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The fabrication of p-type vertical organic field-effect transistors (VOFETs) based on a reduced graphene oxide (rGO) electrode is a big challenge. Due to the insufficient injection barrier at the rGO/p-type organic semiconductor heterojunction, the current on/off ratio of the device is usually poor. To improve device performance and enable its application in future organic complementary circuits with their n-type counterparts, different types of interfacial layers were explored in this study. Results suggest that the highest occupied molecular orbital level and the surface morphology of the interfacial layer play an important role in device performance, while the hole mobility of the interfacial layer has less impact. In addition, the effect of the interfacial layer thickness was systematically investigated, indicating that an ultrathin interfacial layer was preferred in terms of the on-current density. Notably, the device with a 1 nm thick C60 interfacial layer gave the best device performance, exhibiting the highest current on/off ratio exceeding 5 × 103 and a maximum current density over 30 mA/cm2 under an operation voltage of −3 V. This is the first p-type VOFETs based on the work-function-tunable rGO electrode, which may open the door to rGO-based organic complementary circuits. [ABSTRACT FROM AUTHOR]

Bioinspired electronics have shown great potential in the field of artificial intelligence and brain‐like science. Low energy consumption and multifunction are key factors for its application. Here, multisensory artificial synapse and neural networks based on electrolyte‐gated vertical organic field‐effect transistors (VOFETs) are first developed. The channel length of the organic transistor is scaled down to 30 nm through cross‐linking strategy. Owing to the short channel length and extremely large capacitance of the electric double layer formed at the electrolyte–channel interface, the minimum power consumption of one synaptic event is 0.06 fJ, which is significantly lower than that required by biological synapses (1–10 fJ). Moreover, the artificial synapse can be trained to learn and memory images in a 5 × 5 synapse array and emulate the human brain's spatiotemporal information processing and sound azimuth detection. Finally, the artificial tongue is designed using the synaptic transistor that can discriminate acidity. Overall, this study provides new insights into realizing energy‐efficient artificial synapses and mimicking biological sensory systems. [ABSTRACT FROM AUTHOR]

Artificial synapses have shown great potential in the research of artificial intelligence and brain‐like computing. Artificial synaptic devices based on vertical organic field‐effect transistors (VOFETs) exhibit shorter carrier transmission distances and more stable source–drain currents than conventional planar organic transistors due to their smaller channel lengths. By taking advantage of the vertical structure, low working voltage can be achieved. Here, vertical synaptic devices with working voltage as low as 10 µV and ultra‐low power consumption (≈1.3 fJ per spike) are proposed. VOFET‐based artificial photonic synaptic devices can successfully simulate typical synaptic behavior, including excitatory post‐synaptic current, short‐term plasticity, and long‐term plasticity. Furthermore, VOFET arrays are demonstrated to enable image contrast enhancement function. This work provides a new approach for the realization of artificial synapses through a simple manufacturing process. [ABSTRACT FROM AUTHOR]

A new device architecture for fast organic transistor memory is developed, based on a vertical organic transistor configuration incorporating high-performance ambipolar conjugated polymers and unipolar small molecules as the transport layers, to achieve reliable and fast programming and erasing of the threshold voltage shift in less than 200 ns., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)