Eu²⁺ activated Mg₂Al₄Si₅O₁₈ cordierite phosphor is prepared by sol gel synthesis. The reduction process is carried out in a vacuum atmosphere. X‐ray diffraction, luminescence, decay times, quantum yield and emission thermal stability are studied. The emission from Eu²⁺ ions at different lattice sites, such as magnesium vacancies and inside the interstate channels, are identified and discussed. Considerations on crystal field strength and bond length allow to assign the blue emission band peak at 445 nm to Eu²⁺ ions located inside the interstitial channel, while the red band centered at 615 nm is related to Eu²⁺ ions on Mg site. It is found that the Mg₂Al₄Si₅O₁₈:Eu²⁺ phosphor excited by UV shows broad emission from 375 to 700 nm with high quantum efficiency (60%). The emission of Eu²⁺ in Mg₂Al₄Si₅O₁₈ has very good thermal stability, at 100 °C the intensity reaches 97% relative to the emission measured at room temperature. The investigations show that cordierite can be used as a temperature sensor with relative sensitivity of 0.45% at 400 °C. Moreover, the fabricated light‐emitting diode composed of 365 nm near‐UV chip and Mg₂Al₄Si₅O₁₈:Eu²⁺ phosphor exhibits bright white light with CIE coordinates (0.32, 0.34) for correlated color temperature of 6282 K and color rendering index of 82.

中文翻译：

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位于Mg2Al4Si5O18堇青石的通道和Mg站点中的Eu2 +的高效发射及其作为双功能荧光粉的潜力，对光学温度计和白光LED应用

通过溶胶凝胶合成法制备了Eu ²⁺活化的Mg ₂ Al ₄ Si ₅ O ₁₈堇青石荧光粉。还原过程在真空气氛中进行。研究了X射线衍射，发光，衰减时间，量子产率和发射热稳定性。确定并讨论了Eu ²⁺离子在不同晶格位置（例如镁空位和州际通道内部）的发射。考虑到晶体场强度和键长，可以将445 nm处的蓝色发射带峰分配给位于间隙通道内的Eu ²⁺离子，而中心在615 nm处的红色带与Eu ²⁺相关镁离子。发现由UV激发的Mg ₂ Al ₄ Si ₅ O ₁₈：Eu ²⁺磷光体显示出从375到700nm的宽发射，具有高量子效率（60％）。Mg ₂ Al ₄ Si ₅ O ₁₈中Eu ²⁺的发射具有非常好的热稳定性，在100°C下，其强度相对于室温下的发射达到97％。研究表明，堇青石可用作温度传感器，在400°C下的相对灵敏度为0.45％。此外，由365 nm近紫外芯片和Mg ₂ Al ₄ Si组成的发光二极管₅ O ₁₈：Eu ²⁺荧光粉显示亮的白光，其CIE坐标为（0.32，0.34），相关色温为6282 K，显色指数为82。