Development of light-sensing organic transistors for optoelectronic and image sensor array applications

传统上，有机场效应管(OFET)一直被用作有机集成电路和有源矩阵柔性显示器中的电子开关。然而，最近，具有附加功能的场效应管，即双功能场效应管也首次亮相，最引人注目的例子是发光(LE-OFET)和光敏(LS-OFET)晶体管。本项目的目标是设计、开发和研究用于各种光电应用的双功能OFET。特别是，我们的目标是展示具有高光响应性和快速开关特性的LS-OFET，主要用于集成光电探测器、光电电路和全色/单色图像传感器阵列。我们的方法是基于使用合适的双极型场效应管和在用光照射设备时出现的可测量的光感应电流。光激发时产生的大量自由载流子可以调制流经通道的电流，从而将晶体管转换为电光开关。双极LS-OFET的使用有可能最大化器件的光响应，而适当的半导体系统的结合有望导致具有波长选择特性的LS-OFET的展示。有朝一日，这种设备可能会被用于低成本、大面积和灵活的图像传感器阵列应用。此外，高性能LS-OFET的展示也将为电光电路铺平道路，在电光电路中，信号处理涉及到光和电信号的使用。到目前为止，这些想法还没有得到任何重大考虑，因此等待着加以利用。如果成功，这项拟议的工作有可能重塑传统有机电子产品的面貌。

Traditionally, organic field-effect transistors (OFETs) have been explored as electronic switches in organic integrated circuits and active-matrix flexible displays. Recently, however, OFETs with additional functionalities, i.e. bi-functional OFETs, have also made their debut with most notable examples the light-emitting (LE-OFETs) and light-sensing (LS-OFETs) transistors. It is the aim of this project to design, develop and study bifunctional OFETs for use in various optoelectronic applications. In particular, we aim to demonstrate LS-OFETs with high photoresponsivity and fast switching characteristics for use, primarily, in integrated photodetectors, electro-optical circuits and full-colour/monochromatic image sensor arrays. Our approach is based on the use of suitable ambipolar OFETs and the measurable photoinduced current present upon illumination of the device with light. The significant concentration of free carriers, generated upon photoexcitation, can modulate the current flow across the channel and hence transform the transistor to an electro-optical switch. Use of ambipolar LS-OFETs has the potential to maximise the photoresponse of the devices while incorporation of appropriate semiconductor systems is expected to lead to demonstration of LS-OFETs with a wavelength selective characteristics. Such devices could one day be exploited in low-cost, large-area and flexible image sensor array applications. Furthermore, demonstration of high-performance LS-OFETs will also pave the way towards electro-optical circuits, in which signal processing involves the use of both optical and electrical signals. To date these ideas have not been given any significant consideration and are therefore waiting to be exploited. If succeed the proposed work has the potential to reshape the landscape of traditional organic electronics.