Efficient and photostable ZnS-passivated CdS:Mn quantum dots

초록

Efficient photostable ZnS-passivated CdS:Mn (CdS:Mn/ZnS core/shell) luminescent quantum dots (Qdots) were synthesized using a reverse microemulsion process. Inorganically passivated Qdots with a core (CdS:Mn) diameter of ∼2.3 nm and a ZnS-shell thickness of ∼0.4 nm exhibited improved quantum yield (18 %), as compared to similar n-dodecanethiol-capped (organically passivated) CdS:Mn Qdots (3 %). Upon UV-irradiation in air for 3 hrs, CdS:Mn/ZnS Qdots exhibited photo-brightening and a stable emission with a quantum yield of 28 %. X-ray photoelectron spectroscopy (XPS) data revealed that this photo-brightening correlated with the development of a ZnSO4 layer on the Qdot surface. A direct current electroluminescence (EL) device with a hybrid organic/inorganic multilayer structure of lTO//PEDOT-PSS//PVK//CdS:Mn/ ZnS//Al was tested. The EL data suggested that the electron-hole recombination zone was confined to Mn in the Qdot layer. copyright The Electrochemical Society.