Spectroelectrochemistry of CdSe/CdS Core-Shell Quantum Dots

Abstract

Understanding the effect of excess charges either in the excited state or in trap states in semiconductor nanocrystals is vital for optimizing their luminescence efficiency. Here, we report the effects of electrochemically injected holes and electrons on the optical properties of CdSe/CdS with varying shell thicknesses (0-8 monolayers). Electron injection leads to quasi-reversible changes to the optical properties of QDs, and the reversibility improves with increasing shell thickness. In contrast, hole injection induces lattice corrosion in bare CdSe QDs. However, the presence of CdS shells obviates decomposition and leads instead to carrier trapping and trion formation. We demonstrate that ..