UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers

Abstract

AbstractThis study demonstrates UV‐sensing semitransparent organic field‐effect transistors (OFETs) with wide bandgap small molecular channel and polymeric gate‐insulating layers. N,N′‐di(1‐naphthyl)‐N,N′‐diphenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPB) is employed as the wide bandgap channel layer, while poly(methyl methacrylate) is introduced as the wide bandgap gate‐insulating layer. The performance of OFETs is optimized by NPB thickness control and thermal treatment. Results show that the best device performance (on/off ratio = 4.7 × 106 and hole mobility = 4.2 × 10−5 cm2 V−1 s−1) is achieved by thermal treatment of the 130 nm thick NPB layers at 70 °C for 30 min leading to a noticeably changed surface morphology in the NPB layers. The optimized OFETs exhibit excellent operation stability without hysteresis, while those with semitransparent silver electrodes deliver quite a good transparency. The semitransparent OFETs can sensitively detect a UV light with high stability even though no photoresponse is measured under a visible light.