Abstract: LiMgPO₄ and LiMgPO₄∶Dy were synthesized by high-temperature solid-state method and sol-gel method. The effects of different synthesis methods on crystal structure, morphology and luminescence properties of LiMgPO₄∶Dy were studied using thermogravimetry-differential thermal analyzor, X-ray diffractometer, Fourier transform infrared spectrometer, scanning electron microscope, ultraviolet-visible spectrophotometer and fluorospectro-photometer. The results show that the lowest synthesis temperature by sol-gel method is 750 ℃ and no other crystal phases are found in the crystal, while a small amount of Mg₃(PO₄)₂ crystal phases are found in the sample synthesized by high-temperature solid-state method at 950 ℃. The morphology of the samples synthesized by sol-gel method is better than that synthesized by high-temperature solid-state method. Samples synthesized by both methods show low absorbance in the visible region. In the ultraviolet region, the absorbance of the sample synthesized by high-temperature solid-state method is higher than that synthesized by sol-gel method. The optical band gap range of LiMgPO₄∶Dy synthesized by high-temperature solid-state method is 3.76~3.93 eV, and that of LiMgPO₄∶Dy synthesized by sol-gel method is 3.85~3.94 eV. The synthesis method has little effect on the optical band gap of the sample. The optimal excitation wavelength of LiMgPO₄∶Dy is 350 nm, and the strongest emission wavelength is 579 nm. The luminescence intensity of the samples synthesized by sol-gel method is better than that synthesized by high-temperature solid-state method.

Key words: LiMgPO₄∶Dy, sol-gel method, high-temperature solid-state method, crystal structure, optical band gap, luminescence property