The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics.

It is generally believed that the photoresponse behavior of organic field‐effect transistors (OFETs) reflects the intrinsic property of organic semiconductors. However, this photoresponse hinders the application of OFETs in transparent displays as driven circuits due to the current instability resulting from the threshold voltage shift under light illumination. It is necessary to relieve the photosensitivity of OFETs to keep the devices stable. 2,6‐diphenyl anthracene thin‐film and single‐crystal OFETs are fabricated on different substrates, and it is found that the degree of molecular order in the conducting channels and the defects at the dielectric/semiconductor interface play important roles in determining the phototransistor performance. When highly ordered single‐crystal OFETs are fabricated on polymeric substrates with low defects, the photosensitivity (P) decreases by more than 105 times and the threshold voltage shift (ΔVT) is almost eliminated compared with the corresponding thin‐film OFETs. This phenomenon is further verified by using another three organic semiconductors for similar characterizations. The decreased P and ΔVT of OFETs ensure a good current stability for OFETs to drive organic light‐emitting diodes efficiently, which is essential to the application of OFETs in flexible and transparent displays.

Efficient charge transport in organic semiconductors is essential for construction of high performance optoelectronic devices. Herein, for the first time, we demonstrate that poly(amic acid) (PAA), a facilely deposited and annealing-free dielectric layer, can tailor the growth of organic semiconductor films with large area and high crystallinity toward efficient charge transport and high mobility in their thin film transistors. Pentacene is used as a model system to demonstrate the concept with mobility up to 30.6 cm V s, comparable to its high quality single crystal devices. The structure of PAA has corrugations with OH groups pointing out of the surface, and the presence of an amide bond further allows adjacent polymer strands to interact via hydrogen bonding, leading to a self-rippled surface perpendicular to the corrugation. On the other hand, the strong polar groups (-COOH/-CONH) of PAA could provide repulsive forces between PAA and pentacene, which results in the vertical orientation of pentacene on the dielectric surface. Indeed, in comparison with its imidized counterpart polyimide (PI), PAA dielectric significantly enhances the film crystallinity, drastically increases the domain size, and decreases the interface trap density, giving rise to superior device performance with high mobility. This concept can be extended to more organic semiconducting systems, e.g., 2,6-diphenylanthracene (DPA), tetracene, copper phthalocyanine (CuPc), and copper hexadecafluorophthalocyanine (FCuPc), demonstrating the general applicability. The results show the importance of combining surface nanogrooves with the strong polarity in orienting the molecular arrangement for high crystallinity toward efficient charge transport in organic semiconductors.

Metal halide perovskites, such as MAPbX 3 (X = Cl, Br, or I) have recently garnered tremendous research efforts for a broad range of photovoltaic and optoelectronic applications, [1][2][3][4][5][6][7] due to their favorable optical and electronic properties such as tunable bandgap, [2] high absorption coefficient, [3] and high photoluminescence quantum yield. [4] In particular, the power-conversion efficiencies of perovskite solar cells have been boosted to over 23% (certified) from a starting point of 3.8% over the past few years. [4][5][6][7][8] Apart from the rapid developments of materials and device architectures, a thorough understanding of fundamental physical processes including charge-carrier transport will be needed for further breakthroughs in device performance. However, a comprehensive physical picture of the intrinsic charge transport in the metal halide perovskites, which is key Optoelectronic devices based on metal halide perovskites, including solar cells and light-emitting diodes, have attracted tremendous research attention globally in the last decade. Due to their potential to achieve high carrier mobilities, organic-inorganic hybrid perovskite materials can enable high-performance, solution-processed field-effect transistors (FETs) for next-generation, low-cost, flexible electronic circuits and displays. However, the performance of perovskite FETs is hampered predominantly by device instabilities, whose origin remains poorly understood. Here, perovskite single-crystal FETs based on methylammonium lead bromide are studied and device instabilities due to electrochemical reactions at the interface between the perovskite and gold source-drain top contacts are investigated. Despite forming the contacts by a gentle, soft lamination method, evidence is found that even at such "ideal" interfaces, a defective, intermixed layer is formed at the interface upon biasing of the device. Using a bottom-contact, bottom-gate architecture, it is shown that it is possible to minimize such a reaction through a chemical modification of the electrodes, and this enables fabrication of perovskite single-crystal FETs with high mobility of up to ≈15 cm 2 V −1 s −1 at 80 K. This work addresses one of the key challenges toward the realization of high-performance solution-processed perovskite FETs. Field-Effect Transistors