Time-Resolved Photoluminescence Spectroscopy of CdTe/CdS/CdSe Quantum Dot Complexes for Photon Upconversion

摘要

Solution-processed core/multi-shell semiconductor quantum dots (QDs) could be tailored to facilitate the carrier separation and recombination mechanisms necessary to implement photon upconversion. We have synthesized CdTe cores capped with CdS and then CdSe shells. We present steady-state and time-resolved photoluminescence (PL) spectroscopy measurements of these QDs as a function of varying shell thicknesses. We quantify and report carrier emission energies and lifetimes as a function of shell addition and shell thicknesses. The results provide a framework for understanding how CdS and CdSe shells affect carrier separation and recombination dynamics, and thus inform the design of core/multi-shell QDs for efficient photon upconversion.