Organic Phototransistors Based on Self-Assembled Microwires of n-Type Distyrylbenzene Derivative

Abstract

Molecular design and crystallinity control are important issues for the development of high-performance organic optoelectronic devices. Here, a highly photo-responsive n-type organic small molecular semiconductor, (2Z,2′Z)-3,3′-(2,5-dimethoxy-1,4-phenylene)bis(2-(3,5-bis(trifluoro-methyl)phenyl)acrylonitrile) (DM-R), was synthesized and the photoelectronic properties of self-assembled DM-R microwire organic phototransistors (MW-OPTs) were studied. Significant enhancement in the electron mobility (μe) of MW-OPTs (μe: 0.16 cm2 V−1 s−1) was observed as compared to thin-film-OPTs (μe: 2.7×10−3 cm2 V−1 s−1), most likely due to the single-crystalline nature of the self-assembled MWs. Moreover, the photoresponsivity of MW-OPTs showed 23.53 (A W−1), which was 130 times higher than that of thin-film OPTs (0.18 A W−1). Furthermore, the MW-OPTs exhibited stable photoswitching properties and a faster charge accumulation/release rate than those of thin-film OPTs. The results obtained herein demonstrate a facile solution-based approach for the fabrication of high-performance n-type organic MW-OPTs and provide a systematic analysis platform of the photo-generated charge carrier dynamics.