Synthesis and spectroscopic characterization of YPO4 activated with Tb3+ and effect of Bi3+ co-doping on the luminescence properties

Single crystals of YPO4:Tb3+(1%) have been grown from Pb2P2O7 flux and their emission dynamics have been characterized by steady state and time resolved optical spectroscopy. The investigation has then been extended to green emitting phosphors with composition Y0.95−xTb0.05BixPO4 (x=0, 0.0025, 0.005, 0.01, 0.025), synthesized by the Pechini sol–gel method and by solid state reaction. The former procedure has yielded higher quality materials in terms of size and morphology of the particles and of emission performance. The effect of the Bi3+ co-doping on the emission properties has been related to the Bi3+→Tb3+ energy transfer process as well as to the influence of the bismuth ions on the optical properties of the host lattice. - Graphical abstract: The intensity of the 370 nm excited luminescence increases with the Bi3+ content. A possible mechanism accounting for this behavior is proposed and discussed. Highlights: ► Green emitting YPO4:Tb3+ phosphors were synthesized by different methods. ► The emission dynamics have been investigated under different experimental conditions. ► The co-doping with Bi3+ ions increases the emission performance of the phosphors.