Controlled Synthesis of Ag2S Quantum Dots and Experimental Determination of the Exciton Bohr Radius

Ag2S quantum dots (QDs) have attracted increasing attention due to their appealing optical properties in the near-infrared regime. However, a full understanding of the quantum confinement effect of Ag2S QDs has not been achieved so far. Herein, for the first time, the size-dependent excited state optical properties of Ag2S QDs are systematically investigated by photoluminescence (PL), PL excitation (PLE), and time-resolved PL spectroscopy. Experimentally, we determine the exciton Bohr radius of Ag2S QDs as 2.2 nm, which is highly consistent with theoretical results.