Aqueous Synthesis of Multidentate-Polymer-Capping Ag<sub>2</sub>Se Quantum Dots with Bright Photoluminescence Tunable in a Second Near-Infrared Biological Window

A new strategy for fabricating water-dispersible Ag<sub>2</sub>Se quantum dots (QDs) is presented. A multidentate polymer (MDP) was synthesized and used as a capping agent for Ag<sub>2</sub>Se QDs. The MDP-capping Ag<sub>2</sub>Se QDs were synthesized in aqueous solution at room temperature, which are highly photoluminescent in a second near-infrared (NIR-II) biological window and possess good photostability. These readily prepared NIR-II fluorescent nanoprobes have great potential for biomedical applications, especially useful for in vivo imaging.