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.