Doping Colloidal Quantum Dots

Doping has been an important method for tuning semiconductor electronic and optical properites, yet doping quantum dots (QDs) still presents a challenge. Herein, we report a facile method to dope PbS, CdSe, and CsPbBr₃ quantum dots with Ag, Na and Bi using ligand chemistry. Adding a solution of the metal oleates to a QD solution produces a bleach in the QD exciton absorption in the UV-VIS spectrum, and a intraband absorption in the FTIR. We found a higher free-carrier conductivity in solution-doped coupled QD films, compared to as-synthesized, using sheet resistance measurements. This study demonstrates the ability to dope QDs in solution while maintaining colloidal stability and increasing conductivity of the QD solids.