Upconversion Performance Enhancement of NaYF 4:Yb/Tm by Codoping Hf 4+ as Energy Migrator
Huang Qingming, Yu Han, Zhang Xinqi, Cao Wenbing, Yu Jianchang
Acta Chim. Sinica . 2016, (2): 191 -198 .  DOI: 10.6023/A15040257