Articles de revues : « Organic Films - Electrical Transport »

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CAMPBELL, I. H., et D. L. SMITH. « ELECTRICAL TRANSPORT IN ORGANIC SEMICONDUCTORS ». International Journal of High Speed Electronics and Systems 11, n^o 02 (juin 2001) : 585–615. http://dx.doi.org/10.1142/s0129156401000952.

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Organic semiconductors have processing and performance advantages for low cost and/or large area applications that have led to their rapid commercialization. Organic semiconductors are π conjugated materials, either small molecules or polymers. Their electrical transport properties are fundamentally distinct from those of inorganic semiconductors. Organic semiconductor thin films are amorphous or polycrystalline and their electronic structures consist of a distribution of localized electronic states with different energies. The localized sites are either individual molecules or isolated conjugated segments of a polymer chain. Electrical transport results from carrier hopping between neighboring sites. At room temperature, equilibration between neighboring sites of different energy is fast enough that carrier transport can be described using a mobility picture. Hopping transport in these disordered systems leads to a mobility that can depend strongly on both the electric field and carrier density. This article presents experimental measurements and theoretical analysis of the electrical transport properties of representative organic semiconductors.

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Kumar, Arvind, R. Prasad, A. K. Debnath, Ajay Singh, S. Samanta, D. K. Aswal et S. K. Gupta. « Growth and Electrical Transport Properties of Organic Semiconductor Thin Films ». Solid State Phenomena 209 (novembre 2013) : 1–5. http://dx.doi.org/10.4028/www.scientific.net/ssp.209.1.

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Hexadecafluorophthalocyanine (F16CuPc) and Cobalt phthalocyanone (CoPc) thin films of different thickness (20-200nm) have been grown by Molecular Beam Epitaxy (MBE) using different deposition rate (0.2 – 1.0 Å/s). For nanowire type growth lower deposition rate and for films of smooth surface higher deposition rate are found suitable. Charge transport (J~V) of CoPc and F16CuPc films is governed by bulk-limited processes with a bias dependent crossover from Ohmic to trap-free space-charge-limited conduction. The mobility (μ) values at 300 K were found 4.5 and 5.5 cm2 V−1 s−1 for CoPc and F16CuPc films respectively. Mechanism of reverse rectification behavior of an organic heterojunction comprising of CoPc and F16CuPc is explained by Kelvin Probe measurement.

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Robaschik, Peter, Pablo F. Siles, Daniel Bülz, Peter Richter, Manuel Monecke, Michael Fronk, Svetlana Klyatskaya et al. « Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt ». Beilstein Journal of Nanotechnology 5 (11 novembre 2014) : 2070–78. http://dx.doi.org/10.3762/bjnano.5.215.

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The optical and electrical properties of terbium(III) bis(phthalocyanine) (TbPc2) films on cobalt substrates were studied using variable angle spectroscopic ellipsometry (VASE) and current sensing atomic force microscopy (cs-AFM). Thin films of TbPc2 with a thickness between 18 nm and 87 nm were prepared by organic molecular beam deposition onto a cobalt layer grown by electron beam evaporation. The molecular orientation of the molecules on the metallic film was estimated from the analysis of the spectroscopic ellipsometry data. A detailed analysis of the AFM topography shows that the TbPc2 films consist of islands which increase in size with the thickness of the organic film. Furthermore, the cs-AFM technique allows local variations of the organic film topography to be correlated with electrical transport properties. Local current mapping as well as local I–V spectroscopy shows that despite the granular structure of the films, the electrical transport is uniform through the organic films on the microscale. The AFM-based electrical measurements allow the local charge carrier mobility of the TbPc2 thin films to be quantified with nanoscale resolution.

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Niemelä, J. P., A. J. Karttunen et M. Karppinen. « Inorganic–organic superlattice thin films for thermoelectrics ». Journal of Materials Chemistry C 3, n^o 40 (2015) : 10349–61. http://dx.doi.org/10.1039/c5tc01643f.

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Nanoscale layer-engineering using the combined atomic/molecular layer deposition (ALD/MLD) technique for the fabrication of oxide–organic thin-film superlattices is an attractive way to tailor the performance of thermoelectric materials as it potentially allows us to suppress thermal conductivity without significantly hindering the electrical transport properties.

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Ebrahim, Shaker. « Electrical Transport Mechanism in Polyaniline/Formvar Blend Films ». High Performance Polymers 21, n^o 4 (13 octobre 2008) : 468–83. http://dx.doi.org/10.1177/0954008308095839.

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Wang, Xiaoxue, Xu Zhang, Lei Sun, Dongwook Lee, Sunghwan Lee, Minghui Wang, Junjie Zhao et al. « High electrical conductivity and carrier mobility in oCVD PEDOT thin films by engineered crystallization and acid treatment ». Science Advances 4, n^o 9 (septembre 2018) : eaat5780. http://dx.doi.org/10.1126/sciadv.aat5780.

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Air-stable, lightweight, and electrically conductive polymers are highly desired as the electrodes for next-generation electronic devices. However, the low electrical conductivity and low carrier mobility of polymers are the key bottlenecks that limit their adoption. We demonstrate that the key to addressing these limitations is to molecularly engineer the crystallization and morphology of polymers. We use oxidative chemical vapor deposition (oCVD) and hydrobromic acid treatment as an effective tool to achieve such engineering for conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). We demonstrate PEDOT thin films with a record-high electrical conductivity of 6259 S/cm and a remarkably high carrier mobility of 18.45 cm2V−1s−1by inducing a crystallite-configuration transition using oCVD. Subsequent theoretical modeling reveals a metallic nature and an effective reduction of the carrier transport energy barrier between crystallized domains in these thin films. To validate this metallic nature, we successfully fabricate PEDOT-Si Schottky diode arrays operating at 13.56 MHz for radio frequency identification (RFID) readers, demonstrating wafer-scale fabrication compatible with conventional complementary metal-oxide semiconductor (CMOS) technology. The oCVD PEDOT thin films with ultrahigh electrical conductivity and high carrier mobility show great promise for novel high-speed organic electronics with low energy consumption and better charge carrier transport.

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Scheunemann, Dorothea, Emmy Järsvall, Jian Liu, Davide Beretta, Simone Fabiano, Mario Caironi, Martijn Kemerink et Christian Müller. « Charge transport in doped conjugated polymers for organic thermoelectrics ». Chemical Physics Reviews 3, n^o 2 (juin 2022) : 021309. http://dx.doi.org/10.1063/5.0080820.

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Research on conjugated polymers for thermoelectric applications has made tremendous progress in recent years, which is accompanied by surging interest in molecular doping as a means to achieve the high electrical conductivities that are required. A detailed understanding of the complex relationship between the doping process, the structural as well as energetic properties of the polymer films, and the resulting thermoelectric behavior is slowly emerging. This review summarizes recent developments and strategies that permit enhancing the electrical conductivity of p- and n-type conjugated polymers via molecular doping. The impact of the chemical design of both the polymer and the dopant, the processing conditions, and the resulting nanostructure on the doping efficiency and stability of the doped state are discussed. Attention is paid to the interdependence of the electrical and thermal transport characteristics of semiconductor host-dopant systems and the Seebeck coefficient. Strategies that permit to improve the thermoelectric performance, such as an uniaxial alignment of the polymer backbone in both bulk and thin film geometries, manipulation of the dielectric constant of the polymer, and the variation of the dopant size, are explored. A combination of theory and experiment is predicted to yield new chemical design principles and processing schemes that will ultimately give rise to the next generation of organic thermoelectric materials.

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Yang, Lin, Madeleine P. Gordon, Akanksha K. Menon, Alexandra Bruefach, Kyle Haas, M. C. Scott, Ravi S. Prasher et Jeffrey J. Urban. « Decoupling electron and phonon transport in single-nanowire hybrid materials for high-performance thermoelectrics ». Science Advances 7, n^o 20 (mai 2021) : eabe6000. http://dx.doi.org/10.1126/sciadv.abe6000.

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Organic-inorganic hybrids have recently emerged as a class of high-performing thermoelectric materials that are lightweight and mechanically flexible. However, the fundamental electrical and thermal transport in these materials has remained elusive due to the heterogeneity of bulk, polycrystalline, thin films reported thus far. Here, we systematically investigate a model hybrid comprising a single core/shell nanowire of Te-PEDOT:PSS. We show that as the nanowire diameter is reduced, the electrical conductivity increases and the thermal conductivity decreases, while the Seebeck coefficient remains nearly constant—this collectively results in a figure of merit, ZT, of 0.54 at 400 K. The origin of the decoupling of charge and heat transport lies in the fact that electrical transport occurs through the organic shell, while thermal transport is driven by the inorganic core. This study establishes design principles for high-performing thermoelectrics that leverage the unique interactions occurring at the interfaces of hybrid nanowires.

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Baschir, Laurentiu, Madalin Rusu, Valeriu Savu et Daniel Tenciu. « Study of some Complex Organic Materials Characteristics in Thin Films ». Applied Mechanics and Materials 760 (mai 2015) : 233–38. http://dx.doi.org/10.4028/www.scientific.net/amm.760.233.

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Studies were carried out in order to investigate the sensitivity of some thin films, to ultraviolet light, based on barium stearate and carbon nanotubes structures. A three – five monolayers structures were developed using the Langmuir – Blodgett technique onto ceramic substrate. Obtained Langmuir – Blodgett complex thin films shows sensitivity to ultra violet light radiation, taking into consideration the presence of carbon nanotubes that facilitates the charge carriers transport. Also the investigations performed, revealed the properties of carbon nanotubes and point out the fine chemistry of these materials. Based on this premise we proceed to investigate and characterize the photo – electrical behavior of the obtained structures.

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Yurasik G. A., Kulishov A. A., Givargizov M. E. et Postnikov V. A. « Dedicated to the memory of V.D. Aleksandrov Effect of annealing in an inert atmosphere on the electrical properties of crystalline pentacene films ». Technical Physics Letters 48, n^o 15 (2022) : 30. http://dx.doi.org/10.21883/tpl.2022.15.55278.18983.

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The results of a study of the effect of annealing at 150^oC in an inert atmosphere (Ar + 5% H2) on the electrical properties of organic field-effect transistors based on pentacene are presented. Crystalline pentacene films with a thickness of 95±5 nm were obtained using thermal vacuum deposition. The transfer and output characteristics of field-effect transistors before and after annealing for 15 hours are investigated. It was found that as a result of heat treatment, the hole mobility in the saturation regime increased by an average of 30%, and the threshold voltage decreased approximately two times. According to the data of atomic force microscopy, annealing led to a more than twofold decrease in the surface roughness of pentacene films, as well as to a noticeable enlargement of grains, which led to a decrease in the concentration of traps for hole electric transport in the channel of the field-effect transistor. Keywords: pentacene, vacuum thermal deposition, crystalline films, organic field-effect transistors, hole mobility, annealing in an inert atmosphere.

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Dinh, Nguyen Nang, Do Ngoc Chung, Tran Thi Thao et David Hui. « Study of Nanostructured Polymeric Composites Used for Organic Light Emitting Diodes and Organic Solar Cells ». Journal of Nanomaterials 2012 (2012) : 1–6. http://dx.doi.org/10.1155/2012/190290.

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Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2nanoparticles for the hole transport layer and emission layer were prepared, respectively, for organic emitting diodes (OLEDs). The composite of MEH-PPV+nc-TiO2was used for organic solar cells (OSCs). The characterization of these nanocomposites and devices showed that electrical (I-Vcharacteristics) and spectroscopic (photoluminescent) properties of conjugate polymers were enhanced by the incorporation of nc-TiO2in the polymers. The organic light emitting diodes made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the organic solar cells made from MEH-PPV+nc-TiO2composite, a fill factor reached a value of about 0.34. Under illumination by light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency was about 0.15% corresponding to an open circuit voltageVoc= 0.126 V and a shortcut circuit current densityJsc= 1.18 mA/cm2.

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Sánchez Vergara, María Elena, María José Canseco Juárez, Ricardo Ballinas Indili, Genaro Carmona Reyes, José Ramón Álvarez Bada et Cecilio Álvarez Toledano. « Studies on the Structure, Optical, and Electrical Properties of Doped Manganese (III) Phthalocyanine Chloride Films for Optoelectronic Device Applications ». Coatings 12, n^o 2 (14 février 2022) : 246. http://dx.doi.org/10.3390/coatings12020246.

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In the last few years, significant advances have been achieved in the development of organic semiconductors for use in optoelectronic devices. This work reports the doping and deposition of semiconducting organic thin films based on manganese (III) phthalocyanine chloride (MnPcCl). In order to enhance the semiconducting properties of the MnPcCl films, different types of pyridine-based chalcones were used as dopants, and their influence on the optical and electric properties of the films was analyzed. The morphology and structure of the films were studied using IR spectroscopy and scanning electron microscopy (SEM). Optical properties of MnPcCl–chalcone films were investigated via UV–Vis spectroscopy, and the absorption spectra showed the Q band located between 630 and 800 nm, as well as a band related to charge transfer (CT) in the region between 465 and 570 nm and the B band in the region between 280 and 460 nm. Additionally, the absorption coefficient measurements indicated that the films had an indirect transition with two energy gaps: the optical bandgap of around 1.40 eV and the fundamental gap of around 2.35 eV. The electrical behavior is strongly affected by the type of chalcone employed; for this reason, electrical conductivity at room temperature may vary from 1.55 × 10−5 to 3.02 × 101 S·cm−1 at different voltages (0.1, 0.5, and 1.0 V). Additionally, the effect of temperature on conductivity was also measured; electrical conductivity increases by two orders of magnitude with increasing temperature from 25 to 100 °C. The doping effect of chalcone favors electronic transport, most likely due to its substituents and structure with delocalized π-electrons, the formation of conduction channels caused by anisotropy, and the bulk heterojunction induced by the dopant. In terms of optical and electrical properties, the results suggest that the best properties are obtained with chalcones that have the methoxy group as a substituent. However, all MnPcCl–chalcone films are candidates for use in optoelectronic devices.

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Bottiglieri, Lorenzo, Ali Nourdine, Joao Resende, Jean-Luc Deschanvres et Carmen Jiménez. « Optimized Stoichiometry for CuCrO2 Thin Films as Hole Transparent Layer in PBDD4T-2F:PC70BM Organic Solar Cells ». Nanomaterials 11, n^o 8 (19 août 2021) : 2109. http://dx.doi.org/10.3390/nano11082109.

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The performance and stability in atmospheric conditions of organic photovoltaic devices can be improved by the integration of stable and efficient photoactive materials as substituent of the chemically unstable poly (3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS), generally used as organic hole transport layer. Promising candidates are p-type transparent conductive oxides, which combine good optoelectronic and a higher mechanical and chemical stability than the organic counterpart. In this work, we synthesize Cu-rich CuCrO2 thin films by aerosol-assisted chemical vapour deposition as an efficient alternative to PEDOT:PSS. The effect of stoichiometry on the structural, electrical, and optical properties was analysed to find a good compromise between transparency, resistivity, and energy bands alignment, to maximize the photovoltaic performances., Average transmittance and bandgap are reduced when increasing the Cu content in these out of stoichiometry CuCrO2 films. The lowest electrical resistivity is found for samples synthesized from a solution composition in the 60–70% range. The optimal starting solution composition was found at 65% of Cu cationic ratio corresponding to a singular point in Hackee’s figure of merit of 1 × 10−7 Ω−1. PBDD4T-2F:PC70BM organic solar cells were fabricated by integrating CuCrO2 films grown from a solution composition ranging between 40% to 100% of Cu as hole transport layers. The solar cells integrating a film grown with a Cu solution composition of 65% achieved a power conversion efficiency as high as 3.1%, representing the best trade-off of the optoelectronic properties among the studied candidates. Additionally, despite the efficiencies achieved from CuCrO2-based organic solar cells are still inferior to the PEDOT:PSS counterpart, we demonstrated a significant enhancement of the lifetime in atmospheric conditions of optimal oxides-based organic photovoltaic devices.

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Thulasiraman, Sundarajoo, Noor Mona Md Yunus, Pradeep Kumar, Zayyan Rafi Kesuma, Nadia Norhakim, Cecilia Devi Wilfred, Teuku Muhammad Roffi, Mohamad Faizal Hamdan et Zainal Arif Burhanudin. « Effects of Ionic Liquid, 1-Ethyl-3-methylimidazolium Chloride ([EMIM]Cl), on the Material and Electrical Characteristics of Asphaltene Thin Films ». Materials 15, n^o 8 (12 avril 2022) : 2818. http://dx.doi.org/10.3390/ma15082818.

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Asphaltene is a component of crude oil that has remained relatively unexplored for organic electronic applications. In this study, we report on its extraction technique from crude oil tank bottom sludge (COTBS) and its thin-film characteristics when 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) ionic liquid (IL) was introduced as dopants. The extraction technique yielded asphaltene with more than 80% carbon content. The IL resulted in asphaltene thin films with a typical root-mean-square surface roughness of 4 nm, suitable for organic electronic applications. The thin films each showed an optical band gap of 3.8 eV and a sheet resistance as low as 105 Ω/□. When the film was used as a conductive layer in organic field-effect transistors (OFET), it exhibited hole and electron conduction with hole (µh) and electron (µe) mobilities in the order of 10−8 and 10−6 cm2/Vs, respectively. These characteristics are just preliminary in nature. With the right IL, asphaltene thin films may become a good alternative for a transport layer in organic electronic applications.

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Verma, Anil Kumar, Swati Sahu, Mohan Patel et Sanjay Tiwari. « Preparation, Fabrication and Characterization of Sol-Gel ZnO Thin Films for Organic Solar Cells ». Journal of Ravishankar University (PART-B) 33, n^o 1 (4 juillet 2020) : 24–30. http://dx.doi.org/10.52228/jrub.2020-33-1-5.

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In this work, ZnO has been prepared by the sol-gel method and thin films have been deposited onto the ITO (Indium-Tin-Oxide) coated glass substrates by spin coating method at different ZnO concentration and spin parameters. For this, Sol-gel ZnO was synthesized by Zinc acetate dehydrate, 2-methoxethanol and ethanolamine as a starting material, solvent and stabilizer respectively. The study of deposition parameters on the structural, optical and electrical properties of the ZnO thin films was carried out. The Roughness and thickness were calculated by Profilometer. X-ray diffraction (XRD) analysis of the films showed the polycrystalline nature of the prepared films. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) was used to describe the surface morphology and optical properties were studied using UV-VIS-IR Spectroscopy. The fabricated results showed that ZnO thin films is crystalline and low-cost techniques with good features that will be useful for Organic Solar Cells (OSCs) device as an electron transport layer.

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Chung, Do, Nguyen Dinh, Tran Thao, Nguyen Nam, Tran Trung et David Hui. « Study of nanostructured polymeric composites used for organic light emitting diodes and organic solar cells ». World Journal of Engineering 9, n^o 5 (1 octobre 2012) : 399–406. http://dx.doi.org/10.1260/1708-5284.9.5.399.

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Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2 nanoparticles were prepared, respectively for the hole transport layer (HTL) and emission layer (EL) in Organic Light Emitting Diodes (OLED). The composite of MEH-PPV + nc-TiO2 was used for Organic Solar Cells (OCS). The results from the characterization of the properties of the nanocomposites and devices showed that electrical (I-V characteristics) and spectroscopic (photoluminescent) properties of the conjugate polymers were enhanced due to the incorporation of nc-TiO2 in the polymers. The OLEDs made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the OSC made from MEH-PPV + nc-TiO2 composite, the fill factor (FF) reached a value as high as 0.34. Under illumination of light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency (PEC) was found to be of 0.15% corresponding to an open circuit voltage VOC = 1.15 V and a short-cut circuit current density JSC = 0.125 mA/cm2.

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Sánchez Vergara, María Elena, María José Agraz Rentería, América R. Vázquez-Olmos, Karen L. Rincón-Granados, José Ramón Álvarez Bada et Roberto Y. Sato-Berrú. « Fabrication and Characterization of Hybrid Films Based on NiFe2O4 Nanoparticles in a Polymeric Matrix for Applications in Organic Electronics ». Nanomaterials 13, n^o 9 (30 avril 2023) : 1525. http://dx.doi.org/10.3390/nano13091525.

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Hybrid films for applications in organic electronics from NiFe2O4 nanoparticles (NPs) in poly(3,4 ethylene dioxythiophene), poly(4-styrenesulfonate) (PEDOT:PSS), and poly(methyl methacrylate) (PMMA) were fabricated by the spin-coating technique. The films were characterized by infrared spectroscopy, atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy to subsequently determine their optical parameters. The electronic transport of the hybrid films was determined in bulk heterojunction devices. The presence of NiFe2O4 NPs reinforces mechanical properties and increases transmittance in the hybrid films; the PEDOT:PSS-NiFe2O4 NPs film is the one that has a maximum stress of 28 MPa and a Knoop hardness of 0.103, while the PMMA-NiFe2O4 NPs film has the highest transmittance of (87%). The Tauc band gap is in the range of 3.78–3.9 eV, and the Urbach energy is in the range of 0.24–0.33 eV. Regarding electrical behavior, the main effect is exerted by the matrix, although the current carried is of the same order of magnitude for the two devices: glass/ITO/polymer-NiFe2O4 NPs/Ag. NiFe2O4 NPs enhance the mechanical, optical, and electrical behavior of the hybrid films and can be used as semi-transparent anodes and as active layers.

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Song, Ruo-Nong, et Wen-Cheng Ke. « Improving contact performance of graphene on p-type GaN thin films with V-pits microstructures ». International Journal of Modern Physics B 32, n^o 19 (18 juillet 2018) : 1840052. http://dx.doi.org/10.1142/s0217979218400520.

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This study presents the electrical properties of graphene that directly is contact on two types of p-type GaN thin films. The diameter of several hundred nanometer V-pits were formed on the p-GaN thin films by adjusting the NH3 flow rate during the metal organic chemical vapor deposition epitaxial process. The single-layer graphene with a high transmittance of 97% in the visible range was transferred on p-GaN thin films to form an Ohmic contact. The V-pits provide more carrier transport paths that promote the carrier tunneling into p-GaN thin films, resulting in a better Ohmic contact performance. In addition, the increased current value was attributed to the presence of V-pits on the p-GaN thin films.

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Chen, Dong-Hui, Hartmut Gliemann et Christof Wöll. « Layer-by-layer assembly of metal-organic framework thin films : Fabrication and advanced applications ». Chemical Physics Reviews 4, n^o 1 (mars 2023) : 011305. http://dx.doi.org/10.1063/5.0135019.

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Metal-organic frameworks (MOFs) are a class of crystalline porous coordination materials, which are assembled from inorganic nodes and organic linkers. Numerous applications, such as gas storage, molecule separation, catalysis, optical sensing, and charge transport, benefit from the outstanding properties of MOF materials. More advanced applications, e.g., in the electronics and optoelectronics area, demand homogeneous and monolithic MOF thin films. Recent studies demonstrated that surface-mounted MOFs (SURMOFs) are well suited to fulfill the requirements for the integration of MOFs into devices. As a crystalline thin-film material with tunable thickness, SURMOFs have been widely used in the optimization of chromophore stacking, electrical transport, stimuli-response, etc. The fabrication of SURMOFs is carried out employing a layer-by-layer (LbL) assembly technique, and it can yield MOF thin films with a well-defined orientation, tunable thickness, and editable crystalline heterostructure. We summarize the LbL assembly methods for SURMOF fabrication and the realization of advanced SURMOF architectures, including optical and electronic applications as well as the integration of photoactive SURMOFs and SURMOF-derived materials in technical devices. We conclude with a discussion of the challenges and prediction of the future of SURMOF materials.

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Sadiq, Niyaz M., Shujahadeen B. Aziz et Mohd F. Z. Kadir. « Development of Flexible Plasticized Ion Conducting Polymer Blend Electrolytes Based on Polyvinyl Alcohol (PVA) : Chitosan (CS) with High Ion Transport Parameters Close to Gel Based Electrolytes ». Gels 8, n^o 3 (2 mars 2022) : 153. http://dx.doi.org/10.3390/gels8030153.

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In the current study, flexible films of polyvinyl alcohol (PVA): chitosan (CS) solid polymer blend electrolytes (PBEs) with high ion transport property close enough to gel based electrolytes were prepared with the aid of casting methodology. Glycerol (GL) as a plasticizer and sodium bromide (NaBr) as an ionic source provider are added to PBEs. The flexible films have been examined for their structural and electrical properties. The GL content changed the brittle and solid behavior of the films to a soft manner. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) methods were used to examine the structural behavior of the electrolyte films. X-ray diffraction investigation revealed that the crystalline character of PVA:CS:NaBr declined with increasing GL concentration. The FTIR investigation hypothesized the interaction between polymer mix salt systems and added plasticizer. Infrared (FTIR) band shifts and fluctuations in intensity have been found. The ion transport characteristics such as mobility, carrier density, and diffusion were successfully calculated using the experimental impedance data that had been fitted with EEC components and dielectric parameters. CS:PVA at ambient temperature has the highest ionic conductivity of 3.8 × 10 S/cm for 35 wt.% of NaBr loaded with 55 wt.% of GL. The high ionic conductivity and improved transport properties revealed the suitableness of the films for energy storage device applications. The dielectric constant and dielectric loss were higher at lower frequencies. The relaxation nature of the samples was investigated using loss tangent and electric modulus plots. The peak detected in the spectra of tanδ and M” plots and the distribution of data points are asymmetric besides the peak positions. The movements of ions are not free from the polymer chain dynamics due to viscoelastic relaxation being dominant. The distorted arcs in the Argand plot have confirmed the viscoelastic relaxation in all the prepared films.

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Qu, Sanyin, Chen Ming, Qin Yao, Wanheng Lu, Kaiyang Zeng, Wei Shi, Xun Shi, Ctirad Uher et Lidong Chen. « Understanding the Intrinsic Carrier Transport in Highly Oriented Poly(3-hexylthiophene) : Effect of Side Chain Regioregularity ». Polymers 10, n^o 8 (25 juillet 2018) : 815. http://dx.doi.org/10.3390/polym10080815.

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The fundamental understanding of the influence of molecular structure on the carrier transport properties in the field of organic thermoelectrics (OTEs) is a big challenge since the carrier transport behavior in conducting polymers reveals average properties contributed from all carrier transport channels, including those through intra-chain, inter-chain, inter-grain, and hopping between disordered localized sites. Here, combining molecular dynamics simulations and experiments, we investigated the carrier transport properties of doped highly oriented poly(3-hexylthiophene) (P3HT) films with different side-chain regioregularity. It is demonstrated that the substitution of side chains can not only take effect on the carrier transport edge, but also on the dimensionality of the transport paths and as a result, on the carrier mobility. Conductive atomic force microscopy (C-AFM) study as well as temperature-dependent measurements of the electrical conductivity clearly showed ordered local current paths in the regular side chain P3HT films, while random paths prevailed in the irregular sample. Regular side chain substitution can be activated more easily and favors one-dimensional transport along the backbone chain direction, while the irregular sample presents the three-dimensional electron hopping behavior. As a consequence, the regular side chain P3HT samples demonstrated high carrier mobility of 2.9 ± 0.3 cm2/V·s, which is more than one order of magnitude higher than that in irregular side chain P3HT films, resulting in a maximum thermoelectric (TE) power factor of 39.1 ± 2.5 μW/mK2 at room temperature. These findings would formulate design rules for organic semiconductors based on these complex systems, and especially assist in the design of high performance OTE polymers.

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Otalora, Camilo A., Andres F. Loaiza et Gerardo Gordillo. « Study of Electrical Transport Properties of Thin Films Used as HTL and as Active Layer in Organic Solar Cells, through Impedance Spectroscopy Measurements ». Advances in Materials Science and Engineering 2016 (2016) : 1–7. http://dx.doi.org/10.1155/2016/7267634.

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Impedance spectroscopy (IS) is used for studying the electrical transport properties of thin films used in organic solar cells with structure ITO/HTL/active layer/cathode, where PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid) and CuPC (tetrasulfonated copper-phthalocyanine) were investigated as HTL (hole transport layer) and P3HT:PCBM (poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester) blends prepared from mesitylene and chlorobenzene based solutions were studied as active layer and Ag and Al were used as cathode. The study allowed determining the influence of the type of solvent used for the preparation of the active layer as well as the speed at which the solvents are removed on the carriers mobility. The effect of exposing the layer of P3HT to the air on its mobility was also studied. It was established that samples of P3HT and P3HT:PCBM prepared using mesitylene as a solvent have mobility values significantly higher than those prepared from chlorobenzene which is the solvent most frequently used. It was also determined that the mobility of carriers in P3HT films strongly decreases when this sample is exposed to air. In addition, it was found that the electrical properties of P3HT:PCBM thin films can be improved by removing the solvent slowly which is achieved by increasing the pressure inside the system of spin-coating during the film growth.

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Hinds, Bruce J., Richard J. McNeely, Daniel B. Studebaker, Tobin J. Marks, Timothy P. Hogan, Jon L. Schindler, Carl R. Kannewurf, Xiao Feng Zhang et Dean J. Miller. « Thin films for superconducting electronics : Precursor performance issues, deposition mechanisms, and superconducting phase formation-processing strategies in the growth of Tl2Ba2CaCu2O8 films by metal-organic chemical vapor deposition ». Journal of Materials Research 12, n^o 5 (mai 1997) : 1214–36. http://dx.doi.org/10.1557/jmr.1997.0171.

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Epitaxial Tl2Ba2CaCu2O8 thin films with excellent electrical transport characteristics are grown in a two-step process involving metal-organic chemical vapor deposition (MOCVD) of a BaCaCuO(F) thin film followed by a postanneal in the presence of Tl2O vapor. Vapor pressure characteristics of the recently developed liquid metal-organic precursors Ba(hfa)2 • mep (hfa = hexafluoroacetylacetonate, mep = methylethylpentaglyme), Ca(hfa)2 • tet (tet = tetraglyme), and the solid precursor Cu(dpm)2 (dpm = dipivaloylmethanate) are characterized by low pressure thermogravimetric analysis. Under typical film growth conditions, transport is shown to be diffusion limited. The transport rate of Ba(hfa)2 • mep is demonstrated to be stable for over 85 h at typical MOCVD temperatures (120 °C). In contrast, the vapor pressure stability of the commonly used Ba precursor, Ba(dpm)2, deteriorates rapidly at typical growth temperatures, and the decrease in vapor pressure is approximately exponential with a half-life of ∼9.4 h. These precursors are employed in a low pressure (5 Torr) horizontal, hot-wall, film growth reactor for growth of BaCaCuO(F) thin films on (110) LaAlO3 substrates. From the dependence of film deposition rate on substrate temperature and precursor partial pressure, the kinetics of deposition are shown to be mass-transport limited over the temperature range 350–650 °C at a 20 nm/min deposition rate. A ligand exchange process which yields volatile Cu(hfa)2 and Cu(hfa) (dpm) is also observed under film growth conditions. The MOCVD-derived BaCaCuO(F) films are postannealed in the presence of bulk Tl2Ba2CaCu2O8 at temperatures of 720–890 °C in flowing atmospheres ranging from 0–100% O2. The resulting Tl2Ba2CaCu2O8 films are shown to be epitaxial by x-ray diffraction and transmission electron microscopic (TEM) analysis with the c-axis normal to the substrate surface, with in-plane alignment, and with abrupt film-substrate interfaces. The best films exhibit a Tc = 105 K, transport-measured Jc= 1.2 × 105 A/cm2 at 77 K, and surface resistances as low as 0.4 mΩ (40 K, 10 GHz).

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Gopalakrishnan, N., Subramaniam Gowrishankar, T. R. Devidas et L. Balakrishnan. « Optimization of Anodic Layer and Fabrication of Organic Light Emitting Diode ». Advanced Materials Research 488-489 (mars 2012) : 1348–52. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.1348.

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Ga doped ZnO (GZO) films of different concentrations (1, 2 and 4 mol%) have been deposited on glass substrates by RF magnetron sputtering. The grown layers at room temperature have been subjected to structural, optical and electrical characterization. It has been found that 2 mol% Ga doped ZnO has best structural, optical and electrical properties which has been used as anode layer for the fabrication of Organic Light Emitting Diode (OLED). The Zn0.98Ga0.02O film was then deposited at a lower working pressure of 0.015 mbar to obtain a good carrier concentration. The OLED structure has been fabricated with best GZO as anode layer, [N, N*-Diphenyl N, N*-Di-p-Tolylbenzene-1] as hole emitting layer and (Alq3) as electron transport layer. The fabricated OLED device has been subjected to current-voltage characteristics.

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Kumar, Satish, Muhammad A. Alam et Jayathi Y. Murthy. « Computational Model for Transport in Nanotube-Based Composites With Applications to Flexible Electronics ». Journal of Heat Transfer 129, n^o 4 (25 août 2006) : 500–508. http://dx.doi.org/10.1115/1.2709969.

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Thermal and electrical transport in a new class of nanocomposites composed of random isotropic two-dimensional ensembles of nanotubes or nanowires in a substrate (host matrix) is considered for use in the channel region of thin-film transistors (TFTs). The random ensemble of nanotubes is generated numerically and each nanotube is discretized using a finite volume scheme. To simulate transport in composites, the network is embedded in a background substrate mesh, which is also discretized using a finite volume scheme. Energy and charge exchange between nanotubes at the points of contact and between the network and the substrate are accounted for. A variety of test problems are computed for both network transport in the absence of a substrate, as well as for determination of lateral thermal and electrical conductivity in composites. For nanotube networks in the absence of a substrate, the conductance exponent relating the network conductance to the channel length is computed and found to match experimental electrical measurements. The effective thermal conductivity of a nanotube network embedded in a thin substrate is computed for a range of substrate-to-tube conductivity ratios. It is observed that the effective thermal conductivity of the composite saturates to a size-independent value for large enough samples, establishing the limits beyond which bulk behavior obtains. The effective electrical conductivity of carbon nanotube-organic thin films used in organic TFTs is computed and is observed to be in good agreement with the experimental results.

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Rawat, S. S., Ashish Kumar, R. Srivastava et C. K. Suman. « Efficiency Enhancement in Organic Solar Cells by Use of Cobalt Phthalocyanine (CoPc) Thin Films ». Journal of Nanoscience and Nanotechnology 20, n^o 6 (1 juin 2020) : 3703–9. http://dx.doi.org/10.1166/jnn.2020.17517.

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Cobalt phthalocyanine (CoPc) nano thin films have been introduced as a hole buffer layer in organic solar cells with active layer of Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The surface morphology and opto-electrical properties of the CoPc thin films have made it an applicable materials for organic solar cells. The nano-thin films of CoPc are continuously distributed over the studied area and the roughness are around 5 to 7 nm for all thickness. The dominant optical absorptions are in the visible range of wavelengths 500 to 800 nm. The CoPc buffer layer is suitable for energy level matching in energy level diagram and enhances the absorption spectrum as well, which facilitate the charge carrier generation, increases charge transport, decreases charge recombination, hence enhance the all device parameters short circuit current density (Jsc), open circuit voltage (Voc) and fill factor (FF). The solar cells efficiency increases by ˜70% and the fill factor increases by ˜45% in comparison to the standard cells. The increase in efficiency and the fill factors of the solar cells may also be attributed to the increasing of shunt and lowering the series resistance of the cells. The cole–cole plots of the devices may be modeled in electrical circuit as a single parallel resistance Rb and capacitance Cb network with a series resistance Rc.

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Spivak, Yuliya, Ekaterina Muratova, Vyacheslav Moshnikov, Alexander Tuchkovsky, Igor Vrublevsky et Nikita Lushpa. « Improving the Conductivity of the PEDOT:PSS Layers in Photovoltaic Cells Based on Organometallic Halide Perovskites ». Materials 15, n^o 3 (27 janvier 2022) : 990. http://dx.doi.org/10.3390/ma15030990.

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Among conductive polymers, PEDOT films find the widest application in electronics. For photovoltaic applications, studies of their optical properties, stability, and electrical conductivity are of greatest interest. However, the PEDOT:PSS transport layers, when used in photovoltaic cells, have a high electrical resistance, which prevents solar cells from increasing their efficiency. One of the promising ways to improve their electrical properties is the use of composite materials based on them, in which the conductivity can be increased by introducing various additives. In this work, conductive polymer films PEDOT:PSS (poly (3,4-ethylenedioxythiophene):polystyrene sulfonate acid) doped with a number of amines (Pentylamine, Octylamine, Diethylamine, Aniline with carbon nanotubes) were obtained and studied. It is shown that, depending on the concentration of dopants, the electrical conductivity of PEDOT:PSS films can be significantly improved. In this case, the light transmission of the films practically does not change. The process of improving the conductivity by treating the surface of the finished film with amines, followed by heat treatment, was studied. It is assumed that the improvement in conductivity is the result of the self-assembly of monolayers of organic molecules on the surface of the PEDOT:PSS film leading to its p-doping due to intermolecular interaction.

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Akhtar, Naureen, Michiel C. Donker, Tenzin Kunsel, Paul H. M. van Loosdrecht, Thomas T. M. Palstra et Petra Rudolf. « Ultrathin molecule-based magnetic conductors : A step towards flexible electronics ». MRS Advances 4, n^o 61-62 (2019) : 3353–64. http://dx.doi.org/10.1557/adv.2019.464.

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ABSTRACTOrganic-inorganic hybrid materials have shown a remarkable and rapid development during the past decade because they can be tailored to obtain new device concepts with controlled physical properties. Here, we report on the electronic and magnetic properties of multilayer organic-inorganic hybrid films. Electrical transport properties arising from the π electrons in the organic layer are characteristic of a metallic state at high temperature and evolve into a state described by two-dimensional variable range hopping when temperature decreases below 150 K. The intrinsic electronic behavior of the hybrid films was further studied via the optical properties in the IR range. The optical response confirms the metallic character of the hybrid films. In the second part, the magnetic properties are discussed. A long-range ferromagnetic order with an ordering temperature of ∼ 1 K is revealed in the Gd-based hybrid film. The Cu-based hybrid film, however, shows more extended ferromagnetic exchange interactions than the Gd-based hybrid LB film.

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Юрасик, Г. А., А. А. Кулишов, М. Е. Гиваргизов et В. А. Постников. « Посвящается памяти В.Д. Александрова Влияние отжига в инертной атмосфере на электрические свойства кристаллических пленок пентацена ». Письма в журнал технической физики 47, n^o 23 (2021) : 40. http://dx.doi.org/10.21883/pjtf.2021.23.51783.18983.

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The results of a study of the effect of annealing at 150 °C in an inert atmosphere (Ar + 5% H2) on the electrical properties of organic field-effect transistors based on pentacene are presented. Crystalline pentacene films with a thickness of 95 ± 5 nm were obtained using thermal vacuum deposition. The transfer and output characteristics of field-effect transistors before and after annealing for 15 hours are investigated. It was found that as a result of heat treatment, the hole mobility in the saturation regime increased by an average of 30%, and the threshold voltage decreased approximately two times. According to the data of atomic force microscopy, annealing led to a more than twofold decrease in the surface roughness of pentacene films, as well as to a noticeable enlargement of grains, which led to a decrease in the concentration of traps for hole electric transport in the channel of the field-effect transistor.

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Ki, Wooseok, Xiaoying Huang, Jing Li, David L. Young et Yong Zhang. « Highly conductive group VI transition metal dichalcogenide films by solution-processed deposition ». Journal of Materials Research 22, n^o 5 (mai 2007) : 1390–95. http://dx.doi.org/10.1557/jmr.2007.0179.

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A new soluble synthetic route was developed to fabricate thin films of layered structure transition metal dichalcogendies, MoS2 and WS2. High-quality thin films of the dichalcogenides were prepared using new soluble precursors, (CH3NH3)2MS4 (M = Mo, W). The precursors were dissolved in organic solvents and spun onto substrates via both single- and multistep spin coating procedures. The thin films were formed by the thermal decomposition of the coatings under inert atmosphere. Structural, electrical, optical absorption, thermal, and transport properties of the thin films were characterized. Surface morphology of the films was analyzed by atomic force microscopy and scanning electron microscopy. Highly conductive and textured n-type MoS2 films were obtained. The measured room temperature conductivity ∼50 Ω−1 cm−1 is substantially higher than the previously reported values. The n-type WS2 films were prepared for the first time using solution-processed deposition. WS2 displays a conductivity of ∼6.7 Ω−1 cm−1 at room temperature.

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Ghiyasi, Ramin, Girish C. Tewari et Maarit Karppinen. « Organic-Component Dependent Crystal Orientation and Electrical Transport Properties in ALD/MLD Grown ZnO–Organic Superlattices ». Journal of Physical Chemistry C 124, n^o 25 (1 juin 2020) : 13765–70. http://dx.doi.org/10.1021/acs.jpcc.0c03053.

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Xu, Yujie, Hang Zhou, Pengyi Duan, Baojie Shan, Wenjing Xu, Jian Wang, Mei Liu, Fujun Zhang et Qianqian Sun. « Improving the Efficiency of Organic Solar Cells with Methionine as Electron Transport Layer ». Molecules 27, n^o 19 (27 septembre 2022) : 6363. http://dx.doi.org/10.3390/molecules27196363.

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Interface modification is an important way to get better performance from organic solar cells (OSCs). A natural biomolecular material methionine was successfully applied as the electron transport layer (ETL) to the inverted OSCs in this work. A series of optical, morphological, and electrical characterizations of thin films and devices were used to analyze the surface modification effects of methionine on zinc oxide (ZnO). The analysis results show that the surface modification of ZnO with methionine can cause significantly reduced surface defects for ZnO, optimized surface morphology of ZnO, improved compatibility between ETL and the active layer, better-matched energy levels between ETL and the acceptor, reduced interface resistance, reduced charge recombination, and enhanced charge transport and collection. The power conversion efficiency (PCE) of OSCs based on PM6:BTP-ec9 was improved to 15.34% from 14.25% by modifying ZnO with methionine. This work shows the great application potential of natural biomolecule methionine in OSCs.

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Al-hashimi, Mohammed K., Burak Y. Kadem et Aseel K. Hassan. « Rutile TiO2 films as electron transport layer in inverted organic solar cell ». Journal of Materials Science : Materials in Electronics 29, n^o 9 (2 février 2018) : 7152–60. http://dx.doi.org/10.1007/s10854-018-8703-2.

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Andreone, A., A. Cassinese, F. Palomba, G. Pica, M. Salluzzo, G. Malandrino, V. Ancarani et I. L. Fragalà. « Properties of TBCCO 2212 Thin Films for Electronic Applications ». International Journal of Modern Physics B 13, n^o 09n10 (20 avril 1999) : 1321–26. http://dx.doi.org/10.1142/s0217979299001375.

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We report on the synthesis and structural and electrical characterization of high quality Tl 2 Ba 2 Ca 1 Cu 2 O x superconducting thin films. The samples have been prepared ex-situ by a combined approach of Metal-Organic Chemical Vapor Deposition (MOCVD) and thallium vapor diffusion. The films have been grown on 10×10 mm 2 (100) LaAlO 3 substrates. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analyses (EDX) have investigated the morphological and compositional nature of the films. The transport properties have been measured using both a four-probes and an inductive method. The highest critical temperature and critical current density are 104 K and 1 × 106A/cm2 respectively. The microwave response of two samples has been studied using a microstrip resonator technique. The best surface resistance values are below 200 μΩ at 1.2 GHz and 4.2 K. Measurements of the field dependence of the surface resistance have been performed.

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Schober, Matthias, Selina Olthof, Mauro Furno, Björn Lüssem et Karl Leo. « Single carrier devices with electrical doped layers for the characterization of charge-carrier transport in organic thin-films ». Applied Physics Letters 97, n^o 1 (5 juillet 2010) : 013303. http://dx.doi.org/10.1063/1.3460528.

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Lubberts, G. « Transport critical current density and electrical characterization of patterned high‐Tcsuperconducting thin films prepared by metallo‐organic decomposition ». Journal of Applied Physics 68, n^o 2 (15 juillet 1990) : 688–94. http://dx.doi.org/10.1063/1.346799.

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Elshorbagy, Mahmoud H., et Rehab Ramadan. « Electrochromic Electrodes with Enhanced Performance : Review of Morphology and Ion Transport Mechanism Modifications ». Energies 16, n^o 5 (28 février 2023) : 2327. http://dx.doi.org/10.3390/en16052327.

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The electrochromic (EC) performance of smart windows is highly dependent on the rate of ions insertion/extraction. A direct way to increase the ion exchange in EC device is to modify the structure of the EC electrodes. Structural changes also affect the electrical conduction between the transparent electrodes and the EC layers, leading to efficient smart windows. In more detail, modifying the structure of the EC electrodes results in an increase in the surface-to-volume ratio, which is combined with the increase in charge transfer reaction between the insertion and extraction of ions. The current review summarizes the enhancement in the EC performance due to the fabrication of nano/microstructures or hybrid structures on the surface of the EC electrodes to increase their surface area. Moreover, metal oxide thin films have poor electrical conduction, which leads to a high charge transport barrier. Accordingly, improving the electrical conductivity of the EC layer is considered another effective strategy to enhance the ion transport between the transparent conductor layer and the EC electrode. This behavior could be applied by combining the transition metal oxide with metallic nanoparticles or suitable organic/inorganic transparent conducting materials.

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Qi, De Jiang, Xiao Hong Yang, Xiao Guo Bi et Hong Qiang Ru. « Morphology and Electrical Characteristics of (PEO)₁₀LiClO₄ Electrolyte with Nanosized CeO₂ ». Advanced Materials Research 224 (avril 2011) : 65–69. http://dx.doi.org/10.4028/www.scientific.net/amr.224.65.

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In the present work, using nanosized rare earth oxide CeO2 as filler and acetonitrile as organic solvent, a novel solid-state composite polymer electrolyte (CPE) films (PEO)10LiClO4-x wt.%CeO2 (x=0,2,6,9,12,15) was prepared by solution-casting technique. The effect of CeO2 filler concentration on morphology and electrical characteristics of CPE films has been investigated and analyzed. The AC impedance measurements show that the ionic conductivity of CPE can be efficiently enhanced by adding appropriate CeO2. The highest room temperature (25OC) ionic conductivity of 1.71×10-5S•cm-1 is achieved with the CeO2 content of 9 wt.%. With the CeO2 content continues to increase, CPE ionic conductivity begin to decline. This is because appropriate CeO2 can disorder the chain structure and effectively inhibit the crystallization of PEO, which expands the amorphous region required for the lithium-ion transport.

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Sittishoktram, M., Udom Asawapirom et Tanakorn Osotchan. « Time-of-Flight Measurement of Poly(3-Hexylthiophene) Thin Films ». Advanced Materials Research 55-57 (août 2008) : 673–76. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.673.

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Poly(3-hexylthiophene) (P3HT) is one of the most studied conjugated polymer for molecular electronics especially for organic field effect transistors (OFETs) and organic light-emitting devices (OLEDs). This is mainly due to the fact that P3HT provides excellent electrical properties and showed high carrier mobility. In this research we studied the photo generated charge carrier transport of P3HT film by the time-of-flight (TOF) method. For device fabrication, P3HT was dissolved in chloroform with concentration of 8 mg/ml then the solution was spun directly onto an ITO pattern coated on glass substrate. Then the aluminum electrode was prepared on film by thermal evaporation. In TOF measurement, the constant voltage was applied to electrode of sample and the film were photo-excited by irradiation of a short pulsed laser light (λ=650 nm). This caused charge separation within the film. The generated charge carrier was used to calculate the mobility of the film. The TOF mobility was determined as a function of applied voltage and light condition.

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REMIL, ABDERRAHMANNE, YOUNES MOUCHAAL, ABDELKARIM BENDOUKHA REGUIG, ABDERAHMANNE LAKHDAR TOUMI, HAMOU GHERRASS, AISHA HACHEMAOUI, AHMED YAHIAOUI et ABDELBACET KHELIL. « SYNTHESIS OF NEW NITROBENZYLIDENE DERIVATIVES AND PYRROLE-BASED COPOLYMERS FOR DYE-SENSITIZED SOLAR CELLS : EFFECT OF SUBSTITUENT ON OPTO-ELECTRICAL PROPERTIES OF DIP-COATED THIN FILMS ». Surface Review and Letters 25, n^o 06 (août 2018) : 1850116. http://dx.doi.org/10.1142/s0218625x18501160.

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The mastery of the optoelectronic properties of conjugated copolymers by substituting their radicals is a promising way for increasing the light absorption and charge career transport in the organic devices active layer. In this paper, we present the chemical synthesis of four different conjugated benzaldehyde derivatives and pyrrole-based copolymers (P–P:B) followed by their conception in thin films on glass substrates by dip coating root from a solution in dichloromethane. UV–Vis measurements showed absorption in good part of the visible region, with an optical gap around 2 eV. Morphological properties observed by scanning electron microscope of the four P–P:B based thin films illustrated homogenous and continuous surfaces with roughness and surface shape that can be modulated according to Nitrobenzylidene derivative that contains the copolymer. First oxidation ([Formula: see text]) and reduction ([Formula: see text]) potentials of synthetized copolymers have been estimated by cyclic voltammetry which led us to estimate the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), respectively. The HOMO and LUMO energy level diagram of P–P:B compared with the most commonly used organic materials as donor/acceptor couples showed a cascade shape, which allowed us to opt for organic solar cells based on multiple active layers in our aim to improve its performance.

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Базанова, А. А., В. Н. Петров et А. Н. Алешин. « Проводимость композитных пленок на основе проводящего полимера PEDOT : PSS, оксида графена и наночастиц TiO-=SUB=-2-=/SUB=- для контактных слоев перовскитных фотовольтаических структур ». Физика твердого тела 61, n^o 4 (2019) : 773. http://dx.doi.org/10.21883/ftt.2019.04.47429.334.

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AbstractThe electrical properties of composite films based on conductive polymer PEDOT: PSS, graphene oxide (GO), and titanium dioxide nanoparticles (TiO_2) (PEDOT: PSS– TiO_2 and GO–TiO_2) used as contact layers of organic and perovskite photovoltaic structures have been studied. As a result of the study of morphology by atomic force microscopy, it was found that the PEDOT: PSS–TiO_2 and GO–TiO_2 films have a globular structure with a grain size of ~200–300 nm. The current–voltage characteristics of the PEDOT: PSS–TiO_2 and GO–TiO_2 films are measured in the temperature range of 80–300 K, the dependences of the resistivity versus temperature, ρ( T ), which have an activation character, are obtained. It is established that as the temperature decreases, the ρ( T ) dependences show a transition from large values of the activation energy (570 meV and 329 meV) to lower values (25 meV and 2.2 meV) for the PEDOT: PSS–TiO_2 and GO–TiO_2 films, respectively. The mechanisms of transport of charge carriers in the materials studied are discussed.

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Алешин, А. Н., И. П. Щербаков, Д. А. Кириленко, Л. Б. Матюшкин et В. А. Мошников. « Светоизлучающие полевые транзисторы на основе композитных пленок полифлуорена и нанокристаллов CsPbBr-=SUB=-3-=/SUB=- ». Физика твердого тела 61, n^o 2 (2019) : 388. http://dx.doi.org/10.21883/ftt.2019.02.47142.244.

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Abstract—Light-emitting organic field-effect transistors (LE-FETs) on the basis of composite films that consist of perovskite nanocrystals (CsPbBr_3) embedded in a matrix of conjugated polymer—polyfluorene (PFO)—have been obtained, and their electrical and optical properties have been investigated. Output and transfer current-voltage characteristics (I-Vs) of FETs based on PFO : CsPbBr_3 films (component ratio 1 : 1) have a slight hysteresis at temperatures of 100–300 K and are characteristic of hole transport. The hole mobility is ∼3.3 and ∼1.9 cm^2/(V s) at the modes of the saturation and low fields, respectively, at 250 K and reaches ∼5 cm^2/(V s) at 100 K. It has been shown that the application of pulsed voltage to LE-FETs based on PFO : CsPbBr_3 can reduce the ionic conductivity and provide electroluminescence in this structure at 300 K.

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Arutyunov K. Yu., Belyaev K. A., Artemov V. V., Vasiliev A. L., Yusupov A. R., Karamov D. D. et Lachinov A. N. « Transport properties of layered heterostructures based on conducting polymer ». Physics of the Solid State 65, n^o 1 (2023) : 145. http://dx.doi.org/10.21883/pss.2023.01.54989.490.

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Polydiphenylenephthalide (PDP) belongs to the class of organic dielectrics, which exhibit electric conductive properties when an external electrostatic field and/or mechanical stress are applied. In this work, the transport properties of thin-film layered lead-PDP-lead structures were experimental-ly studied in a wide temperature range. At sufficiently high temperatures, the volt-ampere depend-ences are satisfactorily described in terms of the injection model of currents limited by the space charge. At temperatures below ~7.5 K, a number of samples exhibit features that can be explained by the effect of induced superconductivity in a thin film of a conducting polymer enclosed between two massive superconductors (lead). Keywords: thin films, conducting polymer, superconductivity.

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Shin, Hyunji, Hyeonju Lee, Bokyung Kim, Xue Zhang, Jin-Hyuk Bae et Jaehoon Park. « Effects of Blended Poly(3-hexylthiophene) and 6,13-bis(triisopropylsilylethynyl) pentacene Organic Semiconductors on the Photoresponse Characteristics of Thin-Film Transistors ». Korean Journal of Metals and Materials 60, n^o 3 (5 mars 2022) : 198–205. http://dx.doi.org/10.3365/kjmm.2022.60.3.198.

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In this study, we demonstrate high-performance optical wavelength-selective organic thin-film transistors (TFTs) that incorporate heterogeneous organic semiconductor materials, poly(3-hexylthiophene) (P3HT) and 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene). The electrical characteristics of the fabricated transistors were analyzed in the dark to determine how the P3HT:TIPS-pentacene ratio of the semiconductor affected the performance of the transistor. Specifically, the P3HT:TIPS-pentacene weight ratio was varied (1:0, 1:0.25, 1:0.5, 1:0.75, 1:1, and 0:1) by blending 1 wt% P3HT dissolved in chloroform, and 1 wt% TIPS-pentacene dissolved in anisole. The UV-visible light absorbance characteristics of the films containing the P3HT, TIPS-pentacene, and P3HT:TIPS-pentacene blends were analyzed. Monochromatic light at wavelengths of 515 and 450 nm was used to clarify the influence of irradiation on the electrical characteristics of the TFTs. The results confirmed that the TFT containing P3HT:TIPS-pentacene at a blending ratio of 1:0.5 had the largest light-to-dark current ratio, i.e., approximately 33.8 and 23.5 when exposed to monochromatic light at wavelengths of 515 nm and 450 nm, respectively. The TFT with the P3HT:TIPS-pentacene blending ratio of 1:0.5 exhibited the highest photosensitivity values of 261.9 and 49.6 upon irradiation with light at wavelengths of 515 nm and 450 nm, respectively. The observed improvement in the performance of the heterogeneously blended organic transistors is discussed in relation to the morphological structure and charge transport path of the P3HT:TIPS-pentacene blended semiconductor films.

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Qin, Shijiao, Yujia Wu, Hao Tian, Yun Liu, Huan Kan, Defa Hou, Xu Lin, Yunwu Zheng, Zhifeng Zheng et Can Liu. « Ion-Modified Starch Film Enables Rapid Detection of Spoiled Fruit Juices ». International Journal of Molecular Sciences 23, n^o 23 (25 novembre 2022) : 14732. http://dx.doi.org/10.3390/ijms232314732.

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Juice, as a liquid foodstuff, is subject to spoilage and damage due to complications during transport and storage. The appearance of intact outer packaging often makes spoilage and damage difficult to detect. Therefore, it of particular importance to develop a fast, real-time material to evaluate liquid foodstuffs. In this paper, starch films with pH response characteristics are successfully prepared by inorganic ion modification by utilizing whole starch and amylopectin as raw materials. The mechanical properties, stability properties, hydrophilic properties and pH electrical signal response indices of the films are analyzed and measured. The films exhibit good electrical conductivity values with 1.0 mL of ion addition (10 mmol/L), causing the composite film to respond sensitively to solutions with varying pH values. In the test of spoiled orange juice, the full-component corn starch (CS) film has more sensitive resistance and current responses, which is more conducive for applications in the quality monitoring of juice. The results indicate that modified starch films can potentially be applied in the real-time monitoring of the safety of liquid foodstuffs.

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Palai, Akshaya K., Jihee Lee, Tae Joo Shin, Amit Kumar, Seung-Un Park et Seungmoon Pyo. « Solution-grown single-crystalline microwires of a molecular semiconductor with improved charge transport properties ». Chem. Commun. 50, n^o 64 (2014) : 8845–48. http://dx.doi.org/10.1039/c4cc02055c.

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Preparation and structural analysis of highly ordered single crystalline wires of a diketopyrrolopyrrole (DPP) molecular semiconductor grown through a solution process are reported, and the static/dynamic electrical response of an organic electronic device using the DPP semiconductor has been analyzed.

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McCulloch, Iain, Clare Bailey, Kristijonas Genevicius, Martin Heeney, Maxim Shkunov, David Sparrowe, Steven Tierney et al. « Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 364, n^o 1847 (22 août 2006) : 2779–87. http://dx.doi.org/10.1098/rsta.2006.1854.

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Organic electronics technology, in which at least the semiconducting component of the integrated circuit is an organic material, offers the potential for fabrication of electronic products by low-cost printing technologies, such as ink jet, gravure offset lithography and flexography. The products will typically be of lower performance than those using the present state of the art single crystal or polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification tag and other low performance electronics. Organic semiconductors that offer both electrical performance and stability with respect to storage and operation under ambient conditions are required. This work describes the development of reactive mesogen semiconductors, which form large crosslinked LC domains on polymerization within mesophases. These crosslinked domains offer mechanical stability and are inert to solvent exposure in further processing steps. Reactive mesogens containing conjugated aromatic cores, designed to facilitate charge transport and provide good oxidative stability, were prepared and their liquid crystalline properties evaluated. The organization and alignment of the mesogens, both before and after crosslinking, were probed by grazing incidence wide-angle X-ray scattering of thin films. Both time-of-flight and field effect transistor devices were prepared and their electrical characterization reported.

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Hamui, Leon, Maria Elena Sánchez-Vergara, Ricardo Corona-Sánchez, Omar Jiménez-Sandoval et Cecilio Álvarez-Toledano. « Innovative Incorporation of Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) as Hole Carrier Transport Layer and as Anode for Organic Solar Cells Performance Improvement ». Polymers 12, n^o 12 (27 novembre 2020) : 2808. http://dx.doi.org/10.3390/polym12122808.

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In this work, we present a comparative study of benzoid poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as electrode and as hole carrier transport layer (HTL) in the manufacture of organic photovoltaic devices using Fischer metal-carbene complexes. The performance of the different devices was evaluated for solar cell applications. Scanning electronic microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the thin films that integrated the devices. A more ordered and crystallized active film microstructure is observed when using benzoid PEDOT:PSS as nucleation layer. The optical gap for both direct and indirect electronic transitions was evaluated from ultraviolet-visible spectroscopy data (UV-vis), as well as the absorption coefficient (α), and the values are in the range of 2.10–2.93 eV. Photovoltaic devices with conventional architecture, using two different chromium carbenes as active layers, were manufactured, and their electrical behavior was studied. The devices were irradiated with different wavelengths between the infrared and ultraviolet regions of the electromagnetic spectrum. Using the PEDOT:PSS film as hole carrier transport layer (HTL) decreases the slope on the ohmic and space charge limited current (SCLC) regions and eliminates the trap-charge limited current (T-CLC) mechanism. Furthermore, a saturation current of ~1.95 × 10−10 A and higher current values ~1.75 × 10−2 A at 4 V, ~4 orders in magnitude larger were observed. The PEDOT:PSS films as HTL in the devices reduced the injection barrier, thus showing a better performance than as anodes in this type of organic solar cells.

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DONG, Z. C., X. L. GUO, Y. WAKAYAMA et J. G. HOU. « MOLECULAR-SCALE ORGANIC ELECTROLUMINESCENCE FROM TUNNEL JUNCTIONS ». Surface Review and Letters 13, n^o 02n03 (avril 2006) : 143–47. http://dx.doi.org/10.1142/s0218625x06008207.

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We report the generation and detection of bipolar organic electroluminescence of porphyrin molecules from a nanoscale junction in an ultrahigh vacuum scanning tunneling microscope (STM). Clear molecular fluorescence from porphyrin molecules near metal substrates has been realized through highly localized electrical excitation of molecules in proximity to a sharp tip apex. The molecular origin of the luminescence, arising from the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) radiative transitions of neutral molecules, is clearly established by the observed well-defined vibrationally resolved fluorescence spectra that match perfectly with conventional photoluminescence data from molecular thin films. The molecules fluoresce at low onset voltages for both bias polarities, presenting an example of bipolar organic electroluminescence at the nanoscale. Such bipolar operation suggests a double-barrier model for electron transport, with hot electron injection into unoccupied states of molecules in both polarities. The optical behavior of molecules in the tunnel junction is also found sensitive to the electronic properties of molecules and energy level alignment at the interface. These results offer new information to the optoelectronic behavior of molecules in a nanoscopic environment and may open up new routes to the development of single-molecule science and molecular scale electronics.

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Thuau, Damien. « (Invited) Organic Thin Films Transistors : From Mechanical to Biochemical Sensors ». ECS Meeting Abstracts MA2022-02, n^o 35 (9 octobre 2022) : 1287. http://dx.doi.org/10.1149/ma2022-02351287mtgabs.

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Interest in organic electronic materials, and in particular their potential for low-cost fabrication over large areas, led to the development of organic field-effect transistors (OFETs). The potential of OFETs has been demonstrated in a variety of applications, including pixel drivers for displays, bionic skin, wearable electronics and sensitive chemical sensors that can operate in aqueous environments. OFETs use conjugated, semiconducting small molecules and polymers and offer an alternative to inorganic devices for applications in which facile processing on different substrates and tunable electronic properties are required. The flexibility requirement implies either performance stability towards deformation, or conversely, detectable response to the deformation itself. The knowledge of the electromechanical response of organic semiconductors to external stresses is therefore not only interesting from a fundamental point of view, but also necessary for the development of real world applications. To this end, this presentation highlights the importance of the choice of functional materials (organic semiconductors and dielectrics) as well as the relationship structure/properties in transistors based sensors. Organic semiconductors (OSCs) are promising transducer materials when applied in OFETs taking advantage of their electrical properties that highly depend on the morphology of the semiconducting film. The effects of a high-performance p-type organic semiconductor, namely dinaphtho [2,3-b:2,3-f] thieno [3,2–b] thiophene (DNTT) thickness on its piezoresistive sensitivity are presented. A critical thickness corresponding to the appearance of charge carriers percolation paths in the material can tune the gauge factors (GFs) by a factor 10. In addition, single crystal OSC are regarded as promising electroactive materials for strain sensing application. Herein this talk, we will present how strain induces simultaneous mobility changes along all three axes, and that in some cases the response is higher along directions orthogonal to the mechanical deformation. These variations cannot be explained by the modulation of intermolecular distances, but only by a more complex molecular reorganisation, which is particularly enhanced, in terms of response, by p-stacking and herringbone stacking. This microscopic knowledge of the relation between structural and mobility variations is essential for the interpretation of electromechanical measurements for crystalline organic semiconductors, and for the rational design of electronic devices. Alternatively, this talk will highlight how the use of an active gate dielectric layer such as poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer can lead to highly efficient electro-mechanical sensitivity. In such case, the sensing mechanism of the electro-mechanical transducer originates from the piezoelectric material itself, which affects the electrical behavior of the transistor as signature of a mechanical event. The second part of this talk will focus on another kind of TFT based sensor, namely the organic electrochemical transistors (OECTs) which have found recently applications in chemical and biological sensing and interfacing and neuromorphic computing. OECT rely on ions that are injected from the electrolyte into polymer-based mixed conductors, thereby changing its doping state and hence its conductivity. While great progress has been achieved, organic mixed conductors frequently experience significant volumetric changes during ion uptake/rejection, i.e., during doping/ de-doping and charging/discharging. Although ion dynamics may be enhanced in expanded networks, these volumetric changes can have undesirable consequences, e.g., negatively affecting hole/electron conduction and severely shortening device lifetime. New materials able to transport ions and electrons/holes and that exhibits low swelling will be presented, expanding the materials-design toolbox for the creation of low-swelling soft mixed conductors with tailored properties and applications in bioelectronics and beyond.

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