. Conclusions
In summary, a series of CMW:Bi3+ yellow-emitting phosphors are synthesized by high temperature solid-state reaction method in air. The crystal structures, fluorescence lifetimes, and luminescence properties are investigated. XRD patterns confirm that all samples have a pure phase CMW. Host CMW with excitation 297 nm emits blue light and the corresponding CIE chromaticity coordinate is (0.169, 0.16). CMW:Bi3+ phosphor with excitation 338 nm can emit yellow light and the corresponding CIE chromaticity coordinate is (0.383, 0.477). Broad PL band peaking at ~550 nm of CMW:Bi3+ phosphor with excitation 338 nm can be observed in the range of 400–780 nm due to the 3P1,0 → 1S0 transitions of Bi3+ ion and the D → 1S0 radiative decay. PLE spectrum of CMW:Bi3+ phosphor monitored at 550 nm contains two PLE bands with the range 200–400 nm, which are attributed to O2− → W6+ CT in the [WO6] group (200–300 nm) and 1S0 → 3P1 transitions of Bi3+ ion (300–400 nm), respectively. The optimal Bi3+ ion actual concentration is about 0.38 mol% in CMW:Bi3+ phosphor. The luminous mechanism of CMW:Bi3+ phosphor is analyzed and explained by using energy level diagram of Bi3+ ion in solid including d0 cation. The experimental results are helpful to develop and research new Bi3+-doped materials.
Acknowledgments