Toward efficient blue-emitting thiol-capped Zn1−xCdxSe nanocrystals

Abstract

In order to explore synthetic approaches to strongly emitting nanoparticles covering the UV–blue spectral region, the photochemical treatment of ZnSe and Zn_1−xCd_xSe nanocrystals (NCs) capped by thioglycolic acid (TGA) in the presence of Zn²⁺ and Cd²⁺ ions was investigated. A reproducible method of tuning the luminescence of these NCs from the UV to the blue spectral region was developed. Using this method, stable aqueous NCs emitting in the visible region with photoluminescence (PL) maxima ranging from 390 to 460 nm and with photoluminescence quantum efficiencies (PL QEs) of 20–30% were obtained. The effects of the experimental conditions and of the initial composition of the NCs on their optical properties are discussed.