Co-precipitation synthesis and photoluminescence properties of (Ca1−x−y,Lny)MoO4: xEu3+ (Ln = Y, Gd) red phosphors

(Ca1−x−y,Lny)MoO4: xEu3+ (Ln = Y, Gd) red phosphors were prepared by co-precipitation method with NH4HCO3–NH3·H2O system as the precipitating agent. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), and energy-dispersive X-ray spectrometer (EDS) were used to characterize the structure and composition of the phosphors. The synthesized (Ca1−x−y,Lny)MoO4: xEu3+ have scheelite structure with pure phase. FT-IR spectra show strong absorption peaks between 914 and 730 cm−1 which are assigned to the vibration of O–Mo–O in MoO42− tetrahedron. The EDS analysis reveals that the red phosphors have been successfully prepared by co-precipitation method according to theoretic ratio. Photoluminescence spectra show a red emission around 614 with 394 and 464 nm excitation, which is match well with the output wavelength of commercial ultraviolet and blue LED chips. The luminescent intensity of (Ca,Ln)MoO4: Eu3+ is obviously higher than that of CaMoO4: Eu3+.