Eu3+ red luminescence in new phosphomolybdates La0.8−xCaxP1−xMoxO4:0.2 Eu3+ (x = 0.1, 0.2 and 0.3) under broad excitation for WLED applications

Abstract

Eu³⁺ red phosphors in new phosphomolybdates, La_0.8−xCa_xP_1−xMo_xO₄ were developed by high-temperature ceramic route. These phosphors show intense red emission under broad excitation of the charge transfer band (CTB) (345 nm), near UV (394 nm) and blue (464 nm) wavelengths. The incorporation of CaMoO₄ in LaPO₄ reduces CTB energy of MoO₄²⁻ tetrahedron, making it to overlap with Eu³⁺ excitations and also enhances the distortion of Eu³⁺ environment. These factors facilitate the effective energy transfer from the host to Eu³⁺ excitation levels leading to intense red emissions unlike orange emission in LaPO₄. The Commission International d'Eclairage colour coordinates of phosphors (0.66, 0.34), are very close to the standard red phosphor. Thus, the new phosphomolybdate red phosphors are a mode to enhance the Eu³⁺ absorptions making them promising candidates for white light-emitting diode applications.