基于场效应晶体管(FET)结构的光电探测器能通过栅压抑制噪声信号并具有光电信号放大的功能。有机半导体材料已经被广泛应用到光敏晶体管中，全有机探测器对于实现大面积器件制备、降低成本及柔性器件具有十分重大的意义。然而，多层有机聚合物的成膜，必须避免在溶液制备过程中的“溶剂腐蚀”问题。实验中，采用顶栅底接触(TGBC)FET结构及正交溶剂(orthogonal solvent)的方法，以乙酸丁酯作为聚(甲基丙烯酸甲酯)(PMMA)的溶剂，避免对聚(3-己基噻吩)(P3HT)有源层的破坏，成功制备了性能优良的全有机光电探测器Au(源漏极)/P3HT(150 nm)/PMMA(800 nm)/Al(栅极)，其“开/关”电流比达到10³，迁移率达8×10^-3 cm²·V^-1·s^-1。该器件对350~650 nm的光照均有响应，在0.1 mW/cm²光照下其“明/暗”电流比达75。在600 nm光照下，其最大响应度达到0.28 A/W，其响应度变化趋势与P3HT的吸收光谱情况相似。

The noise signals can be compressed and the optoelectronic signals can be amplified by the applied gate voltages in field-effect transistor(FET)-based photodetector. Organic materials have been widely applied in phototransistors, it is meaningful to fabricate all-organic photodetectors for large area, low cost and flexible device applications. However, multiple polymer layers are usually fabricated through solution processing and the 'solution corrosion' should be avoided during its fabrication process. Therefore, top-gate-bottom-contact(TGBC) FET configuration and orthogonal solvent were adopted in the experiments, and the bulty acetate was used as the solvent of poly(methyl methacrylate)(PMMA) to prevent destroying the poly(3-hexylthiophene)(P3HT) active layer. In this way, the FET-based all-organic photodetectors Au(Source, Drain)/P3HT(150 nm)/PMMA(800 nm)/Al(Gate) had been successfully prepared, showing an on-off current ratio of 103 and a maximum mobility of 8×10^-3 cm²·V^-1·s^-1. The photocurrent shown an obvious increment under illumination of a broad range of incident wavelengths from 350 nm to 650 nm, giving a maximum photo-to-dark current ratio of 75 under 0.1 mW/cm2 illumination. The largest photoresponsivity of ~0.28 A/W was obtained under the illumination of 600 nm, and the trend of photoresponsivity corresponds to that of the absorption of P3HT film.