High-Performance UV-Sensitive Organic Phototransistors Based on Benzo[1,2-b:4,5-b '] dithiophene Dimers Linked with Unsaturated Bonds

Obvious differentiated response of organic phototransistors (OPTs) to the lights with different wavelengths is a challenge but a prerequisite for wave-length-selective applications. In this manuscript, highly UV-sensitive OPTs are fabricated based on benzo[1,2-b:4,5-b'] dithiophene dimers (BBDT, BBDTE, and BBDTY). The BBDTE-based organic single-crystal transistors (OSCTs), which show carrier mobility up to 1.62 cm(2) V-1 s(-1), exhibit a maximum photoresponsivity up to 9821 A W-1 and a maximum photosensitivity up to 10 5 towards UV light (37 mu W cm(-2)), and the photosensitivity observed within tested light intensity range is unexpectedly stable. The BBDTY-based OPTs also exhibit differentiated response between UV and visible lights, even with thin-film state of organic semiconductor, and the highest photoresponsivity and photosensitivity to UV light reached 9336 A W-1 and 4429, respectively. This selective and highly sensitive performance enables unsaturated bond-linked benzo[1,2-b:4,5-b'] dithiophene dimers promising candidates for UV detectors.