Luminescence Enhancement of ZnS:Cu Nanocrystals by Zinc Sulfide Coating with Core/Shell Structure

Abstract

Via wet chemical method with organic assistant, ZnS:Cu/ZnS core/shell structure was prepared. X-ray diffraction measurements showed that ZnS:Cu was formed with zinc blende structure, and ZnS shell growth on the surface was indicated through a redshift in the UV-Vis absorption spectra with increasing particle size. The emission peak at about 510 nm was observed, which should be assigned to recombination of an electron from the shallow delocalized donor levels at the t 2 level of Cu 2+ centers. As passivation layer, effect of ZnS shell on luminescence intensity and lifetime of ZnS:Cu were investigated. Comparing with uncoated ZnS:Cu, ZnS shell really enhanced the luminescence intensity and lifetime significantly, which resulted from the reduction of nonradiative recombination sites.

Photoluminescence Enhancement of SiO2‐Coated LaPO4:Eu3+ Inverse Opals by Surface Plasmon Resonance of Ag Nanoparticles

“…For the removing of surface defects, one of the effective solutions is to coat a shell around the nanosized skeleton surface of inverse opal to form inverse opal with shell–core structures. Such a method has been proved to be useful for the PL enhancement of nanocrystal systems . In addition, surface plasmon resonance (SPR) of noble metal NPs is electromagnetic surface modes from collective electron oscillation, which could cause electric field strength enhancement around the NPs, resulting in the enhancement of excitation and emission efficiency of rare earth ions .…”

“…Such a method has been proved to be useful for the PL enhancement of nanocrystal systems. [11][12][13][14][15] In addition, surface plasmon resonance (SPR) of noble metal NPs is electromagnetic surface modes from collective electron oscillation, which could cause electric field strength enhancement around the NPs, resulting in the enhancement of excitation and emission efficiency of rare earth ions. [16][17][18][19][20] In this study, the Ag NPs infilling silica-coated LaPO 4 :Eu 3+ inverse opals were prepared by the sol-gel method, and the influence of the Ag NPs on the PL of silica-coated LaPO 4 :Eu 3+ inverse opals was investigated.…”