Upconversion Modulation through Pulsed Laser Excitation for Anti-counterfeiting.

ABSTRACT: Lanthanide-doped upconversion nanomaterials are emerging as promising candidates in optoelectronics, volumetric display, anti-counterfeiting as well as biological imaging and therapy. Typical modulations of upconversion through chemical methods, such as controlling phase, composition, morphology and size enable us to rationally manipulate emission profiles and lifetimes of lanthanide ions by using continuous-wave laser excitation. Here we demonstrate that under pulsed laser excitation the emission color of NaYF₄:Er/Tm (2/0.5%)@NaYF₄ core-shell nanoparticles has an obvious transformation from green to red colors. Moreover, both pulse duration and repetition frequency are responsible for manipulating the upconversion emission color. The mechanism of the phenomena may be

SUBMITTER: Han Y 

PROVIDER: S-EPMC5430986 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature