of Fe3O4@PANI nanohybrid toward catechol was studied using UV/vis/NIR spectroscopy. The binding activity of the biomagnetic particles to catechol through Brownian relaxation was evident from AC susceptibility measurements. The proposed sensor was used for successful recovery of catechol in tap water samples.

  20. Tuning carbon nanotube assembly for flexible, strong and conductive films

    NASA Astrophysics Data System (ADS)

    Wang, Yanjie; Li, Min; Gu, Yizhuo; Zhang, Xiaohua; Wang, Shaokai; Li, Qingwen; Zhang, Zuoguang

    2015-02-01

    Carbon nanotubes are ideal scaffolds for designing and architecting flexible graphite films with tunable mechanical, electrical and thermal properties. Herein, we demonstrate that the assembly of aligned carbon nanotubes with different aggregation density and morphology leads to different mechanical properties and anisotropic electrical conduction along the films. Using drying evaporation under tension treatment, the carbon nanotubes can be assembled into strong films with tensile strength and Young's modulus as high as 3.2 GPa and 124 GPa, respectively, leading to a remarkable toughness of 54.38 J g-1, greatly outperforming conventional graphite films, spider webs and even Kevlar fiber films. Different types of solvents may result in the assembly of CNTs with different aggregation morphology and therefore different modulus. In addition, we reveal that the high density assembly of aligned CNTs correlates with better electric conduction along the axial direction, enabling these flexible graphite films to be both strong and conductive.Carbon nanotubes are ideal scaffolds for designing and architecting flexible graphite films with tunable mechanical, electrical and thermal properties. Herein, we demonstrate that the assembly of aligned carbon nanotubes with different aggregation density and morphology leads to different mechanical properties and anisotropic electrical conduction along the films. Using drying evaporation under tension treatment, the carbon nanotubes can be assembled into strong films with tensile strength and Young's modulus as high as 3.2 GPa and 124 GPa, respectively, leading to a remarkable toughness of 54.38 J g-1, greatly outperforming conventional graphite films, spider webs and even Kevlar fiber films. Different types of solvents may result in the assembly of CNTs with different aggregation morphology and therefore different modulus. In addition, we reveal that the high density assembly of aligned CNTs correlates with better electric conduction

  1. Minimum thermal conductivity considerations in aerogel thin films

    NASA Astrophysics Data System (ADS)

    Hopkins, Patrick E.; Kaehr, Bryan; Piekos, Edward S.; Dunphy, Darren; Jeffrey Brinker, C.

    2012-06-01

    We demonstrate the use time domain thermoreflectance (TDTR) to measure the thermal conductivity of the solid silica network of aerogel thin-films. TDTR presents a unique experimental capability for measuring the thermal conductivity of porous media due to the nanosecond time domain aspect of the measurement. In short, TDTR is capable of explicitly measuring the change in temperature with time of the solid portion of porous media independently from the pores or effective media. This makes TDTR ideal for determining the thermal transport through the solid network of the aerogel film. We measure the thermal conductivity of the solid silica networks of an aerogel film that is 10% solid, and the thermal conductivity of the same type of film that has been calcined to remove the terminating methyl groups. We find that for similar densities, the thermal conductivity through the silica in the aerogel thin films is similar to that of bulk aerogels. We theoretically describe the thermal transport in the aerogel films with a modified minimum limit to thermal conductivity that accounts for porosity through a reduction in phonon velocity. Our porous minimum limit agrees well with a wide range of experimental data in addition to sound agreement with differential effective medium theory. This porous minimum limit therefore demonstrates an approach to predict the thermal conductivity of porous disordered materials with no a priori knowledge of the corresponding bulk phase, unlike differential effective medium theory.

  2. Photovoltaic device having light transmitting electrically conductive stacked films

    DOEpatents

    Weber, Michael F.; Tran, Nang T.; Jeffrey, Frank R.; Gilbert, James R.; Aspen, Frank E.

    1990-07-10

    A light transmitting electrically conductive stacked film, useful as a light transmitting electrode, including a first light transmitting electrically conductive layer, having a first optical thickness, a second light transmitting layer, having a second optical thickness different from the optical thickness of the first layer, and an electrically conductive metallic layer interposed between and in initimate contact with the first and second layers.

  3. High conductivity transparent carbon nanotube films deposited from superacid.

    PubMed

    Hecht, David S; Heintz, Amy M; Lee, Roland; Hu, Liangbing; Moore, Bryon; Cucksey, Chad; Risser, Steven

    2011-02-18

    Carbon nanotubes (CNTs) were deposited from a chlorosulfonic superacid solution onto PET substrates by a filtration/transfer method. The sheet resistance and transmission (at 550 nm) of the films were 60 Ω/sq and 90.9% respectively, which corresponds to a DC conductivity of 12,825 S cm(-1) and a DC/optical conductivity ratio of 64.1. This is the highest DC conductivity reported for CNT thin films to date, and attributed to both the high quality of the CNT material and the exfoliation/doping by the superacid. This work demonstrates that CNT transparent films have not reached the conductivity limit; continued improvements will enable these films to be used as the transparent electrode for applications in solid state lighting, LCD displays, touch panels, and photovoltaics.

  4. Aptameric Recognition-Modulated Electroactivity of Poly(4-Styrenesolfonic Acid)-Doped Polyaniline Films for Single-Shot Detection of Tetrodotoxin

    PubMed Central

    Fomo, Gertrude; Waryo, Tesfaye T.; Sunday, Christopher E.; Baleg, Abd A.; Baker, Priscilla G.; Iwuoha, Emmanuel I.

    2015-01-01

    The work being reported is the first electrochemical sensor for tetrodotoxin (TTX). It was developed on a glassy carbon electrodes (C) that was modified with poly(4-styrenesolfonic acid)-doped polyaniline film (PANI/PSSA). An amine-end functionalized TTX-binding aptamer, 5′-NH2-AAAAATTTCACACGGGTGCCTCGGCTGTCC-3′ (NH2-Apt), was grafted via covalent glutaraldehyde (glu) cross-linking. The resulting aptasensor (C//PANI+/PSSA-glu-NH2-Apt) was interrogated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in sodium acetate buffer (NaOAc, pH 4.8) before and after 30 min incubation in standard TTX solutions. Both CV and EIS results confirmed that the binding of the analyte to the immobilized aptamer modulated the electrochemical properties of the sensor: particularly the charge transfer resistance (Rct) of the PANI+/PSSA film, which served as a signal reporter. Based on the Rct calibration curve of the TTX aptasensor, the values of the dynamic linear range (DLR), sensitivity and limit of detection (LOD) of the sensor were determined to be 0.23–1.07 ng·mL−1 TTX, 134.88 ± 11.42 Ω·ng·mL−1 and 0.199 ng·mL−1, respectively. Further studies are being planned to improve the DLR as well as to evaluate selectivity and matrix effects in real samples. PMID:26370994

  5. Electrochemical determination of L-phenylalanine at polyaniline modified carbon electrode based on β-cyclodextrin incorporated carbon nanotube composite material and imprinted sol-gel film.

    PubMed

    Hu, Yu-fang; Zhang, Zhao-hui; Zhang, Hua-bin; Luo, Li-juan; Yao, Shou-zhuo

    2011-04-15

    A sensitive and selective electrochemical sensor based on a polyaniline modified carbon electrode for the determination of L-phenylalanine has been proposed by utilizing β-cyclodextrin (β-CD) incorporated multi-walled carbon nanotube (MWNT) and imprinted sol-gel film. The electrochemical behavior of the sensor towards L-phenylalanine was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometric i-t curve. The surface morphologies of layer-by-layer assembly electrodes were displayed by scanning electron microscope (SEM). The response mechanism of the imprinted sensor for L-phenylalanine was based on the inclusion interaction of β-CD and molecular recognition capacity of the imprinted film for L-phenylalanine. A linear calibration plot was obtained covering the concentration range from 5.0 × 10(-7) to 1.0 × 10(-4) mol L(-1) with a detection limit of 1.0 × 10(-9) mol L(-1). With excellent sensitivity, selectivity, stability, reproducibility and recovery, the electrochemical imprinted sensor was used to detect L-phenylalanine in blood plasma samples successfully.

  6. Modelling heat conduction in polycrystalline hexagonal boron-nitride films.

    PubMed

    Mortazavi, Bohayra; Pereira, Luiz Felipe C; Jiang, Jin-Wu; Rabczuk, Timon

    2015-08-19

    We conducted extensive molecular dynamics simulations to investigate the thermal conductivity of polycrystalline hexagonal boron-nitride (h-BN) films. To this aim, we constructed large atomistic models of polycrystalline h-BN sheets with random and uniform grain configuration. By performing equilibrium molecular dynamics (EMD) simulations, we investigated the influence of the average grain size on the thermal conductivity of polycrystalline h-BN films at various temperatures. Using the EMD results, we constructed finite element models of polycrystalline h-BN sheets to probe the thermal conductivity of samples with larger grain sizes. Our multiscale investigations not only provide a general viewpoint regarding the heat conduction in h-BN films but also propose that polycrystalline h-BN sheets present high thermal conductivity comparable to monocrystalline sheets.

  7. Modelling heat conduction in polycrystalline hexagonal boron-nitride films

    PubMed Central

    Mortazavi, Bohayra; Pereira, Luiz Felipe C.; Jiang, Jin-Wu; Rabczuk, Timon

    2015-01-01

    We conducted extensive molecular dynamics simulations to investigate the thermal conductivity of polycrystalline hexagonal boron-nitride (h-BN) films. To this aim, we constructed large atomistic models of polycrystalline h-BN sheets with random and uniform grain configuration. By performing equilibrium molecular dynamics (EMD) simulations, we investigated the influence of the average grain size on the thermal conductivity of polycrystalline h-BN films at various temperatures. Using the EMD results, we constructed finite element models of polycrystalline h-BN sheets to probe the thermal conductivity of samples with larger grain sizes. Our multiscale investigations not only provide a general viewpoint regarding the heat conduction in h-BN films but also propose that polycrystalline h-BN sheets present high thermal conductivity comparable to monocrystalline sheets. PMID:26286820

  8. Formation of conducting nanochannels in diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Evtukh, A.; Litovchenko, V.; Semenenko, M.; Yilmazoglu, O.; Mutamba, K.; Hartnagel, H. L.; Pavlidis, D.

    2006-09-01

    A sharp increase of the emission current at high electric fields and a decrease of the threshold voltage after pre-breakdown conditioning of diamond-like carbon (DLC) films have been measured. This effect was observed for DLC-coated silicon tips and GaAs wedges. During electron field emission (EFE) at high electric fields the energy barriers caused by an sp3 phase between sp2 inclusions can be broken, resulting in the formation of conducting nanochannels between the semiconductor-DLC interface and the surface of the DLC film. At high current densities and the resulting local heating, the diamond-like sp3 phase transforms into a conducting graphite-like sp2 phase. As a result an electrical conducting nanostructured channel is formed in the DLC film. The diameter of the conducting nanochannel was estimated from the reduced threshold voltage after pre-breakdown conditioning to be in the range of 5-25 nm. The presence of this nanochannel in an insulating matrix leads to a local enhancement of the electric field and a reduced threshold voltage for EFE. Based on the observed features an efficient method of conducting nanochannel matrix formation in flat DLC films for improved EFE efficiency is proposed. It mainly uses a silicon tip array as an upper electrode in contact with the DLC film. The formation of nanochannels starts at the interface between the tips and the DLC film. This opens new possibilities of aligned and high-density conducting channel formation.

  9. In situ measurement of conductivity during nanocomposite film deposition

    NASA Astrophysics Data System (ADS)

    Blattmann, Christoph O.; Pratsinis, Sotiris E.

    2016-05-01

    Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (Tg) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing Tg. Proper selection of the host polymer in combination with in situ resistance monitoring therefore enable the optimal preparation of conductive nanocomposite films.

  10. Electroactivity of transparent composite films from conducting poly(thiophenes)

    SciTech Connect

    Roncali, J.; Garnier, F.

    1988-02-11

    Conducting composite films containing an electropolymerizable conducting polymer such as poly(3-methylthiophene) (PMeT) alloyed with poly(vinyl chloride) (PVC) have been prepared in a one-step process from synthesis media already containing dissolved PVC. This procedure based on the simultaneous electropolymerization and dip-cutting processes allows a large control of the composition, morphology, optical transmittance, conductivity, and electroactivity of the composite films. The growth of PMeT in synthesis media containing dissolved PVC has been analyzed. Increasing the PVC concentration produces a slight decrease of the MeT electropolymerization rate with no apparent modification of the polymerization mechanism. The electrochemical properties of the composite films have been investigated in acetonitrile by using cyclic voltammetry and chronoamperometry. At low scan rate (10 mV/s), the electrochemical responses of the composite films are identical with that of bare PMeT films prepared under the same conditions. At higher scan rates, a dependence of the electroactivity of the films on their PVC content is observed and the electrochemical response turns progressively from an adsorption-like behavior to a diffusion-controlled one. It is shown that the electrolyte concentration used for the synthesis of the composite films is the key factor controlling their electrochemical behavior. The incorporation of PMeT within the PVC matrix does not affect its spectroelectrochemical properties and furthermore leads to an improved electrochemical stability of the film under redox cycling.

  11. Highly transparent, conductive, flexible resin films embedded with silver nanowires.

    PubMed

    Jiang, Yaqiu; Xi, Jun; Wu, Zhaoxin; Dong, Hua; Zhao, Zhixu; Jiao, Bo; Hou, Xun

    2015-05-05

    In this article, a low sheet resistance and highly transparent silver nanowire (AgNW) resin composite film was demonstrated, which was prepared by a simple and efficacious two-step spin-coating method. By burying the AgNWs below the surface of the transparent resin matrix which was cured at 150 °C in air, we achieved a uniform, highly transparent, conductive, flexible film. Compared to the reported transparent electrodes, this composite transparent and conductive film showed 10 Ω/□ sheet resistance and nearly 90% mean optical transmittance over the UV-visible range simultaneously. Undergoing hundreds of cycles of tensile and compression folding, the composite film slightly increased its sheet resistance by less than 5%, displaying good electromechanical flexibility. These characteristics of the composite AgNW-resin films were expected to be used in applications of flexible optoelectronics.

  12. Detection of Secondhand Cigarette Smoke via Nicotine Using Conductive Polymer Films

    PubMed Central

    2013-01-01

    Introduction: The 2006 U.S. Surgeon General’s Report found that there is no safe level of exposure to secondhand smoke (SHS). Many smokers attempt to protect others from exposure to SHS; however, it is difficult to assess effectiveness of these behavior changes. There is a need for personal monitoring devices that provide real-time SHS exposure data; at present, there is no device that measures ambient nicotine levels in real time. The development of such a sensor is the objective of this research. Methods: A nicotine sensing film comprising the conductive polymer polyaniline was linked with a reporting layer, recording changes in chemiresistance due to adsorption of nicotine. Experiments were carried out in a microprocessor-controlled smoking chamber using sidestream smoke from standard reference cigarettes; up to 10 cigarettes were smoked simultaneously. The exposure chamber was calibrated for total suspended particle, carbon monoxide, and nicotine concentrations. Results: We found significant real-time increases in the resistance of films upon exposure to SHS. The sensors were shown to be sensitive to the number of cigarettes consumed and ambient nicotine and demonstrated reasonable recovery between measurements. The sensors have sufficient sensitivity to detect off-gassing of nicotine or “thirdhand smoke.” Conclusions: A sensing element has been developed that can reliably detect secondhand and thirdhand tobacco smoke in real time through the adsorption of ambient nicotine vapor. The device was calibrated to the number of smoked cigarettes and to nicotine concentration. Development of integrated personal sensors to record exposure to SHS using this technology is currently underway. PMID:23482719

  13. Thermal conductance of nanoscale Langmuir-Blodgett films

    NASA Astrophysics Data System (ADS)

    Ziade, Elbara; Goni, Miguel; Sato, Toshiyuki; Czubarow, Pawel; Schmidt, Aaron J.

    2015-11-01

    Thermal transport across organic-inorganic interfaces is fundamental to understanding heat transfer in polymer-based composites, microelectronics, and energy conversion systems. We used the Langmuir-Blodgett (LB) technique to deposit nanometer-thick films of poly(vinyl acetate) (PVAc) on silicon and gold substrates in two distinct states: Liquid condensed (Lc) and Liquid expanded (Le). We used frequency domain thermoreflectance to measure the thermal conductivity of the PVAc film and its thermal interface conductance to the substrate. We found that PVAc films prepared through the LB process have a higher thermal conductivity when compared to bulk. We measured the thermal interface conductance between PVAc and gold to be approximately 90 MW/m2 K for both the Le and Lc states, and the thermal interface conductance between PVAc and silicon to be approximately 70 MW/m2 K for both the Le and Lc states.

  14. Thermal conductivity measurement of thin films by a dc method.

    PubMed

    Yang, Junyou; Zhang, Jiansheng; Zhang, Hui; Zhu, Yunfeng

    2010-11-01

    A dc method, which needs no complex numerical calculation and expensive hardware configuration, was developed to measure the cross-plane thermal conductivity of thin films in this paper. Two parallel metallic heaters, which were deposited on different parts of the sample, serve simultaneously as the heaters and temperature sensors during the measurement. A direct current was flowed through the same two metallic strips to heat the thin-film sample. The heating power and the heater's temperature were obtained by a data acquisition device, and the thermal conductivity of thin film was calculated. To verify the validity of the dc method, several SiO(2) films with different thicknesses were deposited on Si wafers, respectively, and their thermal conductivities were measured by both the dc method and 3ω method. The results of two methods are in good agreement within an acceptable error, and they are also inconsistent with some of previously published data.

  15. Effect of ionizing radiation on polyaniline solutions

    NASA Astrophysics Data System (ADS)

    Wolszczak, M.; Kroh, J.; Abdel-Hamid, M. M.

    1996-06-01

    This communication presents the optical studies associated with transition doped (metallic)-neutral (semiconductor or insulator) state for conducting polymers. Special attention is focused on the electronic properties of polyaniline. The interconversion of different oxidation states of polyanilines has been studied by chemical and radiolytic methods. The polyaniline system is described by three sets of chromophores of three different oxidation states: fully reduced leucoemeraldine base (LB), partially oxidized emeraldine base (EB), and fully oxidized pernigraniline (PB). Each oxidation state can exist in its protonated form by treatment with an acid. All members of polyaniline family are spectroscopically distinguishable. The radiolytic study presents evidence that the polyaniline can exist in a continuum of oxidation states. The highly conducting form of polymer, i.e. emeraldine salt can be converted by using ionizing radiation into leucoemeraldine salt. The leucoemeraldine base is the final product of radiolysis of emeraldine base solution. The fully oxidized form of polyaniline can also be obtained by the irradiation of EB in the presence of CCl 4 or chlorobenzene.

  16. Conduction Mechanisms in Thick Film Microcircuits

    DTIC Science & Technology

    1975-12-01

    precipitation process was strengthened by comparing the predicted growth behaviour of the particles by a diffusion controlled solution-precipitation...Metallograph with Video Cameras 45 3.7 Metallograph Hot Stage 47 3.8 Three Roll Dispersing .ill Schematic 49 3.9 Laboratory Three Roll Mill 50 3.10...conducting phase must include an oxide or an oxidizable metal for the resistaice to vary continuously over a wide composition range (volume fraction of glass

  17. Using Film to Conduct Historical Inquiry with Middle School Students

    ERIC Educational Resources Information Center

    Woelders, Adam

    2007-01-01

    Challenged to re-consider his teaching practices, the author conducted a classroom research study designed to investigate and improve how he uses film to teach middle school students about history. He conducted this study in collaboration with his class of twenty-nine grade eight social studies students, who represented a range of ethnic…

  18. High carrier concentration p-type transparent conducting oxide films

    DOEpatents

    Yan, Yanfa; Zhang, Shengbai

    2005-06-21

    A p-type transparent conducting oxide film is provided which is consisting essentially of, the transparent conducting oxide and a molecular doping source, the oxide and doping source grown under conditions sufficient to deliver the doping source intact onto the oxide.

  19. Modulating conductivity, environmental stability of transparent conducting nanotube films on flexible substrates by interfacial engineering.

    PubMed

    Han, Joong Tark; Kim, Jun Suk; Jeong, Hae Deuk; Jeong, Hee Jin; Jeong, Seung Yol; Lee, Geon-Woong

    2010-08-24

    We have characterized the previously undescribed parameters for engineering the electrical properties of single-walled carbon nanotube (SWCNT) films for technological applications. First, the interfacial tension between bare SWCNT network films and a top coating passivation material was shown to dictate the variability of the films' sheet resistance (R(s)) after application of the top coating. Second, the electrical stability of the coated SWCNT films was affected by the mismatch between the CTE of the supporting substrate and the SWCNT network film. An upshift in the Raman G-band spectrum of SWCNTs on bare PET suggested that compressive strain was induced by the CTE mismatch after heating and cooling. These findings provide important guidelines for the choice of substrate and passivation coating materials that promote environmental stability in SWCNT-based transparent conductive films.

  20. Slightly Conductive Transparent Films for Space Applications: Manufacturability and Durability

    NASA Technical Reports Server (NTRS)

    Uppala, N.; Griffin, J.; Vemulapalli, J.; Hambourger, P. D.

    2001-01-01

    Highly transparent, slightly conductive films of co-deposited indium tin oxide (ITO) and MgF, have possible applications for environmental protection of exterior surfaces of spacecraft. Reliable preparation of films with the desired sheet resistivity (approximately 10(exp 8) ohms/square) is difficult because the electrical properties of ITO-Mg F, are highly dependent on film composition. We have investigated the use of plasma emission monitoring to improve the reproducibility of films prepared by RF magnetron sputtering. While considerable improve ment was observed, it appears that some in-situ electrical or optica l characterization will be needed for reliable production coating wit h ITO-MgF,. We have also done further evaluation of a possibly undesi rable photoconductive effect previously observed in these films.

  1. Strong and Conductive Dry Carbon Nanotube Films by Microcombing.

    PubMed

    Zhang, Liwen; Wang, Xin; Xu, Weizong; Zhang, Yongyi; Li, Qingwen; Bradford, Philip D; Zhu, Yuntian

    2015-08-01

    In order to maximize the carbon nanotube (CNT) buckypaper properties, it is critical to improve their alignment and reduce their waviness. In this paper, a novel approach, microcombing, is reported to fabricate aligned CNT films with a uniform structure. High level of nanotube alignment and straightness was achieved using sharp surgical blades with microsized features at the blade edges to comb single layer of CNT sheet. These microcombs also reduced structural defects within the film and enhanced the nanotube packing density. Following the microcombing approach, the as-produced CNT films demonstrated a tensile strength of up to 3.2 GPa, Young's modulus of up to 172 GPa, and electrical conductivity of up to 1.8 × 10(5) S m(-1) , which are much superior to previously reported CNT films or buckypapers. More importantly, this novel technique requires less rigorous process control and can construct CNT films with reproducible properties.

  2. Reduced temperature-dependent thermal conductivity of magnetite thin films by controlling film thickness

    NASA Astrophysics Data System (ADS)

    Park, No-Won; Lee, Won-Yong; Kim, Jin-A.; Song, Kyungjun; Lim, Hyuneui; Kim, Wan-Doo; Yoon, Soon-Gil; Lee, Sang-Kwon

    2014-02-01

    We report on the out-of-plane thermal conductivities of epitaxial Fe3O4 thin films with thicknesses of 100, 300, and 400 nm, prepared using pulsed laser deposition (PLD) on SiO2/Si substrates. The four-point probe three-omega (3- ω) method was used for thermal conductivity measurements of the Fe3O4 thin films in the temperature range of 20 to 300 K. By measuring the temperature-dependent thermal characteristics of the Fe3O4 thin films, we realized that their thermal conductivities significantly decreased with decreasing grain size and thickness of the films. The out-of-plane thermal conductivities of the Fe3O4 films were found to be in the range of 0.52 to 3.51 W/m · K at 300 K. For 100-nm film, we found that the thermal conductivity was as low as approximately 0.52 W/m · K, which was 1.7 to 11.5 order of magnitude lower than the thermal conductivity of bulk material at 300 K. Furthermore, we calculated the temperature dependence of the thermal conductivity of these Fe3O4 films using a simple theoretical Callaway model for comparison with the experimental data. We found that the Callaway model predictions agree reasonably with the experimental data. We then noticed that the thin film-based oxide materials could be efficient thermoelectric materials to achieve high performance in thermoelectric devices.

  3. Cadmium-Tin Oxide Transparent Conductive Thin Films

    NASA Astrophysics Data System (ADS)

    Stapinski, T.; Leja, E.; Marszalek, K.

    1986-09-01

    Cadmium-tin oxide (CTO) films have been prepared by d.c. reactive sputtering of Cd-Sn alloy targets in Ar-02 gas mixture. The electrical, optical and structural properties as well as the chemical composition of transparent conducting CTO films were found to depend on sputtering conditions. The value of optical band gap, optical constants, effective mass and relaxation time of electrons have been determined.

  4. Application of solid phase extraction with the use of silica modified with polyaniline film for pretreatment of samples from plant material before HPLC determination of triterpenic acids.

    PubMed

    Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Rokicka, Kamila; Kocjan, Ryszard; Szymczak, Grażyna

    2014-05-01

    The new sorbent based on silica gel coated with a film of polyaniline (Si-PANI) was obtained in a process of in situ polymerization directly on carrier particles and its potential application for pretreatment of plant material samples with the use of solid phase extraction (SPE) was investigated. Parameters such as cartridge conditioning, the volume and concentration of the sample, the type and volume of the elution solvent were optimized and compared with parameters obtained for RP-18 and aminopropyl silica cartridges. The high recovery values above 97% after the SPE procedure with the use of Si-PANI cartridges proves their utility for analysis of triterpenic acids. The sorbent tested was successfully used for clean-up of extracts from Salvia officinalis L., Syzygium aromaticum (L.) Merrill., and Origanum vulgare L. prior to HPLC-DAD determination of oleanolic, ursolic and betulinic acid. The efficiency of sample purification was verified by monitoring of chromatograms in the region between 190 nm and 400 nm during the gradient elution. The fewest components or their lowest concentrations were observed for all the investigated samples after the SPE procedures.

  5. Fabrication and characterization of solid-state, conducting polymer actuators

    SciTech Connect

    Xie, J.; Sansinena, J. M.; Gao, J.; Wang, H. L.

    2004-01-01

    We report here the fabrication and characterization of solid-state, conducting polymer actuators. The electrochemical activity of polyaniline (PANI) thin film coated with solid-state polyelectrolyte is very similar to the polyaniline thin film in an aqueous solution. The solid-state actuator is adhere to a lever arm of an force transducer and the force generation is measured in real time. The force generated by the actuator is found to be length dependent. However, the overall torques generated by the actuators with different lengths remains essentially the same. The effect of stimulation signals such as voltage, current, on the bending angle and displacement is also studied using square wave potential.

  6. Photochemical switching in conductive Langmuir-Blodgett films

    SciTech Connect

    Tachibana, Hiroaki; Nakamura, Takayoshi; Matsuboto, Mutsuyoshi; Komizu, Hideo; Manda, Eiichiro; Niino, Hiroyuki; Yabe, Akira; Kawabata, Yasujiro )

    1989-04-12

    Conductive Langmuir-Blodgett (LB) films have recently attracted much interest from the viewpoint of ultrathin film conductors at the molecular level. We have reported that the structure of the TCNQ (7,7,8,8-tetracyanoquinodimethane) column in the LB film of N-docosylpyridinium 7,7,8,8-tetracyanoquinodimethane is changed by the variation of the subphase temperature. In addition, a partial charge transfer state of N-docosylpyridinium bis(7,7,8,8-tetracyanoquinodimethane) is stable at the air-water interface and the as-deposited LB film is highly conductive without doping or any other treatments. It will open up a wide scope of applications of the functions of the LB films can be controlled by external stimuli such as light, heat, or chemical treatments. One of the most promising candidates for this purpose is to introduce a switching unit into an amphiphilic molecule. When the switching unit is triggered by an external stimulus, the signal is conveyed through the transmission unit to the working unit and induces a change in the structure and functions of the working unit. In this paper, we use the azobenzene as the switching unit, the alkyl chain as the transmission unit, and the charge-transfer complex of TCNQ as the working unit. In this arrangement, the photoisomerization of the azobenzene induces the reversible change in the lateral conductivity of the LB film.

  7. Soluble Precursor Route to Polyanilines

    DTIC Science & Technology

    1993-01-01

    condensation were not successful, but further work produced polymer under the following conditions: Synthesis Diketone I (2.40 g, 10.0 mmol) in 10 mL...goal of producing a processible form of the conducting polymer polyaniline (PANI), the Phase I program concentrated on development of the synthesis of...extension of the original research to a Phase II effort. Diketone - Diamine Polycondensation Towards a Soluble PAni Precursor To achieve the

  8. Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films

    NASA Astrophysics Data System (ADS)

    Kim, Semin; Jang, Lindy K.; Park, Hyun S.; Lee, Jae Young

    2016-07-01

    Electrode surfaces have been widely modified with electrically conductive polymers, including polypyrrole (PPY), to improve the performance of electrodes. To utilize conductive polymers for electrode modification, strong adhesion between the polymer films and electrode substrates should be ensured with high electrical/electrochemical activities. In this study, PPY films were electrochemically polymerized on electrodes (e.g., indium tin oxide (ITO)) with dopamine as a bio-inspired adhesive molecule. Efficient and fast PPY electrodeposition with dopamine (PDA/PPY) was found; the resultant PDA/PPY films exhibited greatly increased adhesion strengths of up to 3.7 ± 0.8 MPa and the modified electrodes had electrochemical impedances two to three orders of magnitude lower than that of an unmodified electrode. This electrochemical deposition of adhesive and conductive PDA/PPY offers a facile and versatile electrode modification for various applications, such as biosensors and batteries.

  9. Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films.

    PubMed

    Kim, Semin; Jang, Lindy K; Park, Hyun S; Lee, Jae Young

    2016-07-27

    Electrode surfaces have been widely modified with electrically conductive polymers, including polypyrrole (PPY), to improve the performance of electrodes. To utilize conductive polymers for electrode modification, strong adhesion between the polymer films and electrode substrates should be ensured with high electrical/electrochemical activities. In this study, PPY films were electrochemically polymerized on electrodes (e.g., indium tin oxide (ITO)) with dopamine as a bio-inspired adhesive molecule. Efficient and fast PPY electrodeposition with dopamine (PDA/PPY) was found; the resultant PDA/PPY films exhibited greatly increased adhesion strengths of up to 3.7 ± 0.8 MPa and the modified electrodes had electrochemical impedances two to three orders of magnitude lower than that of an unmodified electrode. This electrochemical deposition of adhesive and conductive PDA/PPY offers a facile and versatile electrode modification for various applications, such as biosensors and batteries.

  10. Magnetic Transparent Conducting Oxide Film And Method Of Making

    DOEpatents

    Windisch, Jr., Charles F.; Exarhos, Gregory J.; Sharma, Shiv K.

    2006-03-14

    Cobalt-nickel oxide films of nominal 100 nm thickness, and resistivity as low as 0.06 O·cm have been deposited by spin-casting from both aqueous and organic precursor solutions followed by annealing at 450° C. in air. An increase in film resistivity was found upon substitution of other cations (e.g., Zn2+, Al3+) for Ni in the spinel structure. However, some improvement in the mechanical properties of the films resulted. On the other hand, addition of small amounts of Li decreased the resistivity. A combination of XRD, XPS, UV/Vis and Raman spectroscopy indicated that NiCo2O4 is the primary conducting component and that the conductivity reaches a maximum at this stoichiometry. When x<0.67, NiO forms leading to an increase in resistivity; when x>0.67, the oxide was all spinel but the increased Co content lowered the conductivity.

  11. Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films

    PubMed Central

    Kim, Semin; Jang, Lindy K.; Park, Hyun S.; Lee, Jae Young

    2016-01-01

    Electrode surfaces have been widely modified with electrically conductive polymers, including polypyrrole (PPY), to improve the performance of electrodes. To utilize conductive polymers for electrode modification, strong adhesion between the polymer films and electrode substrates should be ensured with high electrical/electrochemical activities. In this study, PPY films were electrochemically polymerized on electrodes (e.g., indium tin oxide (ITO)) with dopamine as a bio-inspired adhesive molecule. Efficient and fast PPY electrodeposition with dopamine (PDA/PPY) was found; the resultant PDA/PPY films exhibited greatly increased adhesion strengths of up to 3.7 ± 0.8 MPa and the modified electrodes had electrochemical impedances two to three orders of magnitude lower than that of an unmodified electrode. This electrochemical deposition of adhesive and conductive PDA/PPY offers a facile and versatile electrode modification for various applications, such as biosensors and batteries. PMID:27459901

  12. Two-Dimensional Infrared Vibrational Echo Spectroscopy Measurements of the Structural Dynamics Occurring in Conducting Polymer Thin Films

    NASA Astrophysics Data System (ADS)

    Eigner, Audrey Ann

    2011-12-01

    The research presented in this thesis is concerned with the elucidation of the origin of structural dynamics and their relationship to charge mobility in conducting polymer systems. In the past thirty years, research in the field of electrically conducting polymers has grown immensely. Interest in such polymers is due mainly to their unique semiconducting properties and thus their potential application in plastic electronics. While it is known that the charge transport of such polymers is linked to their molecular structure, very little is known about the relationship between charge transport and structural dynamics. In particular, this work has focused on the conducting polymers poly(3-hexylthiophene) (P3HT) and polyaniline (PANI). Samples of each polymer were studied using two-dimensional infrared vibrational echo spectroscopy (2D-IR VES), as well as one-dimensional infrared, UV-visible, and fluorescence spectroscopies. Additional characterizations of the polymers were performed, and included transmission electron microscopy (TEM), hole-mobility and resistance measurements. The vibrational echo technique was especially well suited for this study because it removed inhomogeneous broadening and allowed for the monitoring of the time evolution of molecular structure on the picosecond time scale. Viewed together, the studies presented in this work have begun to correlate specific structural dynamics with changes in the film conductivities.

  13. Latent synthesis of electrically conductive surface-silvered polyimide films.

    PubMed

    Davis, Luke M; Abelt, Christopher J; Scott, Joseph L; Orlova, Evguenia; Thompson, David W

    2009-01-01

    A facile ambient temperature route to the fabrication of surface silver-metallized polyimide films is described. Silver(I) trifluoromethanesulfonate or silver(I) nitrate and a polyimide, derived from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and an equimolar amount of 4,4'-oxydianiline and 3,5-diaminobenzoic acid, were dissolved together in dimethylacetamide. Silver(I)-doped films were prepared at thicknesses of 25-40 microm and depleted of solvent by evaporation at ambient temperature and low humidity. The silver(I)-ion-containing films were then treated with aqueous solutions of the reducing agents hydrazine hydrate and hydroxylamine, which brought forth surface-silvered films exhibiting conductivity on the order of bulk polycrystalline silver accompanied by modest-to-high specular reflectivity.

  14. VOx effectively doping CVD-graphene for transparent conductive films

    NASA Astrophysics Data System (ADS)

    Ji, Qinghua; Shi, Liangjing; Zhang, Qinghong; Wang, Weiqi; Zheng, Huifeng; Zhang, Yuzhi; Liu, Yangqiao; Sun, Jing

    2016-11-01

    Chemical vapor deposition(CVD)-synthesized graphene is potentially an alternative for tin-doped indium oxide (ITO) transparent conductive films (TCFs), however its sheet resistance is still too high to meet many demands. Vanadium oxide has been widely applied as smart window materials, however, no study has been reported to use it as dopant to improve the conductivity of graphene TCFs. In this study, we firstly reported that VOx doping can effectively lower the sheet resistance of CVD-graphene films while keeping its good optical properties, whose transmittance is as high as 86-90%. The optimized VOx-doped graphene exhibits a sheet resistance as low as 176 Ω/□, which decreases by 56% compared to the undoped graphene films. The doping process is convenient, stable, economical and easy to operate. What is more, VOx can effectively increase the work function(WF) of the film, making it more appropriate for use in solar cells. The evolution of the VOx species annealed at different temperatures below 400 °C has been detailed studied for the first time, based on which the doping mechanism is proposed. The prepared VOx doped graphene is expected to be a promising candidate for transparent conductive film purposes.

  15. Influence of film thickness on the phase separation mechanism in ultrathin conducting polymer blend films.

    PubMed

    Meier, Robert; Ruderer, Matthias A; Diethert, Alexander; Kaune, Gunar; Körstgens, Volker; Roth, Stephan V; Müller-Buschbaum, Peter

    2011-03-31

    The film morphology of thin polymer blend films based on poly[(1-methoxy)-4-(2-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and poly(N-vinylcarbazole) (PVK) is probed as a function of film thickness. Blend films are prepared with spin-coating of polymer solutions with different concentrations on top of solid supports. The blending ratio of both conducting polymers is kept constant. The film and surface morphology is probed with grazing incidence ultrasmall-angle X-ray scattering (GIUSAXS) and atomic force microscopy (AFM). A linear dependence between the film thickness and the averaged phase separation is found. In addition, X-ray reflectivity measurements show an enrichment of PVK at the substrate interface. UV/vis spectroscopy measurements indicate a linearly increasing amount of both homopolymers in the blend films for increasing film thicknesses. The generalized knowledge about the influence of the film thickness on the phase separation behavior in conducting polymer blend films is finally used to describe the phase separation formation during the spin-coating process, and the results are discussed in the framework of an adapted Flory-Huggins theory for rodlike polymers.

  16. Effects of alkali treatments on Ag nanowire transparent conductive films

    NASA Astrophysics Data System (ADS)

    Kim, Sunho; Kang, Jun-gu; Eom, Tae-yil; Moon, Bongjin; Lee, Hoo-Jeong

    2016-06-01

    In this study, we employ various alkali materials (alkali metals with different base strengths, and ammonia gas and solution) to improve the conductivity of silver nanowire (Ag NW)-networked films. The alkali treatment appears to remove the surface oxide and improve the conductivity. When applied with TiO2 nanoparticles, the treatment appears more effective as the alkalis gather around wire junctions and help them weld to each other via heat emitted from the reduction reaction. The ammonia solution treatment is found to be quick and aggressive, damaging the wires severely in the case of excessive treatment. On the other hand, the ammonia gas treatment seems much less aggressive and does not damage the wires even after a long exposure. The results of this study highlight the effectiveness of the alkali treatment in improving of the conductivity of Ag NW-networked transparent conductive films.

  17. Strain-controlled thermal conductivity in ferroic twinned films

    PubMed Central

    Li, Suzhi; Ding, Xiangdong; Ren, Jie; Moya, Xavier; Li, Ju; Sun, Jun; Salje, Ekhard K. H.

    2014-01-01

    Large reversible changes of thermal conductivity are induced by mechanical stress, and the corresponding device is a key element for phononics applications. We show that the thermal conductivity κ of ferroic twinned thin films can be reversibly controlled by strain. Nonequilibrium molecular dynamics simulations reveal that thermal conductivity decreases linearly with the number of twin boundaries perpendicular to the direction of heat flow. Our demonstration of large and reversible changes in thermal conductivity driven by strain may inspire the design of controllable thermal switches for thermal logic gates and all-solid-state cooling devices. PMID:25224749

  18. Perpendicularly Aligned, Anion Conducting Nanochannels in Block Copolymer Electrolyte Films

    SciTech Connect

    Arges, Christopher G.; Kambe, Yu; Suh, Hyo Seon; Ocola, Leonidas E.; Nealey, Paul F.

    2016-03-08

    Connecting structure and morphology to bulk transport properties, such as ionic conductivity, in nanostructured polymer electrolyte materials is a difficult proposition because of the challenge to precisely and accurately control order and the orientation of the ionic domains in such polymeric films. In this work, poly(styrene-block-2-vinylpyridine) (PSbP2VP) block copolymers were assembled perpendicularly to a substrate surface over large areas through chemical surface modification at the substrate and utilizing a versatile solvent vapor annealing (SVA) technique. After block copolymer assembly, a novel chemical vapor infiltration reaction (CVIR) technique selectively converted the 2-vinylpyridine block to 2-vinyl n-methylpyridinium (NMP+ X-) groups, which are anion charge carriers. The prepared block copolymer electrolytes maintained their orientation and ordered nanostructure upon the selective introduction of ion moieties into the P2VP block and post ion-exchange to other counterion forms (X- = chloride, hydroxide, etc.). The prepared block copolymer electrolyte films demonstrated high chloride ion conductivities, 45 mS cm(-1) at 20 degrees C in deionized water, the highest chloride ion conductivity for anion conducting polymer electrolyte films. Additionally, straight-line lamellae of block copolymer electrolytes were realized using chemoepitaxy and density multiplication. The devised scheme allowed for precise and accurate control of orientation of ionic domains in nanostructured polymer electrolyte films and enables a platform for future studies that examines the relationship between polymer electrolyte structure and ion transport.

  19. Highly conductive grain boundaries in copper oxide thin films

    NASA Astrophysics Data System (ADS)

    Deuermeier, Jonas; Wardenga, Hans F.; Morasch, Jan; Siol, Sebastian; Nandy, Suman; Calmeiro, Tomás; Martins, Rodrigo; Klein, Andreas; Fortunato, Elvira

    2016-06-01

    High conductivity in the off-state and low field-effect mobility compared to bulk properties is widely observed in the p-type thin-film transistors of Cu2O, especially when processed at moderate temperature. This work presents results from in situ conductance measurements at thicknesses from sub-nm to around 250 nm with parallel X-ray photoelectron spectroscopy. An enhanced conductivity at low thickness is explained by the occurrence of Cu(II), which is segregated in the grain boundary and locally causes a conductivity similar to CuO, although the surface of the thick film has Cu2O stoichiometry. Since grains grow with an increasing film thickness, the effect of an apparent oxygen excess is most pronounced in vicinity to the substrate interface. Electrical properties of Cu2O grains are at least partially short-circuited by this effect. The study focuses on properties inherent to copper oxide, although interface effects cannot be ruled out. This non-destructive, bottom-up analysis reveals phenomena which are commonly not observable after device fabrication, but clearly dominate electrical properties of polycrystalline thin films.

  20. Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

    SciTech Connect

    Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S.

    2015-05-15

    Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

  1. Synthesis of novel electrically conducting polymers: Potential conducting Langmuir-Blodgett films and conducting polymers on defined surfaces

    NASA Technical Reports Server (NTRS)

    Zimmer, Hans

    1993-01-01

    Based on previous results involving thiophene derived electrically conducting polymers in which it was shown that thiophene, 3-substituted thiophenes, furans, and certain oligomers of these compounds showed electrical conductivity after polymerization. The conductivity was in the order of up to 500 S/cm. In addition, these polymers showed conductivity without being doped and most of all they were practically inert toward ambient conditions. They even could be used in aqueous media. With these findings as a guide, a number of 3-long-chain-substituted thiophenes and 1-substituted-3-long-chain substituted pyrrols were synthesized as monomers for potential polymeric electrically conducting Langmuir-Blodgett films.

  2. Transparent conducting thin films of GaInO3

    NASA Astrophysics Data System (ADS)

    Phillips, Julia M.; Kwo, J.; Thomas, G. A.; Carter, S. A.; Cava, R. J.; Hou, S. Y.; Krajewski, J. J.; Marshall, J. H.; Peck, W. F.; Rapkine, D. H.; Dover, R. B. van

    1994-07-01

    GaInO3 is recently identified transparent conducting material which is structurally and chemically distinct from indium tin oxide [R. J. Cava, J. M. Phillips, J. Kwo, G. A. Thomas, R. B. van Dover, S. A. Carter, J. J. Krajewski, W. F. Peck, Jr., J. H. Marshall, and D. H. Rapkine, Appl. Phys. Lett. 64, 2071 (1994)]. We have used both dc reactive sputtering in the on- and off-axis geometries and pulsed laser deposition to grow films of this material. Layers of pure GaInO3 as well as those partially substituted with Ge for Ga or Sn for In have been studied. Both growth techniques are capable of producing films with conductivity ˜400 (Ω cm)-1 and transmission as high as 90% throughout the visible spectrum for ˜1-μm-thick films. The growth techniques differ in the morphology of the films produced as well as in the degree of dopant incorporation that can be achieved. A post-growth anneal in H2 can help produce an optimized oxygen content and a reduction of resistivity. Hall measurements indicate a carrier concentration up to 4×1020 cm-3 for all films and a Hall mobility up to 10 cm2/(V s). Doping appears to be due both to oxygen vacancies and aliovalent ion substitution.

  3. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    1985-12-01

    The first surfce acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposted on the acoustic progagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectric coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in N2 has been demonstrated.

  4. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    The first surface acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposited on the acoustic propagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectic coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in Ne was demonstrated.

  5. Reduced temperature-dependent thermal conductivity of magnetite thin films by controlling film thickness.

    PubMed

    Park, No-Won; Lee, Won-Yong; Kim, Jin-A; Song, Kyungjun; Lim, Hyuneui; Kim, Wan-Doo; Yoon, Soon-Gil; Lee, Sang-Kwon

    2014-02-26

    We report on the out-of-plane thermal conductivities of epitaxial Fe3O4 thin films with thicknesses of 100, 300, and 400 nm, prepared using pulsed laser deposition (PLD) on SiO2/Si substrates. The four-point probe three-omega (3-ω) method was used for thermal conductivity measurements of the Fe3O4 thin films in the temperature range of 20 to 300 K. By measuring the temperature-dependent thermal characteristics of the Fe3O4 thin films, we realized that their thermal conductivities significantly decreased with decreasing grain size and thickness of the films. The out-of-plane thermal conductivities of the Fe3O4 films were found to be in the range of 0.52 to 3.51 W/m · K at 300 K. For 100-nm film, we found that the thermal conductivity was as low as approximately 0.52 W/m · K, which was 1.7 to 11.5 order of magnitude lower than the thermal conductivity of bulk material at 300 K. Furthermore, we calculated the temperature dependence of the thermal conductivity of these Fe3O4 films using a simple theoretical Callaway model for comparison with the experimental data. We found that the Callaway model predictions agree reasonably with the experimental data. We then noticed that the thin film-based oxide materials could be efficient thermoelectric materials to achieve high performance in thermoelectric devices.

  6. Laser structuring of conducting films on transparent substrates

    NASA Astrophysics Data System (ADS)

    Račiukaitis, G.; Brikas, M.; Darčianovas, G.; Ruthe, D.; Zimmer, K.

    2007-06-01

    The fast growing market of organic electronics, including organic light-emitting devices (OLED), Solar cells and radio-frequency identification devices (RFID), stimulates development of versatile technologies for patterning the thin-film materials on rigid and flexible substrates. Thin films of the transparent conducting oxides (TCO) are important materials for making transparent contacts, conductors or antennas in such devices. High repetition rate lasers with a short, picosecond pulse duration offer new possibilities for high efficiency structuring of transparent conductors on glass and other substrates. The results of ablation of the indium-tin oxide (ITO) layer on glass and ITO and ZnO layers on polymers with picosecond lasers at various wavelengths are presented. Laser radiation initiated ablation of the material, forming trenches in TCO. UV radiation at the 266 nm provided the widest working window for TCO ablation without damage of the substrate. Subcomponents of the thin-film devices were made in order to test the structuring technology.

  7. Transparent electrical conducting films by activated reactive evaporation

    DOEpatents

    Bunshah, R.; Nath, P.

    1982-06-22

    Process and apparatus for producing transparent electrical conducting thin films by activated reactive evaporation is disclosed. Thin films of low melting point metals and alloys, such as indium oxide and indium oxide doped with tin, are produced by physical vapor deposition. The metal or alloy is vaporized by electrical resistance heating in a vacuum chamber, oxygen and an inert gas such as argon are introduced into the chamber, and vapor and gas are ionized by a beam of low energy electrons in a reaction zone between the resistance heater and the substrate. There is a reaction between the ionized oxygen and the metal vapor resulting in the metal oxide which deposits on the substrate as a thin film which is ready for use without requiring post deposition heat treatment. 1 fig.

  8. Transparent electrical conducting films by activated reactive evaporation

    DOEpatents

    Bunshah, Rointan; Nath, Prem

    1982-01-01

    Process and apparatus for producing transparent electrical conducting thin films by activated reactive evaporation. Thin films of low melting point metals and alloys, such as indium oxide and indium oxide doped with tin, are produced by physical vapor deposition. The metal or alloy is vaporized by electrical resistance heating in a vacuum chamber, oxygen and an inert gas such as argon are introduced into the chamber, and vapor and gas are ionized by a beam of low energy electrons in a reaction zone between the resistance heater and the substrate. There is a reaction between the ionized oxygen and the metal vapor resulting in the metal oxide which deposits on the substrate as a thin film which is ready for use without requiring post deposition heat treatment.

  9. Electrically Conducting Polyaniline Microtube Blends

    DTIC Science & Technology

    2007-11-02

    Acknowledgment The authors would like to acknowledge Dr. Nathan Presser and Mr. Paul Adams for their respective microscopy and spectroscopy work. iii Contents I...to minimize solar absorbtivity . One method to minimize this color is to modify the geometry of PANI from granular to tube shaped. Recently, Wan, et al...electro-optics, solid-state laser design, micro-optics, optical communications, and fiber-optic sensors; atomic frequency standards, applied laser

  10. Stable, concentrated solutions of polyaniline using amines as gel inhibitors

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2002-01-01

    Stable, concentrated solutions of high-molecular weight polyaniline using amines as gel inhibitors. Certain amine compounds (gel inhibitors) are used to form highly concentrated, stable solutions of the emeraldine base form of polyaniline in numerous organic solvents from which coatings, films and fibers are readily prepared without problems associated with rapid gelation which occurs when concentrated solutions are attempted without the use of the gel inhibitors of the present invention. Tertiary amines are used to solubilize low-molecular weight fractions (M.sub.w <120,000, M.sub.n <30,000) of the pernigraniline, emeraldine, and leucoemeraldine oxidation states of polyaniline as concentrated (>20 wt. %) polyaniline solutions, while primary and secondary amines are used to produce solutions having 15-40 wt % of high-molecular weight polyaniline [M.sub.w.gtoreq.120,000, M.sub.n.gtoreq.30,000]. Concentrated solutions of polyaniline co-polymers or ring and/or nitrogen-substituted polyanilines may also be prepared.

  11. Transparent Conductive Two-Dimensional Titanium Carbide Epitaxial Thin Films.

    PubMed

    Halim, Joseph; Lukatskaya, Maria R; Cook, Kevin M; Lu, Jun; Smith, Cole R; Näslund, Lars-Åke; May, Steven J; Hultman, Lars; Gogotsi, Yury; Eklund, Per; Barsoum, Michel W

    2014-04-08

    Since the discovery of graphene, the quest for two-dimensional (2D) materials has intensified greatly. Recently, a new family of 2D transition metal carbides and carbonitrides (MXenes) was discovered that is both conducting and hydrophilic, an uncommon combination. To date MXenes have been produced as powders, flakes, and colloidal solutions. Herein, we report on the fabrication of ∼1 × 1 cm(2) Ti3C2 films by selective etching of Al, from sputter-deposited epitaxial Ti3AlC2 films, in aqueous HF or NH4HF2. Films that were about 19 nm thick, etched with NH4HF2, transmit ∼90% of the light in the visible-to-infrared range and exhibit metallic conductivity down to ∼100 K. Below 100 K, the films' resistivity increases with decreasing temperature and they exhibit negative magnetoresistance-both observations consistent with a weak localization phenomenon characteristic of many 2D defective solids. This advance opens the door for the use of MXenes in electronic, photonic, and sensing applications.

  12. The Onset of Conduction and Superconductivity in Thin Lead Films

    NASA Astrophysics Data System (ADS)

    Barber, Richard Paul, Jr.

    1990-01-01

    DC conduction of Pb layers is investigated during deposition onto a dielectric substrate and subsequent annealing. The films are evaporated under ultra-high vacuum conditions. Amounts of Pb corresponding to a uniform 90 A layer are necessary to bring the sheet resistance, R_{ square}, of a film deposited onto an 11 K substrate below 1 MOmega. In agreement with other work, such barely conducting layers show slowly increasing R_{square }, as the temperature is lowered to a film critical temperature, T_sp{rm C}{rm F}, just below the superconducting transition temperature of bulk Pb. Below T_sp {rm C}{rm F} the rise becomes more rapid and the resistance becomes strongly current dependent. The measurements suggest that the resistance increases without bound in the limits of low temperature and current. Annealing such films at temperatures below 40 K reduces R_{square} (11 K) in an easily controlled fashion by factors as large as 2000. Coupled with this effect is a change from an increasing resistance below T_sp {rm C}{rm F} to the approach to zero resistance usually expected for a superconductor. This change occurs in the present samples, as with films made in a wide variety of ways, at a normal state sheet resistance on the order of 6 kOmega . These coupled changes are similar to those known from experiments in which superconducting metals are deposited in consecutive layers. It is argued that the experimental evidence supports a picture in which electrical conduction in the barely conducting films is by quantum mechanical tunneling between islands. The transition below T_sp{ rm C}{rm F} from an increasing to a decreasing resistance with decreasing temperature results from a change from quasiparticle to Josephson dominated tunneling. It is proposed that the large amount of Pb required for appreciable electrical conduction and the lowering of resistance by annealing are principally controlled by the diffusion of Pb atoms over the dielectric substrate and over the Pb

  13. Ultrahigh electrical conductivity in solution-sheared polymeric transparent films

    PubMed Central

    Worfolk, Brian J.; Andrews, Sean C.; Park, Steve; Reinspach, Julia; Liu, Nan; Toney, Michael F.; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2015-01-01

    With consumer electronics transitioning toward flexible products, there is a growing need for high-performance, mechanically robust, and inexpensive transparent conductors (TCs) for optoelectronic device integration. Herein, we report the scalable fabrication of highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films via solution shearing. Specific control over deposition conditions allows for tunable phase separation and preferential PEDOT backbone alignment, resulting in record-high electrical conductivities of 4,600 ± 100 S/cm while maintaining high optical transparency. High-performance solution-sheared TC PEDOT:PSS films were used as patterned electrodes in capacitive touch sensors and organic photovoltaics to demonstrate practical viability in optoelectronic applications. PMID:26515096

  14. Nonvolatile multilevel conductance and memory effects in organic thin films

    NASA Astrophysics Data System (ADS)

    Lauters, M.; McCarthy, B.; Sarid, D.; Jabbour, G. E.

    2005-12-01

    Organic thin-film structures, including organic light-emitting diodes, are demonstrated to contain multiple nonvolatile conductance states at low-read voltages. Retention time of states is more than several weeks, and more than 20 000 write-read-rewrite-read cycles have been performed with minimal degradation. The electrical characteristics of these devices are consistent with metal diffusion or filament phenomena found in metal-insulator-metal structures, suggesting a possible mechanism by which the states are stored.

  15. Magnetic transparent conducting oxide film and method of making

    DOEpatents

    Windisch, Jr., Charles F.; Exarhos, Gregory J.; Sharma, Shiv K.

    2004-07-13

    Cobalt-nickel oxide films of nominal 100 nm thickness, and resistivity as low as 0.06 .OMEGA..multidot.cm have been deposited by spin-casting from both aqueous and organic precursor solutions followed by annealing at 450.degree. C. in air. Films deposited on sapphire substrates exhibit a refractive index of about 1.7 and are relatively transparent in the wavelength region from 0.6 to 10.0 .mu.m. They are also magnetic. The electrical and spectroscopic properties of the oxides have been studied as a function of x=Co/(Co+Ni) ratio. An increase in film resistivity was found upon substitution of other cations (e.g., Zn.sup.2+, Al.sup.3+) for Ni in the spinel structure. However, some improvement in the mechanical properties of the films resulted. On the other hand, addition of small amounts of Li decreased the resistivity. A combination of XRD, XPS, UV/Vis and Raman spectroscopy indicated that NiCo.sub.2 O.sub.4 is the primary conducting component and that the conductivity reaches a maximum at this stoichiometry. When x<0.67, NiO forms leading to an increase in resistivity; when x>0.67, the oxide was all spinel but the increased Co content lowered the conductivity. The influence of cation charge state and site occupancy in the spinel structure markedly affects calculated electron band structures and contributes to a reduction of p-type conductivity, the formation of polarons, and the reduction in population of mobile charge carriers that tend to limit transmission in the infrared.

  16. Conductivity of oriented bis-azo polymer films.

    PubMed

    Apitz, Dirk; Bertram, Ralph Peter; Benter, Nils; Sommer-Larsen, Peter; Johansen, Per Michael; Buse, Karsten

    2006-02-13

    The conductivity properties of electro-optic, photoaddressable, dense bis-azo chromophore polymer films are investigated by using samples corona poled at various temperatures. A dielectric spectrometer is applied to measure the frequency dependence of the conductivity at different temperatures before and after heating the material to above the glass transition temperature. The results show that the orientation of the chromophores changes the charge-carrier mobility. Ionic conductivity dominates in a more disordered configuration of the material, while the competing process of hole hopping takes over as a transition to a liquid-crystalline phase occurs when the material is heated to much higher than the glass transition temperature. Such microcrystallization strongly enhances the conductivity.

  17. Colloidal polyaniline

    DOEpatents

    Armes, Steven P.; Aldissi, Mahmoud

    1990-01-01

    Processable electrically conductive latex polymer compositions including colloidal particles of an oxidized, polymerized amino-substituted aromatic monomer, a stabilizing effective amount of a random copolymer containing amino-benzene type moieties as side chain constituents, and dopant anions, and a method of preparing such polymer compositions are provided.

  18. Proton Transport on Modified Sulfonated Polyaniline Electrodes

    DTIC Science & Technology

    1992-06-25

    The pH in the vicinity of a thin self-doped conducting polyaniline electrode was electrochemically modulated in aqueous solutions using both cyclic ... voltammetry and step potential techniques. Changes in pH were measured directly by using a microcombination pH probe. The experimental evidences verify

  19. Electronic Phenomena in Polyanilines

    DTIC Science & Technology

    1992-06-05

    base; (c) pernigraniline base; (d) emeraldine hydrochloride salt polymer; (e) poly(orthotoluidine) (emeraldine base form); (f) sulfonated polyaniline ...order in determining electronic properties [17,21,22], while replacement of a H on one-half the rings with a sulfonic acid group, -SO 3H, Fig. 2f, leads...stability [231. The change in doping level with temperature for emeraldine hychloride and ring- sulfonated polyaniline is estimated by assuming that the

  20. Transparent Conductive Two-Dimensional Titanium Carbide Epitaxial Thin Films

    PubMed Central

    2014-01-01

    Since the discovery of graphene, the quest for two-dimensional (2D) materials has intensified greatly. Recently, a new family of 2D transition metal carbides and carbonitrides (MXenes) was discovered that is both conducting and hydrophilic, an uncommon combination. To date MXenes have been produced as powders, flakes, and colloidal solutions. Herein, we report on the fabrication of ∼1 × 1 cm2 Ti3C2 films by selective etching of Al, from sputter-deposited epitaxial Ti3AlC2 films, in aqueous HF or NH4HF2. Films that were about 19 nm thick, etched with NH4HF2, transmit ∼90% of the light in the visible-to-infrared range and exhibit metallic conductivity down to ∼100 K. Below 100 K, the films’ resistivity increases with decreasing temperature and they exhibit negative magnetoresistance—both observations consistent with a weak localization phenomenon characteristic of many 2D defective solids. This advance opens the door for the use of MXenes in electronic, photonic, and sensing applications. PMID:24741204

  1. Flexible and conductive MXene films and nanocomposites with high capacitance

    SciTech Connect

    Ling, Zheng; Ren, Chang E.; Zhao, Meng-Qiang; Yang, Jian; Giammarco, James M.; Qiu, Jieshan; Barsoum, Michel W.; Gogotsi, Yury

    2014-11-11

    MXenes, a new family of 2D materials, combine hydrophilic surfaces with metallic conductivity. Delamination of MXene produces single-layer nanosheets with thickness of about a nanometer and lateral size of the order of micrometers. The high aspect ratio of delaminated MXene renders it promising nanofiller in multifunctional polymer nanocomposites. In this study, Ti3C2Tx MXene was mixed with either a charged polydiallyldimethylammonium chloride (PDDA) or an electrically neutral polyvinyl alcohol (PVA) to produce Ti3C2Tx/polymer composites. The as-fabricated composites are flexible and have electrical conductivities as high as 2.2 × 104 S/m in the case of the Ti3C2Tx/PVA composite film and 2.4 × 105 S/m for pure Ti3C2Tx films. The tensile strength of the Ti3C2Tx/PVA composites was significantly enhanced compared with pure Ti3C2Tx or PVA films. The intercalation and confinement of the polymer between the MXene flakes not only increased flexibility but also enhanced cationic intercalation, offering an impressive volumetric capacitance of ~530 F/cm3 for MXene/PVA-KOH composite film at 2 mV/s. Finally, to our knowledge, this study is a first, but crucial, step in exploring the potential of using MXenes in polymer-based multifunctional nanocomposites for a host of applications, such as structural components, energy storage devices, wearable electronics, electrochemical actuators, and radiofrequency shielding, to name a few.

  2. Flexible and conductive MXene films and nanocomposites with high capacitance

    PubMed Central

    Ling, Zheng; Ren, Chang E.; Zhao, Meng-Qiang; Yang, Jian; Giammarco, James M.; Qiu, Jieshan; Barsoum, Michel W.; Gogotsi, Yury

    2014-01-01

    MXenes, a new family of 2D materials, combine hydrophilic surfaces with metallic conductivity. Delamination of MXene produces single-layer nanosheets with thickness of about a nanometer and lateral size of the order of micrometers. The high aspect ratio of delaminated MXene renders it promising nanofiller in multifunctional polymer nanocomposites. Herein, Ti3C2Tx MXene was mixed with either a charged polydiallyldimethylammonium chloride (PDDA) or an electrically neutral polyvinyl alcohol (PVA) to produce Ti3C2Tx/polymer composites. The as-fabricated composites are flexible and have electrical conductivities as high as 2.2 × 104 S/m in the case of the Ti3C2Tx/PVA composite film and 2.4 × 105 S/m for pure Ti3C2Tx films. The tensile strength of the Ti3C2Tx/PVA composites was significantly enhanced compared with pure Ti3C2Tx or PVA films. The intercalation and confinement of the polymer between the MXene flakes not only increased flexibility but also enhanced cationic intercalation, offering an impressive volumetric capacitance of ∼530 F/cm3 for MXene/PVA-KOH composite film at 2 mV/s. To our knowledge, this study is a first, but crucial, step in exploring the potential of using MXenes in polymer-based multifunctional nanocomposites for a host of applications, such as structural components, energy storage devices, wearable electronics, electrochemical actuators, and radiofrequency shielding, to name a few. PMID:25389310

  3. Flexible and conductive MXene films and nanocomposites with high capacitance

    DOE PAGES

    Ling, Zheng; Ren, Chang E.; Zhao, Meng-Qiang; ...

    2014-11-11

    MXenes, a new family of 2D materials, combine hydrophilic surfaces with metallic conductivity. Delamination of MXene produces single-layer nanosheets with thickness of about a nanometer and lateral size of the order of micrometers. The high aspect ratio of delaminated MXene renders it promising nanofiller in multifunctional polymer nanocomposites. In this study, Ti3C2Tx MXene was mixed with either a charged polydiallyldimethylammonium chloride (PDDA) or an electrically neutral polyvinyl alcohol (PVA) to produce Ti3C2Tx/polymer composites. The as-fabricated composites are flexible and have electrical conductivities as high as 2.2 × 104 S/m in the case of the Ti3C2Tx/PVA composite film and 2.4 ×more » 105 S/m for pure Ti3C2Tx films. The tensile strength of the Ti3C2Tx/PVA composites was significantly enhanced compared with pure Ti3C2Tx or PVA films. The intercalation and confinement of the polymer between the MXene flakes not only increased flexibility but also enhanced cationic intercalation, offering an impressive volumetric capacitance of ~530 F/cm3 for MXene/PVA-KOH composite film at 2 mV/s. Finally, to our knowledge, this study is a first, but crucial, step in exploring the potential of using MXenes in polymer-based multifunctional nanocomposites for a host of applications, such as structural components, energy storage devices, wearable electronics, electrochemical actuators, and radiofrequency shielding, to name a few.« less

  4. Thin film photovoltaic devices with a minimally conductive buffer layer

    DOEpatents

    Barnes, Teresa M.; Burst, James

    2016-11-15

    A thin film photovoltaic device (100) with a tunable, minimally conductive buffer (128) layer is provided. The photovoltaic device (100) may include a back contact (150), a transparent front contact stack (120), and an absorber (140) positioned between the front contact stack (120) and the back contact (150). The front contact stack (120) may include a low resistivity transparent conductive oxide (TCO) layer (124) and a buffer layer (128) that is proximate to the absorber layer (140). The photovoltaic device (100) may also include a window layer (130) between the buffer layer (128) and the absorber (140). In some cases, the buffer layer (128) is minimally conductive, with its resistivity being tunable, and the buffer layer (128) may be formed as an alloy from a host oxide and a high-permittivity oxide. The high-permittivity oxide may further be chosen to have a bandgap greater than the host oxide.

  5. Polyaniline-based optical ammonia detector

    DOEpatents

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2002-01-01

    Electronic absorption spectroscopy of a polyaniline film deposited on a polyethylene surface by chemical oxidation of aniline monomer at room temperature was used to quantitatively detect ammonia gas. The present optical ammonia gas detector was found to have a response time of less than 15 s, a regeneration time of less than 2 min. at room temperature, and a detection limit of 1 ppm (v/v) for ammonia, with a linear dynamic range from 180 ppm to 18,000 ppm.

  6. Electrical Conductivity, Thermal Behavior, and Seebeck Coefficient of Conductive Films for Printed Thermoelectric Energy Harvesting Systems

    NASA Astrophysics Data System (ADS)

    Ankireddy, Krishnamraju; Menon, Akanksha K.; Iezzi, Brian; Yee, Shannon K.; Losego, Mark D.; Jur, Jesse S.

    2016-11-01

    Printed electronics is being explored as a rapid, facile means for manufacturing thermoelectric generators (TEGs) that can recover useful electrical energy from waste heat. This work examines the relevant electrical conductivity, thermal resistance, thermovoltage, and Seebeck coefficient of printed films for use in such printed flexible TEGs. The thermoelectric performance of TEGs printed using commercially relevant nickel, silver, and carbon inks is evaluated. The microstructure of the printed films is investigated to better understand why the electrical conductivity and Seebeck coefficient are degraded. Thermal conduction is shown to be relatively insensitive to the type of metalized coating and nearly equivalent to that of an uncoated polymer substrate. Of the commercially available conductive ink materials examined, carbon-nickel TEGs are shown to exhibit the highest thermovoltage, with a value of 10.3 μV/K. However, silver-nickel TEGs produced the highest power generation of 14.6 μW [from 31 junctions with temperature difference (Δ T) of 113°C] due to their low electrical resistance. The voltage generated from the silver-nickel TEG was stable under continuous operation at 275°C for 3 h. We have also demonstrated that, after a year of storage in ambient conditions, these devices retain their performance. Notably, the electrical conductivity and Seebeck coefficient measured for individual materials were consistent with those measured from actual printed TEG device structures, validating the need for further fundamental materials characterization to accelerate flexible TEG device optimization.

  7. Transport Properties of Doped-Polyaniline Near the Insulator - Metal Transition.

    NASA Astrophysics Data System (ADS)

    Lee, W. P.; Du, G.; Kohlman, R. S.; Epstein, A. J.; Min, Y.; MacDiarmid, A. G.; Joo, J.

    1996-03-01

    Temperature dependent thermoelectric power and dc conductivity of polyaniline camphor sulfonic acid films prepared from m-cresol and stretched PAN-HCl films have been investigated. Differential and four-probe methods have been used for thermoelectric power and dc conductivity measurements, respectively. For PAN-CSA film with σ_DC(300K) ~ 240 S/cm and σ(4.2K)/σ(300K) ~ 0.5, the room temperature thermoelectric power is +8.5 ± 0.5 μV/K with nearly linear temperature dependence similar to that reported earlier for PAN-CSA fibers.(Y.Z. Wang, et al.), Synth. Met. 68, 207 (1995) Thermoelectric power data of polyaniline samples with different compositions and conductivities is discussed in terms of an effective medium model in accord with inhomogeneous disorder present.(F. Zuo, et al.), Phys. Rev. B 36, 3475 (1987) ^*Supported in part by NIST ATP 1993-01-0149 and NSF DMR 950723.

  8. RESISTIVITY OF A THIN FILM DEPOSITED ON A CONDUCTIVE SUBSTRATE

    NASA Technical Reports Server (NTRS)

    Oberle, L. G.

    1994-01-01

    Resistivity of a Thin Film Deposited on a Conductive Substrate is a computer program developed to aid in the solution of the class of problems where resistivity measurements are needed for a substance deposited on a substrate of higher resistivity than the deposited layer. One of the ways in which a semiconductor material is characterized is by measurement of its resistivity. In the development of silicon carbide (SiC) for use as a semiconductor material for high temperature applications, it became necessary to measure the resistivity of the thin SiC film while it was still attached to the silicon upon which it had been grown epitaxially. The problem is that the presence of the silicon substrate will introduce error in the measured resistivity of the SiC. This program assumes that the resistivity of a thin film of conducting material deposited on another layer of conducting material is measured using the four-point probe. Using the four-point probe measurements, this program calculates the "true" resistivity of the deposited layer on a substrate of finite and different resistivity. Starting from basic principles, an expression for the ratio of measured voltage difference to injected current is developed. This expression involves the probe spacing, relative thicknesses of the layers, and the substrate resistivity as parameters, as well as the unknown resistivity of the deposited layer. The unknown resistivity can be found by iteratively evaluating the theoretical expression. This must be done numerically. The program is written in FORTRAN 77 and targeted for use on an IBM PC or compatible. It can be modified for use on any machine with a FORTRAN 77 compiler. It requires 46K of memory and has been implemented under MS-DOS 3.2.1. The program was developed in 1986.

  9. Processible Polyaniline Copolymers and Complexes.

    NASA Astrophysics Data System (ADS)

    Liao, Yun-Hsin

    1995-01-01

    Polyaniline (PANI) is an intractable polymer due to the difficulty of melt processing or dissolving it in common solvents. The purpose of the present investigation was to prepare a new class of conducting polyanilines with better solubility both in base and dope forms by (1) adding external salt to break aggregated chains, (2) introducing ring substituted units onto the backbone without disturbing the coplanar structure, and (3) complexing with polymeric dopants to form a soluble polymer complex. Aggregation of PANI chains in dilute solution was investigated in N-methyl-2-pyrrolidinone (NMP) by light scattering, gel permeation chromatography, and viscosity measurements. The aggregation of chains resulted in a negative second virial coefficient in light scattering measurement, a bimodal molecular weight distribution in gel permeation chromatography, and concave reduced viscosity curves. The aggregates can be broken by adding external salt, which resulting in a higher reduced viscosity. The driving force for aggregation is assumed to be a combination of hydrogen bonding between the imine and amine groups, and the rigidity of backbone. The aggregation was modeled to occur via side-on packing of PANI chains. The ring substituted PANI copolymers, poly(aniline -co-phenetidine) were synthesized by chemical oxidation copolymerization using ammonium persulfate as an oxidant. The degree of copolymerization declined with an increasing feed of o-phenetidine in the reaction mixture. The o-phenetidine had a higher reactivity than aniline in copolymerization resulting in a higher content of o-phenetidine in copolymers. The resulting copolymers can be readily dissolved in NMP up to 20% (w/w), and other common solvents, and solutions possess a longer gelation time. The highly soluble copolymer with 20 mole % o-phenetidine in the backbone has same order of conductivity as the unsubstituted PANI after it is doped by HCl. Complexation of PANI and polymeric dopant, poly

  10. Conducting Electronic Polymers by Non-Redox Processes

    DTIC Science & Technology

    1988-09-30

    optimized. Use of a weaker oxidant may enable the synth,;sis of more linear and conductive polyaniline emeraldine acid salts. Genies and co-workers found...undergo polymerization to polyaniline at low potentials. Only a small amount of p-dianiline in an acidic aniline solution is needed to allow polyaniline ... polyaniline product shows little evidence of crosslinking. A CV of this polyaniline product taken in an acid solution with no aniline or p-dianiline present

  11. Conductivity behavior of very thin gold films ruptured by mass transport in photosensitive polymer film

    NASA Astrophysics Data System (ADS)

    Linde, Felix; Sekhar Yadavalli, Nataraja; Santer, Svetlana

    2013-12-01

    We report on conductivity behavior of very thin gold layer deposited on a photosensitive polymer film. Under irradiation with light interference pattern, the azobenzene containing photosensitive polymer film undergoes deformation at which topography follows a distribution of intensity, resulting in the formation of a surface relief grating. This process is accompanied by a change in the shape of the polymer surface from flat to sinusoidal together with a corresponding increase in surface area. The gold layer placed above deforms along with the polymer and ruptures at a strain of 4%. The rupturing is spatially well defined, occurring at the topographic maxima and minima resulting in periodic cracks across the whole irradiated area. We have shown that this periodic micro-rupturing of a thin metal film has no significant impact on the electrical conductivity of the films. We suggest a model to explain this phenomenon and support this by additional experiments where the conductivity is measured in a process when a single nanoscopic scratch is formed with an AFM tip. Our results indicate that in flexible electronic materials consisting of a polymer support and an integrated metal circuit, nano- and micro cracks do not alter significantly the behavior of the conductivity unless the metal is disrupted completely.

  12. Conductivity behavior of very thin gold films ruptured by mass transport in photosensitive polymer film

    SciTech Connect

    Linde, Felix; Sekhar Yadavalli, Nataraja; Santer, Svetlana

    2013-12-16

    We report on conductivity behavior of very thin gold layer deposited on a photosensitive polymer film. Under irradiation with light interference pattern, the azobenzene containing photosensitive polymer film undergoes deformation at which topography follows a distribution of intensity, resulting in the formation of a surface relief grating. This process is accompanied by a change in the shape of the polymer surface from flat to sinusoidal together with a corresponding increase in surface area. The gold layer placed above deforms along with the polymer and ruptures at a strain of 4%. The rupturing is spatially well defined, occurring at the topographic maxima and minima resulting in periodic cracks across the whole irradiated area. We have shown that this periodic micro-rupturing of a thin metal film has no significant impact on the electrical conductivity of the films. We suggest a model to explain this phenomenon and support this by additional experiments where the conductivity is measured in a process when a single nanoscopic scratch is formed with an AFM tip. Our results indicate that in flexible electronic materials consisting of a polymer support and an integrated metal circuit, nano- and micro cracks do not alter significantly the behavior of the conductivity unless the metal is disrupted completely.

  13. Research on resistance properties of conductive layer materials of microchannel plate film dynode

    NASA Astrophysics Data System (ADS)

    Peng, Ling-ling; Duanmu, Qingduo; Yang, Ji-kai; Wang, Guo-zheng

    2015-03-01

    Silicon Microchannel Plate - MCP - is a new image multiplier devices based semiconductor process technology. Compared with the traditional glass MCP, Silicon MCP has an advantage in technology that the dynode materials and the substrate materials are separate. At the same time, the dynode preparation process and the microchannel arrays are also separate. Two different dynode conductive layer films are prepared: polysilicon conductive films prepared by low pressure chemical vapor deposition (LPCVD) and AZO thin films coated by atomic layer deposition (ALD). The conductive films coated by ALD are superior to dynode conductive films prepared by LPCVD. By comparing the resistivity of conductive polysilicon thin film and AZO thin film of different Al concentrations doped, AZO thin film of different Al concentrations doped is a more suitable conductive layer dynode material to satisfy the MCP conductive layer resistivity requirements.

  14. Device and method for measuring thermal conductivity of thin films

    NASA Technical Reports Server (NTRS)

    Amer, Tahani R. (Inventor); Subramanian, Chelakara (Inventor); Upchurch, Billy T. (Inventor); Alderfer, David W. (Inventor); Sealey, Bradley S. (Inventor); Burkett, Jr., Cecil G. (Inventor)

    2001-01-01

    A device and method are provided for measuring the thermal conductivity of rigid or flexible, homogeneous or heterogeneous, thin films between 50 .mu.m and 150 .mu.m thick with relative standard deviations of less than five percent. The specimen is sandwiched between like material, highly conductive upper and lower slabs. Each slab is instrumented with six thermocouples embedded within the slab and flush with their corresponding surfaces. A heat source heats the lower slab and a heat sink cools the upper slab. The heat sink also provides sufficient contact pressure onto the specimen. Testing is performed within a vacuum environment (bell-jar) between 10.sup.-3 to 10.sup.-6 Torr. An anti-radiant shield on the interior surface of the bell-jar is used to avoid radiation heat losses. Insulation is placed adjacent to the heat source and adjacent to the heat sink to prevent conduction losses. A temperature controlled water circulator circulates water from a constant temperature bath through the heat sink. Fourier's one-dimensional law of heat conduction is the governing equation. Data, including temperatures, are measured with a multi-channel data acquisition system. On-line computer processing is used for thermal conductivity calculations.

  15. Carbon nanotube based transparent conductive films: progress, challenges, and perspectives

    PubMed Central

    Zhou, Ying; Azumi, Reiko

    2016-01-01

    Abstract Developments in the manufacturing technology of low-cost, high-quality carbon nanotubes (CNTs) are leading to increased industrial applications for this remarkable material. One of the most promising applications, CNT based transparent conductive films (TCFs), are an alternative technology in future electronics to replace traditional TCFs, which use indium tin oxide. Despite significant price competition among various TCFs, CNT-based TCFs have good potential for use in emerging flexible, stretchable and wearable optoelectronics. In this review, we summarize the recent progress in the fabrication, properties, stability and applications of CNT-based TCFs. The challenges of current CNT-based TCFs for industrial use, in comparison with other TCFs, are considered. We also discuss the potential of CNT-based TCFs, and give some possible strategies to reduce the production cost and improve their conductivity and transparency. PMID:27877899

  16. Laser Processing of Carbon Nanotube Transparent Conducting Films

    NASA Astrophysics Data System (ADS)

    Mann, Andrew

    Transparent conducting films, or TCFs, are 2D electrical conductors with the ability to transmit light. Because of this, they are used in many popular electronics including smart phones, tablets, solar panels, and televisions. The most common material used as a TCF is indium tin oxide, or ITO. Although ITO has great electrical and optical characteristics, it is expensive, brittle, and difficult to pattern. These limitations have led researchers toward other materials for the next generation of displays and touch panels. The most promising material for next generation TCFs is carbon nanotubes, or CNTs. CNTs are cylindrical tubes of carbon no more than a few atoms thick. They have different electrical and optical properties depending on their atomic structure, and are extremely strong. As an electrode, they conduct electricity through an array of randomly dispersed tubes. The array is highly transparent because of gaps between the tubes, and size and optical properties of the CNTs. Many research groups have tried making CNT TCFs with opto-electric properties similar to ITO but have difficultly achieving high conductivity. This is partly attributed to impurities from fabrication and a mix of different tube types, but is mainly caused by low junction conductivity. In functionalized nanotubes, junction conductivity is impaired by covalently bonded molecules added to the sidewalls of the tubes. The addition of this molecule, known as functionalization, is designed to facilitate CNT dispersion in a solvent by adding properties of the molecule to the CNTs. While necessary for a good solution, functionalization decreases the conductivity in the CNT array by creating defects in the tube's structures and preventing direct inter-carbon bonding. This research investigates removing the functional coating (after tube deposition) by laser processing. Laser light is able to preferentially heat the CNTs because of their optical and electrical properties. Through local conduction

  17. Polyaniline nanostructures expedient as working electrode materials in supercapacitors

    NASA Astrophysics Data System (ADS)

    Gedela, Venkata Ramana; Srikanth, Vadali Venkata Satya Siva

    2014-04-01

    Granular type polyaniline (PANi), PANi nanofibers (NFs), and PANi nanotubes (NTs) expedient as working electrode materials for supercapacitors are synthesized. The synthesis procedure used in this work facilitates not only the synthesis of solid powders of the PANi nanostructures, but also thin films constituted by the same PANi nanostructures in the same experiment. PANi NFs are found to exhibit faster electrode kinetics and better capacitance when compared to PANi NTs and granular PANi. Specific capacitance and energy storage per unit mass of PANi NFs are 239.47 Fg-1 (at 0.5 Ag-1) and 43.2 Wh kg-1, respectively. Electrical conductivity of PANi NFs is also better when compared to the other two nanostructures. Properties of the three PANi nanostructures are explicated in correlation with crystallinity, intrinsic oxidation state, doping degree, BET surface area, and ordered mesoporosity pertaining to the nanostructures.

  18. Electrochemical deposition of conducting ruthenium oxide films from solution

    SciTech Connect

    Anderson, D.P.; Warren, L.F.

    1984-02-01

    In the last decade, ruthenium oxide, RuO /sub x/ (x less than or equal to 2), has been used extensively as the active anode electrocatalyst constituent for Cl/sub 2/ and O/sub 2/ evolution reactions, in chlorate production, and in metal electrowinning from mixed chloride-sulfate solutions. More recently, this material has been incorporated in several light-induced water electrolysis schemes and apparently possesses the ability to inhibit CdS photocorrosion by acting as a hole scavenger. The numerous applications for this catalyst material certainly warrant further studies of its electrochemical properties on a variety of substrates, e.g., semiconductors. The lack of a simple technique for controlled deposition of ruthenium oxide onto conducting substrates prompted us to investigate an electrochemical approach to this problem. We describe here a new way to electrochemically deposit conducting films of hydrated ruthenium oxide from an aqueous solution of the benzeneruthenium (II)aqua complex. The films slowly dissolve in aqueous electrolytes upon potential cycling, yet appear to be catalytic with regards to water oxidation.

  19. Electric conductivity of polymer films filled with magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Rumyantsev, B. M.; Bibikov, S. B.; Bychkova, A. V.; Leontiev, V. G.; Berendyaev, V. I.; Sorokina, O. N.; Kovarskii, A. L.

    2016-12-01

    The conductivity of polymer composites with magnetic nanoparticles (MNP) containing magnetite and other MNP (Ni, Cu-Ni) in the layers and planar cells with Al electrodes is studied. For soluble polymers (polyvinylpyrrolidone and polyvinyl alcohol) containing 1-10 wt % of magnetite MNP, a substantial effect of MNP on surface conductivity is detected over a wide range (from 10-10 to 10-3 Ω-1). It is shown that the addition of magnetite MNP not only results in a considerable change in cell conductivity, but also leads to its partially irreversible variation (by an order of magnitude or more) via minor modifications of the experimental conditions (temperature, electric field). For high-resistance samples with low probabilities of conducting chain formation, temperature current peaks are observed upon moderate heating (up to 350 K). These peaks are similar to the maxima observed upon polymer electret thermodischarges when the charges are captured by the deep centers associated with separate MNP or MNP aggregates. The type and position of the maxima are determined by the characteristics of the polymer matrix. For polyvinylpyrrolidone composites, the maxima are observed some time after heating (the echo effect). With composites based on solventborne polymers (polyalkanesterimides, soluble polyimide) and Ni, Cu-Ni MNP, no change in film conductivity measured electrophotographically is observed, due to the formation of a dielectric coating formed by polymer macromolecules adsorbed on the MNP surface. An explanation based on the possible formation of magnetic aggregates of magnetite MNP and conducting chains is proposed. Magnetic aggregation IPM is proposed as one way of controlling cell conductivity.

  20. Effect of Applied Potential on the Electrochemical Deposition of Styrene-Butadiene Co-Polymer Based Conducting Polymer Composite

    NASA Astrophysics Data System (ADS)

    Mathew, Anisha Mary; Neena, P.

    2011-10-01

    Homogeneous conducting polymer composite films with improved electrical properties are synthesized via electrochemical polymerization of polyaniline on Styrene butadiene rubber coated steel electrode. The electrochemical polymerization is carried out by potentiostatic method using an aqueous solution of 0.2 M aniline and 1.5 M sulphuric acid as electrolyte in a single compartment electrochemical cell. The optical studies show successful incorporation of polyaniline into the matrix polymer film. The effect of applied potential on the electrodeposition of composite is studied by cyclic voltammetry and by impedance spectroscopic measurements.

  1. Permeable polyaniline articles for gas separation

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2004-09-28

    Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

  2. Permeable polyaniline articles for gas separation

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2009-07-21

    Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

  3. Transparent conductive thin-film encapsulation layers (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Behrendt, Andreas; Gahlmann, Tobias; Trost, Sara; Polywka, Andreas; Görrn, Patrick; Riedl, Thomas

    2015-10-01

    Gas diffusion barriers (GDB) are inevitable to protect sensitive organic materials or devices against ambient gases. Typically, thin-film gas diffusion barriers are insulators, e.g. Al2O3 or multilayers of Al2O3/ZrO2, etc.. A wide range of applications would require GDB which are at the same time transparent and electrically conductive. They could serve as electrode and moisture barrier simultaneously, thereby simplifying production. As of yet, work on transparent conductive GDB (TCGDBs) is very limited. TCGDBs based on ZnO prepared by atomic layer deposition (ALD) have been reported. Due to the chemical instability of ZnO, it turns out that their electrical conductivity severely deteriorates by orders of magnitude upon exposure to damp heat conditions after very short time. We will show that these issues can be overcome by the use of tin oxide (SnO2). Conductivities of up to 300 S/cm and extremely low water vapor transmission rates (WVTR) on the order of 10-6 g/(m2 day) can been achieved in SnOx layers prepared by ALD at low temperatures (<150°C). A sandwich of SnOx/Ag/SnOx is shown to provide an average transmittance of 82% and a low sheet resistance of 9 Ohm/sq. At the same time the resulting electrodes are extremely robust. E.g., while unprotected Cu and Ag electrodes degrade within a few minutes at 85°C/85%rH (e.g. Cu lost 7 orders of magnitude in electrical conductivity), sandwich structures of SnOx/(Cu or Ag)/SnOx remain virtually unchanged even after 100 h. The SnOx in this work will also provide corrosion protection for the metal in case of harsh processing steps on top these electodes (e.g. acidic). We demonstrate the application of these TCGDBs as electrodes for organic solar cells and OLEDs.

  4. Thin film conductive polymer for microactuator and micromuscle applications

    SciTech Connect

    Lee, A.P.; Hong, K.; Trevino, J.; Northrup, M.A.

    1994-04-14

    Conductive polymer/polyimide bimorphic microcantilevers have been actuated vertically (out-of-plane) upon the volumetric changes induced by electrochemical doping of the polymer. The microcantilevers that are 200-500 {mu}m in length and 50-100 {mu}m in width can be fully extended from a circularly-curled geometry, and thus generate more than 100 {mu}m displacement. Dynamically the microcantilevers have been driven as fast as 1.2 Hz and the polymer was stable for over a week stored in air and light. Residual stresses in the polymer film is estimated to be as high as 254 MPa, and actuation stresses are as high as 50 MPa.

  5. Preparation and electrochemical properties of polyaniline nanofibers using ultrasonication

    SciTech Connect

    Manuel, James; Kim, Miso; Fapyane, Deby; Chang, In Seop; Ahn, Hyo-Jun; Ahn, Jou-Hyeon

    2014-10-15

    Highlights: • Nanofibrous structured polyaniline (PANI) was prepared by simple ultrasonication. • PANI nanofibers prepared at 5 °C are uniform with an average diameter of 50 nm. • The conductivity is increased by 2 × 10{sup 8} times after doping with LiClO{sub 4}. • The cell with PANI-LiClO{sub 4} shows good cycle performance at high current densities. - Abstract: Polyaniline nanofibers have been successfully prepared by applying ultrasonic irradiation during oxidative polymerization of aniline in dilute hydrochloric acid and evaluated for suitability in lithium cells after doping with lithium perchlorate salt. Polyaniline nanofibers are confirmed by Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, and transmission electron microscopy, and the efficiency of doping is confirmed by DC conductivity measurements at different temperatures. Electrochemical properties of nanofibers are evaluated, of which a remarkable increase in cycle stability is achieved when compared to polyaniline prepared by simple oxidative polymerization of aniline. The cell with nanofibrous polyaniline doped with LiClO{sub 4} delivers an initial discharge capacity value of 86 mA h g{sup −1} at 1 C-rate which is about 60% of theoretical capacity, and the capacity is slightly lowered during cycle and reaches 50% of theoretical capacity after 40 cycles. The cell delivers a stable and higher discharge capacity even at 2 C-rate compared to that of the cell prepared with bulk polyaniline doped with LiClO{sub 4}.

  6. Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor

    PubMed Central

    Shrestha, R.; Lee, K. M.; Chang, W. S.; Kim, D. S.; Rhee, G. H.; Choi, T. Y.

    2013-01-01

    In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 μm to 5 μm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m−1 K−1 at room temperature. PMID:23556837

  7. Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor.

    PubMed

    Shrestha, R; Lee, K M; Chang, W S; Kim, D S; Rhee, G H; Choi, T Y

    2013-03-01

    In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 μm to 5 μm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m(-1) K(-1) at room temperature.

  8. Preparation and Properties of Silver Nanowire-Based Transparent Conductive Composite Films

    NASA Astrophysics Data System (ADS)

    Tian, Ji-Li; Zhang, Hua-Yu; Wang, Hai-Jun

    2016-06-01

    Silver nanowire-based transparent conductive composite films with different structures were successfully prepared using various methods, including liquid polyol, magnetron sputtering and spin coating. The experimental results revealed that the optical transmittance of all different structural composite films decreased slightly (1-3%) compared to pure films. However, the electrical conductivity of all composite films had a great improvement. Under the condition that the optical transmittance was greater than 78% over the wavelength range of 400-800 nm, the AgNW/PVA/AgNW film became a conductor, while the AZO/AgNW/AZO film and the ITO/AgNW/ITO film showed 88.9% and 94% reductions, respectively, for the sheet resistance compared with pure films. In addition, applying a suitable mechanical pressure can improve the conductivity of AgNW-based composite films.

  9. Conductance Thin Film Model of Flexible Organic Thin Film Device using COMSOL Multiphysics

    NASA Astrophysics Data System (ADS)

    Carradero-Santiago, Carolyn; Vedrine-Pauléus, Josee

    We developed a virtual model to analyze the electrical conductivity of multilayered thin films placed above a graphene conducting and flexible polyethylene terephthalate (PET) substrate. The organic layers of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole conducting layer, poly(3-hexylthiophene-2,5-diyl) (P3HT), as a p-type, phenyl-C61-butyric acid methyl ester (PCBM) and as n-type, with aluminum as a top conductor. COMSOL Multiphysics was the software we used to develop the virtual model to analyze potential variations and conductivity through the thin-film layers. COMSOL Multiphysics software allows simulation and modeling of physical phenomena represented by differential equations such as heat transfer, fluid flow, electromagnetism, and structural mechanics. In this work, using the AC/DC, electric currents module we defined the geometry of the model and properties for each of the six layers: PET/graphene/PEDOT:PSS/P3HT/PCBM/aluminum. We analyzed the model with varying thicknesses of graphene and active layers (P3HT/PCBM). This simulation allowed us to analyze the electrical conductivity, and visualize the model with varying voltage potential, or bias across the plates, useful for applications in solar cell devices.

  10. Functional Multilayered Transparent Conducting Oxide Thin Films for Photovoltaic Devices

    SciTech Connect

    Noh, J. H.; Lee, S.; Kim, J. Y.; Lee, J. K.; Han, H. S.; Cho, C. M.; Cho, I. S.; Jung, H. S.; Hong, K. S.

    2009-01-01

    In this study, we present a thermally stable multilayered transparent conducting oxide (TCO) functionalized for dye-sensitized solar cells (DSSCs). Nb-doped TiO{sub 2} (NTO) layers deposited on conventional Sn-doped In{sub 2}O{sub 3} (ITO) substrates using pulsed laser deposition (PLD) enhanced the optical-to-electrical conversion efficiency of the DSSCs by as much as 17% compared to that of bare ITO-based DSSCs. The electrical properties and J-V characteristics of the multilayered NTO/ITO films showed that the improved cell performance was due to the facilitated charge injection from TiO{sub 2} to ITO that resulted from the formation of an ohmic contact with ITO, as well as the conserved high conductivity of ITO after the oxidizing annealing process. Moreover, the NTO/ITO-based DSSC exhibited higher efficiency than a F-doped SnO{sub 2}(FTO)-based one, which demonstrates that optimization of multilayered NTO-based TCOs is a realistic approach for achieving highly efficient photoenergy conversion devices.

  11. Terahertz conductivity of MnSi thin films

    NASA Astrophysics Data System (ADS)

    Dodge, J.; Mohtashemi, Laleh; Farahani, Amir; Karhu, Eric; Monchesky, Theodore

    2013-03-01

    We present measurements of the low-frequency optical conductivity of MnSi thin films, using time-domain terahertz spectroscopy. At low temperatures and low frequencies, we extract the DC resistivity, scattering life time and plasma frequency from a Drude fit. We obtain a value of ωp ~= 1 . 0 eV, which can be used to estimate the renormalization coefficient through comparison with band theory. At higher temperatures, deviations from Drude behavior are observed, suggesting a loss of quasi-particle coherence. In the region of low temperatures and high frequencies, we see evidence for a crossover to the anomalous power law dependence observed by Mena et al. As the temperature increases, the anomalous frequency dependence becomes more pronounced, and the plasma frequency inferred from a Drude fit decreases dramatically. Above T ~ 50 K, σ2 (ω) develops a negative slope that is inconsistent with both a Drude model and the anomalous power law observed earlier, indicating a sharp pseudogap in the conductivity spectrum.

  12. Fabrication and characterization of polyaniline/PVA humidity microsensors.

    PubMed

    Yang, Ming-Zhi; Dai, Ching-Liang; Lin, Wei-Yi

    2011-01-01

    This study presents the fabrication and characterization of a humidity microsensor that consists of interdigitated electrodes and a sensitive film. The area of the humidity microsensor is about 2 mm(2). The sensitive film is polyaniline doping polyvinyl alcohol (PVA) that is prepared by the sol-gel method, and the film has nanofiber and porous structures that help increase the sensing reaction. The commercial 0.35 μm Complimentary Metal Oxide Semiconductor (CMOS) process is used to fabricate the humidity microsensor. The sensor needs a post-CMOS process to etch the sacrificial layer and to coat the sensitive film on the interdigitated electrodes. The sensor produces a change in resistance as the polyaniline/PVA film absorbs or desorbs vapor. Experimental results show that the sensitivity of the humidity sensor is about 12.6 kΩ/%RH at 25 °C.

  13. Fabrication and Characterization of Polyaniline/PVA Humidity Microsensors

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Lin, Wei-Yi

    2011-01-01

    This study presents the fabrication and characterization of a humidity microsensor that consists of interdigitated electrodes and a sensitive film. The area of the humidity microsensor is about 2 mm2. The sensitive film is polyaniline doping polyvinyl alcohol (PVA) that is prepared by the sol-gel method, and the film has nanofiber and porous structures that help increase the sensing reaction. The commercial 0.35 μm Complimentary Metal Oxide Semiconductor (CMOS) process is used to fabricate the humidity microsensor. The sensor needs a post-CMOS process to etch the sacrificial layer and to coat the sensitive film on the interdigitated electrodes. The sensor produces a change in resistance as the polyaniline/PVA film absorbs or desorbs vapor. Experimental results show that the sensitivity of the humidity sensor is about 12.6 kΩ/%RH at 25 °C. PMID:22164067

  14. In situ conductance measurements of copper phthalocyanine thin film growth on sapphire [0001].

    PubMed

    Murdey, Richard; Sato, Naoki

    2011-06-21

    The current flowing through a thin film of copper phthalocyanine vacuum deposited on a single crystal sapphire [0001] surface was measured during film growth from 0 to 93 nm. The results, expressed as conductance vs. nominal film thickness, indicate three distinct film growth regions. Conductive material forms below about 5 nm and again above 35 nm, but in the intermediate thicknesses the film conductance was observed to decrease with increasing film thickness. With the aid of ac-AFM topology images taken ex situ, the conductance results are explained based on the Stranski-Krastanov (2D + 3D) film growth mechanism, in which the formation of a thin wetting layer is followed by the growth of discrete islands that eventually coalesce into an interpenetrating, conductive network.

  15. Effect of microstructure on thermal conductivity of Cu, Ag thin films.

    PubMed

    Ryu, Sang; Juhng, Woonam; Kim, Youngman

    2010-05-01

    Thin film type materials are widely used in modern industries, such as semiconductor devices, functional superconductors, machining tools, and so on. The thermal properties of material in semiconductor are very important factors for stable operation because the heat generated during device operation may increase clock frequency. Even though thermal properties of thin films may play a major role in assessing reliability of parts, the measurement methods of thin film thermal properties are generally known to be complex to devise. In this study, a temperature distribution method was applied for the measurement of thermal conductivity of Cu and Ag thin film on borosilicate glass substrate. Cu and Ag thin films were deposited on borosilicate glass using thermal evaporation processes. To measure the thermal conductivity changes according to the microstructure of metallic thin film, the processing variables for the Cu and Ag thin film deposition were changed. To minimize the effect of film thickness, the film thickness was fixed to the thickness of approximately 500 nm throughout experiments. The thermal conductivities of thin films were measured to be much lower than those of bulk materials. Thin film with larger grain size showed higher thermal conductivity probably due to the lower number density of grain boundary. Weidman-Franz law could be applied to thin films produced in this study. Thermal conductivity was also estimated from the resistivity of thin film and Lorenz number of bulk material.

  16. Electrical conduction mechanism in annealed and light soaked silver doped CdSe thin films

    NASA Astrophysics Data System (ADS)

    Kaur, Jagdish; Tripathi, S. K.

    2015-08-01

    Thin films of silver (Ag) doped CdSe are prepared on glass substrates by thermal evaporation technique in inert gas atmosphere. SEM micrograph reveals uniform and homogenous distribution of nanoparticles on the glass substrates. The composition of the film is investigated by EDX analysis. Thin films are thermally annealed and light soaked to study the thermally and optically induced effect. Electrical conduction in annealed thin films exhibits different conduction mechanisms in low and high temperature region while conduction in light soaked thin films is single thermally activated process. The activation energies for dark and photoconductivities are also investigated.

  17. Conducting polymer films fabricated by oxidative graft copolymerization of aniline on poly(acrylic acid) grafted poly(ethylene terephthalate) surfaces.

    PubMed

    Wang, Jiku; Liu, Xuyan; Choi, Ho-Suk; Kim, Jong-Hoon

    2008-11-27

    A conductive polyaniline/poly(ethylene terephthalate) (PANI/PET) composite film was fabricated via the oxidative graft copolymerization of aniline (ANI) onto the plasma-induced poly(acrylic acid) (PAAc) grafted PET surface. The attenuated total reflectance Fourier transform infrared spectroscopy spectra (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that PANI was successfully grafted onto the surface of the PAAc-g-PET films. The effects of the experimental conditions on the percentage of PANI grafted onto the PAAc-g-PET films were extensively investigated. A very high grafting percentage of ANI can be obtained through the acid-base reaction between the aniline monomer and PAAc on the PAAc-g-PET surface at high temperature. As a result, the grafting percentage of PANI can be increased to as high as 12.18 wt %, which causes the surface resistance of the PANI-g-PAAc-g-PET film to be reduced to about 1000 Omega/sq. We predicted that this is because of the high flexibility of the PAAc molecular chains and high solubility of aniline, both of which facilitate the binding of aniline to PAAc during this high temperature acid-base reaction. It was observed by atomic force microscopy (AFM) that the PANI-modified PET surface exhibits higher size irregularity and surface roughness, which further indicated that a much greater number of aniline molecules can be reactively bonded to and distributed along the grafted AAc chains and that the PANI-g-PAAc-g-PET surface resulting from the sequential oxidative graft copolymerization can possess higher electrical conductivity.

  18. Acid diffusion through polyaniline membranes

    SciTech Connect

    Su, T.M.; Huang, S.C.; Conklin, J.A.

    1995-12-01

    Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

  19. Laser Drilling and Conducting Film Formation of Vias in Silicon

    NASA Astrophysics Data System (ADS)

    Hidai, Hirofumi; Matsusaka, Souta; Chiba, Akira; Morita, Noboru

    2015-12-01

    Smaller vias are required to connect interlayers in semiconductor devices, glass interposers, and printed circuit boards. However, plating metals on the inner walls of these fine holes is becoming difficult. We demonstrate that laser illumination of stacked materials results in laser drilling and spontaneous coating of the inner surface. This process drilled through the upper materials of the stack and then evaporated the lower material, which re-deposited on the inner surface of the upper materials. Laser illumination of samples composed of stacked borosilicate glass, silicon, and copper formed vias with diameters of ˜15 μm in the silicon wafer (thickness of 100 μm) and spontaneously deposited the copper film on the inner surface. We observed the inner surfaces of the drilled holes in the silicon wafer with a field-emission scanning electron microscope equipped with an energy-dispersive x-ray spectroscope accessory. The conductivity of the vias was ˜100 Ω. We expect that, by changing the lower material, various materials could be deposited on the upper material, making this technique useful in many applications.

  20. Flexibility and non-destructive conductivity measurements of Ag nanowire based transparent conductive films via terahertz time domain spectroscopy.

    PubMed

    Hwang, Gyujeong; Balci, Soner; Güngördü, M Zeki; Maleski, Alex; Waters, Joseph; Lee, Sunjong; Choi, Sangjun; Kim, Kyoungkook; Cho, Soohaeng; Kim, Seongsin M

    2017-02-20

    Highly stable and flexible transparent electrodes are fabricated based on silver nanowires (AgNWs) on both polyethylene-terephthalate (PET) and polyimide (PI) substrates. Terahertz time domain spectroscopy (THz-TDS) was utilized to probe AgNW films while bended with a radius 5 mm to discover conductivity of bended films which was further analyzed through Drude-Smith model. AgNW films experience little degradation in conductivity (<3%) before, after, and during 1000 bending cycles. Highly stable AgNW flexible electrodes have broad applications in flexible optoelectronic and electronic devices. THz-TDS is an effective technique to investigate the electrical properties of the bended and flattened conducting films in a nondestructive manner.

  1. Transparent electrically conducting thin films for spacecraft temperature control applications

    NASA Technical Reports Server (NTRS)

    Hass, G.; Heaney, J. B.; Toft, A. R.

    1979-01-01

    Thin transparent films of In2O3 or In2O3 + SnO2 prepared by evaporation or sputtering have been tested for use as surface layers for spacecraft temperature control coatings. The films are intended to prevent nonuniform electric charge buildup on the spacecraft exterior. Film thicknesses of 300 to 500 A were found to be optimal in terms of durability and minimum impact on the solar absorptance and the thermal emissivity of the underlayers. As a verification of their suitability for long-duration space missions, the films were subjected to simulated solar UV plus proton irradiation in a vacuum.

  2. Improved thermal-conducting and current-confining film

    NASA Technical Reports Server (NTRS)

    Hawrylo, F. Z.

    1980-01-01

    Ge film that replaces SiO2 coating in method of fabricating room-temperature CW laser diodes achieves greater heat dissipation while maintaining effectiveness as current-confining medium. Film also lessens certain unwanted strain parameters and ultimately increases lifetime of lasers. Method is applicable to fabrication of InP and (AlGa)As CW lasers.

  3. Lustrous copper nanoparticle film: Photodeposition with high quantum yield and electric conductivity

    NASA Astrophysics Data System (ADS)

    Miyagawa, Masaya; Yonemura, Mari; Tanaka, Hideki

    2016-11-01

    Cu nanoparticle (NP) film has attracted much attention due to its high electric conductivity. In the present study, we prepared a Cu NP film on a TiO2-coated substrate by photoreduction of copper acetate solution. The obtained film showed high electric conductivity and metallic luster by the successive deposition of Cu NP. Moreover, the film was decomposed on exposure to fresh air, and its decomposition reaction mechanisms were proposed. Hence, we concluded that the obtained lustrous film was composed of Cu NP, even though its physical properties was similar to bulk copper.

  4. Temperature dependence electrical conduction of solution-processed CZTS films in dark and under light

    NASA Astrophysics Data System (ADS)

    Ghediya, Prashant R.; Chaudhuri, Tapas K.; Patel, K. C.

    2016-09-01

    Electrical conduction of solution-processed Cu2ZnSnS4 (CZTS) films has been reported in dark and under light in the temperature range of 85 to 300 K. The films show nearest neighbor hopping mode of transport at below 200 K, while above 200 K the films were dominated by thermionic emission over grain boundary barriers, following, Seto's model for polycrystalline films. The hopping energy and grain boundary barrier height of CZTS films are found be decreases under illumination due to the photoconductivity. The films were pure kesterite CZTS as revealed from X-Ray diffraction and Raman spectroscopy.

  5. Polyaniline Membranes for Separation Applications

    DTIC Science & Technology

    2007-11-02

    High quality membranes of poly aniline/ethylaniline copolymers along with polyaniline /polyimide blends have been synthesized . Water permeates... polyaniline is among the most selective membranes yet developed for water/acetic acid separations: e.g. at 50% water/50% acetic acid the selectivity alpha is

  6. Conducting and Optical Properties of Transparent Conducting Indium-Doped Zinc Oxide Thin Films by Sol-Gel Processing

    SciTech Connect

    Huang, S.; Kaydanova, T.; Miedaner, A.; Ginley, D.S.

    2004-01-01

    Transparent conducting oxides were successfully prepared from mixed zinc nitrate hexahydrate and indium nitrate hydrate solutions in ethylene glycol using sol-gel technique. The In content in the film was varied (0, 2, 10, 20, 40, 75 and 100 atom %). Films were prepared by spin coating of the liquid precursors followed by thermal decomposition at 400° C after each layer. According to X-ray diffraction (XRD) measurements, the pure ZnO and pure InO films (0 and at 100 % In) were crystalline as-deposited. The crystallinity was suppressed in mixed compositions such that the films with compositions between 10 and 75 at % were amorphous. All the films were transparent with the transmission cut-off frequency near 400 nm, which is characteristic of TCO materials. All as-deposited films were conductive with 0 and 100 atom % In having the lowest resistivities. The resistivity of all compositions were improved by post-deposition reducing anneal in pure Ar at 300° C. The lowest resistivity of 0.2 Ωcm was obtained for the pure ZnO after Ar anneal. It was two-orders of magnitude higher than reported in the literature for the In-doped ZnO, which was attributed to the low processing temperature. The resistivities of as-deposited and annealed in Ar films were increased by consequent air anneal at 300° C.

  7. Biofield-effect protein-sensor: Plasma functionalization of polyaniline, protein immobilization, and sensing mechanism

    NASA Astrophysics Data System (ADS)

    Cho, Chae-Ryong; Lee, Hyun-Uk; Ahn, Kyun; Jeong, Se-Young; Choi, Jun-Hee; Kim, Jinwoo; Cho, Jiung

    2014-06-01

    We report the fabrication of a biofield-effect protein-sensor (BioFEP) based on atmospheric-pressure plasma (AP) treatment of a conducting polyaniline (PANI) film. Successive H2 and O2 AP (OHAP) treatment generated dominant hydrophilic -OH and O=CO- functional groups on the PANI film surface, which served as strong binding sites to immobilize bovine serum albumin (BSA) protein molecules. The output current changes of the BioFEP as a function of BSA concentration were obtained. The resistance of the OHAP surface could be sensitively increased from 2.5 × 108 Ω to 2.0 × 1012 Ω with increasing BSA concentrations in the range of 0.025-4 μg/ml. The results suggest that the method is a simple and cost-effective tool to determine the concentration of BSA by measuring electrical resistance.

  8. Electrical, optical and dielectric properties of HCl doped polyaniline nanorods

    NASA Astrophysics Data System (ADS)

    Chutia, P.; Kumar, A.

    2014-03-01

    In this report we have investigated the optical, electrical and dielectric properties of HCl doped polyaniline nanorods synthesized by the interfacial polymerization technique. High resolution transmission electron microscope (HRTEM) micrographs confirm the formation of nanorods. X-ray diffraction pattern shows the semicrystalline nature of polyaniline nanorods with a diameter distribution in the range of 10-22 nm. The chemical and electronic structures of the polyaniline nanorods are investigated by micro-Raman and UV-vis spectroscopy. Dielectric relaxation spectroscopy has been applied to study the dielectric permittivity, modulus formalism and ac conductivity as a function of frequency and temperature. The ac conductivity follows a power law with frequency. The variation of frequency exponent with temperature suggests that the correlated barrier hopping is the dominant charge transport mechanism. The existence of both polaron and bipolaron in the transport mechanism has been confirmed from the binding energy calculations.

  9. Calculation of the high-frequency conductivity and the Hall constant of a thin semiconductor film

    NASA Astrophysics Data System (ADS)

    Savenko, O. V.; Romanov, D. N.; Kuznetsova, I. A.

    2016-12-01

    The task about calculation of high-frequency conductivity and Hall constant of a thin semiconductor film is solved by the kinetic method. This film is placed in transverse stationary magnetic field and longitudinal alternative electric field. The ratio between film thickness and mean free path of charge carriers is assumed to be arbitrary. Skin effect is negligible. The diffuse-specular mechanism of charge carriers scattering from film surfaces is considered in the view of equal mirrority coefficients of the upper and lower film surfaces. The dependences of non-dimensional conductivity and Hall constant on non-dimensional parameters: electric field frequency, magnetic field induction and film thickness are investigated. The comparative analysis of obtained results with the calculations for the case of a metal film are made.

  10. Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

    DOEpatents

    Wu, Xuanzhi; Coutts, Timothy J.; Sheldon, Peter; Rose, Douglas H.

    1999-01-01

    A photovoltaic device having a substrate, a layer of Cd.sub.2 SnO.sub.4 disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd.sub.2 SnO.sub.4, and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd.sub.2 SnO.sub.4 layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd.sub.2 SnO.sub.4, and depositing an electrically conductive film onto the thin film of semiconductor materials.

  11. Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

    DOEpatents

    Wu, X.; Coutts, T.J.; Sheldon, P.; Rose, D.H.

    1999-07-13

    A photovoltaic device is disclosed having a substrate, a layer of Cd[sub 2]SnO[sub 4] disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd[sub 2]SnO[sub 4], and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd[sub 2]SnO[sub 4] layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd[sub 2]SnO[sub 4], and depositing an electrically conductive film onto the thin film of semiconductor materials. 10 figs.

  12. Assembly of Ultrathin Gold Nanowires into Honeycomb Macroporous Pattern Films with High Transparency and Conductivity.

    PubMed

    He, Ying; Chen, Yuan; Xu, Qingchi; Xu, Jun; Weng, Jian

    2017-03-01

    Because of its promising properties, honeycomb macroporous pattern (HMP) film has attracted increasing attention. It has been realized in many artificial nanomaterials, but the formation of these HMPs was attributed to templates or polymer/supermolecule/surfactant assistant assembly. Pure metal HMP film has been difficult to produce using a convenient colloidal template-free method. In this report, a unique template-free approach for preparation of Au HMP film with high transparency and conductivity is presented. Ultrathin Au nanowires, considered a linear polymer analogue, are directly assembled into HMP film on various substrates using a traditional static breath figure method. Subsequent chemical cross-linking and oxygen plasma treatment greatly enhance the stability and conductivity of the HMP film. The resulting HMP film exhibits great potential as an ideal candidate for transparent flexible conductive nanodevices.

  13. Silver Nanowire Transparent Conductive Films with High Uniformity Fabricated via a Dynamic Heating Method.

    PubMed

    Jia, Yonggao; Chen, Chao; Jia, Dan; Li, Shuxin; Ji, Shulin; Ye, Changhui

    2016-04-20

    The uniformity of the sheet resistance of transparent conductive films is one of the most important quality factors for touch panel applications. However, the uniformity of silver nanowire transparent conductive films is far inferior to that of indium-doped tin oxide (ITO). Herein, we report a dynamic heating method using infrared light to achieve silver nanowire transparent conductive films with high uniformity. This method can overcome the coffee ring effect during the drying process and suppress the aggregation of silver nanowires in the film. A nonuniformity factor of the sheet resistance of the as-prepared silver nanowire transparent conductive films could be as low as 6.7% at an average sheet resistance of 35 Ω/sq and a light transmittance of 95% (at 550 nm), comparable to that of high-quality ITO film in the market. In addition, a mechanical study shows that the sheet resistance of the films has little change after 5000 bending cycles, and the film could be used in touch panels for human-machine interactive input. The highly uniform and mechanically stable silver nanowire transparent conductive films meet the requirement for many significant applications and could play a key role in the display market in a near future.

  14. The Effect of Processing Parameters on the Microwave Absorption by Polyaniline/PMMA Composites

    DTIC Science & Technology

    2005-01-01

    conductivity σdc dc conductivity σmw microwave conductivity PAni Polyaniline PMMA poly(methyl methacrylate) pTsA para-toluene sulfonic acid RAM radar...chemicals and was distilled in vacuo prior to usage. para-toluene sulfonic acid (pTsA, 98 %), ammonium peroxydisulfate (APS) were used as purchased...Defence R&D Canada – Atlantic DEFENCE DÉFENSE & The Effect of Processing Parameters on the Microwave Absorption by Polyaniline /PMMA Composites Darren

  15. Reduced Graphene Oxide Films with Ultrahigh Conductivity as Li-Ion Battery Current Collectors.

    PubMed

    Chen, Yanan; Fu, Kun; Zhu, Shuze; Luo, Wei; Wang, Yanbin; Li, Yiju; Hitz, Emily; Yao, Yonggang; Dai, Jiaqi; Wan, Jiayu; Danner, Valencia A; Li, Teng; Hu, Liangbing

    2016-06-08

    Solution processed, highly conductive films are extremely attractive for a range of electronic devices, especially for printed macroelectronics. For example, replacing heavy, metal-based current collectors with thin, light, flexible, and highly conductive films will further improve the energy density of such devices. Films with two-dimensional building blocks, such as graphene or reduced graphene oxide (RGO) nanosheets, are particularly promising due to their low percolation threshold with a high aspect ratio, excellent flexibility, and low cost. However, the electrical conductivity of these films is low, typically less than 1000 S/cm. In this work, we for the first time report a RGO film with an electrical conductivity of up to 3112 S/cm. We achieve high conductivity in RGO films through an electrical current-induced annealing process at high temperature of up to 2750 K in less than 1 min of anneal time. We studied in detail the unique Joule heating process at ultrahigh temperature. Through a combination of experimental and computational studies, we investigated the fundamental mechanism behind the formation of a highly conductive three-dimensional structure composed of well-connected RGO layers. The highly conductive RGO film with high direct current conductivity, low thickness (∼4 μm) and low sheet resistance (0.8 Ω/sq.) was used as a lightweight current collector in Li-ion batteries.

  16. Controlling preferred orientation and electrical conductivity of zinc oxide thin films by post growth annealing treatment

    NASA Astrophysics Data System (ADS)

    Kennedy, J.; Murmu, P. P.; Leveneur, J.; Markwitz, A.; Futter, J.

    2016-03-01

    We report the microstructural evolution of the preferred orientation and electrical conductivity of zinc oxide (ZnO) thin films prepared by ion beam sputtering. Elastic recoil detection analysis results showed 0.6 at% H in as-deposited film which decreased to 0.35 at% in air annealed film due to H diffusion. XRD results showed that the preferred orientation can be tuned by selecting annealing conditions. Vacuum annealed films exhibited (1 0 0) orientation, whereas air annealed film showed (0 0 2) orientation. The annealing conditions caused a dramatic increase in the resistivity of air annealed films (∼106 Ω cm), whereas vacuum annealed films showed lower resistivity (∼10-2 Ω cm). High resistivity in air annealed film is attributed to the lack of hydrogen interstitials and hydrogen-oxygen vacancy complexes. Raman results supported the XRD results which demonstrated that annealing assisted in recovery of the crystalline disorder in as-deposited films. Air annealed film exhibited the highest optical transmission (89.7%) in the UV-vis region compared to as-deposited and vacuum annealed films (∼85%). Optical bandgap was found to vary between 3.11 eV and 3.18 eV in as-deposited and annealed films, respectively. The bandgap narrowing is associated with the intrinsic defects which introduced defect states resulting in band tail in ZnO films.

  17. Continuous production of flexible carbon nanotube-based transparent conductive films.

    PubMed

    Fraser, I Stuart; Motta, Marcelo S; Schmidt, Ron K; Windle, Alan H

    2010-08-01

    This work shows a simple, single-stage, scalable method for the continuous production of high-quality carbon nanotube-polymer transparent conductive films from carbon feedstock. Besides the ease of scalability, a particular advantage of this process is that the concentration of nanotubes in the films, and thus transparency and conductivity, can be adjusted by changing simple process parameters. Therefore, films can be readily prepared for any application desired, ranging from solar cells to flat panel displays. Our best results show a surface resistivity of the order of 300 Ω square(-1) for a film with 80% transparency, which is promising at this early stage of process development.

  18. Continuous production of flexible carbon nanotube-based transparent conductive films

    NASA Astrophysics Data System (ADS)

    Fraser, I. Stuart; Motta, Marcelo S.; Schmidt, Ron K.; Windle, Alan H.

    2010-08-01

    This work shows a simple, single-stage, scalable method for the continuous production of high-quality carbon nanotube-polymer transparent conductive films from carbon feedstock. Besides the ease of scalability, a particular advantage of this process is that the concentration of nanotubes in the films, and thus transparency and conductivity, can be adjusted by changing simple process parameters. Therefore, films can be readily prepared for any application desired, ranging from solar cells to flat panel displays. Our best results show a surface resistivity of the order of 300 Ω square-1 for a film with 80% transparency, which is promising at this early stage of process development.

  19. Transparent conducting properties of Re-doped β-MoO3 films

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kuniko; Shimizu, Ryota; Shiraki, Susumu; Hitosugi, Taro

    2016-09-01

    We report the significant increase in the electrical conductivity, by five orders of magnitude, of Re-doped β-MoO3 epitaxial films grown using reactive DC magnetron sputtering. Re atoms were successfully incorporated into the films by using Mo-Re alloy targets, although the film compositions deviated significantly from those of the targets. Pristine β-MoO3 exhibited a conductivity below 10-7 S/cm, whereas β-Mo0.982Re0.018O3 exhibited a conductivity of 1.2 × 10-2 S/cm and a high optical transmittance of 67% (average) in the visible region. Furthermore, transparent conducting properties were reproduced in a polycrystalline film grown on a glass substrate, indicating the high potential of these films for use as transparent conductors.

  20. Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

    NASA Astrophysics Data System (ADS)

    Liu, Zhiming; Wang, Xuefeng; Li, Mei; Wu, Wenjian

    2015-11-01

    Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10-9 M after being loaded with CaM proteins.

  1. Effect of dopant ions on piezo-response of polyaniline-poly(vinylidine flouride) blends

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, S.; Kar, Swarendu B.

    2002-11-01

    Electromechanical sensors and actuators are important for robotic and aerospace applications. Among various material, poly(vinylidene fluoride) ir its co-polymers are known to exhibit high piezosensitivity. However, due to their higher electrical resistivity the input impedance of subsequent signal processign circuits is required to be very high. A novel technique to decrease the impedance would be blending PVDF with conducting polyaniline (PANI) but without affecting the piezosensitivyt of PVDF. Polyaniline (PANI) was synthesized by well known standard chemical route using dopants HCl and dodecyl benzene sulfonic acid. These PANI powder were blended with PVDF which was first dissolved in DMAc at 50 degrees C to which were added requisite amounts of two types of PANI ranging from 2 to 25 wt percent, stirred for 24 hours to form a homogeneous mixture which was cast in glass petri-dish, followed by complete solvent evaporation at 50 degrees C and then drying under vacuum for 24 hours to give films of PANI-PVDF blends. The piezo-sensitivity of these blends was measured before and after poling in electrical field. The sensitivity factor was dependent on the composition, type of dopant as well as the electric polarization of the blend. The HCl doped PANI blends in PVDF were highly piezo-sensitive than other blend compositions. These various results have been explained on the basis of compatibility, discrete domain formation, nonlinear conduction process for charge transport, orientation of dipoles, and trapping of space charge at inter-domain sites.

  2. Structural properties of highly conductive ultra-nanocrystalline diamond films grown by hot-filament CVD

    NASA Astrophysics Data System (ADS)

    Mertens, M.; Lin, I.-N.; Manoharan, D.; Moeinian, A.; Brühne, K.; Fecht, H. J.

    2017-01-01

    In this work we show the correlation of the electrical conductivity of ultra-nanocrystalline (UNCD) diamond films grown by hot filament chemical vapor deposition (HFCVD) with their structural properties. The substrate temperature, the methane to hydrogen ratio and the pressure are the main factor influencing the growth of conductive UNCD films, which extends from electrical resistive diamond films (<10-4 S/cm) to highly conductive diamond films with a specific conductivity of 300 S/cm. High-resolution-transmission-electron-microscopy (HRTEM) and electron-energy-loss-spectroscopy (EELS) have been done on the highly conductive diamond films, to show the origin of the high electrical conductivity. The HRTEM results show random oriented diamond grains and a large amount of nano-graphite between the diamond crystals. EELS investigations are confirming these results. Raman measurements are correlated with the specific conductivity, which shows structural changes of sp2 carbons bonds as function of conductivity. Hall experiments complete the results, which lead to a model of an electron mobility based conductivity, which is influenced by the structural properties of the grain boundary regions in the ultra-nanocrystalline diamond films.

  3. Fabrication and characterization of solid state conducting polymer actuators

    NASA Astrophysics Data System (ADS)

    Xie, Jian; Sansinena, Jose-Maria; Gao, Junbo; Wang, Hsing-Lin

    2004-07-01

    We report here the fabrication and characterization of solid-state conducting polymer actuators. The electrochemical activity of polyaniline (PANI) thin film coated with solid-state polyelectrolyte is very similar to the polyaniline thin film in an aqueous solution. The solid-state actuator is adhered to a lever arm of a force transducer and the force generation is measured in real time. The force generated by the actuator is found to be length dependent. However, the overall torque generated by the actuators with different lengths remains essentially the same. The effect of stimulation signals such as voltage, and current, on the bending angle and displacement is also studied using square wave potential.

  4. XPS Study of Sulfonated Polyaniline.

    DTIC Science & Technology

    1991-08-07

    WORK UMaT Arlington, VA 22203-17 14 ELEMENT NO. INO. NO. CCESSION No 11. TITLE (tinclude Security Clisification) "XPS STUDY OF SULFONATED POLYANILINE ...by block nvjmhet) FlIELD GROUP $u-GOP sulfonated polyaniline , x-ray photoelectron spectroscopy O(IPS) 19. ABSTRACT (Continue on reverse if nvessary...STUDY OF SULFONATED POLYANiLINE " by J. Yue, AJ. Epstein and A.G. MacDiarrnid Published in PMSE Preprints, (In Press 1991) University of Pennsylvania

  5. Post-Deposition Induced Conductivity in Pulsed Laser Irradiated Metal Doped Zinc Oxide Films

    SciTech Connect

    Wang, Lisa J; Exarhos, Gregory J

    2009-12-03

    The optical and electrical properties of doped solution-deposited and rf sputter-deposited thin metal oxide films were investigated following post deposition pulsed laser irradiation. Solution deposited films were annealed at 450 ºC. Following the heating regiment, the transparent metal oxide films were subjected to 355 nm pulsed Nd:YAG laser irradiation (4 nsec pulsewidth) at fluences between 5 and 150 mJ/cm2. Irradiation times at pulse frequencies of 30 Hz ranged from seconds to tens of minutes. Film densification, index change and a marked increase in conductivity were observed following irradiation in air and under vacuum of Al:ZnO (AZO), Ga:ZnO (GZO), and In:ZnO (IZO) films deposited on silica substrates. Despite the measured increase in conductivity, all films continued to show high transparency on the order of 90% at wavelengths from the band edge well into the near infrared region of the spectrum. Laser energies required for turning on the conductivity of these films varied depending upon the dopant. Irradiations in air yielded resistivity measurements on the order of 16.cm. Resistivities of films irradiated under vacuum were on the order of 0.1.cm. The increase in conductivity can be attributed to the formation of oxygen vacancies and subsequent promotion of free carriers into the conduction band. All irradiated films become insulating after around 24 hours. Oxygen atoms in air become reduced by electrons in the metal conduction band and diffuse into the vacancies in the lattice. The rate of this reduction process depends on the type of dopant. This work also sheds light on the damage threshold, correlating the optical properties with the presence of free carriers that have been introduced into the conduction band. All films were characterized by means of UV-VIS-NIR transmission spectroscopy, visible and UV Raman spectroscopy and Hall measurements. Analysis of interference fringes in measured transmission spectra allowed film density and refractive index

  6. Novel p-Type Conductive Semiconductor Nanocrystalline Film as the Back Electrode for High-Performance Thin Film Solar Cells.

    PubMed

    Zhang, Ming-Jian; Lin, Qinxian; Yang, Xiaoyang; Mei, Zongwei; Liang, Jun; Lin, Yuan; Pan, Feng

    2016-02-10

    Thin film solar cells, due to the low cost, high efficiency, long-term stability, and consumer applications, have been widely applied for harvesting green energy. All of these thin film solar cells generally adopt various metal thin films as the back electrode, like Mo, Au, Ni, Ag, Al, graphite, and so forth. When they contact with p-type layer, it always produces a Schottky contact with a high contact potential barrier, which greatly affects the cell performance. In this work, we report for the first time to find an appropriate p-type conductive semiconductor film, digenite Cu9S5 nanocrystalline film, as the back electrode for CdTe solar cells as the model device. Its low sheet resistance (16.6 Ω/sq) could compare to that of the commercial TCO films (6-30 Ω/sq), like FTO, ITO, and AZO. Different from the traditonal metal back electrode, it produces a successive gradient-doping region by the controllable Cu diffusion, which greatly reduces the contact potential barrier. Remarkably, it achieved a comparable power conversion efficiency (PCE, 11.3%) with the traditional metal back electrode (Cu/Au thin films, 11.4%) in CdTe cells and a higher PCE (13.8%) with the help of the Au assistant film. We believe it could also act as the back electrode for other thin film solar cells (α-Si, CuInS2, CIGSe, CZTS, etc.), for their performance improvement.

  7. Vapor sensing mechanism of acid on copper phthalocyanine thin films studied by electrical conductivity

    NASA Astrophysics Data System (ADS)

    Singh, Sukhwinder; Saini, G. S. S.; Tripathi, S. K.

    2013-06-01

    The electrical conductivity of thin films of iron phthalocyanine on glass substrates by thermal evaporation technique have been investigated. The electrical conductivity of thin films of these complexes changes when exposed to oxidizing and reducing gases such as halogens, ammonia, water and NOX. Thermal activation energy in the intrinsic region and impurity scattering region can be calculated by using Arrhenius plot. The dark conductivity and photoconductivity have been taken at different temperatures in the range 312-389 K. These films have been studied as chemical sensors for dilute sulphuric acid.

  8. Photochemical switching of ionic conductivity in composite films containing a crowned spirobenzopyran

    SciTech Connect

    Kimura, Keiichi; Yamashita, Takashi; Yokoyama, Masaaki

    1992-06-25

    Photochemical switching of ionic conductivity in vinyl chloride films with LiClO{sub 4} and a crowned spirobenzopyran revealed isomerization of the crowned spirobenzopyran to its merocyanine form proceeding under UV-irradiated or dark conditions to decrease the the film`s Li{sup +} ionic conductivity in this paper. Visible-light irradiation caused isomerization back to the spiropyran form and restoration of ionic conductivity to its original value; switching the visible light on and off caused 20-fold changes. 10 refs., 7 figs.

  9. Synthesis and characterization of polyaniline-hexaferrite composites

    NASA Astrophysics Data System (ADS)

    Khursheed, Tooba; Islam, M. U.; Asif Iqbal, M.; Ali, Irshad; Shakoor, Abdul; Awan, M. S.; Iftikhar, Aisha; Azhar Khan, Muhammad; Naeem Ashiq, Muhammad

    2015-11-01

    Polyaniline was synthesized by chemical polymerization using aniline as monomer, and Y-type hexaferrite with composition (Co2Mn2Sr1.66Nd0.4Fe10O22) was prepared by co-precipitation assisted by surfactant. Three composites of Polyaniline with different ferrite ratios were prepared by mechanical blending. The synthesized samples were characterized by X-Ray diffraction, Scanning electron microscopy and electrical measurements. The XRD analysis reveals that no second phase was observed in Y-type hexagonal ferrite. In PANI-Ferrite composites, significant changes in resistivity, real and imaginary part of complex permittivity were observed with the increase of ferrite in the polyaniline matrix. At low frequencies the magnitude of dielectric constant and complex permittivity is high with few relaxation peaks. AC conductivity of PANI-Ferrite composites increase with the increase of frequency following Jonscher law. The resistivity and activation energy were found to show similar behavior.

  10. Deposition and post-processing techniques for transparent conductive films

    DOEpatents

    Christoforo, Mark Greyson; Mehra, Saahil; Salleo, Alberto; Peumans, Peter

    2015-01-13

    In one embodiment, a method is provided for fabrication of a semitransparent conductive mesh. A first solution having conductive nanowires suspended therein and a second solution having nanoparticles suspended therein are sprayed toward a substrate, the spraying forming a mist. The mist is processed, while on the substrate, to provide a semitransparent conductive material in the form of a mesh having the conductive nanowires and nanoparticles. The nanoparticles are configured and arranged to direct light passing through the mesh. Connections between the nanowires provide conductivity through the mesh.

  11. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600 °C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600 °C. TiN film deposited at 600 °C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600 °C on Si(111) wafer but the film deposited at 500 °C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600 °C. Nitride film of tungsten deposited at 600 °C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500 °C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600 °C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

  12. Transparent conducting CeO{sub 2}-SiO{sub 2} thin films

    SciTech Connect

    Zhu, B.; Luo, Z.; Xia, C.

    1999-08-01

    A new type of transparent thin films, based on two-phase materials of CeO{sub 2}-SiO{sub 2}, was developed. The films were prepared on indium time oxide (ITO)-coated glass via a sol-gel process. A study of cyclic voltammetry was conducted on the films, using an electrolyte of 1 M LiClO{sub 4} in propylene carbonate. Li{sup +} insertion/disinsertion took place in the film. For a 24 nm thick GeO{sub 2}-SiO{sub 2} film with 50% silica, the capacity of the charge exchange reached 6--7 nC/CM{sup 2}. After 380 cycles, the charge density dropped by {approximately}30%. In both Li{sup +}-intercalated and free states, the films were highly transparent for visible light. Such films have potential application in counter-electrodes for electrochromic smart windows and other electrochemical devices.

  13. Fabrication of biocompatible electro-conductive silk films with natural compounds for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Dimitrakakis, Nikolaos

    In the present study electro conductive natural compounds are incorporated in silk based films, and the effects on film conductivity and dissolution are studied. Natural conducting compounds melanin and riboflavin were blended with silk to increase conductivity. Other compounds such as Fe(0) powder ferrofluid and NaCl solution also improved conductivity. Film properties and dissolution were studied for the different blends, and tuned using addition of glycerol and horseradish peroxidase cross-linking. Techniques such as electrospinning, doctor blade, spin coating, and paper-like film fabrication techniques were also explored to generate films with controlled dimensions and properties. The findings suggest that the incorporation of riboflavin along with NaCl and glycerol in silk films, along with water vapor annealing results in semiconductor films. More specifically, the two compositions of the films that exhibited highest conductivity contain 2 % w/v silk, 20 % w/v glycerol, 2 % w/v polyethylene oxide (PEO), 30 % v/v phosphate buffered saline (PBS) and 5 % w/v silk, 20 % w/v glycerol, 10 % w/v NaCl with conductivities of 5.72*10-2 S/m and 5.96*10-2 S/m at 20 °C. When silk is doped with riboflavin, NaCl, and glycerol, semiconducting behavior similar to drinking water conductivity is observed. Mass loss studies of the films included the immersion of the films for 7 days in 37° C in PBS. Film processing included samples that were heated for 2 hours in 60 °C immediately after casting, as well as those cured at room temperature. The results indicated that the heated samples provided the lowest mass loss of approximately 27 %. In conclusion, the present study demonstrates the correlation between composition and processing of silk films with their conductivity. These semiconductive films have the potential to be applied in tissue engineering applications such as nerve conduits, where conductivity plays an instrumental role in tissue restoration.

  14. Transparent and Conductive Cadmium-Tin Oxide Films Deposited by Atom Beam Sputtering

    NASA Astrophysics Data System (ADS)

    Nakazawa, Tatsuo; Ito, Kentaro

    1988-09-01

    Transparent and conductive cadmium-tin oxide films with resistivities of 9× 10-4 Ω cm and transmittance higher than 80% over the visible range were prepared by atom beam sputtering. The structure of the deposited film was amorphous and its composition was highly deficient in CdO compared with Cd2SnO4. This CTO film was used as the window layer of a heterojunction solar cell.

  15. Effect of light on hopping conduction in kesterite CZTS thin films

    NASA Astrophysics Data System (ADS)

    Ghediya, Prashant R.; Chaudhuri, Tapas K.; Ray, Jaymin R.

    2016-05-01

    Mott variable range hopping conduction in dip-coated CZTS thin films has been studied in the temperature range of 77 to 150 K in dark and under different light intensities. The films were basically p-type and photoconducting. Various hopping parameters such as, Mott characteristic temperature, density of states at Fermi level, hopping distance and hopping energy of the CZTS films were investigated for different light intensities.

  16. PEDOT/PSS-Halloysite Nanotubes (HNTs) Hybrid Films: Insulating HNTs Enhance Conductivity of the PEDOT/PSS Films

    PubMed Central

    Yan, Hu; Zhang, Ping; Li, Juan; Zhao, Xiao-Li; Zhang, Ke; Zhang, Bing

    2015-01-01

    We have for the first time found that completely insulating Halloysite nanotubes (HNTs) significantly enhance electrical conductivity of PEDOT/PSS films by simply mixing. Based on this accident finding we have created highly porous and conductive PEDOT/PSS films hybridized with the HNTs. Through further optimization of the mixing condition we have obtained flexible and conductive hybrid films with high specific surface area. Based on experimental evidences we proposed a plausible mechanism of the phenomenon where the PEDOT/PSS colloidal particle with particle size of several tens nanometers well pack at the nano-channels into well-ordered structures of PEDOT/PSS particles, which show conductivity as higher as several order of magnitude than that of PEDOT/PSS particles in outside of the HNTs. PMID:26686395

  17. Switchable photoluminescence liquid crystal coated bacterial cellulose films with conductive response.

    PubMed

    Tercjak, Agnieszka; Gutierrez, Junkal; Barud, Hernane S; Ribeiro, Sidney J L

    2016-06-05

    Three different low molecular weight nematic liquid crystals (LCs) were used to impregnate bacterial cellulose (BC) film. This simple fabrication pathway allows to obtain highly transparent BC based films. The coating of BC film with different liquid crystals changed transmittance spectra in ultraviolet-visible region and allows to design UVC and UVB shielding materials. Atomic force microscopy results confirmed that liquid crystals coated BC films maintain highly interconnected three-dimensional network characteristic of BC film and simultaneously, transversal cross-section scanning electron microscopy images indicated penetration of liquid crystals through the three-dimensional network of BC nanofibers. Investigated BC films maintain nematic liquid crystal properties being switchable photoluminiscence as a function of temperature during repeatable heating/cooling cycles. Conductive response of the liquid crystal coated BC films was proved by tunneling atomic force microscopy measurement. Moreover, liquid crystal coated BC films maintain thermal stability and mechanical properties of the BC film. Designed thermoresponsive materials possessed interesting optical and conductive properties opening a novel simple pathway of fabrication liquid crystal coated BC films with tuneable properties.

  18. Thermal conductivity of pure silica MEL and MFI zeolite thin films

    NASA Astrophysics Data System (ADS)

    Coquil, Thomas; Lew, Christopher M.; Yan, Yushan; Pilon, Laurent

    2010-08-01

    This paper reports the room temperature cross-plane thermal conductivity of pure silica zeolite (PSZ) MEL and MFI thin films. PSZ MEL thin films were prepared by spin coating a suspension of MEL nanoparticles in 1-butanol solution onto silicon substrates followed by calcination and vapor-phase silylation with trimethylchlorosilane. The mass fraction of nanoparticles within the suspension varied from 16% to 55%. This was achieved by varying the crystallization time of the suspension. The thin films consisted of crystalline MEL nanoparticles embedded in a nonuniform and highly porous silica matrix. They featured porosity, relative crystallinity, and MEL nanoparticles size ranging from 40% to 59%, 23% to 47% and 55 nm to 80 nm, respectively. PSZ MFI thin films were made by in situ crystallization, were b-oriented, fully crystalline, and had a 33% porosity. Thermal conductivity of these PSZ thin films was measured at room temperature using the 3ω method. The cross-plane thermal conductivity of the MEL thin films remained nearly unchanged around 1.02±0.10 W m-1 K-1 despite increases in (i) relative crystallinity, (ii) MEL nanoparticle size, and (iii) yield caused by longer nanoparticle crystallization time. Indeed, the effects of these parameters on the thermal conductivity were compensated by the simultaneous increase in porosity. PSZ MFI thin films were found to have similar thermal conductivity as MEL thin films even though they had smaller porosity. Finally, the average thermal conductivity of the PSZ films was three to five times larger than that reported for amorphous sol-gel mesoporous silica thin films with similar porosity and dielectric constant.

  19. Transparent conducting films of CdSe(ZnS) core(shell) quantum dot xerogels

    PubMed Central

    Korala, Lasantha; Li, Li

    2012-01-01

    A method of fabricating sol-gel quantum dot (QD) films is demonstrated, and their optical, structural and electrical properties are evaluated. The CdSe(ZnS) xerogel films remain quantum confined, yet are highly conductive (10−3 S· cm−1). This approach provides a pathway for the exploitation of QD gels in optoelectronic applications. PMID:22801641

  20. Selective Etching via Soft Lithography of Conductive Multilayered Gold Films with Analysis of Electrolyte Solutions

    ERIC Educational Resources Information Center

    Gerber, Ralph W.; Oliver-Hoyo, Maria T.

    2008-01-01

    This experiment is designed to expose undergraduate students to the process of selective etching by using soft lithography and the resulting electrical properties of multilayered films fabricated via self-assembly of gold nanoparticles. Students fabricate a conductive film of gold on glass, apply a patterned resist using a polydimethylsiloxane…

  1. Selective UV-filter detection with sensors based on stainless steel electrodes modified with polyaniline doped with metal tetrasulfonated phthalocyanine films.

    PubMed

    Moreira, Luiz Fernando; Lanza, Marcos Roberto de Vasconcelos; Tanaka, Auro Atsushi; Sotomayor, Maria Del Pilar Taboada

    2009-07-01

    This work describes the construction and application of two amperometric sensors for sensitive UV-filter determination. The sensors were prepared using stainless steel electrodes in which polyaniline (PANI) was electrochemically polymerized in the presence of nickel (NiPcTS) or iron (FePcTS) tetrasulfonated phthalocyanines. The sensor surface characterizations were carried out using atomic force microscopy (AFM). The PANI/NiPcTS sensor was selective for the chemical UV-filter p-aminobenzoic acid (PABA) and the PANI/FePcTS sensor was selective for octyldimethyl-PABA (ODP), both in a mixture of tetrahydrofuran (THF) and 0.1 mol L(-1) H2SO4 at a volume ratio of 30 : 70, and with an applied potential of 0.0 mV vs. Ag|AgCl. A detailed investigation of the selectivity was carried out for both sensors, in order to determine their responses for ten different UV filters. Finally, each sensor was successfully applied to PABA or ODP quantification in sunscreen formulations and water from swimming pools.

  2. Three-dimensional reduced graphene oxide/polyaniline nanocomposite film prepared by diffusion driven layer-by-layer assembly for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Hong, Xiaodong; Zhang, Binbin; Murphy, Elizabeth; Zou, Jianli; Kim, Franklin

    2017-03-01

    As a simple and versatile method, diffusion driven Layer-by-Layer assembly (dd-LbL) is developed to assemble graphene oxide (GO) into three-dimensional (3D) structure. The assembled GO macrostructure can be reduced through a hydrothermal treatment and used as a high volumetric capacitance electrode in supercapacitors. In this report we use rGO framework created from dd-LbL as a scaffold for in situ polymerization of aniline within the pores of the framework to form rGO/polyaniline (rGO/PANI) composite. The rGO/PANI composite affords a robust and porous structure, which facilitates electrolyte diffusion and exhibits excellent electrochemical performance as binder-free electrodes in a sandwich-configuration supercapacitor. Combining electric double layer capacitance and pseudo-capacitance, rGO/PANI electrodes exhibit a specific capacitance of 438.8 F g-1 at discharge rate of 5 mA (mass of electrodes were 10.0 mg, 0.5 A g-1) in 1 mol L-1 H2SO4 electrolyte; furthermore, the generated PANI nanoparticles in rGO template achieve a higher capacitance of 763 F g-1. The rGO/PANI composite electrodes also show an improved recyclability, 76.5% of capacitance retains after recycled 2000 times.

  3. Enhanced charge transport in highly conducting PEDOT-PSS films after acid treatment

    NASA Astrophysics Data System (ADS)

    Shiva, V. Akshaya; Bhatia, Ravi; Menon, Reghu

    The high electrical conductivity, good stability, high strength, flexibility and good transparency of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS), make it useful for many applications including polymeric anodes for organic photovoltaics, light-emitting diodes, flexible electrodes, supercapacitors, electrochromic devices, field-effect transistors and antistatic-coatings. However, the electrical conductivity of PEDOT-PSS has to be increased significantly for replacement of indium tin oxide (ITO) as the transparent electrode in optoelectronic devices. The as prepared (pristine) PEDOT-PSS film prepared from the PEDOT-PSS aqueous solution usually has conductivity below 1Scm-1, remarkably lower than ITO. Significant conductivity enhancement has been observed on transparent and conductive PEDOT-PSS films after a treatment with inorganic acids. Our study investigates the charge transport in pristine and H2SO4, HNO3, HCl treated PEDOT-PSS films. We have treated the films with various concentrations of acids to probe the effect of the acid treatment on the conduction mechanism. The study includes the measurement of dc and electric field dependent conductivity of films in the temperature range of 4.2K-300K. We have also performed magneto-resistance measurements in the range of 0-5T. An enhancement by a factor of~103 has been observed in the room temperature conductivity. The detailed magneto-transport studies explain the various mechanisms for the conductivity enhancement observed.

  4. Interfacial control of oxygen vacancy doping and electrical conduction in thin film oxide heterostructures.

    PubMed

    Veal, Boyd W; Kim, Seong Keun; Zapol, Peter; Iddir, Hakim; Baldo, Peter M; Eastman, Jeffrey A

    2016-06-10

    Oxygen vacancies in proximity to surfaces and heterointerfaces in oxide thin film heterostructures have major effects on properties, resulting, for example, in emergent conduction behaviour, large changes in metal-insulator transition temperatures or enhanced catalytic activity. Here we report the discovery of a means of reversibly controlling the oxygen vacancy concentration and distribution in oxide heterostructures consisting of electronically conducting In2O3 films grown on ionically conducting Y2O3-stabilized ZrO2 substrates. Oxygen ion redistribution across the heterointerface is induced using an applied electric field oriented in the plane of the interface, resulting in controlled oxygen vacancy (and hence electron) doping of the film and possible orders-of-magnitude enhancement of the film's electrical conduction. The reversible modified behaviour is dependent on interface properties and is attained without cation doping or changes in the gas environment.

  5. Interfacial control of oxygen vacancy doping and electrical conduction in thin film oxide heterostructures

    PubMed Central

    Veal, Boyd W.; Kim, Seong Keun; Zapol, Peter; Iddir, Hakim; Baldo, Peter M.; Eastman, Jeffrey A.

    2016-01-01

    Oxygen vacancies in proximity to surfaces and heterointerfaces in oxide thin film heterostructures have major effects on properties, resulting, for example, in emergent conduction behaviour, large changes in metal-insulator transition temperatures or enhanced catalytic activity. Here we report the discovery of a means of reversibly controlling the oxygen vacancy concentration and distribution in oxide heterostructures consisting of electronically conducting In2O3 films grown on ionically conducting Y2O3-stabilized ZrO2 substrates. Oxygen ion redistribution across the heterointerface is induced using an applied electric field oriented in the plane of the interface, resulting in controlled oxygen vacancy (and hence electron) doping of the film and possible orders-of-magnitude enhancement of the film's electrical conduction. The reversible modified behaviour is dependent on interface properties and is attained without cation doping or changes in the gas environment. PMID:27283250

  6. Thermal conductivity and mechanical properties of AlN-based thin films

    NASA Astrophysics Data System (ADS)

    Moraes, V.; Riedl, H.; Rachbauer, R.; Kolozsvári, S.; Ikeda, M.; Prochaska, L.; Paschen, S.; Mayrhofer, P. H.

    2016-06-01

    While many research activities concentrate on mechanical properties and thermal stabilities of protective thin films, only little is known about their thermal properties being essential for the thermal management in various industrial applications. Based on the 3ω-method, we show the influence of Al and Cr on the temperature dependent thermal conductivity of single-phase cubic structured TiN and single-phase wurtzite structured AlN thin films, respectively, and compare them with the results obtained for CrN thin films. The dc sputtered AlN thin films revealed a highly c-axis oriented growth for deposition temperatures of 250 to 700 °C. Their thermal conductivity was found to increase strongly with the film thickness, indicating progressing crystallization of the interface near amorphous regions during the sputtering process. For the 940 nm AlN film, we found a lower boundary for the thermal conductivity of 55.3 W m-1 K-1 . By the substitution of only 10 at. % Al with Cr, κ significantly reduces to ˜5.0 W m-1 K-1 , although the single-phase wurtzite structure is maintained. The single-phase face centered cubic TiN and Ti0.36Al0.64N thin films exhibit κ values of 3.1 W m-1 K-1 and 2.5 W m-1 K-1 , respectively, at room temperature. Hence, also here, the substitutional alloying reduces the thermal conductivity, although at a significantly lower level. Single-phase face centered cubic CrN thin films show κ values of 3.6 W m-1 K-1 . For all nitride based thin films investigated, the thermal conductivity slightly increases with increasing temperature between 200 and 330 K. This rather unusual behavior is based on the high defect density (especially point defects) within the thin films prepared by physical vapor deposition.

  7. Conductive, magnetic and structural properties of multilayer films

    NASA Astrophysics Data System (ADS)

    Kotov, L. N.; Turkov, V. K.; Vlasov, V. S.; Lasek, M. P.; Kalinin, Yu E.; Sitnikov, A. V.

    2013-12-01

    Composite-semiconductor and composite-dielectric multilayer films were obtained by the ion beam sputtering method in the argon and hydrogen atmospheres with compositions: {[(Co45-Fe45-Zr10)x(Al2O3)y]-[α-Si]}120, {[(Co45-Ta45-Nb10)x(SiO2)y]-[SiO2]}56, {[(Co45-Fe45-Zr10)x(Al2O3)y]-[α-Si:H]}120. The images of surface relief and distribution of the dc current on composite layer surface were obtained with using of atomic force microscopy (AFM). The dependencies of specific electric resistance, ferromagnetic resonance (FMR) fields and width of line on metal (magnetic) phase concentration x and nanolayers thickness of multilayer films were obtained. The characteristics of FMR depend on magnetic interaction among magnetic granules in the composite layers and between the layers. These characteristics depend on the thickness of composite and dielectric or semiconductor nanolayers. The dependences of electric microwave losses on the x and alternating field frequency were investigated.

  8. Conducting mechanisms and magnetic behaviours of Fe-doped In2O3 nanocrystalline films

    NASA Astrophysics Data System (ADS)

    Baqiah, H.; Ibrahim, N. B.; Halim, S. A.; Talib, Z. A.; Flaifel, M. H.; Abdi, M. H.

    The relation between conducting mechanism and magnetic behaviour of Fe-doped In2O3 thin films was investigated. The films were prepared by sol gel method followed by spin coating techniques and characterized by X-rays diffractions, field emission electron microscopy, transmission electron microscopy, Hall Effect at room and low temperature, X-ray photoelectron spectroscopy and vibrating sample magnetometer. Films' lattice parameter decreased with increasing of Fe content. Average grain size of films ranged between 8.4 and 13 nm. Oxygen vacancies of films tended to reduce with increasing of Fe doping. Films with x = 0.025 and 0.05 showed typical semiconducting behaviour while transition from metallic- to semiconducting-like behaviour was observed at 190 K and 230 K for films with x = 0.075 and x = 0.15, respectively. No trend had been found between films saturation magnetization, Ms, and free charge carriers. The magnetic behaviour of films has a correlation with localized electrons of Nearest-Neighbour Hopping conduction.

  9. Gate control of percolative conduction in strongly correlated manganite films.

    PubMed

    Hatano, Takafumi; Sheng, Zhigao; Nakamura, Masao; Nakano, Masaki; Kawasaki, Masashi; Iwasa, Yoshihiro; Tokura, Yoshinori

    2014-05-01

    Gate control of percolative conduction in a phase-separated manganite system is demonstrated in a field-effect transistor geometry, resulting in ambipolar switching from a metallic state to an insulating state.

  10. Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

    NASA Astrophysics Data System (ADS)

    V, Mini; Kamath, Archana; S, Raghu; Chapi, Sharanappa; H, Devendrappa

    2015-06-01

    A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott's parameters show 3D -VRH Type conduction in it.

  11. Tunable thermal conductivity via domain structure engineering in ferroelectric thin films: A phase-field simulation

    DOE PAGES

    Wang, Jian -Jun; Wang, Yi; Ihlefeld, Jon F.; ...

    2016-04-06

    Effective thermal conductivity as a function of domain structure is studied by solving the heat conduction equation using a spectral iterative perturbation algorithm in materials with inhomogeneous thermal conductivity distribution. Using this proposed algorithm, the experimentally measured effective thermal conductivities of domain-engineered {001}p-BiFeO3 thin films are quantitatively reproduced. In conjunction with two other testing examples, this proposed algorithm is proven to be an efficient tool for interpreting the relationship between the effective thermal conductivity and micro-/domain-structures. By combining this algorithm with the phase-field model of ferroelectric thin films, the effective thermal conductivity for PbZr1-xTixO3 films under different composition, thickness, strain,more » and working conditions is predicted. It is shown that the chemical composition, misfit strain, film thickness, film orientation, and a Piezoresponse Force Microscopy tip can be used to engineer the domain structures and tune the effective thermal conductivity. Furthermore, we expect our findings will stimulate future theoretical, experimental and engineering efforts on developing devices based on the tunable effective thermal conductivity in ferroelectric nanostructures.« less

  12. Tunable thermal conductivity via domain structure engineering in ferroelectric thin films: A phase-field simulation

    SciTech Connect

    Wang, Jian -Jun; Wang, Yi; Ihlefeld, Jon F.; Hopkins, Patrick E.; Chen, Long -Qing

    2016-04-06

    Effective thermal conductivity as a function of domain structure is studied by solving the heat conduction equation using a spectral iterative perturbation algorithm in materials with inhomogeneous thermal conductivity distribution. Using this proposed algorithm, the experimentally measured effective thermal conductivities of domain-engineered {001}p-BiFeO3 thin films are quantitatively reproduced. In conjunction with two other testing examples, this proposed algorithm is proven to be an efficient tool for interpreting the relationship between the effective thermal conductivity and micro-/domain-structures. By combining this algorithm with the phase-field model of ferroelectric thin films, the effective thermal conductivity for PbZr1-xTixO3 films under different composition, thickness, strain, and working conditions is predicted. It is shown that the chemical composition, misfit strain, film thickness, film orientation, and a Piezoresponse Force Microscopy tip can be used to engineer the domain structures and tune the effective thermal conductivity. Furthermore, we expect our findings will stimulate future theoretical, experimental and engineering efforts on developing devices based on the tunable effective thermal conductivity in ferroelectric nanostructures.

  13. The tuberculocidal activity of polyaniline and functionalised polyanilines

    PubMed Central

    Robertson, Julia; Dalton, James; Wiles, Siouxsie; Gizdavic-Nikolaidis, Marija

    2016-01-01

    Tuberculosis is considered a leading cause of death worldwide. More than 95% of cases and deaths occur in low- and middle-income countries. In resource-limited countries, hospitals often lack adequate facilities to manage and isolate patients with infectious tuberculosis (TB), relying instead on personal protective equipment, such as facemasks, to reduce nosocomial transmission of the disease. Facemasks impregnated with an antimicrobial agent may be a cost-effective way of adding an extra level of protection against the spread of TB by reducing the risk of disease transmission. Conducting polymers, such as polyaniline (PANI), and their functionalised derivatives are a novel class of antimicrobial agents with potential as non-leaching additives to provide contamination resistant surfaces. We have investigated the antimicrobial action of PANI and a functionalised derivative, poly-3-aminobenzoic acid (P3ABA), against mycobacteria and have determined the optimal treatment time and concentration to achieve significant knockdown of Mycobacterium smegmatis and Mycobacterium tuberculosis on an agar surface. Results indicated that P3ABA is a potential candidate for use as an anti-tuberculoid agent in facemasks to reduce TB transmission. PMID:28028468

  14. Effects of hydrogen atoms on surface conductivity of diamond film

    SciTech Connect

    Liu, Fengbin Cui, Yan; Qu, Min; Di, Jiejian

    2015-04-15

    To investigate the effects of surface chemisorbed hydrogen atoms and hydrogen atoms in the subsurface region of diamond on surface conductivity, models of hydrogen atoms chemisorbed on diamond with (100) orientation and various concentrations of hydrogen atoms in the subsurface layer of the diamond were built. By using the first-principles method based on density functional theory, the equilibrium geometries and densities of states of the models were studied. The results showed that the surface chemisorbed hydrogen alone could not induce high surface conductivity. In addition, isolated hydrogen atoms in the subsurface layer of the diamond prefer to exist at the bond centre site of the C-C bond. However, such a structure would induce deep localized states, which could not improve the surface conductivity. When the hydrogen concentration increases, the C-H-C-H structure and C-3H{sub bc}-C structure in the subsurface region are more stable than other configurations. The former is not beneficial to the increase of the surface conductivity. However, the latter would induce strong surface states near the Fermi level, which would give rise to high surface conductivity. Thus, a high concentration of subsurface hydrogen atoms in diamond would make significant contributions to surface conductivity.

  15. AC conductivity of a niobium thin film in a swept magnetic field.

    PubMed

    Tsindlekht, M I; Genkin, V M; Gazi, S; Chromik, S

    2013-02-27

    We report results of measurements of the ac conductivity of a Nb superconducting thin film in a swept dc magnetic field. In the mixed state the swept dc field creates vortices at the film surface which pass through the film and form the observed ac conductivity. Vortex rate generation does not depend on the value of the dc field and there is a large plateau-like region of dc magnetic fields where the dissipation is approximately constant. A proposed phenomenological model describes quite well the main features of the ac response in these fields, including its dependency on the sweep rate, ac amplitude, frequency, and value of the second and third harmonics.

  16. Conductive nanocomposite films based on functionalized double-walled carbon nanotubes dispersed in PEDOT:PSS

    NASA Astrophysics Data System (ADS)

    De Girolamo Del Mauro, A.; Nenna, G.; Grimaldi, I. A.; Villani, F.; Pandolfi, G.; Minarini, C.

    2012-07-01

    High conductive and transparent nanocomposite films consisting of poly(3,4-ethylenedioxythiphene):poly(4-styrenesulfonate) (PEDOT:PSS) doped with dimethyl sulfoxide (DMSO) and double-walled carbon nanotubes functionalized with carboxylic groups (c-DWCNTs) were spin-coated and their electrical (four-point measurement), optical (UV-Vis spectroscopy), morphological (SEM, AFM) and structural (Raman) properties were investigated. Thin films of c-DWCNT/DMSO-PEDOT:PSS resulted more conductive (950 S/cm) in comparison with the pristine DMSOPEDOT: PSS films (700 S/cm).

  17. Characterization of polyester films used in capacitors. 1: Transient and steady-state conductivity

    NASA Astrophysics Data System (ADS)

    Thielen, A.; Niezette, J.; Feyder, G.; Vanderschueren, J.

    1994-10-01

    Charging and discharging currents flowing through polyethylene terephthalate (PET) ultrathin films (1.5 - 12 micrometers) were measured by the use of a two-electrode configuration involving opposite lateral contacts. A study of the influence of electrification time, applied electric field, film thickness, nature of electrodes, and water content was carried out on both transient and steady-state conduction. The transient behavior can be interpreted in terms of dipolar orientation and relaxation processes while steady-state conductivity can be mainly accounted for in terms of Schottky emission. A comparison between PET and polyethylene naphthalate films is also reported.

  18. Silver nanowire/polyaniline composite transparent electrode with improved surface properties

    SciTech Connect

    Kumar, A.B.V. Kiran; Jiang, Jianwei; Bae, Chang Wan; Seo, Dong Min; Piao, Longhai Kim, Sang-Ho

    2014-09-15

    Highlights: • AgNWs/PANI transparent electrode was prepared by layer-by-layer coating method. • The surface roughness of the electrode reached to 6.5 nm (root mean square). • The electrode had reasonable sheet resistance (25 Ω/□) and transmittance (83.5%). - Abstract: Silver nanowires (AgNWs) are as potential candidates to replace indium tin oxide (ITO) in transparent electrodes because of their preferred conducting and optical properties. However, their rough surface properties are not favorable for the fabrication of optoelectronic devices, such as displays and thin-film solar cells. In the present investigation, AgNWs/polyaniline composite transparent electrodes with better surface properties were successfully prepared. AgNWs were incorporated into polyaniline:polystyrene sulfonate (PANI:PSS) by layer-by-layer coating and mechanical pressing. PANI:PSS decreased the surface roughness of the AgNWs electrode by filling the gap of the random AgNWs network. The transparent composite electrode had decreased surface roughness (root mean square 6.5 nm) with reasonable sheet resistance (25 Ω/□) and transmittance (83.5%)

  19. Stable, concentrated solutions of high molecular weight polyaniline and articles therefrom

    DOEpatents

    Mattes, Benjamin R.; Wang, Hsing-Lin

    2000-01-01

    Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (>15% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.

  20. Stable, concentrated solutions of high molecular weight polyaniline and articles therefrom

    DOEpatents

    Mattes, Benjamin R.; Wang, Hsing-Lin

    1999-11-09

    Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (between 15% and 30% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.

  1. Effect of potential on the conductivity of electrodeposited Cu2O film

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Han, Juan; Ning, Xiaohui; Tang, Hongsheng

    2015-09-01

    The conductivity (i.e., n-type or p-type) of Cu2O films is controlled by the electrodeposition potential. A slightly acidic solution (pH 4.93) containing cupric acetate and sodium dodecyl sulfate (SDS) is used. Photoelectrochemical measurements at zero bias indicate that the Cu2O films deposited at the potentials of 0.00 V and -0.05 V generate the ntype photocurrents and the films deposited at the potentials negative than -0.10 V generate the p-type photocurrents. The X-ray diffraction (XRD) results show that the n-type films are pure Cu2O, however, the metallic copper appear in the ptype Cu2O films. Mott-Schottky measurements show that the donor concentrations of the n-type Cu2O films decrease and the acceptor concentrations of the p-type Cu2O films increase with the decrease of the deposition potential. The SDS molecules adsorbed on electrode surface and the SDS micelles block the diffusion of Cu2+ ions, resulting in a low diffusion rate of Cu2+ ions. Under this circumstance, the growth of Cu2O films are affected significantly by the overpotential. When the potential is positive than -0.05 V, oxygen vacancies are formed in the films leading to the n-type conductivity; however, when the potential is negative than -0.10 V, the Cu2+ ions are reduced to Cu+ rapidly and part of Cu2+ are reduced to metallic copper, the diffused Cu2+ ions to supply to the growth of Cu2O films are insufficient, hence copper vacancies are formed in the films resulting in the p-type conductivity.

  2. Thermal Conductivity Measurement of Thermoelectric Thin Films by a Versatility-Enhanced 2ω Method

    NASA Astrophysics Data System (ADS)

    Okuhata, Ryo; Watanabe, Kentaro; Ikeuchi, Satoaki; Ishida, Akihiro; Nakamura, Yoshiaki

    2016-12-01

    The 2ω method is a technique to measure the cross-plane thermal conductivity, κ, of a film sample based on sinusoidal Joule-heating of a metal film deposited on the sample surface and its thermoreflectance (TR) measurement of surface temperature cooling due to the heat dissipation. The 2ω method is being paid attention because it is more cost-effective and easier to use than the conventional time domain thermoreflectance (TDTR) method or the 3ω method. In some cases, however, it is difficult to apply the conventional 2ω method to the κ measurement of high thermal resistance films such as general thermoelectric films due to its non-linear TR signal response to (2ω)-0.5. Here, we present a 2ω method based on a versatile TR signal analysis which enables the κ measurement of high thermal resistance film more explicitly than the conventional analysis based on a linear TR signal response. This method determines explicitly the thermal conductivities of PbTe films and PbTe/GeS superlattices grown on BaF2(111) substrates by hot wall epitaxy: κ = 2.1 ± 0.13 Wm-1 K-1 and κ = 0.71 ± 0.05 Wm-1 K-1, respectively. Furthermore, a significant impact of PbTe film crystallinity on thermal conductivity is demonstrated by comparative measurements between polycrystalline PbTe film and epitaxial PbTe film grown on the BaF2(111) substrates. These results demonstrate that our method can be a powerful tool to measure the thermal conductivity of thermoelectric films.

  3. Adhesion, Modulus and Thermal Conductivity of Porous Epoxy Film on Silicon Wafers

    NASA Astrophysics Data System (ADS)

    Jagannadham, K.

    2016-11-01

    An 8 μm epoxy film deposited on a 350 μm Si (100) Si wafer with a 0.4 μm Au transducer film deposited on top of the polymer film was used to evaluate the thermal conductivity, the modulus of the porous film, and the initiation of spalling upon laser beam irradiation on the back side of the Si wafer. The polymer films were characterized for pore microstructure using scanning electron microscopy and energy dispersive spectrometry. The polymer films were characterized using transient thermo reflectance (TTR) with laser beams illuminating the Au layer. The TTR signal from the polymer film showed only the thermal component and was characteristic of variations associated with thermal conduction into the film. To induce spalling, the back side was illuminated with a Nd-YAG laser beam with a 532 nm wavelength, pulse energy density 1.8 J/cm2, and a repetition rate of 10 Hz for 10 s in conjunction with TTR measurements on the front side. The TTR signal from the polymer film subjected to laser beam incidence from the backside of the Si wafer showed both the thermal and the acoustic components. The acoustic component was used to detect the initial stages of spalling or delamination. The acoustic oscillations were modeled using a modified wave equation to determine the velocity of sound and the modulus of the film. The results were also used to determine the effect of porosity on the modulus of the polymer film. The TTR signal was found to be very sensitive to detection of delamination without complete separation of the film.

  4. New Anti-Corrosive Coatings with Resin-Bonded Polyaniline and Related Electroactive Groups

    NASA Technical Reports Server (NTRS)

    Weil, Edward D.

    1997-01-01

    molecule associated with conductivity are not necessary for the anticorrosion action. Also, signtficantly, small molecular weight aromatic diamines and diimines resembling the reduced and the oxidized repeating unit in polyaniline showed an interesting degree of anticorrosive activity, suggesting that the polymeric feature of polyaniline is not necessary for anticorrosion action.

  5. Polyaniline Nanofibers as the Hole Transport Medium in an Inverse Dye-Sensitized Solar Cell

    NASA Astrophysics Data System (ADS)

    Hesselsweet, Ian Brock

    spectrum at 100 mW/cm2. Initially prepared devices did not generate a measureable photocurrent due to two materials flaws. The first was traced to the poorly developed conduction band of the titania gel, as deposited from Tyzor LA hydrolysis, resulting in poor electron conduction. This prevented the titania gel from efficiently functioning as the electron transport medium. A remedy was found in adding a layer of sintered anatase TiO2 nanoparticles on the back electrode to serve as the electron transport medium. However, this remedy does not address the issue of the inability of titania gel to efficiently transport electrons photogenerated deep in the nanofiber film to the back electrode. The second flaw was found to originate from fast recombination kinetics between electrons in TiO2 and holes in polyaniline. However, a positive feature was that the titania gel intended to be used as the electron transport medium was found to sufficiently insulate the interface such that the recombination rate slowed enough to allow generation of a measureable photocurrent. Electronic insulation was further enhanced by co-attaching decanoic acid onto the polyaniline nanofibers to fill in pinholes between the dye molecules. While these solutions were not ideal, they were intended to be diagnostic in nature and supplied critical information about the weak links in the device design, thus pointing the way toward improving device performance. Significant enhancements can be expected by addressing these issues in further detail.

  6. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    NASA Astrophysics Data System (ADS)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  7. Characteristics and Mechanisms in Ion-Conducting Polymer Films as Chemical Sensors

    SciTech Connect

    HUGHES,ROBERT C.; YELTON,WILLIAM G.; PFEIFER,KENT B.; PATEL,SANJAY V.

    2000-07-12

    Solid Polymer Electrolytes (SPE) are widely used in batteries and fuel cells because of the high ionic conductivity that can be achieved at room temperature. The ions are usually Li or protons, although other ions can be shown to conduct in these polymer films. There has been very little published work on SPE films used as chemical sensors. The authors have found that thin films of polymers like polyethylene oxide (PEO) are very sensitive to low concentrations of volatile organic compounds (VOCs) such as common solvents. Evidence of a new sensing mechanism involving the percolation of ions through narrow channels of amorphous polymer is presented. They present impedance spectroscopy of PEO films in the frequency range 0.0001 Hz to 1 MHz for different concentrations of VOCs and relative humidity. They find that the measurement frequency is important for distinguishing ionic conductivity from the double layer capacitance and the parasitic capacitance.

  8. Extracting the effective mass of electrons in transparent conductive oxide thin films using Seebeck coefficient

    SciTech Connect

    Wang, Yaqin; Zhu, Junhao; Tang, Wu

    2014-05-26

    A method is proposed that combines Seebeck coefficient and carrier concentration to determine the electron effective mass of transparent conductive oxide (TCO) thin films. Experiments were conducted to test the validity of this approach on the transparent conductive Ga-doped ZnO thin films deposited by magnetron sputtering. An evident agreement of the calculated electron effective mass of the films is observed between the proposed approach and the previous studies. Besides, the optical carrier concentration and mobility derived from the calculated electron effective mass and spectroscopic ellipsometry using a complex dielectric function are consistent with those from direct Hall-effect measurement. The agreements suggest that Seebeck coefficient can serve as an alternative tool for extracting the effective mass of electrons in TCO films.

  9. Tunable electrical conductivity in oriented thin films of tetrathiafulvalene-based covalent organic framework

    SciTech Connect

    Cai, SL; Zhang, YB; Pun, AB; He, B; Yang, JH; Toma, FM; Sharp, ID; Yaghi, OM; Fan, J; Zheng, SR; Zhang, WG; Liu, Y

    2014-09-16

    Despite the high charge-carrier mobility in covalent organic frameworks (COFs), the low intrinsic conductivity and poor solution processability still impose a great challenge for their applications in flexible electronics. We report the growth of oriented thin films of a tetrathiafulvalene-based COF (TTF-COF) and its tunable doping. The porous structure of the crystalline TTF-COF thin film allows the diffusion of dopants such as I-2 and tetracyanoquinodimethane (TCNQ) for redox reactions, while the closely packed 2D grid sheets facilitate the cross-layer delocalization of thus-formed TTF radical cations to generate more conductive mixed-valence TTF species, as is verified by UV-vis-NIR and electron paramagnetic resonance spectra. Conductivity as high as 0.28 S m(-1) is observed for the doped COF thin films, which is three orders of magnitude higher than that of the pristine film and is among the highest for COF materials.

  10. Thermal conductivity of a film of single walled carbon nanotubes measured with infrared thermal imager

    NASA Astrophysics Data System (ADS)

    Feng, Ya; Inoue, Taiki; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    Heat dissipation has restricted the modern miniaturization trend with the development of electronic devices. Theoretically proven to be with high axial thermal conductivity, single walled carbon nanotubes (SWNT) have long been expected to cool down the nanoscale world. Even though the tube-tube contact resistance limits the capability of heat transfer of the bulk film, the high intrinsic thermal conductivity of SWNT still glorify the application of films of SWNT network as a thermal interface material. In this work, we proposed a new method to straightly measure the thermal conductivity of SWNT film. We bridged two cantilevered Si thin plate with SWNT film, and kept a steady state heat flow in between. With the infrared camera to record the temperature distribution, the Si plates with known thermal conductivity can work as a reference to calculate the heat flux going through the SWNT film. Further, the thermal conductivity of the SWNT film can be obtained through Fourier's law after deducting the effect of thermal radiation. The sizes of the structure, the heating temperature, the vacuum degree and other crucial impact factors are carefully considered and analyzed. The author Y. F. was supported through the Advanced Integration Science Innovation Education and Research Consortium Program by the Ministry of Education, Culture, Sport, Science and Technology.

  11. Thin film method of conducting lithium-ions

    DOEpatents

    Zhang, J.G.; Benson, D.K.; Tracy, C.E.

    1998-11-10

    The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li{sub 2}O-CeO{sub 2}-SiO{sub 2} system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications. 12 figs.

  12. Thin film method of conducting lithium-ions

    DOEpatents

    Zhang, Ji-Guang; Benson, David K.; Tracy, C. Edwin

    1998-11-10

    The present invention relates to the composition of a solid lithium-ion electrolyte based on the Li.sub.2 O--CeO.sub.2 --SiO.sub.2 system having good transparent characteristics and high ion conductivity suitable for uses in lithium batteries, electrochromic devices and other electrochemical applications.

  13. Photocatalytic and conductive MWCNT/TiO2 nanocomposite thin films.

    PubMed

    Tettey, Kwadwo E; Yee, Michael Q; Lee, Daeyeon

    2010-09-01

    A conductive and photocatalytic nanocomposite thin film comprising multiwalled carbon nanotubes (MWCNTs) and TiO2 nanoparticles is fabricated based on layer-by-layer (LbL) assembly in a nonpolar solvent, toluene. An amphiphilic surfactant, aerosol OT (AOT), is used to impart opposite surface charge onto MWCNTs and TiO2 in toluene. Our fabrication technique enables the incorporation of unoxidized MWCNTs into the nanocomposite thin films, and at the same time, provides a versatile method of fabricating conformal thin films over a large area. The physicochemical properties of MWCNT/TiO2 nanocomposite thin films, including composition and photocatalytic activity, can be varied by changing the concentration of AOT during assembly. The electrical properties of the nanocomposite film, specifically its sheet resistance and conductivity, can also be tuned through changing the assembly conditions. In addition, we demonstrate that the incorporation of MWCNTs within our films leads to a significant enhancement of the photocatalytic activity of TiO2. The conductivity and enhanced photocatalytic activity of MWCNT/TiO2 thin films make them promising for the generation of highly efficient dye-sensitized solar cells (DSSCs).

  14. Press-Printed Conductive Carbon Black Nanoparticle Films for Molecular Detection at the Microscale.

    PubMed

    Della Pelle, Flavio; Vázquez, Luis; Del Carlo, Michele; Sergi, Manuel; Compagnone, Dario; Escarpa, Alberto

    2016-08-26

    Carbon black nanoparticle (CBNP) press-transferred film-based transducers for the molecular detection at the microscale level were proposed for the first time. Current-sensing atomic force microscopy (CS-AFM) revealed that the CBNP films were effectively press-transferred, retaining their good conductivity. A significant correlation between the morphology and the resistance was observed. The highest resistance was localized at the top of the press-transferred film protrusions, whereas low values are usually obtained at the deep crevices or grooves. The amount of press-transferred CBNPs is the key parameter to obtain films with improved conductivity, which is in good agreement with the electrochemical response. In addition, the conductivity of such optimum films was not only Ohmic; in fact, tunneling/hopping contributions were observed, as assessed by CS-AFM. The CBNP films acted as exclusive electrochemical transducers as evidenced by using two classes of molecules, that is, neurotransmitters and environmental organic contaminants. These results revealed the potential of these CBNP press-transferred films for providing new options in microfluidics and other related micro- and nanochemistry applications.

  15. Fluorine compounds for doping conductive oxide thin films

    DOEpatents

    Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

    2013-04-23

    Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

  16. Bottom-up synthesis of graphene/polyaniline nanocomposites for flexible and transparent energy storage devices

    NASA Astrophysics Data System (ADS)

    Souza, Victor H. R.; Oliveira, Marcela M.; Zarbin, Aldo J. G.

    2017-04-01

    An innovative, single-pot synthesis for chemically producing graphene/polyaniline nanocomposites is presented. The method, which is based on chemical reactions at liquid-liquid interfaces, begins with benzene and aniline and ultimately yields nanocomposites as thin films of polyaniline mixed with graphene. These films self-assembled at the water-benzene interface are easily transferable to any kind of ordinary substrates, plastics included. Nanocomposites prepared with different polymer/graphene ratios show differentiated structures and morphologies, resulting in excellent pseudocapacitive behaviors (specific capacitance of 267.2 F cm-3). The construction of all-solid, transparent, and flexible supercapacitor device from this nanocomposite is also presented.

  17. Conduction noise absorption by ITO thin films attached to microstrip line utilizing Ohmic loss

    SciTech Connect

    Kim, Sun-Hong; Kim, Sung-Soo

    2010-07-15

    For the aim of wide-band noise absorbers with a special design for low frequency performance, this study proposes conductive indium-tin oxide (ITO) thin films as the absorbent materials in microstrip line. ITO thin films were deposited on the polyimide film substrates by rf magnetron cosputtering of In{sub 2}O{sub 3} and Sn targets. The deposited ITO films show a typical value of electrical resistivity ({approx}10{sup -4} {Omega} m) and sheet resistance can be controlled in the range of 20-230 {Omega} by variation in film thickness. Microstrip line with characteristic impedance of 50 {Omega} was used for determining their noise absorbing properties. It is found that there is an optimum sheet resistance of ITO films for the maximum power absorption. Reflection parameter (S{sub 11}) is increased with decrease in sheet resistance due to impedance mismatch. On the while, transmission parameter (S{sub 21}) is decreased with decrease in sheet resistance due to larger Ohmic loss of the ITO films. Experimental results and computational prediction show that the optimum sheet resistance is about 100 {Omega}. For this film, greater power absorption is predicted in the lower frequency region than ferrite thin films of high magnetic loss, which indicates that Ohmic loss is the predominant loss parameter for power absorption in the low frequency range.

  18. Effect of growth temperature on the terahertz-frequency conductivity of the epitaxial transparent conducting spinel NiCo2O4 films

    NASA Astrophysics Data System (ADS)

    Silwal, Punam; La-o-vorakiat, Chan; Chia, Elbert E. M.; Kim, Dae Ho; Talbayev, Diyar

    2013-09-01

    We have measured the terahertz-frequency optical conductivity of the epitaxial inverse spinel NiCo2O4 films grown at different temperatures. The low-temperature-grown film exhibits a metallic behavior with ferrimagnetic ordering, while the high-temperature-grown film shows greatly suppressed magnetization and insulating behavior. Both films exhibit band-like coherent conduction at intermediate temperatures, albeit with very different carrier densities consistent with the proposed models of cation valencies in this mixed-valence material. Both films also display a crossover to incoherent transport at low temperatures, indicating a disorder-induced tendency toward localization.

  19. Study of the structure and mechanical properties of pure and doped polyaniline

    NASA Astrophysics Data System (ADS)

    Shaktawat, Vinodini; Saxena, N. S.; Sharma, Kananbala

    2011-03-01

    Polyaniline (PANI) doped with different protonic acids was chemically synthesized using ammonium persulfate as an oxidant. These samples were characterized through scanning electron microscopy-energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy, which confirms the acid doping. Variation of complex elastic modulus and mechanical loss factor (tan δ) has been studied with temperature of pellet of conducting PANI. It has been observed that complex modulus decreases with temperature due to thermal expansion of films. On the other hand, tan δ increases up to characteristic temperature, beyond which it shows a decreasing trend towards melting. The phase transition temperature of pure PANI is 106.1°C and is shifted to higher temperatures i.e. 137.1°C, 134°C, 138.8°C, 118.3°C, and 109.7°C with doping of PANI by protonic acids.

  20. Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes.

    PubMed

    Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

    2016-02-02

    We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials.

  1. Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films

    SciTech Connect

    Farrow, Tim; Yang, Nan; Doria, Sandra; Belianinov, Alex; Jesse, Stephen; Arruda, Thomas M.; Balestrino, Giuseppe; Kalinin, Sergei V.; Kumar, Amit

    2015-03-17

    Spatial variability of conductivity in ceria is explored using scanning probe microscopy with galvanostatic control. Ionically blocking electrodes are used to probe the conductivity under opposite polarities to reveal possible differences in the defect structure across a thin film of CeO2. Data suggest the existence of a large spatial inhomogeneity that could give rise to constant phase elements during standard electrochemical characterization, potentially affecting the overall conductivity of films on the macroscale. The approach discussed here can also be utilized for other mixed ionic electronic conductor systems including memristors and electroresistors, as well as physical systems such as ferroelectric tunneling barriers

  2. Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films

    DOE PAGES

    Farrow, Tim; Yang, Nan; Doria, Sandra; ...

    2015-03-17

    Spatial variability of conductivity in ceria is explored using scanning probe microscopy with galvanostatic control. Ionically blocking electrodes are used to probe the conductivity under opposite polarities to reveal possible differences in the defect structure across a thin film of CeO2. Data suggest the existence of a large spatial inhomogeneity that could give rise to constant phase elements during standard electrochemical characterization, potentially affecting the overall conductivity of films on the macroscale. The approach discussed here can also be utilized for other mixed ionic electronic conductor systems including memristors and electroresistors, as well as physical systems such as ferroelectric tunnelingmore » barriers« less

  3. Simulation of electrical conduction in thin polycrystalline metallic films: Impact of microstructure

    SciTech Connect

    Rickman, J. M.; Barmak, K.

    2013-10-07

    We examine the impact of microstructural features on the electrical conductivity of a thin metallic film using Monte Carlo simulation. In particular, we obtain the dependence of the conductivity (in the absence of surface scattering) on average grain size and electron scattering mechanisms, the latter parametrized by a transmission coefficient, for a model polycrystal generated by a Voronoi tessellation. We find that the conductivity can be described in limiting cases in terms of either a simplified hopping model or a trapping model. Finally, we compare our results with the Mayadas-Shatzkes model of grain-boundary scattering and with experimental resistivity measurements for polycrystalline copper thin films.

  4. Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films

    SciTech Connect

    Farrow, Tim; Kumar, Amit; Yang, Nan; Doria, Sandra; Balestrino, Giuseppe; Belianinov, Alex; Jesse, Stephen; Kalinin, Sergei V.; Arruda, Thomas M.

    2015-03-01

    Spatial variability of conductivity in ceria is explored using scanning probe microscopy with galvanostatic control. Ionically blocking electrodes are used to probe the conductivity under opposite polarities to reveal possible differences in the defect structure across a thin film of CeO{sub 2}. Data suggest the existence of a large spatial inhomogeneity that could give rise to constant phase elements during standard electrochemical characterization, potentially affecting the overall conductivity of films on the macroscale. The approach discussed here can also be utilized for other mixed ionic electronic conductor systems including memristors and electroresistors, as well as physical systems such as ferroelectric tunneling barriers.

  5. Preparation of Aluminum Nanomesh Thin Films from an Anodic Aluminum Oxide Template as Transparent Conductive Electrodes

    PubMed Central

    Li, Yiwen; Chen, Yulong; Qiu, Mingxia; Yu, Hongyu; Zhang, Xinhai; Sun, Xiao Wei; Chen, Rui

    2016-01-01

    We have employed anodic aluminum oxide as a template to prepare ultrathin, transparent, and conducting Al films with a unique nanomesh structure for transparent conductive electrodes. The anodic aluminum oxide template is obtained through direct anodization of a sputtered Al layer on a glass substrate, and subsequent wet etching creates the nanomesh metallic film. The optical and conductive properties are greatly influenced by experimental conditions. By tuning the anodizing time, transparent electrodes with appropriate optical transmittance and sheet resistance have been obtained. The results demonstrate that our proposed strategy can serve as a potential method to fabricate low-cost TCEs to replace conventional indium tin oxide materials. PMID:26831759

  6. Anisotropic Lithium Ion Conductivity in Single-Ion Diblock Copolymer Electrolyte Thin Films.

    PubMed

    Aissou, Karim; Mumtaz, Muhammad; Usluer, Özlem; Pécastaings, Gilles; Portale, Giuseppe; Fleury, Guillaume; Cloutet, Eric; Hadziioannou, Georges

    2016-02-01

    Well-defined single-ion diblock copolymers consisting of a Li-ion conductive poly(styrenesulfonyllithium(trifluoromethylsulfonyl)imide) (PSLiTFSI) block associated with a glassy polystyrene (PS) block have been synthesized via reversible addition fragmentation chain transfer polymerization. Conductivity anisotropy ratio up to 1000 has been achieved from PS-b-PSLiTFSI thin films by comparing Li-ion conductivities of out-of-plane (aligned) and in-plane (antialigned) cylinder morphologies at 40 °C. Blending of PS-b-PSLiTFSI thin films with poly(ethylene oxide) homopolymer (hPEO) enables a substantial improvement of Li-ion transport within aligned cylindrical domains, since hPEO, preferentially located in PSLiTFSI domains, is an excellent lithium-solvating material. Results are also compared with unblended and blended PSLiTFSI homopolymer (hPSLiTFSI) homologues, which reveals that ionic conductivity is improved when thin films are nanostructured.

  7. Finite element analysis and equivalent parallel-resistance model for conductive multilayer thin films

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Yi; Juang, Jia-Yang

    2016-07-01

    The standard collinear four-point probe method is an indispensable tool and has been extensively used for characterizing conductive thin films with homogeneous and isotropic electrical properties. In this paper, we conduct three-dimensional (3D) finite element simulations on conductive multilayer films to study the relationship between the reading of the four-point probe and the conductivity of the individual layers. We find that a multilayer film may be modeled as a simple equivalent circuit with multiple resistances, connected in parallel for a wide range of resistivity and thickness ratios, as long as its total thickness is smaller than approximately half of the probe spacing. As a result, we may determine the resistivity of each layer sequentially by applying the four-point probe, with the original correction factor π/ln(2), after deposition of each layer.

  8. Charge transport and magnetic properties in polyaniline doped with methane sulphonic acidand polyaniline-polyurethane blend

    NASA Astrophysics Data System (ADS)

    Sanjai, B.; Raghunathan, Anasuya; Natarajan, T. S.; Rangarajan, G.; Thomas, Soloman; Prabhakaran, P. V.; Venkatachalam, S.

    1997-04-01

    Charge transport in polyaniline protonated fully with methane sulphonic acid (MSA) and polyaniline (MSA)-polyurethane [PANI(MSA)-PU] blend has been investigated through measurements of temperature (T) and electric field (E) dependence of conductivity (σ), temperature dependence of thermoelectric power and magnetic susceptibility and electron spin resonance at room temperature. PANI(MSA) exhibits a three-dimensional variable-range hopping (VRH) type of conduction, which is not the case with HCl-doped PANI and the electric field dependence of its conductivity is also consistent with VRH behavior. The thermopower in PANI(MSA) shows metallic behavior. The blend follows a one-dimensional VRH type of conduction and the electric field dependence of its conductivity exhibits the Poole-Frenkel effect. The temperature-dependent magnetic susceptibility measurements indicate the presence of Pauli and Curie spins in both the samples. From electron spin resonance measurements the percentage of Lorentzian and Gaussian spins have been estimated. In PANI-MSA a larger number of spins are found to be delocalized. The conduction mechanism in PANI-PU blend is discussed in comparison to other commercial conducting polymer blends.

  9. Ammonia gas sensing behavior of tanninsulfonic acid doped polyaniline-TiO₂ composite.

    PubMed

    Bairi, Venu Gopal; Bourdo, Shawn E; Sacre, Nicolas; Nair, Dev; Berry, Brian C; Biris, Alexandru S; Viswanathan, Tito

    2015-10-16

    A highly active tannin doped polyaniline-TiO₂ composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO₂ in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO₂. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO₂ and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO₂ composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

  10. Electrically Conductive Thick Film Made from Silver Alkylcarbamates

    NASA Astrophysics Data System (ADS)

    Liu, Jianguo; Li, Xiangyou; Wang, Xiaoye; Zeng, Xiaoyan

    2010-10-01

    A homogeneous electrically conductive silver paste without solid or particle phase was developed using silver alkylcarbamates [(C n H2 n-1NHCOO)2Ag, n ≤ 4] as the precursor of the functional phase. The silver alkylcarbamates were light insensitive and had a low decomposition temperature (below 200°C). The paste was a non-Newtonian fluid with viscosity significantly depending on the content of the thickening agent ethyl cellulose. Array patterns with a resolution of 20 μm were obtained using this paste by a micropen direct-writing method. After the paste with about 48 wt.% silver methylcarbamate [(CH3NHCOO)2Ag] precursor was sintered at 180°C for 15 min, an electrically conductive network consisting of more than 95 wt.% silver was formed, and was found to have a volume electrical resistivity on the order of 10-5 Ω cm and a sheet electrical resistivity on the order of 10-2-10-3 Ω/□. The cohesion strength within the sintered paste and the adhesion strength between the sintered paste layer and the alumina ceramic substrate were tested according to test method B of the American Society for Testing and Materials standard D3359-08. None of the sintered paste layer was detached under the test conditions, and the cohesion and adhesion strengths met the highest grade according to the standard.

  11. Conductivity of PEDOT:PSS on Spin-Coated and Drop Cast Nanofibrillar Cellulose Thin Films

    NASA Astrophysics Data System (ADS)

    Valtakari, Dimitar; Liu, Jun; Kumar, Vinay; Xu, Chunlin; Toivakka, Martti; Saarinen, Jarkko J.

    2015-10-01

    Aqueous dispersion of conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was deposited on spin-coated and drop cast nanofibrillar cellulose (NFC)-glycerol (G) matrix on a glass substrate. A thin glycerol film was utilized on plasma-treated glass substrate to provide adequate adhesion for the NFC-glycerol (NFC-G) film. The effects of annealing temperature, the coating method of NFC-G, and the coating time intervals on the electrical performance of the PEDOT:PSS were characterized. PEDOT:PSS on drop cast NFC-G resulted in 3 orders of magnitude increase in the electrical conductivity compared to reference PEDOT:PSS film on a reference glass substrate, whereas the optical transmission was only slightly decreased. The results point out the importance of the interaction between the PEDOT:PSS and the NFC-G for the electrical and barrier properties for thin film electronics applications.

  12. Controlled Synthesis of Monolayer Graphene Toward Transparent Flexible Conductive Film Application.

    PubMed

    Lee, Byeong-Joo; Yu, Han-Young; Jeong, Goo-Hwan

    2010-07-28

    We demonstrate the synthesis of monolayer graphene using thermal chemical vapor deposition and successive transfer onto arbitrary substrates toward transparent flexible conductive film application. We used electron-beam-deposited Ni thin film as a synthetic catalyst and introduced a gas mixture consisting of methane and hydrogen. To optimize the synthesis condition, we investigated the effects of synthetic temperature and cooling rate in the ranges of 850-1,000°C and 2-8°C/min, respectively. It was found that a cooling rate of 4°C/min after 1,000°C synthesis is the most effective condition for monolayer graphene production. We also successfully transferred as-synthesized graphene films to arbitrary substrates such as silicon-dioxide-coated wafers, glass, and polyethylene terephthalate sheets to develop transparent, flexible, and conductive film application.

  13. 43 CFR 5.15 - When must I ask permission from individual Indians to conduct filming and photography?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Indians to conduct filming and photography? 5.15 Section 5.15 Public Lands: Interior Office of the Secretary of the Interior COMMERCIAL FILMING AND SIMILAR PROJECTS AND STILL PHOTOGRAPHY ON CERTAIN AREAS... permission from individual Indians to conduct filming and photography? Anyone who desires to go on to...

  14. 43 CFR 5.15 - When must I ask permission from individual Indians to conduct filming and photography?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Indians to conduct filming and photography? 5.15 Section 5.15 Public Lands: Interior Office of the Secretary of the Interior COMMERCIAL FILMING AND SIMILAR PROJECTS AND STILL PHOTOGRAPHY ON CERTAIN AREAS... permission from individual Indians to conduct filming and photography? Anyone who desires to go on to...

  15. Conductive thin-film composite hydrogels: Trapping an anionic polyelectrolyte in a polyaziridine host matrix

    SciTech Connect

    Wexler, A.; Suen, C.; Hill, S.

    1995-08-01

    Acid-catalyzed polymerization of sufficiently concentrated aqueous solutions of a trifunctional aziridine monomer affords hydrogels. Dynamic mechanical analysis has been used to demonstrate that composite hydrogels, obtained when the polymerization is effected in the presence of poly(sodium styrenesulfonate), have a composition dependent modulus. A region rich in the polyelectrolyte has a modulus which exceeds that of the {open_quotes}host{close_quotes} homogeneous polyaziridine hydrogel. This is consistent with ionic bonds between protonated sites on the polyaziridine matrix and sulfonate groups on the included polyelectrolyte augmenting the structural stability of the hydrogel. Thin films were prepared from coatings of the incipient hydrogel solutions. When the coatings are dried to a water content of 20%, water-insoluble thin films are obtained provided a critical weight fraction of the monomer is exceeded. Conductive thin films can be obtained, provided a critical weight fraction of polyelectrolyte is exceeded. FTIR analysis of the coatings in the attenuated total reflectance mode shows that conductivity increases as tight ion pairing decreases between the polyelectrolyte and its counter ions in the matrix. The S-shaped dependence of the normalized conductivity on the composition of the thin films is independent of the state of hydration of the film. Effective medium percolation theory, (EMPT), generally fits the S-shaped compositional dependence of the conductivity but overestimates the rate of growth of the conductivity beyond the critical point. 20 refs., 7 figs.

  16. Controllable morphology and conductivity of electrodeposited Cu₂O thin film: effect of surfactants.

    PubMed

    Yang, Ying; Han, Juan; Ning, Xiaohui; Cao, Wei; Xu, Wei; Guo, Liejin

    2014-12-24

    Both the morphology and conductivity of Cu2O films are controlled in a facile electrodeposition process by tuning the concentration of surfactants. With the increase of the concentration of sodium dodecyl sulfate (SDS) in the plating solution, the average size of Cu2O crystals increases, and the electrical conductivity of Cu2O films changes from n-type to p-type. When the concentrations of SDS are lower than 0.85 mM, the electrodeposited Cu2O films show n-type conductivity because of the formation of oxygen vacancies or copper atoms. When the concentration of SDS is higher than 1.70 mM, the electrodeposited Cu2O films show p-type conductivity owing to the formation of copper vacancies. The concentrations of both the donors and the acceptors increase with the concentration of SDS. The effects of surfactants on the morphology and conductivity of electrodeposited Cu2O films are attributed to the adsorption of SDS molecules on the electrode substrate occupying the deposition sites of Cu(2+) ions and the adsorption of SDS micelles to Cu(2+) ions hindering the diffusion of Cu(2+) ions to the electrode, which affect the reduction rate of Cu(2+) ions and the formation of oxygen vacancies or copper vacancies during the electrodeposition.

  17. Mesoporous tin-doped indium oxide thin films: effect of mesostructure on electrical conductivity

    NASA Astrophysics Data System (ADS)

    von Graberg, Till; Hartmann, Pascal; Rein, Alexander; Gross, Silvia; Seelandt, Britta; Röger, Cornelia; Zieba, Roman; Traut, Alexander; Wark, Michael; Janek, Jürgen; Smarsly, Bernd M.

    2011-03-01

    We present a versatile method for the preparation of mesoporous tin-doped indium oxide (ITO) thin films via dip-coating. Two poly(isobutylene)-b-poly(ethyleneoxide) (PIB-PEO) copolymers of significantly different molecular weight (denoted as PIB-PEO 3000 and PIB-PEO 20000) are used as templates and are compared with non-templated films to clarify the effect of the template size on the crystallization and, thus, on the electrochemical properties of mesoporous ITO films. Transparent, mesoporous, conductive coatings are obtained after annealing at 500 °C these coatings have a specific resistance of 0.5 Ω cm at a thickness of about 100 nm. Electrical conductivity is improved by one order of magnitude by annealing under a reducing atmosphere. The two types of PIB-PEO block copolymers create mesopores with in-plane diameters of 20-25 and 35-45 nm, the latter also possessing correspondingly thicker pore walls. Impedance measurements reveal that the conductivity is significantly higher for films prepared with the template generating larger mesopores. Because of the same size of the primary nanoparticles, the enhanced conductivity is attributed to a higher conduction path cross section. Prussian blue was deposited electrochemically within the films, thus confirming the accessibility of their pores and their functionality as electrode material.

  18. Microstructural effects on electrical conductivity relaxation in nanoscale ceria thin films

    SciTech Connect

    Tsuchiya, Masaru; Ramanathan, Shriram; Bojarczuk, Nestor A.; Guha, Supratik

    2009-05-07

    Microstructure evolution and electrical conductivity relaxation kinetics in highly textured and nanocrystalline dense ceria thin films ({approx}65 nm) are reported in this paper. Highly textured films were grown on sapphire c-plane substrates by molecular beam synthesis (MBS) with orientation relationship (111)CeO{sub 2}||(0001)Al{sub 2}O{sub 3} and [110]CeO{sub 2}||[1210]Al{sub 2}O{sub 3}. No significant structural changes were observed in highly textured films even after extensive annealing at high temperature. In contrast to MBS grown films, ceria films grown by electron beam evaporation at room temperature had polycrystalline structure with {approx}10 nm grains, which grew to {approx}30 nm upon annealing at 1173 K. Grain growth kinetics was self-limiting and the out-of-plane orientation was found to be substrate dependent. From conductivity relaxation measurements, oxygen exchange rate in highly textured thin films was found to be much slower than that in polycrystalline films. The response time for highly textured films to changes in P(O{sub 2}) from 1.07x10{sup -12} to 5.43x10{sup -10} Pa at 1148 K was 0.65 s, whereas that for polycrystalline films was 0.13 s under identical conditions. From temperature dependent experiments, activation energy for relaxation time was found to be similar, suggesting similar rate-limiting mechanisms in polycrystalline and highly textured films. The results highlight the importance of near-surface defects in controlling kinetics of oxygen incorporation into nanostructured oxides. In a broader context, the results maybe of relevance to designing catalytic surfaces in solid state ionic devices such as fuel cells.

  19. Pulsed electric field assisted assembly of polyaniline.

    PubMed

    Kumar, Arun; Kazmer, David O; Barry, Carol M F; Mead, Joey L

    2012-08-24

    Assembling conducting polyaniline (PANi) on pre-patterned nano-structures by a high rate, commercially viable route offers an opportunity for manufacturing devices with nanoscale features. In this work we report for the first time the use of pulsed electric field to assist electrophoresis for the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 s, assembly resolution of 100 nm). Moreover, the area coverage increases with the increase in number of pulses. A similar trend was observed with the deposition height and the increase in deposition height followed a linear trend with a correlation coefficient of 0.95. When the experimental mass deposited was compared with Hamaker's theoretical model, the two were found to be very close. The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to thermoplastic polyurethane using the thermoforming process.

  20. Pulsed electric field assisted assembly of polyaniline

    NASA Astrophysics Data System (ADS)

    Kumar, Arun; Kazmer, David O.; Barry, Carol M. F.; Mead, Joey L.

    2012-08-01

    Assembling conducting polyaniline (PANi) on pre-patterned nano-structures by a high rate, commercially viable route offers an opportunity for manufacturing devices with nanoscale features. In this work we report for the first time the use of pulsed electric field to assist electrophoresis for the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 s, assembly resolution of 100 nm). Moreover, the area coverage increases with the increase in number of pulses. A similar trend was observed with the deposition height and the increase in deposition height followed a linear trend with a correlation coefficient of 0.95. When the experimental mass deposited was compared with Hamaker’s theoretical model, the two were found to be very close. The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to thermoplastic polyurethane using the thermoforming process.

  1. Enhanced Conductivity in CZTS/Cu(2-x)Se Nanocrystal Thin Films: Growth of a Conductive Shell.

    PubMed

    Korala, Lasantha; McGoffin, J Tyler; Prieto, Amy L

    2016-02-01

    Poor charge transport in Cu2ZnSnS4 (CZTS) nanocrystal (NC) thin films presents a great challenge in the fabrication of solar cells without postannealing treatments. We introduce a novel approach to facilitate the charge carrier hopping between CZTS NCs by growing a stoichiometric Cu2Se shell that can be oxidized to form a conductive Cu2-xSe phase when exposed to air. The CZTS/Cu2Se core/shell NCs with varying numbers of shell monolayers were synthesized by the successive ionic layer adsorption and reaction (SILAR) method, and the variation in structural and optical properties of the CZTS NCs with varying shell thicknesses was investigated. Solid-phase sulfide ligand exchange was employed to fabricate NC thin films by layer-by-layer dip coating and a 2 orders of magnitude rise in dark conductivity (∼10(-3) S cm(-1) at 0 monolayer and ∼10(-1) S cm(-1) at 1.5 monolayers) was observed with an increase in the number of shell monolayers. The approach described herein is the first key step in achieving a significant increase in the photoconductivity of as-deposited CZTS NC thin films.

  2. Carbon Nanotube/Conductive Additive/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

    NASA Technical Reports Server (NTRS)

    Smith, Joseph G., Jr.; Watson, Kent A.; Delozier, Donavon M.; Connell, John W.

    2003-01-01

    Thin film membranes of space environmentally stable polymeric materials possessing low color/solar absorptivity (alpha) are of interest for potential applications on Gossamer spacecraft. In addition to these properties, sufficient electrical conductivity is required in order to dissipate electrostatic charge (ESC) build-up brought about by the charged orbital environment. One approach to achieve sufficient electrical conductivity for ESC mitigation is the incorporation of single wall carbon nanotubes (SWNTs). However, when the SWNTs are dispersed throughout the polymer matrix, the nanocomposite films tend to be significantly darker than the pristine material resulting in a higher alpha. The incorporation of conductive additives in combination with a decreased loading level of SWNTs is one approach for improving alpha while retaining conductivity. Taken individually, the low loading level of conductive additives and SWNTs is insufficient in achieving the percolation level necessary for electrical conductivity. When added simultaneously to the film, conductivity is achieved through a synergistic effect. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

  3. Li-rich anti-perovskite Li3OCl films with enhanced ionic conductivity

    SciTech Connect

    Lu, XJ; Wu, G; Howard, JW; Chen, AP; Zhao, YS; Daemen, LL; Jia, QX

    2014-08-13

    Anti-perovskite solid electrolyte films were prepared by pulsed laser deposition, and their room-temperature ionic conductivity can be improved by more than an order of magnitude in comparison with its bulk counterpart. The cyclability of Li3OCl films in contact with lithium was evaluated using a Li/Li3OCl/Li symmetric cell, showing self-stabilization during cycling test.

  4. Electrochemical co-deposition of conductive polymer-silica hybrid thin films.

    PubMed

    Raveh, Moran; Liu, Liang; Mandler, Daniel

    2013-07-14

    Conductive polymers, such as polypyrrole (ppy), have been the subject of numerous studies due to their promising applications in organic solar cells, flexible electronics, electrochromic devices, super capacitors, etc. Yet, their application is still limited as a result of poor processability. Silica has been reported to improve the mechanical strength and adhesion of conductive polymer films. In this work, we propose a controllable electrochemical approach for preparing ppy-silica hybrid thin films from a solution containing both pyrrole and silane monomers. It is known that pyrrole can be electropolymerised using anodic potentials, while silica can be electrodeposited under cathodic potentials. Thus, we studied the formation of ppy-silica hybrid thin films on a stainless steel surface by applying alternating potentials, i.e. cathodic followed by anodic pulses (denoted C + A) or anodic followed by cathodic pulses (denoted A + C). We show that by controlling the deposition potential and time for the cathodic and anodic pulses, the film thickness and composition can be manipulated well as analysed using profilometry and EDX. The element depth profile of the films was characterized using secondary ion mass spectroscopy (SIMS). In essence, for the C + A process, pyrrole diffuses through the cathodically electrodeposited wet silica gel layer and undergoes anodic polymerisation on the substrate, while for the A + C process, silane can be electrodeposited both on top of the anodically electrodeposited conductive ppy films as well as on the stainless steel through the pinholes in the ppy film. This offers a simple approach for tuning the structure of conductive polymer-sol-gel composite films.

  5. SHI induced enhancement in conductivity of PbTe thin film for thermoelectric applications

    SciTech Connect

    Gupta, Srashti; Agarwal, D. C.; Singh, J. P.; Tripathi, S. K.; Neeleshwar, S.; Asokan, K.; Panigrahi, B. K.; Avasthi, D. K.

    2012-06-05

    PbTe thin film were synthesized using thermal evaporation and irradiated by 100 MeV Ag ions at different fluences ranging from 3x10{sup 13} and 1x10{sup 14} ions/cm{sup 2}. Pristine films annealed under Ar atm at 250 deg. C for 1 hr. X-ray Diffraction (XRD) of pristine and irradiated films reveals the improvement of PbTe phase with increasing fluence. The thickness of the film is decreased from 195 nm to 150 nm after ion irradiation as indicated by Rutherford backscattering spectrometry (RBS) analysis due to the sputtering. Resistivity measurement using four probe techniques of these films shows the conductivity enhancement with ion fluence. The conductivity is found to be {approx} 6 fold at fluence 3x10{sup 13} ions/cm{sup 2} whereas it decreases to 3 fold after annealing in comparison to pristine sample. On further increasing the fluence from 3x10{sup 13} ions/cm{sup 2}, the properties of the film begin to deteriorate. SHI induced modification may be explained on the basis of oxygen desorption and change in stochiometry of film during irradiation.

  6. Preparation and characterization of conductive and transparent ruthenium dioxide sol-gel films.

    PubMed

    Allhusen, John S; Conboy, John C

    2013-11-27

    RuO2 conductive thin films were synthesized using the sol-gel method and deposited onto transparent insulating substrates. The optical transmission, film thickness, surface morphology and composition, resistivity, and spectroelectrochemical performance have been characterized. The optical transmission values of these films ranged from 70 to 89% in the visible region and from 56 to 88% in the infrared region. Resistivity values of the RuO2 sol-gel films varied from 1.02 × 10(-3) to 1.13 Ω cm and are highly dependent on the initial solution concentration of RuO2 in the sol-gel. The RuO2 sol-gel films were used as electrodes for the electrochemical oxidation and reduction of ferrocenemethanol. The electrochemical behavior of our novel RuO2 sol-gel films was compared to that of a standard platinum disk electrode and showed no appreciable differences in the half-wave potential (E1/2). The mechanical and chemical stability of the coatings was tested by physical abrasion and exposure to highly acidic, oxidizing Piranha solution. Repeated exposure to these extreme conditions did not result in any appreciable decline in electrochemical performance. Finally, the use of the novel RuO2 sol-gel conductive and transparent films was demonstrated in a spectroelectrochemistry experiment in which the oxidation and reduction of ferrocenemethanol was monitored via UV-vis spectroscopy as the applied potential was cycled.

  7. Amorphous semiconducting and conducting transparent metal oxide thin films and production thereof

    DOEpatents

    Perkins, John; Van Hest, Marinus Franciscus Antonius Maria; Ginley, David; Taylor, Matthew; Neuman, George A.; Luten, Henry A.; Forgette, Jeffrey A.; Anderson, John S.

    2010-07-13

    Metal oxide thin films and production thereof are disclosed. An exemplary method of producing a metal oxide thin film may comprise introducing at least two metallic elements and oxygen into a process chamber to form a metal oxide. The method may also comprise depositing the metal oxide on a substrate in the process chamber. The method may also comprise simultaneously controlling a ratio of the at least two metallic elements and a stoichiometry of the oxygen during deposition. Exemplary amorphous metal oxide thin films produced according to the methods herein may exhibit highly transparent properties, highly conductive properties, and/or other opto-electronic properties.

  8. Study of poly (3-hexylthiophene) conducting polymer thin film micro-sensor for hydrazine vapor detection

    NASA Astrophysics Data System (ADS)

    Yang, Hong

    This dissertation discussed the construction and investigation of a poly (3-hexylthiophene) conducting polymer based thin film micro-sensor for a real-time detection of hydrazine vapor at ambient pressure. A type of low cost, small size, passive poly (3-hexylthiophene) thin film micro-sensor was designed and fabricated. The micro-sensor platform consisted of a rectangular shaped inert substrate and gold interdigited electrode pairs. A layer of poly (3-hexylthiophene) thin film was coated onto the sensor platform using a spin coating method, and nitrosonium hexafluorophosphate (NOPF6) was used to dope the poly (3-hexylthiophene) thin film to increase its electrical conductivity and form the finished sensor. The basic responses of the sensor to hydrazine vapor were experimentally investigated. The primary results showed that the sensor responded to hydrazine vapor in less than a few seconds; attained orders of magnitude change in normalized resistance during hydrazine exposure, and was not easily saturated. The interaction between the hydrazine gas molecules and doped poly (3-hexylthiophene) thin film was studied. The plausible mechanism was determined as: Charge carriers inside the doped poly (3-hexylthiophene) thin film were depleted during the oxidation-reduction chemical reaction between the hydrazine vapor and polymer film, resulting a reduction in the polymer film's electrical conductivity. Experiments were also conducted to find out the effects of hydrazine concentration, poly (3-hexylthiophene) thin film thickness, sensor storage time, environment temperature, and environment humidity on the sensor's performance. The response rate of the sensor under different sensing conditions was calculated and discussed. A diffusion-reaction model was applied to simulate the interaction between hydrazine molecules and doped poly (3-hexylthiophene) thin film. The profiles of hydrazine gas diffusion and positive charge carrier neutralization in the polymer film were

  9. Preparation of properties of SWNT/graphene oxide type flexible transparent conductive films.

    PubMed

    Kim, Jin Ho; Jung, Jae Mok; Kwak, Jun Young; Jeong, Jung Hyun; Choi, Byung Chun; Lim, Kwon Taek

    2011-08-01

    Single walled carbon nanotube (SWNT)/graphene oxide (GO) hybrid films were prepared by a facile bar coating method on a polyethylene terephthalate substrate using a mixed solution of SWCNTs and GO. An acryl type polymer was employed as a dispersion agent to obtain SWCNT and GO suspension in ethyl alcohol. The SWCNT/GO hybrid films were highly transparent and electrically conductive, showing 80% transmittance and 1.8 x 10(3) ohm/sq surface resistance. The surface resistance of the SWCNT/GO film could be further improved to 750 ohm/sq by hydrazine vapor reduction.

  10. Improved Transparent Conducting Oxides Boost Performance of Thin-Film Solar Cells (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    Today?s thin-film solar cells could not function without transparent conducting oxides (TCOs). TCOs act as a window, both protecting the cell and allowing light to pass through to the cell?s active layers. Until recently, TCOs were seen as a necessary, but static, layer of a thin-film photovoltaic (PV) cell. But a group of researchers at the National Renewable Energy Laboratory (NREL) has identified a pathway to producing improved TCO films that demonstrate higher infrared transparency. To do so, they have modified the TCOs in ways that did not seem possible a few years ago.

  11. Synthesis, characterization and properties of polyaniline/expanded vermiculite intercalated nanocomposite

    PubMed Central

    Lin, Jianming; Tang, Qunwei; Wu, Jihuai; Sun, Hui

    2008-01-01

    The synthesis characterization and conductivities of polyaniline/expanded vermiculite intercalated nanocomposite are presented in this paper. The conductive emeraldine salt form of polyaniline is inserted into the interlayer of expanded vermiculite to produce the nanocomposite with high conductivity. The structures and properties are characterized by transmission electron microscopy x-ray diffraction spectroscopy fourier transform infrared spectroscopy thermogravimetry analysis and by the measurements of conductivity and stability. The results show that an intercalated nanocomposite with high conductivity and stability is obtained. The synthesis conditions are optimized to obtain the highest conductivity which is 6.80 S cm−1. PMID:27877985

  12. Synthesis, characterization and properties of polyaniline/expanded vermiculite intercalated nanocomposite.

    PubMed

    Lin, Jianming; Tang, Qunwei; Wu, Jihuai; Sun, Hui

    2008-04-01

    The synthesis characterization and conductivities of polyaniline/expanded vermiculite intercalated nanocomposite are presented in this paper. The conductive emeraldine salt form of polyaniline is inserted into the interlayer of expanded vermiculite to produce the nanocomposite with high conductivity. The structures and properties are characterized by transmission electron microscopy x-ray diffraction spectroscopy fourier transform infrared spectroscopy thermogravimetry analysis and by the measurements of conductivity and stability. The results show that an intercalated nanocomposite with high conductivity and stability is obtained. The synthesis conditions are optimized to obtain the highest conductivity which is 6.80 S cm(-1).

  13. Highly conductive Cu2-xS nanoparticle films through room-temperature processing and an order of magnitude enhancement of conductivity via electrophoretic deposition.

    PubMed

    Otelaja, Obafemi O; Ha, Don-Hyung; Ly, Tiffany; Zhang, Haitao; Robinson, Richard D

    2014-11-12

    A facile room-temperature method for assembling colloidal copper sulfide (Cu2-xS) nanoparticles into highly electrically conducting films is presented. Ammonium sulfide is utilized for connecting the nanoparticles via ligand removal, which transforms the as-deposited insulating films into highly conducting films. Electronic properties of the treated films are characterized with a combination of Hall effect measurements, field-effect transistor measurements, temperature-dependent conductivity measurements, and capacitance-voltage measurements, revealing their highly doped p-type semiconducting nature. The spin-cast nanoparticle films have carrier concentration of ∼ 10(19) cm(-3), Hall mobilities of ∼ 3 to 4 cm(2) V(-1) s(-1), and electrical conductivities of ∼ 5 to 6 S · cm(-1). Our films have hole mobilities that are 1-4 orders of magnitude higher than hole mobilities previously reported for heat-treated nanoparticle films of HgTe, InSb, PbS, PbTe, and PbSe. We show that electrophoretic deposition (EPD) as a method for nanoparticle film assembly leads to an order of magnitude enhancement in film conductivity (∼ 75 S · cm(-1)) over conventional spin-casting, creating copper sulfide nanoparticle films with conductivities comparable to bulk films formed through physical deposition methods. The X-ray diffraction patterns of the Cu2-xS films, with and without ligand removal, match the Djurleite phase (Cu(1.94)S) of copper sulfide and show that the nanoparticles maintain finite size after the ammonium sulfide processing. The high conductivities reported are attributed to better interparticle coupling through the ammonium sulfide treatment. This approach presents a scalable room-temperature route for fabricating highly conducting nanoparticle assemblies for large-area electronic and optoelectronic applications.

  14. Chemical doping of large-area stacked graphene films for use as transparent, conducting electrodes.

    PubMed

    Kasry, Amal; Kuroda, Marcelo A; Martyna, Glenn J; Tulevski, George S; Bol, Ageeth A

    2010-07-27

    Graphene is considered a leading candidate to replace conventional transparent conducting electrodes because of its high transparency and exceptional transport properties. The effect of chemical p-type doping on graphene stacks was studied in order to reduce the sheet resistance of graphene films to values approaching those of conventional transparent conducting oxides. In this report, we show that large-area, stacked graphene films are effectively p-doped with nitric acid. The doping decreases the sheet resistance by a factor of 3, yielding films comprising eight stacked layers with a sheet resistance of 90 Omega/(square) at a transmittance of 80%. The films were doped either after all of the layers were stacked (last-layer-doped) or after each layer was added (interlayer-doped). A theoretical model that accurately describes the stacked graphene film system as a resistor network was developed. The model defines a characteristic transfer length where all the channels in the graphene films actively contribute to electrical transport. The experimental data shows a linear increase in conductivity with the number of graphene layers, indicating that each layer provides an additional transport channel, in good agreement with the theoretical model.

  15. Conductivity of copper phthalocyanine-polystyrene composite films in the presence of adsorbed oxygen

    NASA Astrophysics Data System (ADS)

    Pochtennyi, A. E.; Misevich, A. V.; Dolgii, V. K.

    2014-09-01

    The electrical conductivity and adsorption-resistive response to nitrogen dioxide of composite films containing copper phthalocyanine nanoparticles dispersed into the polystyrene matrix are investigated experimentally. The results are analyzed using the two-level model of hopping conductivity. The contributions to the conductivity from intrinsic and impurity localization centers are singled out, and the concentrations of the localization centers in copper phthalocyanines free of impurities as well as the electron localization radii in impurity and intrinsic states are determined.

  16. Highly Conductive Diamond-Graphite Nanohybrid Films with Enhanced Electron Field Emission and Microplasma Illumination Properties.

    PubMed

    Saravanan, Adhimoorthy; Huang, Bohr-Ran; Sankaran, Kamatchi Jothiramalingam; Tai, Nyan-Hwa; Lin, I-Nan

    2015-07-01

    Bias-enhanced nucleation and growth of diamond-graphite nanohybrid (DGH) films on silicon substrates by microwave plasma enhanced chemical vapor deposition using CH4/N2 gas mixture is reported herein. It is observed that by controlling the growth time, the microstructure of the DGH films and, thus, the electrical conductivity and the electron field emission (EFE) properties of the films can be manipulated. The films grown for 30 min (DGHB30) possess needle-like geometry, which comprised of a diamond core encased in a sheath of sp(2)-bonded graphitic phase. These films achieved high conductivity of σ = 900 S/cm and superior EFE properties, namely, low turn-on field of 2.9 V/μm and high EFE current density of 3.8 mA/cm(2) at an applied field of 6.0 V/μm. On increasing the growth time to 60 min (the DGHB60), the acicular grain growth ceased and formed nanographite clusters or defective diamond clusters (n-diamond). Even though DGHB60 films possess higher electrical conductivity (σ = 1549 S/cm) than the DGHB30 films, the EFE properties degraded. The implication of this result is that higher conductivity by itself does not guarantee better EFE properties. The nanosized diamond grains with needle-like geometry are the most promising ones for the electron emission, exclusively when they are encased in graphene-like layers. The salient feature of such materials with unique granular structure is that their conductivity and EFE properties can be tuned in a wide range, which makes them especially useful in practical applications.

  17. Conducting Electronic Polymers by Non-Redox Processes

    DTIC Science & Technology

    1988-06-30

    photoconductivity of polyaniline were measured. The oxidative doping of leucoemeraldine base yields changes in the infrared spectrum that are consistent with...report) we mentioned that we discovered that the kinetics of the electrochemical doping process of polyaniline is strongly dependent on the substrate...rate of electrochemical doping induced color switching, and by examining the polymer morphology of very thin polyaniline films. We found that thin

  18. Fabrication of ion conductive tin oxide-phosphate amorphous thin films by atomic layer deposition

    SciTech Connect

    Park, Suk Won; Jang, Dong Young; Kim, Jun Woo; Shim, Joon Hyung

    2015-07-15

    This work reports the atomic layer deposition (ALD) of tin oxide-phosphate films using tetrakis(dimethylamino)tin and trimethyl phosphate as precursors. The growth rates were 1.23–1.84 Å/cycle depending upon the deposition temperature and precursor combination. The ionic conductivity of the ALD tin oxide-phosphate films was evaluated by cross-plane impedance measurements in the temperature range of 50–300 °C under atmospheric air, with the highest conductivity measured as 1.92 × 10{sup −5} S cm{sup −1} at 300 °C. Furthermore, high-resolution x-ray photoelectron spectroscopy exhibited two O1s peaks that were classified as two subpeaks of hydroxyl ions and oxygen ions, revealing that the quantity of hydroxyl ions in the ALD tin oxide-phosphate films influences their ionic conductivity.

  19. Ultra-low thermal conductivity of nanogranular indium tin oxide films deposited by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Brinzari, Vladimir I.; Cocemasov, Alexandr I.; Nika, Denis L.; Korotcenkov, Ghenadii S.

    2017-02-01

    The authors have shown that nanogranular indium tin oxide (ITO) films, deposited by spray pyrolysis on a silicon substrate, demonstrate ultralow thermal conductivity κ ˜ 0.84 ± 0.12 Wm-1 K-1 at room temperature. This value is approximately by one order of magnitude lower than that in bulk ITO. The strong drop of thermal conductivity is explained by the nanogranular structure and porosity of ITO films, resulting in enhanced phonon scattering on grain boundaries. The experimental results were interpreted theoretically, employing the Boltzmann transport equation approach for phonon transport and filtering model for electronic transport. The calculated values of thermal conductivity are in reasonable agreement with the experimental findings. The presented results show that ITO films with an optimal nanogranular structure may be prospective for thermoelectric applications.

  20. Switching of the electrical conductivity of plasticized PVC films under uniaxial pressure

    NASA Astrophysics Data System (ADS)

    Vlasov, D. V.; Apresyan, L. A.; Vlasova, T. V.; Kryshtob, V. I.

    2011-11-01

    The jumplike switching of the electrical conductivity in wide-band-gap polymer (antistatic plasticized polyvinylchloride) films under uniaxial pressure is studied. In various plasticized PVC materials, the uniaxial pressure inducing a conductivity jump by four orders of magnitude or higher changes from several to several hundreds of bars, and this effect is retained at a film thickness of several hundred microns, which is two orders of magnitude larger than the critical film thicknesses known for other wide-band-gap polymers. In addition to the earlier interpretation of the conductivity anomalies in plasticized PVC, we proposed a phenomenological electron-molecular dynamic nanotrap model, in which local charge transfer is provided by mobile molecule segments in a plasticized polymer.

  1. Tuning thermal conductivity in homoepitaxial SrTiO{sub 3} films via defects

    SciTech Connect

    Brooks, Charles M.; Wilson, Richard B.; Cahill, David G.; Schäfer, Anna; Schubert, Jürgen; Mundy, Julia A.; Holtz, Megan E.; Muller, David A.; Schlom, Darrell G.

    2015-08-03

    We demonstrate the ability to tune the thermal conductivity of homoepitaxial SrTiO{sub 3} films deposited by reactive molecular-beam epitaxy by varying growth temperature, oxidation environment, and cation stoichiometry. Both point defects and planar defects decrease the longitudinal thermal conductivity (k{sub 33}), with the greatest decrease in films of the same composition observed for films containing planar defects oriented perpendicular to the direction of heat flow. The longitudinal thermal conductivity can be modified by as much as 80%—from 11.5 W m{sup −1}K{sup −1} for stoichiometric homoepitaxial SrTiO{sub 3} to 2 W m{sup −1}K{sup −1} for strontium-rich homoepitaxial Sr{sub 1+δ}TiO{sub x} films—by incorporating (SrO){sub 2} Ruddlesden-Popper planar defects.

  2. Conductivity enhancement of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) films post-spincasting

    NASA Astrophysics Data System (ADS)

    Farah, Abdiaziz A.; Rutledge, Steven A.; Schaarschmidt, Antje; Lai, Roger; Freedman, Justin P.; Helmy, Amr S.

    2012-12-01

    Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) thin films on indium tin oxide and glass substrates have been fabricated and subjected to a non-adiabatic annealing process. The films showed subtle changes in their structure and optical properties as well as an increase in conductivity due to the effects of rapid thermal annealing. Through a combination of Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy studies in conjunction with electrical characterization, and four-point probe measurements, material enrichment of conductive PEDOT domains at the polymer-metal interface have been demonstrated, which well explains the surface conductivity improvement of a thin film of PEDOT:PSS after annealing.

  3. Fabrication of flexible transparent conductive films from long double-walled carbon nanotubes

    PubMed Central

    Imazu, Naoki; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2014-01-01

    The fabrication of flexible transparent conducting films (TCFs) is important for the development of the next-generation flexible devices. In this study, we used double-walled carbon nanotubes (DWCNTs) as the starting material and described a fabrication method of flexible TCFs. We have determined in a quantitative way that the key factors are the length and the dispersion states of the DWCNTs as well as the weight-ratios of dispersant polymer/DWCNTs. By controlling such factors, we have readily fabricated a flexible highly transparent (94% transmittance) and conductive (surface resistivity = 320 Ω sq−1) DWCNT film without adding any chemical doping that is often used to reduce the surface resistivity. By applying a wet coating, we have succeeded in the fabrication of large-scale conducting transparent DWCNT films based on the role-to-role method. PMID:27877666

  4. Modifying the thermal conductivity of small molecule organic semiconductor thin films with metal nanoparticles

    PubMed Central

    Wang, Xinyu; Parrish, Kevin D.; Malen, Jonathan A.; Chan, Paddy K. L.

    2015-01-01

    Thermal properties of organic semiconductors play a significant role in the performance and lifetime of organic electronic devices, especially for scaled-up large area applications. Here we employ silver nanoparticles (Ag NPs) to modify the thermal conductivity of the small molecule organic semiconductor, dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT). The differential 3-ω method was used to measure the thermal conductivity of Ag-DNTT hybrid thin films. We find that the thermal conductivity of pure DNTT thin films do not vary with the deposition temperature over a range spanning 24 °C to 80 °C. The thermal conductivity of the Ag-DNTT hybrid thin film initially decreases and then increases when the Ag volume fraction increases from 0% to 32%. By applying the effective medium approximation to fit the experimental results of thermal conductivity, the extracted thermal boundary resistance of the Ag-DNTT interface is 1.14 ± 0.98 × 10−7 m2-K/W. Finite element simulations of thermal conductivity for realistic film morphologies show good agreement with experimental results and effective medium approximations. PMID:26531766

  5. Modifying the thermal conductivity of small molecule organic semiconductor thin films with metal nanoparticles.

    PubMed

    Wang, Xinyu; Parrish, Kevin D; Malen, Jonathan A; Chan, Paddy K L

    2015-11-04

    Thermal properties of organic semiconductors play a significant role in the performance and lifetime of organic electronic devices, especially for scaled-up large area applications. Here we employ silver nanoparticles (Ag NPs) to modify the thermal conductivity of the small molecule organic semiconductor, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). The differential 3-ω method was used to measure the thermal conductivity of Ag-DNTT hybrid thin films. We find that the thermal conductivity of pure DNTT thin films do not vary with the deposition temperature over a range spanning 24 °C to 80 °C. The thermal conductivity of the Ag-DNTT hybrid thin film initially decreases and then increases when the Ag volume fraction increases from 0% to 32%. By applying the effective medium approximation to fit the experimental results of thermal conductivity, the extracted thermal boundary resistance of the Ag-DNTT interface is 1.14 ± 0.98 × 10(-7) m(2)-K/W. Finite element simulations of thermal conductivity for realistic film morphologies show good agreement with experimental results and effective medium approximations.

  6. Persistent conductive footprints of 109° domain walls in bismuth ferrite films

    SciTech Connect

    Stolichnov, I.; Iwanowska, M.; Colla, E.; Setter, N.; Ziegler, B.; Gaponenko, I.; Paruch, P.; Huijben, M.; Rijnders, G.

    2014-03-31

    Using conductive and piezoforce microscopy, we reveal a complex picture of electronic transport at weakly conductive 109° domain walls in bismuth ferrite films. Even once initial ferroelectric stripe domains are changed/erased, persistent conductive paths signal the original domain wall position. The conduction at such domain wall “footprints” is activated by domain movement and decays rapidly with time, but can be re-activated by opposite polarity voltage. The observed phenomena represent true leakage conduction rather than merely displacement currents. We propose a scenario of hopping transport in combination with thermionic injection over interfacial barriers controlled by the ferroelectric polarization.

  7. Laser structuring of conducting films on transparent substrates for electronics devices

    NASA Astrophysics Data System (ADS)

    Račiukaitis, G.

    2008-09-01

    Flat panel displays (FPD), flexible electronics and thin-film photovoltaics are booming in the last few years. Permanent annual growth and huge expectations in the market in the near future stimulate the development of versatile technologies for patterning thin-film materials on rigid and flexible substrates. Utilization of laser radiation provides diversity of processing means for structuring deposited films. The high selectivity and diminishing effect on the surrounding material as well as high speed are required in processing complex multilayered systems in the thin-film photovoltaics. Organic electronics imposes special requirements on the geometrical quality of conductors. The current situation with laser direct writing of thin-films in the production of FPD and solar cells as well as our results are presented. High repetition rate lasers with a short pulse duration offer new possibilities for high efficiency structuring of conducting, semi-conducting and isolating films. Laser structuring with the picosecond and nanosecond pulse duration was applied in shaping the thin films deposited on polymers and glass substrates. Absorption of laser radiation by the film material was essential to initiate its controllable removal. Use of UV laser radiation with fluences close to the ablation threshold made it possible to minimize surface contamination and the recast ridge formation during the ablation process. The flexible technique of patterning was applied in prototyping the components for the OLED matrix, RFID antennas and the thin-film solar cells. Well-defined shapes of isolating trenches and conductor lines were produced by laser ablation with the picosecond pulse duration.

  8. Pulsed photothermal reflectance measurement of the thermal conductivity of sputtered aluminum nitride thin films

    SciTech Connect

    Zhao Yimin; Zhu Chunlin; Wang Sigen; Tian, J.Z.; Yang, D.J.; Chen, C.K.; Cheng Hao; Hing, Peter

    2004-10-15

    We report on measurements of the thermal conductivity of reactively sputtered aluminum nitride (AlN) thin films with different thickness, ranging from 100 nm to 1 {mu}m, on silicon substrates. The measurements were made at room temperature using the pulsed photothermal reflectance technique. The thermal conductivities of the sample are found to be significantly lower than the single-crystal bulk AlN and increase with an increasing thickness. The thermal resistance at the interface between the AlN film and the silicon substrate is found to be about 7-8x10{sup -8} m{sup 2} K/W.

  9. Revisiting the Valence and Conduction Band Size Dependence of PbS Quantum Dot Thin Films

    SciTech Connect

    Miller, Elisa M.; Kroupa, Daniel M.; Zhang, Jianbing; Schulz, Philip; Marshall, Ashley R.; Kahn, Antoine; Lany, Stephan; Luther, Joseph M.; Beard, Matthew C.; Perkins, Craig L.; van de Lagemaat, Jao

    2016-03-22

    We use a high signal-to-noise X-ray photoelectron spectrum of bulk PbS, GW calculations, and a model assuming parabolic bands to unravel the various X-ray and ultraviolet photoelectron spectral features of bulk PbS as well as determine how to best analyze the valence band region of PbS quantum dot (QD) films. X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) are commonly used to probe the difference between the Fermi level and valence band maximum (VBM) for crystalline and thin-film semiconductors. However, we find that when the standard XPS/UPS analysis is used for PbS, the results are often unrealistic due to the low density of states at the VBM. Instead, a parabolic band model is used to determine the VBM for the PbS QD films, which is based on the bulk PbS experimental spectrum and bulk GW calculations. Our analysis highlights the breakdown of the Brillioun zone representation of the band diagram for large band gap, highly quantum confined PbS QDs. We have also determined that in 1,2-ethanedithiol-treated PbS QD films the Fermi level position is dependent on the QD size; specifically, the smallest band gap QD films have the Fermi level near the conduction band minimum and the Fermi level moves away from the conduction band for larger band gap PbS QD films. This change in the Fermi level within the QD band gap could be due to changes in the Pb:S ratio. In addition, we use inverse photoelectron spectroscopy to measure the conduction band region, which has similar challenges in the analysis of PbS QD films due to a low density of states near the conduction band minimum.

  10. Enhanced electron field emission properties of conducting ultrananocrystalline diamond films after Cu and Au ion implantation.

    PubMed

    Sankaran, Kamatchi Jothiramalingam; Chen, Huang-Chin; Panda, Kalpataru; Sundaravel, Balakrishnan; Lee, Chi-Young; Tai, Nyan-Hwa; Lin, I-Nan

    2014-04-09

    The effects of Cu and Au ion implantation on the structural and electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films were investigated. High electrical conductivity of 186 (Ω•cm)(-1) and enhanced EFE properties with low turn-on field of 4.5 V/μm and high EFE current density of 6.70 mA/cm(2) have been detected for Au-ion implanted UNCD (Au-UNCD) films that are superior to those of Cu-ion implanted UNCD (Cu-UNCD) ones. Transmission electron microscopic investigations revealed that Au-ion implantation induced a larger proportion of nanographitic phases at the grain boundaries for the Au-UNCD films in addition to the formation of uniformly distributed spherically shaped Au nanoparticles. In contrast, for Cu-UNCD films, plate-like Cu nanoparticles arranged in the row-like pattern were formed, and only a smaller proportion of nanographite phases along the grain boundaries was induced. From current imaging tunneling spectroscopy and local current-voltage curves of scanning tunneling spectroscopic measurements, it is observed that the electrons are dominantly emitted from the grain boundaries. Consequently, the presence of nanosized Au particles and the induction of abundant nanographitic phases in the grain boundaries of Au-UNCD films are believed to be the authentic factors, ensuing in high electrical conductivity and outstanding EFE properties of the films.

  11. Nanosecond laser-induced damage of transparent conducting ITO film at 1064nm

    NASA Astrophysics Data System (ADS)

    Yoo, Jae-Hyuck; Adams, John J.; Menor, Marlon G.; Olson, Tammy Y.; Lee, Jonathan R. I.; Samanta, Amit; Bude, Jeff; Elhadj, Selim

    2016-12-01

    Transparent conducting films with superior laser damage performance have drawn intense interests toward optoelectronic applications under high energy density environment. In order to make optoelectronic applications with high laser damage performance, a fundamental understanding of damage mechanisms of conducting films is crucial. In this study, we performed laser damage experiments on tin-doped indium oxide films (ITO, Bandgap = 4.0 eV) using a nanosecond (ns) pulse laser (1064 nm) and investigated the underlying physical damage mechanisms. Single ns laser pulse irradiation on ITO films resulted in common thermal degradation features such as melting and evaporation although the laser photon energy (1.03 eV, 1064 nm) was smaller than the bandgap. Dominant laser energy absorption of the ITO film is attributed to free carriers due to degenerate doping. Upon multi-pulse irradiation on the film, damage initiation and growth were observed at lower laser influences, where no apparent damage was formed upon single pulse, suggesting a laser-induced incubation effect.

  12. Flexible transparent conductive films combining flexographic printed silver grids with CNT coating.

    PubMed

    Mo, Lixin; Ran, Jun; Yang, Li; Fang, Yi; Zhai, Qingbin; Li, Luhai

    2016-02-12

    A high-performance ITO-free transparent conductive film (TCF) has been made by combining high resolution Ag grids with a carbon nanotube (CNT) coating. Ag grids printed with flexography have a 20 μm line width at a grid interval of 400 μm. The Ag grid/CNT hybrid film exhibits excellent overall performance, with a typical sheet resistance of 14.8 Ω/□ and 82.6% light transmittance at room temperature. This means a 23.98% reduction in sheet resistance and only 2.52% loss in transmittance compared to a pure Ag grid film. Analysis indicates that filling areas between the Ag grids and interconnecting the silver nanoparticles with the CNT coating are the primary reasons for the significantly improved conductivity of the hybrid film that also exhibits excellent flexibility and mechanical strength compared to an ITO film. The hybrid film may fully satisfy the requirements of different applications, e.g. use as the anode of polymer solar cells (PSCs). The J-V curve shows that the power conversion efficiency (PCE) of the PSCs using the Ag grid/CNT hybrid anode is 0.61%, which is 24.5% higher than that of the pure Ag grids with a PCE of 0.49%. Further investigations to improve the performance of the solar cells based on the printed hybrid TCFs are ongoing.

  13. Flexible transparent conductive films combining flexographic printed silver grids with CNT coating

    NASA Astrophysics Data System (ADS)

    Mo, Lixin; Ran, Jun; Yang, Li; Fang, Yi; Zhai, Qingbin; Li, Luhai

    2016-02-01

    A high-performance ITO-free transparent conductive film (TCF) has been made by combining high resolution Ag grids with a carbon nanotube (CNT) coating. Ag grids printed with flexography have a 20 μm line width at a grid interval of 400 μm. The Ag grid/CNT hybrid film exhibits excellent overall performance, with a typical sheet resistance of 14.8 Ω/□ and 82.6% light transmittance at room temperature. This means a 23.98% reduction in sheet resistance and only 2.52% loss in transmittance compared to a pure Ag grid film. Analysis indicates that filling areas between the Ag grids and interconnecting the silver nanoparticles with the CNT coating are the primary reasons for the significantly improved conductivity of the hybrid film that also exhibits excellent flexibility and mechanical strength compared to an ITO film. The hybrid film may fully satisfy the requirements of different applications, e.g. use as the anode of polymer solar cells (PSCs). The J-V curve shows that the power conversion efficiency (PCE) of the PSCs using the Ag grid/CNT hybrid anode is 0.61%, which is 24.5% higher than that of the pure Ag grids with a PCE of 0.49%. Further investigations to improve the performance of the solar cells based on the printed hybrid TCFs are ongoing.

  14. Magnetoelectric hexaferrite thin film growth on oxide conductive layer for applications at low voltages

    NASA Astrophysics Data System (ADS)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-08-01

    Magnetoelectric (ME) M-type hexaferrite thin films were deposited on conductive oxide layer of Indium-Tin Oxide (ITO) in order to lower applied voltages to observe ME effects at room temperature. The thin film of ME hexaferrites, SrCo2Ti2Fe8O19/ITO buffer layer, were deposited on sapphire substrate using Pulsed Laser Deposition (PLD) technique. The film exhibited ME effects as confirmed by vibrating sample magnetometer (VSM) in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe ME effects were typically 500 V and higher. The thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance. We measured saturation magnetization of 1064 G, and coercive field of 20 Oe for these thin films. The change rate in remanence magnetization was measured with the application of DC voltage at room temperature and it gave rise to changes in remanence in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a ME coupling, α, of 5×10-10 s m-1 in SrCo2Ti2Fe8O19 thin films.

  15. Clear, Conductive, Transparent, Flexible Space Durable Composite Films for Electrostatic Charge Mitigation

    NASA Technical Reports Server (NTRS)

    Watson, Kent A.; Connell, John W.; Delozier, Donavon M.; Smith, Joseph G., Jr.

    2004-01-01

    Space environmentally durable polymeric films with low color and sufficient electrical conductivity to mitigate electrostatic charge (ESC) build-up have been under investigation as part of a materials development activity. These materials have potential applications on advanced spacecraft, particularly on large, deployable, ultra-light weight Gossamer spacecraft. The approach taken to impart sufficient electrical conductivity into the polymer film while maintaining flexibility is to use single wall carbon nanotubes (SWNTs) as conductive additives. Approaches investigated in our lab involved an in-situ polymerization method, addition of SWNTs to a polymer containing reactive end-groups, and spray coating of polymer surfaces. The work described herein is a summary of the current status of this project. Surface conductivities (measured as surface resistance) in the range sufficient for ESC mitigation were achieved with minimal effects on the physical, thermal, mechanical and optical properties of the films. Additionally, the electrical conductivity was not affected by harsh mechanical manipulation of the films. The chemistry and physical properties of these nanocomposites will be discussed.

  16. Highly transparent and conductive thin films fabricated with nano-silver/double-walled carbon nanotube composites.

    PubMed

    Lee, Shie-Heng; Teng, Chih-Chun; Ma, Chen-Chi M; Wang, Ikai

    2011-12-01

    This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3.

  17. Improvement in Mobility and Conductivity of Few-Layer MoS2 Films

    NASA Astrophysics Data System (ADS)

    Ma, Xiying; He, Jie; Chen, Kangye; Lin, La

    2014-12-01

    We present a study of the influence of annealing and doping on the electrical properties of few-layer (FL) MoS2 films on Si and quartz substrates deposited using a self-designed metal sulfide chemical vapor deposition (MSCVD) system. FL MoS2 slices obtained through MSCVD, in the size range of 50-200 nm, were found to be uniformly scattered on the substrates. The conductivity and mobility of these films are greatly enhanced after annealing at 650-850°C. The largest mobility measured for pure MoS2 on quartz substrate is 6.4×103cm2/Vs, almost two orders of magnitude larger than that of bulk MoS2 (500 cm2/Vs). We deduce that the superior charge carrier mobility in our sample is mainly attributed to reduced phonon scattering because of a lower carrier density (1010-1011 cm-2) compared to previously documented values (1012-1013cm-2). Additionally, the conductivity and carrier concentration of FL MoS2 films were enhanced by about two orders of magnitude compared to those of the as-grown films doped with Cu, Na and Ag ions but not doped with B ions. The films doped with Na and Ag exhibit characteristic p-type conductivity, while those doped with Cu and B exhibit n-type conductivity. Moreover, the MoS2/Si heterojunction exhibited good rectification characteristics and excellent conductivity, indicating that the FL MoS2 films will find many applications in high-efficiency nanodevices.

  18. Anti-scratch and transparency properties of transparent conductive carbon nanotube films improved by incorporating polyethoxysiloxane.

    PubMed

    Liu, Bo-Tau; Hsu, Chao-Hsiang

    2011-07-15

    Transparent conductive films of single-walled carbon nanotubes (SWCNTs) were fabricated by a simple method to significantly enhance anti-scratch and transparency properties by the incorporation of polyethoxysiloxane (PES). The reasons for changes in the mechanical properties and transmittance were investigated through the reflection property and morphology of thin films. With the incorporation of PES, the sheet resistance of the SWCNT thin film remained unchanged after the anti-scratch test. It was found that the transmittance of the thin films suddenly increased when the thickness of the PES layer was ca 100 nm. Although the PES incorporation resulted in a slight increase in the sheet resistance, the experimental results revealed that the sheet resistance of the SWCNT thin films with PES was lower than that of films without PES for the same transmittance due to the increase of the transmittance caused by the PES incorporation. We have demonstrated that the sheet resistance was halved at a transmittance of ∼86% due to PES incorporation. SWCNT thin films with PES showed better electrical properties than those without PES after a bend test.

  19. Sol-gel processing of highly transparent conducting Cd2SnO4 thin films

    NASA Astrophysics Data System (ADS)

    Bel-Hadj-Tahar, Radhouane; Bel-Hadj-Tahar, Noureddine; Belhadj Mohamed, Abdellatif

    2015-03-01

    Polycrystalline thin films of cadmium stannate (Cd2SnO4) (CTO) were coated on corning glass substrates by sol-gel method. The films were fired at different temperatures and annealed in inert ambient (N2) at 680°C. The structural, optical, and electrical properties of dip-coated cadmium-tin-oxide (CTO) thin films are discussed. CTO layers with a Hall mobility of 30 cm2/Vs and a carrier density of 1.4 × 1021 cm-3 resulting in a resistivity of 5 × 10-4 Ω cm have been deposited. Dip-coating conditions must be carefully monitored to produce consistent films. The high electronic conductivity is due to two effective mechanisms of n-type doping: (i) stoichiometric deviation and (ii) self-doping.

  20. Nonreciprocal dispersion of spin waves in ferromagnetic thin films covered with a finite-conductivity metal

    NASA Astrophysics Data System (ADS)

    Mruczkiewicz, M.; Krawczyk, M.

    2014-03-01

    We study the effect of one-side metallization of a uniform ferromagnetic thin film on its spin-wave dispersion relation in the Damon-Eshbach geometry. Due to the finite conductivity of the metallic cover layer on the ferromagnetic film, the spin-wave dispersion relation may be nonreciprocal only in a limited wave-vector range. We provide an approximate analytical solution for the spin-wave frequency, discuss its validity, and compare it with numerical results. The dispersion is analyzed systematically by varying the parameters of the ferromagnetic film, the metal cover layer and the value of the external magnetic field. The conclusions drawn from this analysis allow us to define a structure based on a 30 nm thick CoFeB film with an experimentally accessible nonreciprocal dispersion relation in a relatively wide wave-vector range.

  1. Highly conductive and flexible color filter electrode using multilayer film structure

    NASA Astrophysics Data System (ADS)

    Han, Jun Hee; Kim, Dong-Young; Kim, Dohong; Choi, Kyung Cheol

    2016-07-01

    In this paper, a high performance flexible component that serves as a color filter and an electrode simultaneously is suggested. The suggested highly conductive and flexible color filter electrode (CFE) has a multilayer film structure composed of silver (Ag) and tungsten trioxide (WO3). The CFE maintained its color filtering capability even when the films were bent on a polyethylene terephthalate (PET) film. Low sheet resistance of the CFE was obtained using WO3 as a bridge layer that connects two Ag layers electrically. The sheet resistance was less than 2 Ω/sq. and it was negligibly changed after bending the film, confirming the flexibility of the CFE. The CFE can be easily fabricated using a thermal evaporator and is easily patterned by photolithography or a shadow mask. The proposed CFE has enormous potential for applications involving optical devices including large area devices and flexible devices.

  2. Transparent and flexible conducting hybrid film combined with 3-Aminopropyltriethoxysilane-coated polymer and graphene

    NASA Astrophysics Data System (ADS)

    Jung, Daesung; Ko, Yong-Hun; Cho, Jumi; Adhikari, Prashanta Dhoj; Lee, Su Il; Kim, Yooseok; Song, Wooseok; Jung, Min Wook; Jang, Sung Won; Lee, Seung Youb; An, Ki-Seok; Park, Chong-Yun

    2015-12-01

    A simple approach to fabricate graphene hybrid film consisted of Graphene/3-aminopropyltriethoxysilane (APTES)/polyethylene terephthalate (PET) is presented, using self-assembled monolayers (SAMs) for enhancement of conductivity. The SAMs of APTES was prepared on ultraviolet-ozone (UVO)-irradiated PET films via wet chemical technique. The density of APTES was saturated after UV treatment time of 1 h for PET films; the carrier density and the optical transmittance were 9.3 × 10 12/cm2 and 82% for pristine graphene and 1.16 × 1013/cm2 and 86% for graphene hybrid films, respectively, and experienced at inflection point at 30 min in UV treatment time. This behavior can be explained by surface morphology transition due to coalescence or clustering of mobile and low-molecular-weight oxidized components of PET.

  3. Highly conductive and flexible color filter electrode using multilayer film structure.

    PubMed

    Han, Jun Hee; Kim, Dong-Young; Kim, Dohong; Choi, Kyung Cheol

    2016-07-04

    In this paper, a high performance flexible component that serves as a color filter and an electrode simultaneously is suggested. The suggested highly conductive and flexible color filter electrode (CFE) has a multilayer film structure composed of silver (Ag) and tungsten trioxide (WO3). The CFE maintained its color filtering capability even when the films were bent on a polyethylene terephthalate (PET) film. Low sheet resistance of the CFE was obtained using WO3 as a bridge layer that connects two Ag layers electrically. The sheet resistance was less than 2 Ω/sq. and it was negligibly changed after bending the film, confirming the flexibility of the CFE. The CFE can be easily fabricated using a thermal evaporator and is easily patterned by photolithography or a shadow mask. The proposed CFE has enormous potential for applications involving optical devices including large area devices and flexible devices.

  4. Highly conductive and flexible color filter electrode using multilayer film structure

    PubMed Central

    Han, Jun Hee; Kim, Dong-Young; Kim, Dohong; Choi, Kyung Cheol

    2016-01-01

    In this paper, a high performance flexible component that serves as a color filter and an electrode simultaneously is suggested. The suggested highly conductive and flexible color filter electrode (CFE) has a multilayer film structure composed of silver (Ag) and tungsten trioxide (WO3). The CFE maintained its color filtering capability even when the films were bent on a polyethylene terephthalate (PET) film. Low sheet resistance of the CFE was obtained using WO3 as a bridge layer that connects two Ag layers electrically. The sheet resistance was less than 2 Ω/sq. and it was negligibly changed after bending the film, confirming the flexibility of the CFE. The CFE can be easily fabricated using a thermal evaporator and is easily patterned by photolithography or a shadow mask. The proposed CFE has enormous potential for applications involving optical devices including large area devices and flexible devices. PMID:27373804

  5. Highly transparent and conductive ZnO:Al thin films prepared by vacuum arc plasma evaporation

    NASA Astrophysics Data System (ADS)

    Miyata, Toshihiro; Minamino, Youhei; Ida, Satoshi; Minami, Tadatsugu

    2004-07-01

    A vacuum arc plasma evaporation (VAPE) method using both oxide fragments and gas sources as the source materials is demonstrated to be very effective for the preparation of multicomponent oxide thin films. Highly transparent and conductive Al-doped ZnO (AZO) thin films were prepared by the VAPE method using a ZnO fragment target and a gas source Al dopant, aluminum acethylacetonate (Al(C5H7O2)3) contained in a stainless steel vessel. The Al content in the AZO films was altered by controlling the partial pressure (or flow rate) of the Al dopant gas. High deposition rates as well as uniform distributions of resistivity and thickness on the substrate surface were obtained on large area glass substrates. A low resistivity on the order of 10-4 Ω cm and an average transmittance above 80% in the visible range were obtained in AZO thin films deposited on glass substrates. .

  6. High-temperature conductivity in chemical bath deposited copper selenide thin films

    NASA Astrophysics Data System (ADS)

    Dhanam, M.; Manoj, P. K.; Prabhu, Rajeev. R.

    2005-07-01

    This paper reports high-temperature (305-523 K) electrical studies of chemical bath deposited copper (I) selenide (Cu 2-xSe) and copper (II) selenide (Cu 3Se 2) thin films. Cu 2-xSe and Cu 3Se 2 have been prepared on glass substrates from the same chemical bath at room temperature by controlling the pH. From X-ray diffraction (XRD) profiles, it has been found that Cu 2-xSe and Cu 3Se 2 have cubic and tetragonal structures, respectively. The composition of the chemical constituent in the films has been confirmed from XRD data and energy-dispersive X-ray analysis (EDAX). It has been found that both phases of copper selenide thin films have thermally activated conduction in the high-temperature range. In this paper we also report the variation of electrical parameters with film thickness and the applied voltage.

  7. An asymmetric electrically conducting self-aligned graphene/polymer composite thin film for efficient electromagnetic interference shielding

    NASA Astrophysics Data System (ADS)

    Kumar, Pradip; Kumar, Asheesh; Cho, Kie Yong; Das, Tapas Kumar; Sudarsan, V.

    2017-01-01

    Here, we study the self-aligned asymmetric electrically conductive composite thin film prepared via casting of graphene oxide (GO)/poly (vinylidene-hexafluoropropylene) (PVDF-HFP) dispersion, followed by low temperature hydriodic acid reduction. The results showed that composite thin film revealed the high orientation of graphene sheets along the direction of film surface. However, graphene sheets are asymmetrically distributed along the film thickness direction in the composite film. Both sides of as prepared composite film showed different surface characteristics. The asymmetric surface properties of composite film induced distinction of surface resistivity response; top surface resistivity (21 Ohm) is ˜ 4 times higher than bottom surface resistivity (5 Ohm). This asymmetric highly electrically conducting composite film revealed efficient electromagnetic interference (EMI) shielding effectiveness of ˜ 30 dB. This study could be crucial for achieving aligned asymmetric composite thin film for high-performance EMI shielding radiation.

  8. Bombardment induced ion transport - part IV: ionic conductivity of ultra-thin polyelectrolyte multilayer films.

    PubMed

    Wesp, Veronika; Hermann, Matthias; Schäfer, Martin; Hühn, Jonas; Parak, Wolfgang J; Weitzel, Karl-Michael

    2016-02-14

    The dependence of the ionic conductance of ultra-thin polyelectrolyte multilayer (PEM) films on the temperature and the number of bilayers has been investigated by the recently developed low energy bombardment induced ion transport (BIIT) method. To this end multilayers of alternating poly(sodium 4-styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) layers were deposited on a metal electrode and subsequently bombarded by a low energy potassium ion beam. Ions are transported through the film according to the laws of electro-diffusion towards a grounded backside electrode. They are neutralized at the interface between the polymer film and the metal electrode. The detected neutralization current scales linearly with the acceleration potential of the ion beam indicating Ohmic behavior for the (PAH/PSS)x multilayer, where x denotes the number of bilayers. The conductance exhibits a non-monotonic dependence on the number of bilayers, x. For 2 ≤ x ≤ 8 the conductance increases non-linearly with the number of bilayers. For x ≥ 8 the conductance decreases with increasing number of bilayers. The variation of the conductance is rationalized by a model accounting for the structure dependence of the conductivity. The thinnest sample for which the conductance has been measured is the single bilayer reflecting properties dominated by the interface. The activation energy for the ion transport is 0.49 eV.

  9. Electrical Conduction Mechanism in Chemical Vapour Deposition Grown Multi-Wall Carbon Nanotubes Film.

    PubMed

    Al-Hazmi, F S

    2015-07-01

    Multi-walled carbon nanotubes are interesting systems where different aspects of conduction are observed, mostly due to their low dimensionalities and small dimensions. Electrical conduction mechanism in multi wall carbon nanotubes film is studied. The studied multi-walled nanotubes are grown by a low pressure chemical vapour deposition system. To understand the conduction mechanism in these nanotubes, temperature dependence of conductivity of the multi wall nanotubes film over a temperature range of (400-200 K) is studied. On the basis of the results, one may suggest the thermally activated conduction mechanism for the temperature range (400-300 K). The low temperature data is fitted with the hopping conduction for the transport of charge carriers in the temperature range of 300-200 K. This hopping conduction mechanism is characterized by variable range hopping (VRH), which shows complete agreement with the Mott's type of VRH mechanism. Applying this model, a number of Mott's parameters such as density of states, hopping distance, hopping energy are calculated. The calculated values of all the studied parameters matches well the reported results on other multi-wall nanotubes film.

  10. Ion transport study in polymer-nanocomposite films by dielectric spectroscopy and conductivity scaling

    NASA Astrophysics Data System (ADS)

    Tripathi, Namrata; Thakur, Awalendra K.; Shukla, Archana; Marx, David T.

    2015-07-01

    The dielectric and conductivity response of polymer nanocomposite electrolytes (films of PMMA4LiClO4 dispersed with nano-CeO2 powder) have been investigated. The dielectric behavior was analyzed via the dielectric permittivity (ε‧) and dissipation factor (tan δ) of the samples. The analysis has shown the presence of space charge polarization at lower frequencies. The real part of ac conductivity spectra of materials obeys the Jonscher power law. Parameters such as dc conductivity, hopping rate, activation energies and the concentration of charge carriers were determined from conductivity data using the Almond West formalism. It is observed that the higher ionic conductivity at higher temperature is due to increased thermally-activated hopping rates accompanied by a significant increase in carrier concentration. The contribution of carrier concentration to the total conductivity is also confirmed from activation energy of migration conduction and from Summerfield scaling. The ac conductivity results are also well correlated with TEM results.

  11. In situ polymerization of polyaniline in wood veneers.

    PubMed

    Trey, Stacy; Jafarzadeh, Shadi; Johansson, Mats

    2012-03-01

    The present study describes the possibility to polymerize aniline within wood veneers to obtain a semi-conducting material with solid wood acting as the base template. It was determined that it is possible to synthesize the intrinsically conductive polymer (ICP) polyaniline in situ within the wood structure of Southern yellow pine veneers, combining the strength of the natural wood structure with the conductivity of the impregnated polymer. It was found that polyaniline is uniformly dispersed within the wood structure by light microscopy and FT-IR imaging. A weight percent gain in the range of 3-12 wt % was obtained with a preferential formation in the wood structure and cell wall, rather than in the lumen. The modified wood was found to be less hydrophilic with the addition of phosphate doped polyaniline as observed by equilibrium water swelling studies. While wood itself is insulating, the modified veneers had conductivities of 1 × 10(-4) to 1 × 10(-9) S cm(-1), demonstrating the ability to tune the conductivity and allowing for materials with a wide range of applications, from anti-static to charge-dispersing materials. Furthermore, the modified veneers had lower total and peak heat releases, as determined by cone calorimetry, because of the char properties of the ICP. This is of interest if these materials are to be used in building and furniture applications where flame retardance is of importance.

  12. Investigation of optimal silver nanowires film as conductive wires for LED

    NASA Astrophysics Data System (ADS)

    Wu, I. C.; Yang, T. L.; Pan, C. T.; Chen, Y. C.; Hung, K. H.

    2015-03-01

    In the study, the Polyol reduction process was used to fabricate silver nanowires (AgNWs). In the experiment, the ratio of PVP/Ag, silver seed, AgNO3 and the amount of ethylene glycol (EG) were adopted to design orthogonal array with a constant temperature and heating time and the synthesis parameters of AgNWs were obtained. Therefore, the optimal AgNWs solution was obtained, followed by centrifuging to obtain AgNWs which were used to fabricate AgNWs film. The scanning electron microscope (SEM), Fourier Transform Infrared Spectroscope (FTIR), Energy Dispersive Spectrometer (EDS) and four-point probe were used to measure the sheet resistant and transmittance of AgNWs film. Moreover, the AgNWs film was adopted to be the conductive wires of LED. From the experiment results, the synthesis parameter of 15ml EG, 0.01g AgCl, ratio 2 of PVP/Ag and 0.22g AgNO3 could be used to fabricate optimal AgNWs with 45nm average diameter, 5μm average length and aspect ratio of 110. The sheet resistance and transmittance of film fabricated by centrifuged AgNWs was 0.1252 Ω/sq and 70%, respectively. Furthermore, the luminance of LED with conductive wires made of AgNWs film was better than that made of commercial silver plastic. In the future, the AgNWs film can be broadly applied to the conductive films of touch electric products, LCD display and solar panels.

  13. Electrical conductivity and electromagnetic interference shielding characteristics of multiwalled carbon nanotube filled polyurethane composite films

    NASA Astrophysics Data System (ADS)

    Son Hoang, Anh

    2011-06-01

    Multiwalled carbon nanotubes (MWCNTs) were homogeneously dispersed in a pure polyurethane resin by grinding in a planetary ball mill. The structure and surface morphology of the MWCNTs and MWCNT/polyurethane composites were studied by filed emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) methods. The electrical conductivity at room temperature and electromagnetic interference (EMI) shielding effectiveness (SE) of the composite films with different MWCNT loadings were investigated and the measurement of EMI SE was carried out in a frequency range of 8-12 GHz (X-band). The experimental results show that with a low MWCNT concentration the composite films could achieve a high conductivity and their EMI SE has a strong dependence on MWCNT content. For the composite films with 22 wt% of MWCNTs, the EMI SE attained an average value of 20 dB, so that the shielding effect reduced the penetrating power to 1%.

  14. Reduction in thermal conductivity of Bi thin films with high-density ordered nanoscopic pores.

    PubMed

    Kim, Gil-Sung; Lee, Mi-Ri; Lee, Seung-Yong; Hyung, Jung-Hwan; Park, No-Won; Lee, Eun Sun; Lee, Sang-Kwon

    2013-08-30

    We prepared two-dimensional Bi thin films with high-density ordered nanoscopic pores by e-beam evaporation of Bi metal. For this structure, we used polystyrene beads ranging from 200 to 750 nm in diameter as an etch mask. The typical hole and neck sizes of the Bi thin films with approximately 50 nm in thickness on SiO2/Si substrates were in the range of 135 to 490 nm and 65 to 260 nm, respectively. By measuring the thermal characteristics through a 3ω technique, we found that the thermal conductivities of nanoporous Bi thin films are greatly suppressed compared with those of corresponding bulk materials. With a decrease in pore size to approximately 135 nm, the thermal conductivity decreased significantly to approximately 0.46 W/m·K at 300 K.

  15. Nickel vacancy behavior in the electrical conductance of nonstoichiometric nickel oxide film

    SciTech Connect

    Kim, Dong Soo; Lee, Hee Chul

    2012-08-01

    Nickel vacancy behavior in electrical conductance is systematically investigated using various analysis methods on nickel oxide films deposited at different oxygen partial pressures. The results of Rutherford backscattering, x-ray diffraction, and Auger electron spectroscopy analyses demonstrate that the sputtered nickel oxide films are nickel-deficient. Through the deconvolution of Ni2p and O1s spectra in the x-ray photoelectron spectroscopy data, the number of Ni{sup 3+} ions is found to increase with the O{sub 2} ratio during the deposition. According to the vacancy model, nickel vacancies created from the non-stoichiometry are concluded to produce Ni{sup 3+} ions which lead to an increment of the conductivity of the nickel oxide films due to the increase of the hole concentration.

  16. Reduction in thermal conductivity of Bi thin films with high-density ordered nanoscopic pores

    PubMed Central

    2013-01-01

    We prepared two-dimensional Bi thin films with high-density ordered nanoscopic pores by e-beam evaporation of Bi metal. For this structure, we used polystyrene beads ranging from 200 to 750 nm in diameter as an etch mask. The typical hole and neck sizes of the Bi thin films with approximately 50 nm in thickness on SiO2/Si substrates were in the range of 135 to 490 nm and 65 to 260 nm, respectively. By measuring the thermal characteristics through a 3ω technique, we found that the thermal conductivities of nanoporous Bi thin films are greatly suppressed compared with those of corresponding bulk materials. With a decrease in pore size to approximately 135 nm, the thermal conductivity decreased significantly to approximately 0.46 W/m·K at 300 K. PMID:24001222

  17. In situ stress observation in oxide films and how tensile stress influences oxygen ion conduction

    PubMed Central

    Fluri, Aline; Pergolesi, Daniele; Roddatis, Vladimir; Wokaun, Alexander; Lippert, Thomas

    2016-01-01

    Many properties of materials can be changed by varying the interatomic distances in the crystal lattice by applying stress. Ideal model systems for investigations are heteroepitaxial thin films where lattice distortions can be induced by the crystallographic mismatch with the substrate. Here we describe an in situ simultaneous diagnostic of growth mode and stress during pulsed laser deposition of oxide thin films. The stress state and evolution up to the relaxation onset are monitored during the growth of oxygen ion conducting Ce0.85Sm0.15O2-δ thin films via optical wafer curvature measurements. Increasing tensile stress lowers the activation energy for charge transport and a thorough characterization of stress and morphology allows quantifying this effect using samples with the conductive properties of single crystals. The combined in situ application of optical deflectometry and electron diffraction provides an invaluable tool for strain engineering in Materials Science to fabricate novel devices with intriguing functionalities. PMID:26912416

  18. Highly conducting SrMoO{sub 3} thin films for microwave applications

    SciTech Connect

    Radetinac, Aldin Mani, Arzhang; Ziegler, Jürgen; Alff, Lambert; Komissinskiy, Philipp; Melnyk, Sergiy; Nikfalazar, Mohammad; Zheng, Yuliang; Jakoby, Rolf

    2014-09-15

    We have measured the microwave resistance of highly conducting perovskite oxide SrMoO{sub 3} thin film coplanar waveguides. The epitaxial SrMoO{sub 3} thin films were grown by pulsed laser deposition and showed low mosaicity and smooth surfaces with a root mean square roughness below 0.3 nm. Layer-by-layer growth could be achieved for film thicknesses up to 400 nm as monitored by reflection high-energy electron diffraction and confirmed by X-ray diffraction. We obtained a constant microwave resistivity of 29 μΩ·cm between 0.1 and 20 GHz by refining the frequency dependence of the transmission coefficients. Our result shows that SrMoO{sub 3} is a viable candidate as a highly conducting electrode material for all-oxide microwave electronic devices.

  19. Phase transitions from semiconductive amorphous to conductive polycrystalline in indium silicon oxide thin films

    NASA Astrophysics Data System (ADS)

    Mitoma, Nobuhiko; Da, Bo; Yoshikawa, Hideki; Nabatame, Toshihide; Takahashi, Makoto; Ito, Kazuhiro; Kizu, Takio; Fujiwara, Akihiko; Tsukagoshi, Kazuhito

    2016-11-01

    The enhancement in electrical conductivity and optical transparency induced by a phase transition from amorphous to polycrystalline in lightly silicon-doped indium oxide (InSiO) thin films is studied. The phase transition caused by simple thermal annealing transforms the InSiO thin films from semiconductors to conductors. Silicon atoms form SiO4 tetrahedra in InSiO, which enhances the overlap of In 5s orbitals as a result of the distortion of InO6 octahedral networks. Desorption of weakly bonded oxygen releases electrons from deep subgap states and enhances the electrical conductivity and optical transparency of the films. Optical absorption and X-ray photoelectron spectroscopy measurements reveal that the phase transition causes a Fermi energy shift of ˜0.2 eV.

  20. Highly Conductive Graphene and Polyelectrolyte Multilayer Thin Films Produced From Aqueous Suspension.

    PubMed

    Stevens, Bart; Guin, Tyler; Sarwar, Owais; John, Alyssa; Paton, Keith R; Coleman, Jonathan N; Grunlan, Jaime C

    2016-09-27

    Rapid, large-scale exfoliation of graphene in water has expanded its potential for use outside niche applications. This work focuses on utilizing aqueous graphene dispersions to form thin films using layer-by-layer processing, which is an effective method to produce large-area coatings from water-based solutions of polyelectrolytes. When layered with polyethyleneimine, graphene flakes stabilized with cholate are shown to be capable of producing films thinner than 100 nm. High surface coverage of graphene flakes results in electrical conductivity up to 5500 S m(-1) . With the relative ease of processing, the safe, cost effective nature of the ingredients, and the scalability of the deposition method, this system should be industrially attractive for producing thin conductive films for a variety of electronic and antistatic applications.

  1. Current-dependent anisotropic conductivity of locally assembled silver nanoparticles in hybrid polymer films.

    PubMed

    Goel, Pooja; Vinokur, Rostislav; Weichold, Oliver

    2010-12-15

    The electrical behaviour of hybrid poly(ethylene terephthalate) films containing localised, percolating networks of silver nanoparticles separated by pure polymer is studied. The films resemble an array of parallel wires in the submicron range and, thus, exhibit anisotropic conductivity. In the high-conductivity direction at low amplitudes, the films show Ohmic behaviour, while at moderate voltage, non-linearity and a decreasing resistance is observed. The samples were found to heat up during the measurements and the deviation from Ohm's law coincides with the Tg of the polymer. Microstructural analysis of the samples revealed an irreversible agglomeration of the particles at moderate voltages leading to the formation of filaments with higher metallic character than the random particle network.

  2. Correlations between switching of conductivity and optical radiation observed in thin graphite-like films

    NASA Astrophysics Data System (ADS)

    Lebedev, S. G.; Yants, V. E.; Lebedev, A. S.

    2008-06-01

    The satisfactory explanation of anomalous electromagnetics in thin graphite-like carbon films till now is absent. The most comprehensible explanation may be the high-temperature superconductivity (HTSC). The pulse widths of spasmodic switching of electrical conductivity measured in this work in the graphite-like nanostructured carbon films, produced by methods of the carbon arc (CA) and chemical vapor deposition (CVD), are 1 and 2 ns correspondingly. Such fast switching completely excludes the thermal mechanism of the process. According to HTSC logic, in the time vicinity close to jump of electroresistance, it is necessary to expect the generation of optical radiation in the infrared (IR) range. This work presents the first results on registration of IR radiation caused by the sharp change of conductivity in thin graphite-like carbon films.

  3. Thermal and electrical conduction in ultrathin metallic films: 7 nm down to sub-nanometer thickness.

    PubMed

    Lin, Huan; Xu, Shen; Wang, Xinwei; Mei, Ning

    2013-08-12

    For ultrathin metallic films (e.g., less than 5 nm), no knowledge is yet available on how electron scattering at surface and grain boundaries reduces the electrical and thermal transport. The thermal and electrical conduction of metallic films is characterized down to 0.6 nm average thickness. The electrical and thermal conductivities of 0.6 nm Ir film are reduced by 82% and 50% from the respective bulk values. The Lorenz number is measured as 7.08 × 10⁻⁸ W Ω K⁻², almost a twofold increase of the bulk value. The Mayadas-Shatzkes model is used to interpret the experimental results and reveals very strong electron reflection (>90%) at grain boundaries.

  4. Analysis of variance on thickness and electrical conductivity measurements of carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Li, Min-Yang; Yang, Mingchia; Vargas, Emily; Neff, Kyle; Vanli, Arda; Liang, Richard

    2016-09-01

    One of the major challenges towards controlling the transfer of electrical and mechanical properties of nanotubes into nanocomposites is the lack of adequate measurement systems to quantify the variations in bulk properties while the nanotubes were used as the reinforcement material. In this study, we conducted one-way analysis of variance (ANOVA) on thickness and conductivity measurements. By analyzing the data collected from both experienced and inexperienced operators, we found some operation details users might overlook that resulted in variations, since conductivity measurements of CNT thin films are very sensitive to thickness measurements. In addition, we demonstrated how issues in measurements damaged samples and limited the number of replications resulting in large variations in the electrical conductivity measurement results. Based on this study, we proposed a faster, more reliable approach to measure the thickness of CNT thin films that operators can follow to make these measurement processes less dependent on operator skills.

  5. Thin film electronic devices with conductive and transparent gas and moisture permeation barriers

    DOEpatents

    Simpson, Lin Jay

    2015-07-28

    Thin film electronic devices (or stacks integrated with a substrate) that include a permeation barrier formed of a thin layer of metal that provides a light transmitting and electrically conductive layer, wherein the electrical conductive layer is formed on a surface of the substrate or device layer such as a transparent conducting material layer with pin holes or defects caused by manufacturing and the thin layer of metal is deposited on the conductive layer and formed from a self-healing metal that forms self-terminating oxides. A permeation plug or block is formed in or adjacent to the thin film of metal at or proximate to the pin holes to block further permeation of contaminants through the pin holes.

  6. Evaluation of DLVO theory with disjoining-pressure and film-conductance measurements of common-black films stabilized with sodium dodecyl sulfate.

    PubMed

    Yaros, Heather D; Newman, John; Radke, C J

    2003-06-15

    We develop a unique film holder combining a thin-film balance with AC impedance spectroscopy to measure disjoining pressure, film conductance, and film thickness simultaneously. Foam films stabilized by sodium dodecyl sulfate (SDS) are investigated with and without added sodium chloride (NaCl) electrolyte. Classical colloidal theory, Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory, is tested rigorously over a wide range of solution conditions by comparing the surface charge densities fit to disjoining-pressure isotherms with those estimated independently from film-conductance and surface-tension data. Film-conductance measurements strongly suggest that the adsorbed anionic surfactant is partially complexed with counterions. Therefore, to reconcile the different values of charge densities calculated from surface tension and film conductance with those from disjoining pressure, we propose a simple ion-binding electrostatic model. The ion-complexation framework predicts increased ion complexing with increasing solution ionic strength, in agreement with surface-tension and film-conductance data. Unfortunately, it is not possible to describe similarly the trends of the measured disjoining-pressure isotherms because the diffuse-layer charge density increases, or equivalently, the ion complexation decreases with increasing ionic strength. Accordingly, the ion-binding extension of classical DLVO theory does not permit agreement between theory and independent experimental data from surface tension, disjoining pressure, and film conductance.

  7. Nanostructured metal-polyaniline composites

    DOEpatents

    Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

    2010-08-31

    Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

  8. Electrical conduction noise and its correlation with structural properties of Cu2ZnSnS4 thin films

    NASA Astrophysics Data System (ADS)

    Zubair Ansari, Mohd; Munjal, Sandeep; Kumar, Vikram; Khare, Neeraj

    2016-07-01

    Cu2ZnSnS4 (CZTS) thin films have been deposited by ultrasonic assisted chemical vapor deposition in a single step process at different substrate temperatures and structural, morphological, electrical and conduction noise characteristics of the CZTS thin films have been studied. Single phase CZTS thin films are formed at 275 °C and 325 °C deposition temperatures, whereas the CZTS thin film deposited at 375 °C showed secondary phase also. The crystallinity of the films improves and resistivity decreases with the increases of the deposition temperature. The temperature dependent electrical conductivity of the films reveals that in the temperature range 300-250 K, thermally activated conduction is observed. The conduction noise in the CZTS thin films, exhibits 1/f noise in the low frequency region and found to be strongly dependent on the film deposition temperatures. The film deposited at 275 °C and 375 °C shows larger conduction noise, whereas the film deposited at 325 °C shows smaller noise. For the low frequency 1/f noise, the value of α is also found to be the minimum for the film deposited at 325 °C. The higher value of conduction noise in the film deposited at 275 °C is related to poor crystallinity and less compact morphology. For the film deposited at 375 °C, crystallinity and compactness improves, but the presence of the secondary phases seems to be responsible for generating higher noise. The smallest conduction noise of the film deposited at 325 °C is due to single phase film with better crystallinity and smaller trap density ˜5.1 × 1015 cm-2 eV-1.

  9. Polyaniline-Carbon Nanotubes Composite Actuators

    NASA Astrophysics Data System (ADS)

    Rosa, Sabrina; Camargo, Carlos; Campo, Eva; Esteve, Jaume; Ramos, Idalia

    2012-02-01

    The understanding of photoactuation in Carbon Nanotubes (CNT)-polymer composites can contribute to the development of micro- and nano-optical-mechanical systems for applications that include intracellular motors, artificial muscles, and tactile displays for blind people. The integration of CNTs into polymers combines the good processability of polymers with the functional properties of CNTs. CNTs-polymer composite fibers were fabricated using the electrospinning technique. electrospinning process orients the CNTs along the precursor stream and can contribute to enhance photo actuation properties. The addition of polyaniline, an electroactive conductive polymer is expected to enhance the actuation strain of the composite. aim of this research is to study photoactuation in MWCNT-Polyanilile electrospun fibers. fibers were characterized using Scanning Electron Microscopy, Atomic Force Microscopy, and X-Ray Diffraction. Results demonstrate evidence of photo-actuation after irradiating the fibers with visible light. tests are being conducted to understand the mechanisms of the composites response to light stimulation.

  10. Heat, Light, and Videotapes: Experiments in Heat Conduction Using Liquid Crystal Film.

    ERIC Educational Resources Information Center

    Bacon, Michael E.; And Others

    1995-01-01

    Presents a range of experiments in heat conduction suitable for upper-level undergraduate laboratories that make use of heat sensitive liquid crystal film to measure temperature contours. Includes experiments mathematically described by Laplace's equation, experiments theoretically described by Poisson's equation, and experiments that involve…

  11. Thermal conductivity measurement and interface thermal resistance estimation using SiO2 thin film.

    PubMed

    Chien, Heng-Chieh; Yao, Da-Jeng; Huang, Mei-Jiau; Chang, Tien-Yao

    2008-05-01

    In this paper, we describe an easy-to-use method to measure the thermal conductivity of thin films based on an electrical heating/sensing mechanism and a steady-state technique. The method used relative commonly used instruments, and without any signal processing circuit, is easy to be used in such thin-film thermal conductivity measurement. The SiO2 thin-film samples, prepared by thermal oxidation, plasma enhanced chemical vapor deposition (PECVD), and E-beam evaporator, were deposited on a silicon substrate. The apparent thermal conductivity, the intrinsic thermal conductivity of SiO2 films, and the total interface thermal resistance of the heater/SiO2/silicon system were evaluated. Our data showed agreement with those data obtained from previous literatures and from the 3 omega method. Furthermore, by using a sandwiched structure, the interface thermal resistance of Cr/PECVD SiO2 and PECVD SiO2/silicon were also separately evaluated in this work. The data showed that the interface thermal resistance of Cr/PECVD SiO2 (metal/dielectric) is about one order of magnitude larger than that of PECVD SiO2/silicon (dielectric/dielectric).

  12. Electrical conduction mechanism in silicon nitride and oxy-nitride-sputtered thin films

    NASA Astrophysics Data System (ADS)

    Vila, M.; Román, E.; Prieto, C.

    2005-06-01

    We have studied the effect of reactive and nonreactive sputtering preparations on the composition and properties of silicon nitride thin films. Films were prepared from both silicon nitride ceramic and pure silicon targets under different Ar /N2 gas mixtures. For the different resulting samples, we have performed optical, x-ray photoemission spectroscopy (XPS), and transport measurements. The preparation conditions change the sample atomic composition and the effect of oxygen in the films, which in turn determines the dominant conduction mechanism. It becomes important to determine both the nonstoichiometry of the film and the phase where the oxygen is incorporated. Oxygen may appear as silicon oxide, forming a secondary phase inside silicon nitride; or it may consist of silicon oxy-nitride phases. The presence of these different phases, as revealed by XPS, determines the electrical properties and conduction mechanisms. Samples presenting space-charge-limited current as the dominant conduction mechanism correspond to those where a silicon oxy-nitride phase is formed (that becomes Ohmic for overstoichiometric Si content samples), while a Poole-Frenkel conduction behavior is characteristic of the silicon nitride phase.

  13. The effect of nanowire length and diameter on the properties of transparent, conducting nanowire films.

    PubMed

    Bergin, Stephen M; Chen, Yu-Hui; Rathmell, Aaron R; Charbonneau, Patrick; Li, Zhi-Yuan; Wiley, Benjamin J

    2012-03-21

    This article describes how the dimensions of nanowires affect the transmittance and sheet resistance of a random nanowire network. Silver nanowires with independently controlled lengths and diameters were synthesized with a gram-scale polyol synthesis by controlling the reaction temperature and time. Characterization of films composed of nanowires of different lengths but the same diameter enabled the quantification of the effect of length on the conductance and transmittance of silver nanowire films. Finite-difference time-domain calculations were used to determine the effect of nanowire diameter, overlap, and hole size on the transmittance of a nanowire network. For individual nanowires with diameters greater than 50 nm, increasing diameter increases the electrical conductance to optical extinction ratio, but the opposite is true for nanowires with diameters less than this size. Calculations and experimental data show that for a random network of nanowires, decreasing nanowire diameter increases the number density of nanowires at a given transmittance, leading to improved connectivity and conductivity at high transmittance (>90%). This information will facilitate the design of transparent, conducting nanowire films for flexible displays, organic light emitting diodes and thin-film solar cells.

  14. Thermoelectric Properties of Conducting Polymers

    DTIC Science & Technology

    1994-07-01

    polyphenylene sulfide , all of which are made conductive by addition of carbon. Polymers made conductive in this way do not have a high Seebeck...merit. KEYWORDS: Polyaniline, conducting polymer, conductive vinyl, conductive nylon, conductive polyphenylene sulfide , polyoctylthiophene, Schiff’s...directions. Polyphenylene sulfide (Ryton) A conductive form of this material, which is commercially available, is made conductive by the presence of carbon

  15. A facile method for preparing highly conductive and reflective surface-silvered polyimide films

    NASA Astrophysics Data System (ADS)

    Liao, Yuan; Cao, Bing; Wang, Wen-Cai; Zhang, Liqun; Wu, Dezhen; Jin, Riguang

    2009-07-01

    A novel method was developed for the preparation of reflective and electrically conductive surface-silvered polyimide (PI) films. The polyimide films were functionalized with poly(dopamine), simply by dipping the PI films into aqueous dopamine solution and mildly stirring at room temperature. Electroless plating of silver was readily carried out on the poly(dopamine) deposited PI (PI-DOPA) surface. The surface compositions of the modified PI films were studied by X-ray photoelectron spectroscopy (XPS). XPS results show that the PI-DOPA surfaces were successfully deposited with ploy(dopamine) and were ready for electroless deposition of silver. The poly(dopamine) layer was used not only as the chemi-sorption sites for silver particles during the electroless plating of silver, but also as an adhesion promotion layer for the electrolessly deposited silver. The as-prepared silvered PI films show high conductivity and reflectivity, with a surface resistance of 1.5 Ω and a reflectivity of 95%, respectively.

  16. Temperature Dependent Thermal Conductivity and Thermal Interface Resistance of Pentacene Thin Films with Varying Morphology.

    PubMed

    Epstein, Jillian; Ong, Wee-Liat; Bettinger, Christopher J; Malen, Jonathan A

    2016-07-27

    Temperature dependent thermal conductivities and thermal interface resistances of pentacene (Pn) thin films deposited on silicon substrates and self-assembled monolayer-modified [octadecyltrichlorosilane (OTS) and (3-aminopropyl)triethoxysilane (APTES)] silicon substrates were measured using frequency domain thermoreflectance. Atomic force microscopy images were used to derive an effective film thickness for thermal transport that accounts for surface roughness. Data taken over a temperature range of 77-300 K for various morphologies and film thicknesses show that the thermal conductivity increases with increasing Pn grain size. The sum of the substrate-Pn and Pn-gold thermal interface resistances was isolated from the intrinsic thermal resistance of the Pn films and found to be independent of surface chemistry. Corresponding Kapitza lengths of approximately 150 nm are larger than the physical thicknesses of typical Pn thin films and indicate that the interfaces play a dominant role in the total thermal resistance. This study has implications for increasing the performance and effective thermal management of small molecule electronic and energy conversion devices.

  17. Conducting polypyrrole films as a potential tool for electrochemical treatment of azo dyes in textile wastewaters.

    PubMed

    Haque, Md Mominul; Smith, Warren T; Wong, Danny K Y

    2015-01-01

    In this paper, we demonstrate conducting polypyrrole films as a potential green technology for electrochemical treatment of azo dyes in wastewaters using Acid Red 1 as a model analyte. These films were synthesised by anodically polymerising pyrrole in the presence of Acid Red 1 as a supporting electrolyte. In this way, the anionic Acid Red 1 is electrostatically attracted to the cationic polypyrrole backbone formed to maintain electroneutrality, and is thus entrapped in the film. These Acid Red 1-entrapped polypyrrole films were characterised by electrochemical, microscopic and spectroscopic techniques. Based on a two-level factorial design, the solution pH, Acid Red 1 concentration and polymerisation duration were identified as significant parameters affecting the entrapment efficiency. The entrapment process will potentially aid in decolourising Acid Red 1-containing wastewaters. Similarly, in a cathodic process, electrons are supplied to neutralise the polypyrrole backbone, liberating Acid Red 1 into a solution. In this work, following an entrapment duration of 480 min in 2000 mg L(-1) Acid Red 1, we estimated 21% of the dye was liberated after a reduction period of 240 min. This allows the recovery of Acid Red 1 for recycling purposes. A distinctive advantage of this electrochemical Acid Red 1 treatment, compared to many other techniques, is that no known toxic by-products are generated in the treatment. Therefore, conducting polypyrrole films can potentially be applied as an environmentally friendly treatment method for textile effluents.

  18. Edge isolation of transparent conductive polymer (TCP) thin films on flexible substrates using UV laser ablation.

    PubMed

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei

    2012-06-01

    The purpose of this study was to directly use the writing techniques for the complex electrode edge isolation of transparent conductive polymer (TCP) thin films by a nanosecond pulsed UV laser processing system. The processing parameters including the laser pulse energy, the pulse repetition frequency, and the scan speed of galvanometers were examined to ablate the TCP films deposited on polyethylene terephtalate substrates of 188 microm thick. The thickness of TCP films was approximately 20 nm. The laser pulse repetition frequency and the scan speed of galvanometers were applied to calculate the overlapping rate of laser spots and to discuss the patterning region quality. Surface morphology, edge quality, and width and depth of edge isolated patterning structures after laser ablation process were measured by a three-dimensional confocal laser scanning microscope. In addition, the electrical conductivity of ablated TCP films was measured by a four-point probes instrument. After isolated line patterning was formed, the ablated TCP films with a better edge quality were obtained directly when the overlapping rate of laser spots, the scan speed, and the pulse repetition rate were 83.3%, 200 mm/s, and 40 kHz, respectively. The better surface morphology of electrode pattern structures was also obtained when the scan speed and the pulse repetition rate were 500 mm/s and 40 kHz, respectively.

  19. Fabrication and characterization of highly transparent and conductive indium tin oxide films made with different solution-based methods

    NASA Astrophysics Data System (ADS)

    Xia, N.; Gerhardt, R. A.

    2016-11-01

    Solution-based fabrication methods can greatly reduce the cost and broaden the applications of transparent conducting oxides films, such as indium tin oxide (ITO) films. In this paper, we report on ITO films fabricated by spin coating methods on glass substrates with two different ITO sources: (1) a commercial ITO nanopowder water dispersion and (2) a sol-gel ITO solution. A simple and fast air annealing process was used to treat as-coated ITO films on a controlled temperature hot plate. Thermogravimetric analysis and x-ray diffraction showed that highly crystalline ITO films were formed after the annealing steps. The final ITO films had a good combination of optical properties and electrical properties, especially for films made from five layers of sol-gel ITO (92.66% transmittance and 8.7 × 10-3 Ω cm resistivity). The surface morphology and conducting network on the ITO films were characterized by non-contact and current atomic force microscopy. It was found that conducting paths were only partially connected for the nanoparticle ITO dispersion films, whereas the sol-gel ITO films had a more uniformly distributed conducting network on the surface. We also used the sol-gel ITO films to fabricate a simple liquid crystal display (LCD) device to demonstrate the excellent properties of our films.

  20. Electromagnetic nanocomposite of bacterial cellulose using magnetite nanoclusters and polyaniline.

    PubMed

    Park, Minsung; Cheng, Jie; Choi, Jaeyoo; Kim, Jaehwan; Hyun, Jinho

    2013-02-01

    Magnetic BC was biosynthesized by culturing Gluconacetobacter xylinus in a medium containing magnetite nanoparticle (MNP) clusters. The stable dispersion of MNP clusters in an aqueous solution was achieved using amphiphilic comb-like polymer (CLP) stabilizers to disperse the MNPs. Subsequently, a conducting polymer was synthesized on the magnetic BC fibers by the chemical oxidative polymerization of aniline. The BC fiber was fully coated with polyaniline, forming hydrogen bonds. The colloidal stability of the CLP-modified MNPs was characterized by optical imaging and UV-visible spectroscopy. The chemical structure and morphology of the hybrid BC layers were observed using Fourier transform infrared spectroscopy and scanning electron microscopy. Magnetic and conductive properties were measured to confirm the immobilization of MNPs and polyaniline.