In this Letter, the 75P2O5–25SrO phosphate glass co-doped with SnO2/Tm3+ and SnO2/Eu3+ were prepared
and their photoluminescence spectra were investigated. Compared with the singly SnO2, Tm3+ ions or
Eu3+ ions doped glasses, the SnO2/Tm3+ co-doped sample exhibit an enhanced Tm3+ ions emissions at
455 and 698 nm and the constant SnO2 emission, while for the SnO2/Eu3+ co-doped sample, all emissions
of Eu3+ ions increased at the cost of SnO2 emission. The different luminescence behaviors of these glasses
were discussed and an energy transfer mechanism from SnO2 to Tm3+ ions was proposed combined the
down-conversion and the sub-up-conversion processes