Achievement of high photoluminescence quantum yield orange-red phosphors by designing Eu2+ reduction environment for multi applications

Abstract

The high photoluminescence quantum yield (PLQY) orange-red phosphor, which is of great significance for the application of phosphor-converted light-emitting diode (LED). Herein, the novel BaSrLu4O8:Eu2+ orange-red phosphor was synthesized, and the PLQY is enhanced from 30 % to 91 % by Al2O3 assisted sintering. Combined with the trap energy level analysis, it is considered that the addition of Al2O3 introduces new vacancies, which release electrons during high temperature sintering, creating a more favorable environment for the reduction of Eu3+, increasing the Eu2+ luminescence center in the matrix and improving the PLQY. The white LED device prepared with BaSrLu4O8:Eu2+ and Y3(Al,Ga)5O12:Ce3+ has a color rendering index of 84.4 at a low correlated color temperature of 4295 K. Meanwhile, the luminous brightness of the orange LED prepared by BaSrLu4O8:Eu2+ can maintain 89 % of the original light intensity in the simulated foggy day illumination experiment, which proves its excellent lighting prospect as an automobile steering lamp in foggy and smog extreme conditions. The results indicate that this work provides a new strategy for the reduction of Eu2+ while realizing the multi-application of phosphors.