Rate of Cation Exchange and Change in Optical Properties during Transformation of Ternary to Doped Binary Nanocrystals

Abstract

Introduction of intra bandgap state in semiconductor nanocrystals provides an efficient way to control the separation or recombination of charge carriers and enhances their applicability for light emitting, harvesting, and sensing purposes. This manuscript presents the conversion of ternary CIZS nanocrystals to doped binary alloyed nanocrystals and studies the change in the defect/dopant state induced light-emission activities. Adopting an in situ transformation process by facile ion exchange protocol, the ternary CIZS nanocrystals (Cu >10%) are converted to alloyed binary nanocrystals with <2% Cu, and the change in their excitation, de-excitation processes, and consequent photophysical properties are continuously monitored with the variation in composition. Finally, it is concluded that when the ternary CIZS nanocrystals change to doped nanocrystals, the position of the defect state changes and this influences the optical properties of the nanocrystals.