An ultrasensitive narrowband organic phototransistor for solar-blind ultraviolet detection and imaging

Abstract

Solar-blind ultraviolet (SBUV) photodetectors have extensive applications in fields such as military operations, agriculture, and flame detection. However, most current ultraviolet detection is based on inorganic materials, and there is very limited research on solar-blind ultraviolet detection using organic materials. This study investigates a novel SBUV hybrid-layered phototransistor (HLPT) based on wide-band organic materials. The SBUV HLPTs consist of 2,6-bis(4-meth-oxyphenyl)naphthalene (BOPNA) as the conduction channel and a bulk heterojunction (BHJ) of pyromellitic diamide p-(trifluoromethoxy)benzyl (PyDI-BOCF₃)/BOPNA as the photoactive layer, and exhibit outstanding photodetection such as a responsivity (R) of 2.4 × 10³ A W⁻¹, a specific detectivity (D*) of 1.0 × 10¹³ Jones, and an external quantum efficiency (EQE) of 0.8 × 10⁶% under weak light illumination of 50 μW cm⁻². In addition to that, the most critical aspect is that the maximum dark I_photo/I_dark ratio is 10⁷ when the dark current of the device is 1 nA, which is of great significance for highly selective and advanced multilevel SBUV monitors.