Er3+ activated BaLaGaO4 multifunctional green phosphors for optical thermometers and WLEDs

Er 3+ -doped BaLaGaO 4 green phosphors was synthesized through a high-temperature solid-state reaction technique. The phase structure and morphology test results of the phosphor indicate that the BaLaGaO 4 material was successfully synthesized and Er 3+ ions were successfully doped into the main lattice. This doping does change the basic structure of the crystal. BaLaGaO 4 :Er 3+ phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light. The optimal doping concentration is found to be x = 0.04. To quantify the temperature sensitivity of the phosphor, the fluorescence intensity ratio method was used. Within the temperature range of 298–473 K, the maximum relative sensitivities are 1.35%/K (298 K, 381 nm) and 1.45%/K (298 K, 980 nm), respectively. The maximum absolute sensitivities are 0.67%/K (473 K, 381 nm) and 0.69%/K (473 K, 980 nm), respectively. Finally, white light-emitting diodes (WLEDs) with a high colour index of Ra = 82 and a relatively low correlated colour temperature of CCT = 5064 K are obtained by integrating the synthesized BaLaGaO 4 :0.04Er 3+ green phosphor into warm WLEDs devices. These results suggest that Er 3+ -activated BaLaGaO 4 multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion. A new green phosphor BaLaGaO 4 :Er 3+ was synthesized by high temperature solid phase method. It showed good temperature dependence under both 381 and 980 nm excitation. In terms of WLEDs applications, it has good display index and relevant colour temperature. • BaLaGaO 4 :Er 3+ novel green phosphor was firstly synthesized by high-temperature solid-phase method. • BaLaGaO 4 :Er 3+ phosphor exhibits good temperature dependence under excitation at 381 nm and 980 nm with maximum relative sensitivities of 1.35% K -1 (298 K, 381 nm) and 1.45% K -1 (298 K, 980 nm) in the temperature range of 298 – 473 K. • The maximum absolute sensitivities are 0.67% K -1 (473 K, 381 nm) and 0.69% K -1 (473 K, 980 nm), respectively. • The WLED prepared by the phosphor emits white light with excellent color rendering index and correlated color temperature (CRI = 82, CCT = 5064 K).