Temperature and excitation power-resistant white-light emission of the TT-phase (Ba,Ca)2SiO4:Eu2+,Mn2+ phosphor

White-light generation is achieved by codoping a TT-phase Ba1.2±δCa0.8±δSiO4 lattice with Eu2+ and Mn2+ ions. The phosphor exhibits a red emission from Mn2+ and a broad blue–green emission from Eu2+. Both emissions are slowly quenched at the same decay rate as the excitation power/temperature increase resulting in no variation in white-color quality. Optically-active Mn2+ in this structure occupies the six-coordinated site with its different environment from optically-inactive Mn2+ in other orthosilicates. The white-light-emitting diode using this phosphor and a 420 nm chip demonstrated white light with a color temperature of 4600 K and a deluxe color rendering index of 92.