Effects of Li+ Doping Concentration on Structure and Photoluminescence of the Y2O3: Ho3+/Yb3+ Up-conversion Film
Min Sun
School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
Wenbo Hou
School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
Juncheng Liu *
School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
Lifang Nie *
School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
*Author to whom correspondence should be addressed.
Abstract
The Li+ co-doped Y2O3: Ho3+/Yb3+ films were prepared with sol-gel method and spin-coating technique. The effects of Li+ on the structure and luminescent properties of the films were investigated. The results show the grain size increased first and then decreased with the increase of Li+ doping concentration. The crystal size of particles composing the film got the maximum value when Li+ concentration took 4 mol%. As Li+ doping concentration increased, the optical transmittance of the Y2O3: Ho3+/Yb3+ film improved at first then reduced and got the maximum at 3 mol%. Excited with a 980-nm laser, there were two green emissions in the up-conversion emission spectra, one centered at 535 nm, the other at 550 nm, which ascribed to the 5F4→5I8 and 5S2→5I8 transitions of Ho3+, respectively. The up-conversion luminescence intensity also increased firstly and then decreased with the Li+ doping concentration increase, and got the highest value at 2 mol%.
Keywords: Photoluminescence, sol-gel, Y2O3 film, Ho3 /Yb3 , up-conversion.