Optical Properties of Organic Thin Film Transistors

Flexible electronic devices or stretchable electronic devices have recently attracted increasing attention. Organic semiconductor transistors have been intensively studied for such applications, as for the operation of display pixels and various sensors, and for use in logic circuits consisting of organic semiconductor transistors. When organic thin film transistors (OTFTs) are employed for the operation of display pixels or for use as transparent substrate-based sensors, the properties of the OTFTs may be changed by the light illuminating the OTFT from itself or from the outside, thus degrading circuit stability. In the present study, an OTFT was fabricated on a glass substrate by using pentacene, and light of different wavelengths and intensities was illuminated through the top and the bottom of device to investigate the additional photocurrent flowing through the OTFT. The experimental results showed that the photocurrent in a 100 nm-thick OTFT thin film had a symbatic pattern and that the photocurrent nonlinearly increased with increasing light intensity.