The discovery of pure-red emitting phosphor is great meaningful for the achievement of high color rendering index white light emitting diodes, but still a challenge due to the strict crystal field limitations. In this work, we demonstrate the preparation of a 630 nm pure-red emitting CaSiO:Eu phosphor for the first time through a CO reduction strategy. The changes in crystal field strength caused by different methods for the preparation of CaSiO:Eu are investigated and discussed based on the understanding of the thermodynamic theory and structure resolution. Finally, a white light-emitting diode with a high color rendering index (Ra = 98) is accomplished by combining the as-prepared CaSiO:Eu pure-red emitting phosphor with a 375 nm chip and the commercial used blue and green phosphors. The results also demonstrate the generalizability of the weak reduction strategy for the exploration of “redder” Eu doped phosphors.

中文翻译：

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CO还原策略得到的纯红色荧光粉Ca3Si2O7:Eu2+

纯红色荧光粉的发现对于实现高显色指数白光发光二极管具有重要意义，但由于严格的晶体场限制，仍然是一个挑战。在这项工作中，我们首次展示了通过 CO 还原策略制备 630 nm 纯红色发射 CaSiO:Eu 荧光粉。基于对热力学理论和结构分辨率的理解，研究和讨论了不同制备CaSiO:Eu方法引起的晶体场强的变化。最后，将所制备的CaSiO:Eu纯红色荧光粉与375 nm芯片和商用的蓝色和绿色荧光粉相结合，制成了具有高显色指数（Ra = 98）的白光发光二极管。结果还证明了弱还原策略对于探索“更红”Eu 掺杂荧光粉的普适性。