Photoluminescence properties of γ-Ca3(PO4)2:Sm3+ prepared under high-pressure and high-temperature conditions

gamma-Ca-3(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 gamma-Ca-3(PO4)(2):Sm3+ exhibit a series of narrow peaks attributed to the typical f-f transition of Sm3+. The emission spectra of gamma-Ca-3(PO4)(2):Sm3+ compose of four bands attributed to transitions from (4)G(5/2) excited state to H-6(J/2) (J = 5, 7, 9 and 11) ground states of Sm3+. The average decay lifetimes were obtained by fitting the decay curves for H-6(7/2) level of Sm3+ emission using a double exponential function. The photoluminescent spectra of gamma-Ca-3(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 gamma-Ca-3(PO4)(2):Sm3+ samples. The critical concentration of Sm3+ in gamma-Ca-3(PO4)(2) is about 1.0 mol%. (C) 2015 Elsevier B.V. All rights reserved.