Bismuth-Doped Ag2Te Colloidal Quantum Dots for High-Performance Shortwave-Infrared Photodetectors

Recently, silver telluride (Ag2Te) colloidal quantum dots (QDs) have garnered significant attention in short-wave-infrared (SWIR) photodetection owing to their strong SWIR responsivity and environmental benignity. However, the SWIR Ag2Te QDs often suffer from their high defect density, leading to an unsatisfactory utilization efficiency of the photogenerated charge carriers. To address this challenge, here, we have developed bismuth-doped Ag2Te (Bi:Ag2Te) QDs via a hot-injection doping method. The Bi doping effectively suppresses the trap states and modulates the energy band structure of the QDs. Then, the as-prepared Bi:Ag2Te QDs were applied in photodiodes, which exhibits outstanding detective performance in the SWIR range with high external quantum efficiencies of 11.2% and 30% under 0 and 0.3 V bias, respectively, and a specific detectivity (D*) of 7.67 × 1010 Jones at 1460 nm under ambient conditions. This study not only introduces novel QDs for high-performance SWIR photodetectors but also offers a critical reference for modulating the optoelectronic properties of QDs through doping strategies.