基于吸收互补有机半导体本体复合薄膜的高性能柔性光突触晶体管

High-Performance Flexible Photonic Synapse Transistors Based on a Bulk Composite Film of Organic Semiconductors with Complementary Absorption

采用光吸收互补的聚(3-己基噻吩)(P3HT)和引达省并二噻吩-苯并噻二唑共聚物(PIDT-BT),通过溶液法制备了两者的本体复合异质结构有机半导体薄膜,并研究了薄膜的表面结构和光电性质.将PIDT-BT:P3HT复合薄膜作为一类新型光敏沟道层,与聚电解质介电材料相结合,制备了高性能柔性低电压光突触晶体管.考察了不同光刺激条件对光突触晶体管性能的影响及半导体机制,发现PIDT-BT:P3HT器件具有明显光突触特性,并且相较于单纯PIDT-BT或P3HT器件具有更高响应的兴奋性突触后电流.基于PIDT-BT:P3HT薄膜的光突触器件,在绿红双色光刺激下的响应大于两种单色光分别刺激的响应之和,表明附加光刺激可调控器件的记忆效率.该研究为发展高性能光响应半导体薄膜及柔性低功耗光突触器件提供了新策略.

Photonic synapse transistors have attracted growing attention due to their salient advantages in information transmission/processing and good potentials for analog neural computing. Currently, most synapse transistors are rigid devices with the limitations in flexible and highly photosensitive semiconductor channel layers. To achieve high-performance flexible photonic synapse transistors, it is essential to develop stimuli-responsive organic semiconductor thin-films to broaden the photo-response range of devices and accelerate separation of photoinduced carriers for improving synaptic performances.Here, poly(3-hexylthiophene)(P3HT) and poly(indacenodithiophene-co-benzothiadiazole)(PIDT-BT) materials with complementary optical absorption have been used to fabricate a bulk composite film of organic semiconductor heterostructures by a solution-processing method. The surface structures and optoelectronic properties of the PIDT-BT:P3HT film and their single component films are studied. By using the PIDT-BT:P3HT heterostructure film as a novel photoactive channel layer,flexible low-voltage photonic synapse transistors have been designed and fabricated with the combination of polyelectrolyte-based dielectrics. The effects of different optical stimulation conditions on the performance of synapse transistors are investigated with insightful discussion on the semiconductor mechanisms. The flexible synapse transistors based on the PIDT-BT:P3HT film exhibit higher excitatory postsynaptic currents than devices with the single component semiconductor layers at the same optical stimulation. The synaptic response of the PIDT-BT:P3HT-based device is also evaluated under different stimulus variables including the optical spike wavelength, duration and frequency. As results, good synaptic characteristics are observed including the high excitatory postsynaptic current, paired-pulse facilitation, and frequency-dependent properties with the tunable synaptic plasticity. It is found that the response in excitatory postsynaptic current of the synaptic device stimulated by two beams(520 nm green laser and 685 nm red laser) together is greater than the sum of the responses stimulated by each beam alone. These results are useful for the design of high-performance photoresponsive semiconductor films and photonic synapse transistors, which are conducive to the development of low-power flexible optoelectronic devices,artificial synapses and beyond.