The optical behavior and thermal stability of Na₅Y₉F₃₂ single crystals doped with fixed 1 mol% Dy³⁺ and various Sm³⁺ content grown by Bridgman technique were investigated by means of the fluorescence spectra, decay curves and temperature-dependent emission spectra. Upon 365 nm excitation, the emission color shifted from cool white emission to warm white emission as the Sm³⁺ concentration rise from 0 mol% to 1.6 mol%, in which the CIE coordinates experienced from (0.3445, 0.3888) to (0.3727, 0.3695) and the values of correlated color temperature (CCT) descended from 5114 K to 4174 K. The energy transfer (ET) from Dy³⁺ to Sm³⁺ identified by decay curves with emission spectra played significant effect on the change of emission color and the maximum energy transfer efficiency (ETE) was calculated to be 44.5% from the measured decay curves. Based on the Dexter's energy transfer formula, the mechanism of ET from Dy³⁺ to Sm³⁺ was determined as a dipole-dipole interaction. The down-conversion internal quantum yield (QY) of 1 mol% Dy³⁺/0.8 mol% Sm³⁺ co-doped Na₅Y₉F₃₂ single crystal was estimated to be ~15.9%. When excited by 365 nm, Dy³⁺/Sm³⁺ co-doped Na₅Y₉F₃₂ single crystals displayed excellent thermal stability deducing from the temperature-dependent emission spectra, in which the normalized emission intensity can still maintain 83% at 423 K. These results indicated that Dy³⁺/Sm³⁺ co-doped Na₅Y₉F₃₂ single crystal held potential application prospect in warm white light-emitting diodes (w-LEDs.)

通过荧光光谱、衰减曲线和随温度变化的发射，研究了用 Bridgman 技术生长的固定 1 mol% Dy ³⁺和各种 Sm ³⁺含量的 Na ₅ Y ₉ F ₃₂单晶的光学行为和热稳定性。光谱。在 365 nm 激发下，随着 Sm ³⁺浓度从 0 mol% 上升到 1.6 mol%，发射颜色从冷白发射转变为暖白发射，其中 CIE 坐标从 (0.3445, 0.3888) 到 (0.3727, 0.3695) ) 和相关色温 (CCT) 值从 5114 K 下降到 4174 K。 Dy ³⁺到 Sm ³⁺的能量转移 (ET)由衰减曲线与发射光谱确定对发射颜色的变化有显着影响，从测量的衰减曲线计算最大能量转移效率（ETE）为44.5％。基于Dexter 的能量转移公式，ET 从Dy ³⁺到Sm ³⁺的机制被确定为偶极-偶极相互作用。1 mol% Dy ³⁺ /0.8 mol% Sm ³⁺共掺杂Na ₅ Y ₉ F ₃₂单晶的下转换内量子产率（QY）估计为~15.9%。当被 365 nm 激发时，Dy ³⁺ /Sm ³⁺共掺杂 Na ₅ Y ₉ F ₃₂从温度依赖性发射光谱推断，单晶显示出优异的热稳定性，其中归一化发射强度在 423 K 时仍能保持 83%。这些结果表明 Dy ³⁺ /Sm ³⁺共掺杂 Na ₅ Y ₉ F ₃₂单晶在暖白光发光二极管（w-LEDs）中具有潜在的应用前景。