Enhanced photoluminescence property of single-component CaAlSiN3: Ce3+, Eu2+ multicolor phosphor through Ce3+-Eu2+ energy transfer

A series of single-component CaAlSiN3: Ce3+, Eu2+ phosphors with dual emission colors (yellow and red) were successfully prepared via a direct-nitriding method to achieve spectral tuning and broadening of CaAlSiN3: Eu2+ red phosphor. Crystal structure, morphology, photoluminescence properties and energy transfer mechanism were thoroughly investigated. The particular plate-like morphology of CaAlSiN3: Ce3+, Eu2+ phosphor was obtained due to the lattice distortion and preferential orientation growth of host lattice originated from the introduction of Ce3+ into CaAlSiN3. More interestingly, the luminescent intensity of red emission peak was enhanced through an energy transfer process between Ce3+ and Eu2+ ions. Under excitation of 460 nm, CaAlSiN3: 0.02Ce3+, 0.001Eu2+ phosphor exhibited intense and broad emission peaks centered at 580 nm (yellow) and 618 nm (closely near to the red isochromatic region around 615 nm). Furthermore, the energy transfer mechanism from Ce3+ to Eu2+ ion was determined to be electric dipole-dipole interaction and the energy transfer efficiency was 94%. The CaAlSiN3: Ce3+, Eu2+ phosphors showed super broad excitation spectra from 270 to 500 nm, high external quantum efficiency (74%) and small thermal quenching. Evidently, CaAlSiN3: Ce3+, Eu2+ samples may be potential candidates of red phosphor for improving optical performance of illumination-grade light sources.