title: Size dependent ultraviolet upconversion in single YF3:Yb3+/Tm3+ particles.
abstract: Yb3+-Tm3+ codoped YF3 bulk material was synthesized through a facile high-temperature calcinations method. By grinding and selecting, the particles with different desired sizes in microns were obtained. Under 980 nm excitation, optical upconversion (UC) from near-infrared (NIR) to ultraviolet (UV) was studied for each group of particles for the effect of their size on UC. Comparing with the bulk sample, the micro-size particles exhibited strong ability for NIR-to-UV UC. With the particle size decreasing from 800 microm to 20 microm, their UV emission intensities increased rapidly. Two possible mechanisms were proposed and discussed for clarifying the small size effect (SSE).
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science & Engineering, Jilin University, Changchun 130012, P. R. China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Liu
authors.forename: Kezhi
authors.initials: K
authors.lastname: Zheng
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.forename: Weiping
authors.initials: W
authors.lastname: Qin