Exploration of a proquinoidal [1,2,5]thiadiazolo[3,4-g]quinoxaline-based small molecule acceptor toward high-sensitivity shortwave infrared photodetection†

Expanding the detection wavelength into the short-wave infrared region represents a significant challenge for organic photodetectors (OPDs) to enable a wide range of advanced applications. Herein, we developed a small molecule acceptor (SMA) with a spectral response extending beyond 1200 nm by incorporating a proquinoidal [1,2,5]thiadiazolo[3,4-g]quinoxaline derivative as the core unit. Using PTB7-Th as the donor component, organic photodiode devices based on this SMA achieved a notable responsivity of 0.16 A W⁻¹ at 1100 nm and a high specific detectivity (D*) value exceeding 1 × 10¹² Jones across a broad spectral range of 550–1150 nm under photovoltaic mode (0 V bias). Furthermore, we demonstrated high-quality real-time pulse monitoring under an ultra-low light power of 2.42 μW cm⁻² at 1064 nm, highlighting its potential to significantly reduce energy consumption in healthcare applications.