A series of Dy3+ and Eu3+ co-doped Sr3Gd(PO4)3 phosphors were synthesized by a high-temperature solid-state method. The crystal structure, optical band gap energy, luminescence properties, concentration quenching, energy transfer process and thermal stability were investigated. All the phosphors are pure eulytite-type Sr3Gd(PO4)3 in structure. Under different wavelengths’ excitation, the Sr3Gd(PO4)3:Dy3+, Eu3+ phosphors exhibit different emission intensities for Eu3+ and Dy3+. The color and correlated color temperature (CCT) can be tuned from cool white to warm white by adjusting excitation wavelengths and the doping concentration of Eu3+. Under the 351-nm excitation, the optimal Sr3Gd(PO4)3:0.03Dy3+, 0.085Eu3+ phosphor displays a warm white emission with CIE coordinate of (0.3987, 0.3613), CCT of 3409 K, internal quantum efficiency of 44.8% and activation energy of 0.1883 eV. These results suggest that single-phased white-emitting phosphors Sr3Gd(PO4)3:Dy3+, Eu3+ can be used in the near-ultraviolet light-emitting diodes.

中文翻译：

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Eu3+ 共掺杂 Sr3Gd(PO4)3:Dy3+ 荧光粉：NUV-WLED 的发光特性和颜色可调白光发射

采用高温固相法合成了一系列Dy3+和Eu3+共掺杂的Sr3Gd(PO4)3荧光粉。研究了晶体结构、光学带隙能量、发光特性、浓度猝灭、能量转移过程和热稳定性。所有的荧光粉在结构上都是纯钠沸石型Sr3Gd(PO4)3。在不同波长的激发下，Sr3Gd(PO4)3:Dy3+、Eu3+荧光粉对Eu3+和Dy3+表现出不同的发射强度。通过调整激发波长和 Eu3+ 的掺杂浓度，可以将颜色和相关色温 (CCT) 从冷白调到暖白。在 351 nm 激发下，最佳 Sr3Gd(PO4)3:0.03Dy3+, 0.085Eu3+ 荧光粉显示出暖白光发射，CIE 坐标为 (0.3987, 0.3613)，CCT 为 3409 K，内量子效率为 44。8%，活化能为 0.1883 eV。这些结果表明，单相白光荧光粉 Sr3Gd(PO4)3:Dy3+、Eu3+ 可用于近紫外发光二极管。