Photostability of Organic Field-Effect Transistors

Fluctuation in channel current in the organic field-effect transistors (OFETs) under illumination, caused by the photoresponse of the polymer channel layer, is one of the critical factors influencing the operational stability of the OFET-based backplane. In this work, a mechanistic study of the photostability of the OFETs was carried out. A sample front-end driving circuit, comprising an OFET and an organic light-emitting diode unit, was used to analyze the photostability of the OFET under the illumination of near-infrared (850 nm) light, which corresponds to the peak absorption of the polymer channel layer. The results reveal that photostable OFETs with a negligible change in the channel current and the threshold voltage can be realized by mitigating the defect-associated charge trapping and detrapping processes under illumination, enabled by improved molecular packing in the polymer channel layer. The outcomes of this work provide important insight and OFET design knowledge for a plethora of applications in front-end circuits, image sensors, and flexible displays.