Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms. Issue 21 (7th May 2015) - Wang, Zhaofeng
Abstract : The size/morphology dependent upconversion of Lu5 O4 F7 :Er 3+, Yb 3+ was investigated, and an ultra-strong single-band upconversion was obtained in the nanoparticles. Abstract : In this work, we present a two-step method to controllably synthesize novel and highly efficient upconversion materials, Lu5 O4 F7 :Er 3+, Yb 3+ nano/micro-crystals, and investigate their size/morphology induced tunable upconversion properties. In addition to the common phenomenon aroused by a surface quenching effect, direct experimental evidence for the regulation of phonon modes is obtained in nanoparticles. The findings in this work advance the existing mechanisms for the general explanation of size/morphology induced upconversion features. Because of the adjustment of phonon energy and density as well as the surface quenching effect, the biocompatible Lu5 O4 F7 :Er 3+, Yb 3+ nanoparticles exhibit an ultra-strong single-band red upconversion, rendering them promising for biomedical applications.