中国科学院地球化学研究所机构知识库

γ-Ca₃(PO₄)₂:Sm³⁺ samples were synthesized under high-pressure and high-temperature conditions. The samples were characterized by X-ray diffraction measurements. The excitation and emission spectra and fluorescence decay curves of synthesized samples were collected to study the photoluminescence properties. The excitation spectra of γ-Ca₃(PO₄)₂:Sm³⁺ exhibit a series of narrow peaks attributed to the typical f–f transition of Sm³⁺. The emission spectra of γ-Ca₃(PO₄)₂:Sm³⁺ compose of four bands attributed to transitions from ⁴G_5/2 excited state to ⁶H_J/2 (J = 5, 7, 9 and 11) ground states of Sm³⁺. The average decay lifetimes were obtained by fitting the decay curves for ⁶H_7/2 level of Sm³⁺ emission using a double exponential function. The photoluminescent spectra of γ-Ca₃(PO₄)₂:Sm³⁺show that the samples belong to a red-emitting phosphor and can be pumped in the near ultraviolet light region, which can easily be applied for NUV LED chips and thus in WLEDs. There exists a concentration quenching of Sm³⁺ in γ-Ca₃(PO₄)₂:Sm³⁺ samples. The critical concentration of Sm³⁺ in γ-Ca₃(PO₄)₂ is about 1.0 mol%.