Eu2+–Mn2+ energy transfer in white-light-emitting T-phase (Ba,Ca)2SiO4:Eu2+, Mn2+ phosphor

White-light-emitting T-phase Eu2+/Mn2+-codoped (Ba, Ca)2SiO4 phosphors are achieved in terms of the energy transfer between Eu2+ and Mn2+ ions. All spectra consist of the relatively broad green and the red emission bands, which thus result in a warm-white color with a color temperature of ∼4000 K. With increasing Eu2+ ions at fixed Mn2+ concentrations, a strong correlation between the luminescence and the electron paramagnetic resonance spectra is observed. This demonstrates that Eu2+ doping causes a perturbation of Mn2+ sites and the violation of their selection rules that enhances Mn2+-related emissions.