A double perovskite Ca2MgWO6:Bi3+ yellow-emitting phosphor: Synthesis and luminescence properties

Novel double perovskite Ca 2 MgWO 6 :Bi 3+ (CMW:Bi 3+ ) yellow-emitting phosphor is synthesized by solid-state reaction method in air. Host Ca 2 MgWO 6 with excitation 297   nm emits blue light and the chromaticity coordinate is (0.169, 0.160). The spectroscopic properties of CMW:Bi 3+ phosphor are explained on the basis of the Bi 3+ (6s 2 )–W 6+ (5d 0 ) metal-to-metal charge transfer (MMCT) transition. CMW:Bi 3+ phosphor with excitation 338   nm shows yellow light and the chromaticity coordinate is (0.383, 0.477). Broad emission band peaking at ~550   nm of CMW:Bi 3+ phosphor is observed in the range of 400–780   nm due to the D → 1 S 0 radiative decay and the 3 P 1,0 → 1 S 0 transitions of Bi 3+ ion. Monitored at 550   nm, excitation spectrum of CMW:Bi 3+ phosphor including a strong excitation peak at ~338   nm covers the region from 200 to 400   nm owing to the Bi 3+ → W 6+ MMCT transition and the 1 S 0 → 3 P 1 transition of Bi 3+ ion. The optimal Bi 3+ ion actual content is ~0.38   mol%. Emission spectra of CMW:Bi 3+ phosphor with excitation 338   nm shows blue-shift with increasing temperature from 50 to 300   K owing to the influence of temperature to electron transfer . The possible luminous mechanism of CMW:Bi 3+ phosphor is analyzed by energy level diagram of Bi 3+ ion in solid including d 0 cation.