Organic semiconductor

About: Organic semiconductor is a research topic. Over the lifetime, 15905 publications have been published within this topic receiving 533881 citations.

All‐organic thin‐film transistors made of alpha‐sexithienyl semiconducting and various polymeric insulating layers

Abstract: Thin‐film transistors (TFTs) were fabricated with a variety of organic polymer insulators topped with a vacuum evaporated organic semiconductor, α‐sexithienyl (α6T). No field‐enhanced source‐drain current was obtained with polystyrene (PSt) and polymethylmethacrylate (PMMA). The field‐enhanced current is weak with polyvinyl chloride (PVC), but much stronger with polyvinyl alcohol (PVA) and cyanoethylpullulan (CYEPL), a cyanoethylated polysaccharide which possesses a high dielectric constant (er=18.5 at 10 kHz). In these last two instances, the field‐effect mobility surpasses the one measured on TFTs made on a SiO2 insulating layer. A strong correlation is found between the dielectric constant of the insulator and the field‐effect mobility.

Influence of codeposition on the performance of CuPc-C60 heterojunction photovoltaic devices

Abstract: We investigate the effects of introducing codeposited mixed layers on the performance of copper phthalocyanine (CuPc)–fullerene (C60) heterojunction photovoltaic devices. Significant improvements in device performance are seen when mixed layers are used compared to discrete layers. The effects of composition are examined for a series of devices incorporating mixed layers with well-defined composition ratios. Atomic force microscopy and electronic absorption spectroscopy studies show that the mixed layer films are smooth and amorphous, and undergo intermolecular intermixing. Finally, the use of multiple mixed layers leads to additional enhancements due to the creation of a gradient of donor–acceptor compositions that results in improved channels for charge transport.

Materials Requirements and Fabrication of Active Matrix Arrays of Organic Thin-Film Transistors for Displays

Abstract: An overview of the materials requirements and the fabrication processes for the use of organic thin-film transistors in active-matrix backplanes for displays is presented. A summary of current knowledge of the electrical performance of both molecular and polymeric semiconductors is discussed with emphasis on the performance requirements needed for displays. Patterning and deposition processes for conductors, dielectrics, and organic semiconductors that have been used to fabricate organic thin-film transistors are reviewed. Examples of backplanes fabricated with these processes are given, and directions for the future research are outlined.

Long-Living Light-Emitting Electrochemical Cells : Control through Supramolecular Interactions

Abstract: Light-emitting electrochemical cells with lifetimes surpassing 3000 hours at an average luminance of 200 cd m(-2) are obtained with an ionic iridium(III) complex conveniently designed to form a supramolecularly caged structure.

Unique architecture and concept for high-performance organic transistors

Abstract: We report an organic transistor with a vertically stack structure, which consists of a layer-by-layer active cell (drain/organics/source) on top of a capacitor cell (source/dielectrics/gate); the middle source electrode is shared by the capacitor cell and active cell. Three unique characteristics of this transistor, (a) its very thin and rough middle source electrode; (b) its capacitor cell with high charge-storage capability, allow the active cell to be influenced when the gate is biased; and (c) the large cross-section area and small distance between the source and the drain allow current flowing between the source and drain electrodes. Devices have been fabricated by thermal evaporation with the source-drain current well modulated by the gate potential. We have achieved organic transistors with low working voltage (less than 5V) and high current output (up to 10mA or 4A∕cm2) and an ON/OFF ratio of 4×106. A model is proposed for the device operation mechanism. The demonstrated device with its enhanced operating characteristics may open directions for organic transistors and their applications.