Recombination processes in CuInS$_{2}$/ZnS Nanocrystals during steady-state photoluminescence

TL;DR

This study investigates the recombination mechanisms in CuInS₂/ZnS nanocrystals through temperature- and power-dependent photoluminescence, revealing insights into state filling, energy transfer, and Auger recombination effects.

Contribution

It provides new experimental evidence on the recombination processes in CuInS₂/ZnS nanocrystals, highlighting the dominance of Auger recombination at high excitation powers.

Findings

PL spectra blue-shift with increased excitation power

Observation of F"orster resonance energy transfer at low temperature

Sublinear increase of PL intensity indicating Auger recombination

Abstract

We report on temperature- and excitation-power-dependent photoluminescence (PL) study of CuInS$_{2}$/ZnS nanocrystals dispersed on a SiO$_{2}$/Si substrate with a confocal micro-PL system. With increasing the excitation power at 22 K and room temperature, the PL spectra are blue-shifted because of the state filling. At low temperature, a small peak is observed at the low energy side of the spectrum, which could be due to the F$\ddot{o}$rster resonance energy transfer between different nanocrystals. The integrated PL intensity increases sublinearly as a function of excitation power with a power factor of around 2/3, which demonstrates the Auger recombination dominated process in the nanocrystals, especially under the high excitation power.