Using energy transfer to obtain warm white-emitting and thermally stable Ca3Y(AlO)3(BO3)4:Dy3+, Eu3+ phosphors

Abstract

A series of color-tunable warm white-emitting phosphors Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ were synthesized and characterized for their crystal structure, luminescence properties, thermal stability, fluorescence decay and energy transfer mechanism. The results show that the optimal excitation wavelength and doping concentration of Ca3Y(AlO)3(BO3)4:Dy3+ phosphor are 350 nm and 0.05 mol%, respectively, and its concentration quenching is mainly caused by the interaction between nearest neighbor ions. Under the excitation at 350 nm, the Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphor showed prominent emission peaks at 471 nm, 576 nm and 622 nm. The photoluminescence spectrum and lifetime decay curves confirmed the presence of Dy3+→Eu3+ energy transfer in Ca3Y(AlO)3(BO3)4. The phosphor of Ca3Y0·85(AlO)3(BO3)4:0.05Dy3+,0.1Eu3+ exhibited remarkable thermal stability and could maintain 87.68% of the emission intensity at 150 °C. By adjusting the doping ratio of Dy3+ and Eu3+ ions, the CIE coordinates and the related color temperature of Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphors can be adjusted. The w-LED device packaged with Ca3Y0·85(AlO)3(BO3)4:0.05Dy3+,0.1Eu3+ phosphor can emit warm-white light (Tc = 3284 K, Ra = 72.7). These results suggest that Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphor can provide a potential alternative for the warm w-LED market.