Large Stokes Shifts over Visible–Infrared Wavelengths from Multicore/Shell Quantum Dots for Solar-Harvesting Applications

Abstract

Multicore/shell PbCdS quantum dots (QDs) with an extraordinarily large Stokes shift of more than 550 nm are reported in this study. The QDs were prepared from a Pb–Cd cation-exchange method at an elevated reaction temperature for an extended reaction time, resulting in PbS–CdS domain separation within the core/shell PbS/CdS QD matrix. As a result, the QDs with the multidomain structure possess the first exciton absorption and photoluminescence wavelengths of 450 and 1002 nm, respectively, leading to an unusually large Stokes shift. The unique QDs are considered promising in some applications such as a down-shifting layer for solar harvesting.