Enhanced upconversion luminescence of TiO2:Ho3+-Yb3+ nanocrystals with modified structure via tri-doping Li+ ions

摘要

TiO2:Ho3+-Yb3+ nanomaterials with various Li+ concentrations were synthesized by the sol-gel method. The enhancement effect of Li+ ions on the upconversion luminescence of nanomaterials was investigated. Li+ ion doping promotes the dissolution of Ho3+ and Yb3+ in the matrix, as the charge imbalance caused by the substitution of Ti4+ with Ho3+ and Yb3+ can be compensated by Ti4+ - Ho3+ (Yb3+) + Li+ . The upconversion luminescence of TiO2:Ho3+-Yb3+ can be enhanced by improving the crystallinity of the matrix. The results show that maximum luminescence intensity can be obtained when the charge imbalance between Ho3+ (Yb3+) and Ti4+ is fully compensated by Li+ ion doping.