“Flash”\nSynthesis of CdSe/CdS Core–Shell Quantum Dots

Abstract

We report on the “flash”\nsynthesis of CdSe/CdS core–shell quantum dots (QDs). This new\nmethod, based on a seeded growth approach and using an excess of a\ncarboxylic acid, leads to an isotropic and epitaxial growth of a CdS\nshell on a wurtzite CdSe core. The method is particularly fast and\nefficient, allowing the controllable growth of very thick CdS shells\n(up to 6.7 nm in the present study) in no more than 3 min, which is\nconsiderably shorter than in previously reported methods. The prepared\nmaterials present state-of-the-art properties with narrow emission\nand high photoluminescence quantum yields, even for thick CdS shells.\nAdditionally, Raman analyses point to an alloyed interface between\nthe core and the shell, which, in conjunction with the thickness of\nthe CdS shell, results in the observed considerable reduction of the\nblinking rate.