Photoluminescence properties of double perovskite Ca2LuTaO6:Bi3+/Sm3+ white light emitting phosphors

Abstract

The high-temperature solid state reaction approach was used to successfully synthesize novel tunable-color emitting Ca2LuTaO6 phosphors with double perovskite structure that were un-doped, single-doped, and co-doped with Bi3+/Sm3+ ions. The crystal structure, microstructure, steady-state photoluminescence, time-resolved luminescence measurements, and thermal quenching features of the material were studied. The density functional theory method was used to compute the band gap of the Ca2LuTaO6, and Ca2LuTaO6: Bi3+, Sm3+ phosphors. The blue emission at 407 nm (with 313 nm excitation) is due to the host's luminescence, while the cyan emission at 480 nm (under 365 nm excitation) is related to the distinctive 3Pn − 1S0 transitions (n = 0, 1, 2) of Bi3+. Similarly, efficient red emission is observed in the case of Sm3+ single-doped Ca2LuTaO6 phosphors. In addition, the Ca2LuTaO6: 0.04Bi3+, 0.05 S m3+ phosphors exhibit energy transfer phenomena and have excellent thermal stability, the fluorescence intensity at 150 °C maintains 73% of that at 25 °C and has a small chromaticity shift. The intense blue emission at 407 nm was effectively converted to cyan, red, and white light through doping with Bi3+ and Sm3+, and the resulting energy transfer. The results obtained confirm that Ca2LuTaO6: Bi3+, Sm3+ phosphors as a single matrix have great potential for high-power WLED applications.