The interface of organic semiconductor films is of particular importance with respect to various electrochemical devices such as transistors and solar cells. In this study, we developed a new spectroscopic system, namely electrochemical attenuated total reflectance ultraviolet (EC-ATR-UV) spectroscopy, which can access the interfacial area. Ionic liquid-gated organic field-effect transistors (IL-gated OFETs) were successfully fabricated on the ATR prism. Spectral changes of the organic semiconductor were then investigated in relation to the gate voltage application and IL species, and the magnitude of spectral changes was found to correlate positively with the drain current. Additionally, the Stark shifts of not only the organic semiconductor, but also of the IL on the organic semiconductor films were detected. This new method can be applied to other electrochemical devices such as organic thin film solar cells, in which the interfacial region is crucial to their functioning.

有机半导体薄膜的界面对于各种电化学装置如晶体管和太阳能电池特别重要。在这项研究中，我们开发了一种新的光谱系统，即电化学衰减全反射紫外（EC-ATR-UV）光谱，它可以进入界面区域。在 ATR 棱镜上成功制造了离子液体门控有机场效应晶体管（IL 门控 OFET）。然后研究了有机半导体的光谱变化与栅极电压应用和 IL 种类的关系，发现光谱变化的幅度与漏极电流呈正相关。此外，不仅检测到有机半导体的斯塔克位移，还检测到有机半导体膜上的离子液体的斯塔克位移。