Synthesis and upconversion luminescence of NaYF4:Yb3+,Tm3+/TiO2 nanocrystal colloidal solution.
NaYF4:Yb3+,Tm3+ upconversion nanocrystals were synthesized with oleic acid as a capping ligand. The as-prepared samples were redispersed in cyclohexane, forming transparent and stable solutions which perform bright blue upconversion. Inducing TiO2 as the outer layer of the fluoride cores, we investigated the effect of TiO2 on the upconversion process. The transmission electron microscopy (TEM) analysis indicated that titania successfully formed a coating layer on the surface of NaYF4:Yb3+, Tm3+ nanoparticles, and the average diameters of the NaYF4:Yb3+,Tm3+ nanocrystals and the NaYF4:Yb3+, Tm3+/TiO2 nanoparticles are about 14 and 40 nm, respectively. Under the excitation of a 980 nm laser, NaYF4:Yb3+, Tm3+ nanocrystals and TiO2-coated NaYF4:Yb3+, Tm3 core/shell structure sample exhibited distinct upconversion luminescent properties.
Xue
Xiao-Jie
XJ
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China.
Qin
Weiping
W
Zhang
Dai-Sheng
DS
Zhao
Dan
D
Wei
Guo-Dong
GD
Zheng
Ke-Zhi
KZ
Wang
Li-Li
LL
Wang
Guo-Feng
GF