Temperature-induced phase transition and temperature sensing behavior in Yb3+ sensitized Er3+ doped YPO4 phosphors

With the increases of calcination temperature, the phase of yttrium phosphate transforms from hexagonal to tetragonal phase at 700 °C and the fluorescence intensity ratio (FIR) of green UC luminescence originated from 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ also rectilinearly increases.284