Synthesis and Luminescence Properties of Core/Shell ZnS:Mn/ZnO Nanoparticles

Daixun Jiang,Hua Qu,Lixin Cao,Yuanguang Sun,Ge Su,Bohua Dong,Wei Liu

doi:10.1007/s11671-008-9205-6

Abstract

In this paper the influence of ZnO shell thickness on the luminescence properties of Mn-doped ZnS nanoparticles is studied. Transmission electron microscopy (TEM) images showed that the average diameter of ZnS:Mn nanoparticles is around 14 nm. The formation of ZnO shells on the surface of ZnS:Mn nanoparticles was confirmed by X-ray diffraction (XRD) patterns, high-resolution TEM (HRTEM) images, and X-ray photoelectron spectroscopy (XPS) measurements. A strong increase followed by a gradual decline was observed in the room temperature photoluminescence (PL) spectra with the thickening of the ZnO shell. The photoluminescence excitation (PLE) spectra exhibited a blue shift in ZnO-coated ZnS:Mn nanoparticles compared with the uncoated ones. It is shown that the PL enhancement and the blue shift of optimum excitation wavelength are led by the ZnO-induced surface passivation and compressive stress on the ZnS:Mn cores.

Highlights

In recent years, a great deal of attention has been devoted to doped semiconductor nanomaterials mainly due to their unique luminescence properties arising from quantum confinement effects
ZnO-coated ZnS:Mn nanoparticles have been prepared by different groups [23, 27]; the ZnO shells reported in these literatures are of rather poor crystallinity, which is indicated by their X-ray diffraction (XRD) results
The peaks located at 1,021.6, 532.1, and 162.2 eV correspond to Zn2p3/2, O1s, Fig. 2 Transmission electron microscopy (TEM) images of ZnS:Mn and ZnS:Mn/ZnO nanoparticles. a ZnS:Mn. b ZnS:Mn/ZnO(1). c high-resolution TEM (HRTEM) iamge of a single ZnS:Mn nanoparticle. d HRTEM image of ZnS:Mn/ZnO(1) nanoparticle showing the interface between shell and core and S2p, respectively

Summary

Introduction

A great deal of attention has been devoted to doped semiconductor nanomaterials mainly due to their unique luminescence properties arising from quantum confinement effects. Keywords ZnS:Mn/ZnO Á Nanoparticles Á Core/shell structure Á Luminescence Á II-VI Semiconductor Compared with the uncoated nanocrystals, the photoluminescence of the nanocrystals with a core/shell structure is enhanced.

Results

Conclusion