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N,N′-Substituted quinacridones are a novel class of commercially available quinacridones for organic electronics which are reported here.

Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach has to be employed on the OPV materials before using them as retinal implants. In this study, we followed ISO standards to assess the cytotoxicity of D18, Y6, PFN-Br and PDIN individually, and as mixtures of D18/Y6, D18/Y6/PFN-Br and D18/Y6/PDIN. These materials were proven for their high performance as organic solar cells. Human RPE cells were put in direct and indirect contact with these materials to analyze their cytotoxicity by the MTT assay, apoptosis by flow cytometry, and measurements of cell morphology and proliferation by immunofluorescence. We also assessed electrophysiological recordings on mouse retinal explants via microelectrode arrays (MEAs) coated with D18/Y6. In contrast to PFN-Br and PDIN, all in vitro experiments show no cytotoxicity of D18 and Y6 alone or as a D18/Y6 mixture. We conclude that D18/Y6 is safe to be subsequently investigated as a retinal prosthesis.

Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach has to be employed on the OPV materials before using them as retinal implants. In this study, we followed ISO standards to assess the cytotoxicity of D18, Y6, PFN-Br and PDIN individually, and as mixtures of D18/Y6, D18/Y6/PFN-Br and D18/Y6/PDIN. These materials were proven for their high performance as organic solar cells. Human RPE cells were put in direct and indirect contact with these materials to analyze their cytotoxicity by the MTT assay, apoptosis by flow cytometry, and measurements of cell morphology and proliferation by immunofluorescence. We also assessed electrophysiological recordings on mouse retinal explants via microelectrode arrays (MEAs) coated with D18/Y6. In contrast to PFN-Br and PDIN, all in vitro experiments show no cytotoxicity of D18 and Y6 alone or as a D18/Y6 mixture. We conclude that D18/Y6 is safe to be subsequently investigated as a retinal prosthesis.

This work reports on an optimized procedure to synthesize methylammonium bromide perovskite nanoparticles. The ligand-assisted precipitation synthetic pathway for preparing nanoparticles is a cost-effective and promising method due to its ease of scalability, affordable equipment requirements and convenient operational temperatures. Nevertheless, there are several parameters that influence the resulting optical properties of the final nanomaterials. Here, the influence of the choice of solvent system, capping agents, temperature during precipitation and ratios of precursor chemicals is described, among other factors. Moreover, the colloidal stability and stability of the precursor solution is studied. All of the above-mentioned parameters were observed to strongly affect the resulting optical properties of the colloidal solutions. Various solvents, dispersion media, and selection of capping agents affected the formation of the perovskite structure, and thus qualitative and quantitative optimization of the synthetic procedure conditions resulted in nanoparticles of different dimensions and optical properties. The emission maxima of the nanoparticles were in the 508–519 nm range due to quantum confinement, as confirmed by transmission electron microscopy. This detailed study allows the selection of the best optimal conditions when using the ligand-assisted precipitation method as a powerful tool to fine-tune nanostructured perovskite features targeted for specific applications.

A series of novel soluble nature-inspired flavin derivatives substituted with short butyl and bulky ethyl-adamantyl alkyl groups was prepared via simple and straightforward synthetic approach with moderate to good yields. The comprehensive characterization of the materials, to assess their application potential, has demonstrated that the modification of the conjugated flavin core enables delicate tuning of the absorption and emission properties, optical bandgap, frontier molecular orbital energies, melting points, and thermal stability. Moreover, the thin films prepared thereof exhibit smooth and homogeneous morphology with generally high stability over time.

Here, a simple method for controlling the size of the perovskite nanoparticles (PNPs) during preparation is reported. Metal halide PNPs have great potential for application in optoelectronic device...

Organic semiconductors offer great promise through their ease of synthesis in a multitude of derivatives, their low temperature processability and their amenability for fabrication of flexible, stretchable and conformable, even imperceptible devices. Nevertheless, the low charge mobility of organic semiconductors remains one of the limiting factors in delivering high performance for organic electronic devices comparable to their inorganic counterparts. In this study, the effects of purification of eight different organic semiconductors (i.e. n-type, p-type, and ambipolar) were determined by means of analyzing their performance improvement in organic field effect transistors. For this purpose, three purity grades of each organic semiconductor were investigated, and devices were fabricated in an identical fashion. It was found that temperature gradient sublimation improves considerably the quality of the organic semiconductors. The results presented here indicate that the purity of the organic semiconductor is a key parameter to be considered in order to achieve high performance for the field of organic field effect transistors.

Charge-transfer complex crystals have been extensively studied because of their metallic conductivity, photoconductivity, ambipolar charge transport, and high career mobility. Numerous studies of their applications for organic electric devices such as organic field effect transistors and solar cells have reported. However, bulky single crystals of charge-transfer complexes are difficult to handle, specifically to be made into a form of a thin film. Recently, nano/micro crystallization of charge-transfer crystal is attracted to realize thin film applications. In this paper, charge transfer complex nanorods composed of dibenzotetrathiafulvalene-tetracyanoquinodimethane (DBTTF-TCNQ) were prepared by the reprecipitation method. The as-formed nanorods possess a kinetically metastable crystal structure different from the thermodynamically stable bulk crystal prepared by slow evaporation of the solvent. From photoconductive measurement, nanorod stacks show a significant photosensitivity (354.57 μA/W) on par with bulk crystal (417.14 μA/W). These results suggest dibenzotetrathiafulvalene-tetracyanoquinodimethane (DBTTF-TCNQ) nanorods have a favorable crystal structure for carrier transport due to the difference of molecular stacking assembly.

Versatile approaches to nanoparticle synthesis offer unprecedented opportunities for the development of optoelectronics, photonics, and biosciences. With the current advancement of hybrid organic–i...

Robust organic thin-film transistors (OTFTs) with high temperature stability allow device integration with mass production methods like thermoforming and injection molding, and enable operation in extreme environment applications. Herein we elaborate a series of materials to make suitable gate dielectric and active semiconductor layers for high temperature stable OTFTs. We employ an anodized aluminum oxide layer passivated with cross-linked low-density polyethylene (LD-PE) to form a temperature-stable gate capacitor. As the semiconductor, we use quinacridone, an industrial organic colorant pigment produced on a mass scale. Evaporated MoOx/Ag source and drain electrodes complete the devices. Here we evaluate the performance of the OTFTs heating them in air from 100 °C in 25 °C increments up to 225 °C, holding each temperature for a period of 30 minutes. We find large differences in stability between quinacridone and its dimethylated derivative, with the former showing the best performance with only a factor of 2 decline in mobility after heating at 225 °C, and unaffected on/off ratio and threshold voltage. The approach presented here shows how industriallys calable fabrication of thermally robust OTFTs can be rationalized.

Conjugated donor–acceptor molecules with intramolecular charge transfer absorption are employed for single-component organic solar cells. Among the five types of donor–acceptor molecules, the strong push–pull structure of DTDCPB resulted in solar cells with high JSC, an internal quantum efficiency exceeding 20%, and high VOC exceeding 1 V with little photon energy loss around 0.7 eV. The exciton binding energy (EBE), which is a key factor in enhancing the photocurrent in the single-component device, was determined by quantum chemical calculation. The relationship between the photoexcited state and the device performance suggests that the strong internal charge transfer is effective for reducing the EBE. Furthermore, molecular packing in the film is shown to influence photogeneration in the film bulk.

A set of various perovskite precursor formulations was investigated to elucidate correlations between precursor composition and the crystal structure, film morphology as well as photovoltaic activity of H3CNH3PbI3-xClx perovskite solar cells. Three precursor solutions in dimethylfromamide (DMF) with defined ratios of lead(II) halide (PbI2 and/or PbCl2) and methylammonium halide (H3CNH3I (MAI) and H3CNH3Cl (MACl)) such as 1:3 (PbCl2:MAI), 1:1:4 (PbI2:PbCl2:MAI) and 1:1:1 (PbI2:MAI:MACl) were used to prepare solar cells in primarily ambient atmosphere. Processing the 1:3 (PbCl2:MAI) solution in ambient atmosphere yielded perovskite films with rather non-uniform morphology and devices with moderate performance. Perovskite thin films prepared from the 1:1:4 (PbI2:PbCl2:MAI) and 1:1:1 (PbI2:MAI:MACl) formulation showed nearly identical features, high crystallinity, large and compact micrometer-sized crystal domains, and good photovoltaic performance. This indicates that the overall ionic composition in the precursor solution is crucial for the perovskite formation, the source of these ions, however, appears nonrelevant. Furthermore, the effect of different electron transport layers (ETL), PCBM, bis-PCBM, and N-[4-(benzothiadiazol-4-yl)phenyl]-N′-(1-nonyldecyl)perylene-3,4,9,10-tetracarboxdimide (a-PTCDI) on the photovoltaic performance was analyzed. The highest hysteresis-free power conversion efficiency (PCE) was achieved with PCBM (12.8%) followed by a-PTCDI (8.4%) and bis-PCBM (6%). The degradation of MAPbI3-xClx based devices stored in nitrogen atmosphere was primarily revealed by a loss in fill factor.

Optical and semiconducting properties of vacuum-deposited thin films of four hydrogen-bonded pigments were studied. Well-known 1,4-diketo-3,6-diphenyl-pyrrolo-[3,4-c]-pyrrole (Ph-DPP) and 1,4-diketo-3,6-(thiophen-2-yl)-pyrrolo-[3,4-c]-pyrrole (Th-DPP) were transformed to their 1,4-dithioketo heteroanalogues (Ph-DTPP and Th-DTPP) using Lawesson's reagent. X-ray single crystal structure determination confirmed the presence of CS-HN hydrogen bonds and a similar stack formation in both DTPPs, leading to relatively high decomposition temperatures, about 350 °C. According to density functional theory (DFT) calculations, thionation left HOMO (π-type) level almost unchanged, considerably destabilized non-bonding orbital (n-orbital) localized on thioketo group, and significantly decreased LUMO (π*-type) energy. Evolution of HOMO and LUMO energies was confirmed by cyclic voltammetry, establishing LUMO energy at −4.5 eV for both DTPPs, while a signature of high-lying n-orbital was detected through nπ* transition in the far-red/near-infrared area of absorption spectra, interpreted with help of time dependent DFT calculations on monomer and stacked dimer geometry. The lowest optical band-gap among the pigments under study was found to be 1.4 eV for Ph-DTPP thin film. Field effect mobilities, determined on a bottom-gate top-contact transistor, show DPPs as p-type and DTPPs as n-type semiconductors. The highest electron mobility μe = 0.018 cm2 V−1 s−1 was obtained for Ph-DTPP film in the device with aluminium source and drain electrodes.

Cuboid fine crystals of methylammonium lead tribromide (MAPbBr3) perovskite have been synthesized by ligand-free reprecipitation method employing N,N-dimethylformamide (DMF) and 1,2,4-trichlorobenzene (TCB) as good and poor solvents, respectively. A small amount of DMF solution dissolving precursor chemicals of MAPbBr3 was rapidly injected to TCB under vigorous stirring to promote the reprecipitation. Mean crystal size could be varied between 70 and 600 nm by controlled addition of cyclohexane to TCB, since cyclohexane has been found to play a role to retard droplet diffusion. Cyclohexane was miscible with TCB but poorly miscible with DMF. Thus, addition of cyclohexane to TCB retarded diffusion of the injected droplets of DMF solution for reprecipitation of MAPbBr3. As the mixing of good and poor solvents was retarded, the recrystallization process was also slowed down, resulted in a small number of nuclei and their growth to large size. Moreover, extreme addition of cyclohexane has resulted in a hollow core spherical particles of MAPbBr3 due to aggregation of the cuboid fine crystals at the boundary between the added droplet and the poor solvent, so that the spheres formed preserving the shape of the droplet. Due to the limited miscibility of cyclohexane to DMF, increasing the cyclohexane content resulted in reduced rate of diffusion of the injected MAPbBr3 solution, thus increasing the size of the crystals.

Combining the unique properties of peptides as versatile tools for nano- and biotechnology with lead halide perovskite nanoparticles can bring exceptional opportunities for the development of optoelectronics, photonics, and bioelectronics. As a first step towards this challenge sub 10 nm methylammonium lead bromide perovskite colloidal nanoparticles have been synthetizes using commercial cyclic peptide Cyclo(RGDFK), containing 5 amino acids, as a surface stabilizer. Perovskite nanoparticles passivated with Cyclo(RGDFK) possess charge transfer from the perovskite core to the peptide shell, resulting in lower photoluminescence quantum yields, which however opens a path for the application where charge transfer is favorable.

Novel ethyladamantyl solubilization side groups were found to induce π–π interactions between the conjugated cores through adamantyl–adamantyl stacking in soluble diketopyrrolopyrrole (DPP) derivatives. The closeness of the DPP cores amplifies charge transfer in the material, as far as the π–π interaction is a dominant charge-hopping pathway. As a result, tenfold enhancement of hole mobilities exceeding those obtained for insoluble derivatives was reached. Moreover, due to high crystallinity and co-planarity of the conjugated cores, electron transfer was preserved with a mobility of 0.2 cm2 V−1 s−1 for dithiophene-DPP. At the same time, the material remained soluble, which is a significant advantage for purification and processing. This approach can be universally applied for many types of semiconducting organic materials containing the imide motif, where solubilization is achieved by side-group substitution.

Four conjugated polymers (P1-P4) consisting of alternating anthracene-9,10-diyl and 1,4-phenylene building blocks connected via ethynylene as well as vinylene (P1 and P2), ethynylene-only (P3), and vinylene-only (P4) moieties, respectively, were synthesized and studied. The phenylene units in all four polymers bear 2-ethylhexyloxy side-chains to promote good solubility. The three polymers with vinylene units (P1, P2, and P4) were prepared using the Horner-Wadsworth-Emmons reaction. For the synthesis of the arylene-ethynylene polymer P3, the palladium-catalyzed Sonogashira cross-coupling reaction was used. The polymers were characterized by NMR, Fourier transform infrared spectroscopy, and Raman spectroscopy. Photophysical, absorption and photoluminescence, and electrochemical properties were studied. Spectroscopic ellipsometry measurements were performed to gain more insight on the optical properties. In addition, the transport properties were investigated using admittance spectroscopy. The bulk hole mobility and its dependence on the electric field were evaluated for P1 and P2. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 129-143

Organic microboxes composed of charge-transfer molecule (HB194) were prepared by the reprecipitation method. HB194 dissolved in an organic solvent was rapidly injected into water to produce nanopar...

Weak localization describes a metallic system, where due to the presence of disorder the electrical transport is governed by inelastic electron relaxation. Therefore the theory defines a threshold of spatial and of energetic disorder, at which a metal-insulator transition takes place. To achieve a metallic state in an inherently disordered system such as a conductive polymer, one has to overcome the threshold of localization. In this work we show that the effective suppression of disorder is possible in solution-processible poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate). We grow polymer films under optimized conditions allowing self-organization in solution. Interestingly, we find the requisite threshold, at which the system becomes finally metallic. We characterize the transition using a complementary morphology and magneto-electrical transport study and find coherent electron interactions, which emerge as soon as local order exceeds the macromolecular dimensions. These insights can be used for discrete improvement in the electrical performance, in particular for tailoring conductive polymers to alternative metal-like conductors.

Hydrogen-bonded pigments are remarkably stable high-crystal lattice energy organic solids. Here a lesser-known family of compounds, the epindolidiones, which demonstrates electronic transport with extraordinary stability, even in highly demanding aqueous environments, is reported. Hole mobilities in the range 0.05-1 cm2 V-1 s-1 can be achieved, with lower electron mobilities of up to 0.1 cm2 V-1 s-1. To help understand charge transport in epindolidiones, X-ray diffraction is used to solve the crystal structure of 2,8-difluoroepindolidione and 2,8-dichloroepindolidione. Both derivatives crystallize with a linear-chain H-bonding lattice featuring two-dimensional ?-? stacking. Powder diffraction indicates that the unsubstituted epindolidione has very similar crystallinity. All types of epindolidiones measured here display strong low-energy optical emission originating from excimeric states, which coexists with higher-energy fluorescence. This can be exploited in light-emitting diodes, which show the same hybrid singlet and low-energy excimer electroluminescence. Low-voltage FETs are fabricated with epindolidione, which operate reliably under repeated cyclic tests in different ionic solutions within the pH range 3-10 without degradation. Finally, in order to overcome the insolubility of epindolidiones in organic solvents, a chemical procedure is devised to allow solution-processing via the introduction of suitable thermolabile solubilizing groups. This work shows the versatile potential of epindolidione pigments for electronics applications. Epindolidiones are H-bonded organic pigment semiconductors with excellent operational stability, including in aqueous media. Their crystal structure, electrochemical properties, and photophysics, which are dominated by excimeric effects, are reported. Transistor and light-emitting devices are demonstrated. Routes for solution processing of epindolidiones using transient solubilizing groups are explored.

Indigoidine is a blue natural pigment, which can be efficiently synthetized in E. coli. In addition to its antioxidant and antimicrobial activities indigoidine due to its stability and deep blue color can find an application as an industrial, environmentally friendly dye. Moreover, similarly to its counterpart regular indigo dye, due to its molecular structure, indigoidine is an organic semiconductor. Fully conjugated aromatic moiety and intermolecular hydrogen bonding of indigoidine result in an unusually narrow bandgap for such a small molecule. This, in its turn, result is tight molecular packing in the solid state and opens a path for a wide range of application in organic and bio-electronics, such as electrochemical and field effect transistors, organic solar cells, light and bio-sensors etc.

Mixed ionic/electronic conduction in conducting polymers introduces new physics/chemistry and an additional functionality in organic optoelectronic devices. The incorporation of an ionic species in a conjugated polymer matrix results in the increase in electrical conductivity associated with the electrochemical doping of the material. In recent years polymer light emitting electrochemical cells (LECs) have been demonstrated. In such electrochemical optoelectronic devices, mobile ions facilitate the efficient injection of electronic charge carriers creating “in situ” doping regions near the electrodes and lead to efficient electroluminescence light emission. Here, we introduce the same concept of an LEC in the organic field effect transistors (OFETs). The presence of both electronic and ionic charge carriers in the active layers of OFETs brings high charge carrier mobility and light emission even using symmetric source and drain metal electrodes., Highlights ► Light emission from an electrochemically doped organic field effect transistor. ► High charge carrier mobility as high as 3 cm2 V−1 s−1. ► Light emission intensity can be controlled by the gate as well as drain voltages.

Injection-charge extraction by linearly increasing voltage in metal-insulator-semiconductor structures (MIS-CELIV) is applied for the hole mobility measurement of N,N’-Bis(naphthalen-1-yl)-N,N’-bis(phenyl)-benzidine (NPB), which is a standard hole-transporting material for organic light-emitting diodes. Ideal transient currents in agreement with the theory are observed in the NPB film due to its amorphous and homogenous structure, which is regarded as a continuous dielectric. This ideal response enables us to discuss the validity of the MIS-CELIV mobility by comparing its absolute value with that of the conventional space-charge-limited current method. In addition, to establish an experimental guideline for precise measurements, the effect of the voltage drop on the insulator is investigated.

Charge-transfer (CT) complex crystals composed of organic electron donor (D) and acceptor (A) have been extensively studied because of their attractive properties such as metallic conductivity, photoconductivity, ambipolar charge transport, and high career mobility. Numerous research efforts have been made for their use in devices such as organic field effect transistors and organic photocells. However, bulky single crystals of CT complexes are difficult to handle, specifically to be made into a form of a thin film needed for solar cell applications. Nano/micro crystallization is a promising path to overcome the above mentioned problem. However, the growth of high-quality nanocrystals is imperative for photoconductivity but often hampered, since CT complexes are poorly soluble and vapor pressures of donor and acceptor molecules are imbalanced[1-2]. Here we presente the “reprecipitation method” as facile synthesis route to obtain high quality organic CT complex nanocrystals. The process of nanocrystallization can be explained in four steps[3]; 1) A small amount of a solution of the target compound in its good solvent is injected into a large amount of its poor solvent under vigorous stirring. 2) The tiny droplets formed by the injection diffuse into the poor solvent as the two solvents are chosen to be miscible. 3) Nucleation and crystal growth of the target compound proceed due to its supersaturation at the boundary of good/poor solvents. 4) As the good solvent is completely diffused, nanocrystals are stably dispersed in the poor solvents. All these events are expected to occur in a short time (within tens of milliseconds[4]) and thus nanocrystals with kinetically stable structures are often obtained, which are different from thermodynamically stable single bulk crystal structures[5]. In this work, we have successfully applied the reprecipitation method to dibenzotetrathiafulvalene (DBTTF)-tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF)-TCNQ to obtain its nanocrystal. The DBTTF-TCNQ nanocrystals were prepared by typical reprecipitation method from D-A mixed solution. The nanocrystals prepared in such a way have been found to possess kinetically stable crystal structure, different from the bulk material. Moreover, a direct current device employing a polycrystalline thin film of the nanocrystals prepared by simple filtration an equivalent photosensitivity (354.57 μA/W) with that of a bulk crystal (417.14 μA/W) despite of the presence of many grain boundaries, indicating a favorable molecular stacking in the nanocrystals for career transport. In addition, the TTF-TCNQ nanocrystals were prepared by two-step reprecipitation method. TTF (TCNQ) solution was injected to TCNQ (TTF) nanoparticle water dispersion. The TTF-TCNQ nanocrystals were formed when the nanoparticles reacted and the dispersion color was changed immediately from yellow to black. Details of morphology, characteristic and crystallization process of the nanocrystals will be discussed in presentation. Reference [1] M. Hiraoka, T. Hasegawa, T. Yamada, Y. Takahashi, S. Horiuchi, and Y. Tokura, Adv. Mater. 19, 3248 (2007). [2] Y. Takahashi, T. Hasegawa, Y. Abe, Y. Tokura, and G. Saito, Appl. Phys. Lett. 88, 073504 (2006). [3] K. Shito, N. Ito, and A. Masuhara, Jpn. J. Appl. Phys. 54, 06FK05-1 (2015). [4] J. Mori, Y. Miyashita, D Oliveira, H. Kasai, H. Oikawa, and H. Nakanishi, J. Cryst. Growth 311, 553 (2009). [5] L. Huang, Q. Liao, H. Fu, J. Ma, and J. Yao, J. Mater. Chem. 20, 159 (2010).

Bombyx Mori is a representative of natural fibers which is known for its mechanical stability. In this study, electrical discharge of the fibers exposed to different voltages for certain periods was examined and mechanical lifetime was measured and also the structure parameters Uo and γ were calculated. We observed that crosslinks might be formed at the silk fibers exposed to high voltages and as a result, fibers become more resistant to mechanical effects.

Since the discovery of electrical conductivity in chemically doped polyacetylene (Shirakawa et al., 1977; Chiang et al., 1977; Chiang et al., 1978), enormous progress has been made in the design, synthesis and detailed studies of the properties and applications of -conjugated polymers (Yu et al., 1998; Skotheim et al., 1998; Hadziioannou et al., 1998). The award of the Nobel prize in Chemistry three decades later in the year 2000 to Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa for the abovementioned discovery and development of semiconducting polymers, was greeted worldwide among researchers as a recognition for the intensified research, which has been going on in the field of organic -conjugated polymers (Shirakawa, 2001). Such polymers are advantageous compared to inorganic semiconductors due to their low production cost, ease of processability, flexibility as well as tenability of their optical and electronic properties through chemical modifications. These outstanding properties make them attractive candidates as advanced materials in the field of photonics and electronics (Forrest, 2004; Klauk, 2006; Bao & Locklin, 2007; Sun & Dalton, 2008; Moliton, 2006; Hadziioannou & Mallarias, 2007; Shinar & Shinar, 2009; Nalwa, 2008). Among the most used polymers in optoelectronic devices are the poly(p-phenylenevinylene)s (PPV), polyfluorenes, polythiophenes and their derivatives. The insertion of side-chains in these polymers reduces the rigidity of the backbone, increases their solubility and enables the preparation of films through inexpensive, solution-based methods, such as spin-coating (Akcelrud, 2003). Besides, these ramifications can also be used to tune the photophysical and electrochemical properties of these polymers using a variety of routes. Solar cells based on solution-processable organic semiconductors have shown a considerable performance increase in recent years, and a lot of progress has been made in the understanding of the elementary processes of photogeneration (Hoppe & Sariciftci, 2004; Mozer & Sariciftci, 2006; Gunes et al., 2007). Recently, organic bulk heterojunction solar cells with almost 100% internal quantum yield were presented, resulting in up to almost 8% power conversion efficiency (Park et al., 2009; Green et al., 2010). This device concept has

We report on the demonstration of an organic electrochemical light emitting field effect transistor. The device fabricated in bottom gate/bottom contact geometry using a conjugated polymer poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) mixed with polymer electrolyte poly(ethylene oxide) including lithium trifluoromethanesulfonate (Li triflate) as active layer and poly(vinyl alcohol) as gate dielectric. Orange-yellow light emission is observed from the device. The output characteristics (source-drain current versus the source-drain voltage) and transfer characteristics (source-drain current versus the gate voltage) of the device are reported.