MGa2B2O7:Bi3+,Al3+ (M = Sr, Ba) blue phosphors with a quantum yield of 99% and negative thermal quenching

Abstract

By optimizing the Debye temperature, we identified two extremely efficient phosphors based on the S–P transition of Bi³⁺. The quantum yields of Sr_0.99Ga_1.50B₂O₇:0.01Bi³⁺,0.50Al³⁺ and Ba_0.995Ga_1.60B₂O₇:0.005Bi³⁺,0.40Al³⁺ phosphors reach 96% and 99%, respectively. Moreover, Sr_0.99Ga_1.50B₂O₇:0.01Bi³⁺,0.50Al³⁺ exhibits negative thermal quenching, which shows unique advantages for practical application. The blue phosphors with quantum efficiencies close to unity and superior thermal stability can be competitive candidates for practical applications.