Photoluminescence enhancement and excellent thermal stability of Ca2ZnSi2O7:Pr3+ red-emitting phosphors through charge compensator A+ (Li+, Na+ and K+) co-doping for w-LED applications

Abstract

The red-emitting Ca2ZnSi2O7:Pr3+ phosphor was synthesized via a solid-state method and alkali metal ions A+ (Li+, Na+, K+) were introduced to improve the photoluminescence performance of Pr3+. XRD results confirmed that the sample structure did not change markedly with appropriate Pr3+/A+ co-doping. Under the blue light excitation of 447 nm, the as-prepared Ca2ZnSi2O7:Pr3+ efficiently emitted a characteristic red luminescence peak at 601 nm. The luminescence intensity of Pr3+ was obviously enhanced with A+ co-doping due to the charge compensation effect and the emission intensity of Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ reached 142.1% compared to Ca2ZnSi2O7:0.005Pr3+. Furthermore, at 210 °C the luminescence intensity of the Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ phosphor remained at ∼93% compared to at 30 °C, showing high thermal stability. The w-LED device packaged with Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ produced a bright white emission. All these results indicated the potential application prospects of red-emitting Ca2ZnSi2O7:Pr3+, A+ phosphors in the field of white light-emitting diodes.