Organic photomemory based on heterojunction phototransistor has been fabricated utilizing vanadyl-phthalocyanine (VOPc) on para-sexiphenyl (p-6P) thin films. Under 365 nm ultraviolet light irradiation, the ratio of photocurrent and dark current (I_ph/I_dark) and photoresponsivity of phototransistors are about 1.5 × 10⁵ and 87 A/W, respectively. Such devices can transduce the input light signals into electrical signals and the output signals can be stored for recording the light simulation. After applying a light pulse (4.2 mW/cm², 100 ms) on the device, the stored current level lasted for ∼5000 s with only a 20% decrease, indicating a good photomemory behavior. Importantly, the photomemory behavior is effectively modulated by gate voltage. Multilevel photomemory behaviors are observed by modulating light pulse duration and light power intensity. Because of the construction of type-I heterojunction, the superior photomemory characteristics are mainly originated from efficient charge trapping at VOPc/p-6P interface. In situ current sensitive atomic force microscopy (CSAFM) is used for monitoring surface current of the VOPc/p-6P heterojunctions. A change of conductivity in grains is observed upon 365 nm light illumination. After turning off the light, the current of grains did not rapidly decrease, but displayed the behavior of photomemory. This study provides a guide for designing high-performance organic photomemory devices.

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基于钒基酞菁/对-亚硒基异质结的多级非挥发性有机光敏存储器

基于异质结光电晶体管的有机光敏存储器已经在对-联苯并（p -6P）薄膜上利用钒基-酞菁（VOPc）进行了制备。在365 nm紫外线照射下，光电流与暗电流之比（I _ph / I _dark）和光电晶体管的光响应性分别约为1.5×10 ⁵和87 A / W。这样的设备可以将输入的光信号转换为电信号，并且可以存储输出信号以记录光模拟。施加光脉冲后（4.2 mW / cm ²，例如100 ms），存储的电流水平持续了约5,000 s，仅下降了20％，表明光记忆性能良好。重要的是，光记忆行为可通过栅极电压有效调节。通过调制光脉冲持续时间和光功率强度，可以观察到多级光记忆行为。由于I型异质结的构造，优异的光记忆特性主要来自于VOPc / p -6P接口处的有效电荷俘获。原位电流敏感原子力显微镜（CSAFM）用于监测VOPc / p的表面电流-6P异质结。在365 nm光照下观察到晶粒中电导率的变化。熄灯后，晶粒的电流并没有迅速减小，而是表现出光记忆的行为。这项研究为设计高性能有机光存储器件提供了指南。