Ce:(Lu,Sr)3(Al,Si)5O12 transparent ceramics for high-power white LEDs/LDs with ultra-high luminance saturation threshold

Abstract

As a new generation solid state lighting source, high-power phosphor-converted white light-emitting diode or laser diode (LED/LD) lighting has drawn much attention. However, under the excitation of a high power density laser, the high temperature induced performance degradation of thermal stability and color quality for green conversion materials becomes the major challenge. In this work, heavy atom Sr²⁺ and highly charged Si⁴⁺ were used to substitute Lu³⁺ and Al³⁺, displaying the effect of lattice relaxation depression. The remarkable 98% emission intensity of TCs was retained at 150 °C, and the abnormal thermal quenching phenomenon was discovered. The optimized TC-based LD devices exhibited an ultra-high luminance saturation threshold of 65 W mm⁻², and the ceramic surface temperature was dramatically reduced to 114.4 °C at ∼50 W mm⁻². More importantly, the luminous efficiency of radiation (LER) was also maintained to be as high as 261.98 lm W⁻¹. Ce:LSASG TCs showed excellent thermal quenching behavior and the highest saturation threshold. This result provides a new path to design innovative photoelectric materials with favorable thermal stability for high power devices.