A red phosphor Mg3Y2Ge3O12: Bi3+, Eu3+ with high brightness and excellent thermal stability of luminescence for white light-emitting diodes

Abstract

Abstract In the past few decades, a variety of red phosphors have been designed and developed. However, most of them are not satisfying for the sake of low brightness and poor thermal stability. Here, we report the preparation and luminescence properties of a promising red phosphor Mg3Y2Ge3O12: Bi3+, Eu3+. Eu3+ singly doped samples can emit bright reddish light. In Bi3+ and Eu3+ co-doped samples, there exists effective energy transfer from Bi3+ to Eu3+. The co-doping of Bi3+ can remarkably enhance the luminescence of Eu3+. The integrated emission intensity of Mg3Y1.19Ge3O12: 0.01Bi3+, 0.8Eu3+ is greater than that of commercial red phosphor Y2O3: 0.05Eu3+. More importantly, the luminescence of this phosphor also shows excellent thermal stability and relatively high quantum efficiency (63.89%). When the ambient temperature rises to 423 K, the integrated emission intensity remains 94.42% of the one at room temperature and quantum efficiency still remains 51.24%. All these investigation results prove that Mg3Y2Ge3O12: Bi3+, Eu3+ is a promising red phosphor for white light-emitting diodes.