A long-term stable zero-thermal-quenching blue-emitting phosphor for sustainable and human-centric lighting

Abstract

Human-centric lighting can reduce the proportion of harmful short-wave blue light, relieve visual fatigue, and regulate the normal physiological rhythm of human beings. However, the development of healthy lighting is stringently restricted because few blue phosphors can be efficiently pumped by violet LED chips (395–405 nm). Herein, we have developed a blue-emitting phosphor Sr_1.91Mg_0.66Al_22.33O₃₆:Eu²⁺ with high internal quantum efficiency under 395 nm excitation, which contains more cyan and fewer blue components. Surprisingly, the material shows zero-thermal-quenching even when the temperature is as high as 200 °C. The defect related thermal quenching mechanism was demonstrated through thermoluminescence and electron paramagnetic resonance analysis. Moreover, the phosphor exhibits good long-term stability when it is exposed to air for 2.5 years. Finally, a blue light weakened warm white light-emitting diode (WLED) has been achieved by packaging commercial phosphors and Sr_1.91Mg_0.66Al_22.33O₃₆:Eu²⁺ on a 395 nm LED chip, with a low correlated color temperature of 3919 K and a high color index of 90.2. All results indicate that the Sr_1.91Mg_0.66Al_22.33O₃₆:Eu²⁺ phosphor has the ability to promote sustainable and human-centric lighting.