Quantitative Analysis of Photo-Thermal Stability of CdSe/CdS Core-Shell Nanocrystals

TL;DR

This study quantitatively compares the luminescence stability of bare and CdS-capped CdSe nanocrystals under infrared radiation, highlighting the role of oxide layer formation and particle size reduction in luminescence degradation.

Contribution

It provides a quantitative analysis of how oxide layer growth affects the photo-thermal stability of CdSe/CdS nanocrystals, using diffusion theory to elucidate the underlying mechanisms.

Findings

Oxide layer volume critically influences luminescence loss.

Bare CdSe particles are less stable than core-shell structures.

Particle size reduction correlates with decreased light output.

Abstract

We report here investigations on the instability in luminescence of bare (TOPO-stabilized) and CdS- capped CdSe particles under infrared radiation. During photo-thermal annealing the formation of oxide layers on the surfaces of the particles create defect states. Consequently there is a reduction in particle size. These two effects control the light output from the samples. We make a quantitative comparison of the stability of bare CdSe and core-shell type CdSe-CdS particles under photo-annealing. Using diffusion theory, we show that the volume of the oxide layer, adhered to the crystallites, play a dominant role in controlling the luminosity of the particles.