A new dithieno[3,2-b:2′,3′-d]thiophene derivative for high performance single crystal organic field-effect transistors and UV-sensitive phototransistors

Abstract

Organic phototransistors (OPTs), as the basic unit for organic image sensors, are emerging as one of the most promising light signal detectors. High performance UV-sensitive phototransistors are highly desired for the detection of UV light. Herein, by introducing the anthracene group to the 2,6-positions of dithieno[3,2-b:2′,3′-d]thiophene, we designed and synthesized a new dithieno[3,2-b:2′,3′-d]thiophene derivative, 2,6-di(anthracen-2-yl)dithieno[3,2-b:2′,3′-d]thiophene (2,6-DADTT). The single crystal structure of 2,6-DADTT presents classical herringbone packing with multiple intermolecular interactions, including S⋯S (3.470 Å), S⋯C (3.304 Å, 3.391 Å, 3.394 Å) and C–H⋯π (2.763 Å, 2.822 Å, 2.846 Å, 2.865 Å, 2.885 Å, 2.890 Å) contacts. Single crystal organic field-effect transistors (SC-OFETs) based on 2,6-DADTT reach a highest mobility of 1.26 cm² V⁻¹ s⁻¹ and an average mobility of 0.706 cm² V⁻¹ s⁻¹. 2,6-DADTT-based single crystal organic phototransistors (OPTs) demonstrate photosensitivity (P) of 2.49 × 10⁶, photoresponsivity (R) of 6.84 × 10³ A W⁻¹ and ultrahigh detectivity (D*) of 4.70 × 10¹⁶ Jones to UV light, which are among the best figures of merit for UV-sensitive OPTs. These excellent comprehensive performances indicate its good application prospects in integrated optoelectronics.