CdTe_(1-x)Se_x/Cd_(0.5)Zn_(0.5)S core/shell quantum dots: core composition and property

摘要

Alloy CdTe_(1-x)Se_x quantum dots (QDs) have been fabricated by an organic route using Cd, Te and Se precursors in a mixture of trioctylamine and octadecylphosphonic acid at 280 °C. The variation of photoluminescence (PL) peak wavelength of the CdTe_(1-x)Se_x QDs compared with CdTe QDs confirmed the formation of an alloy structure. The Se component drastically affected the stability of CdTe_(1-x)Se_x QDs. A Cd_(0.5)Zn_(0.5)S shell coating on CdTe_(1-x)Se_x cores was carried out using oleic acid as a capping agent. CdTe_(1-x)Se_x/Cd_(0.5)Zn_(0.5)S core/shell QDs revealed dark red PL while a yellow PL peak was observed for the CdTe_(1-x)Se_x cores. The PL efficiency of the core/shell QDs was drastically increased (less than 1% for the cores and up to 65% for the core/shell QDs). The stability of QDs in various buffer solutions was investigated. Core/shell QDs can be used for biological applications because of their high stability, tunable PL and high PL efficiency.