Narrow-band red-emitting phosphors are a critical component in phosphor-converted light-emitting diodes for highly efficient illumination-grade lighting. In this work, we report the discovery of a quantitative descriptor for narrow-band Eu2+-activated emission identified through a comparison of the electronic structure of known narrow-band and broad-band phosphors. We find that a narrow emission bandwidth is characterized by a large splitting of more than 0.1 eV between the two highest Eu2+ 4f7 bands. By incorporating this descriptor in a high throughput first principles screening of 2,259 nitride compounds, we identify five promising new nitride hosts for Eu2+-activated red-emitting phosphors that are predicted to exhibit good chemical stability, thermal quenching resistance and quantum efficiency, as well as narrow-band emission. Our findings provide important insights into the emission characteristics of rare-earth activators in phosphor hosts, and a general strategy to the discovery of phosphors with a desired emission peak and bandwidth.
Uncovering the origin of the emitting states in Bi3+-activated CaMO3 (M = Zr, Sn, Ti) perovskites: metal-to-metal charge transfer versus s-p transitions
Importance of long-range channel Sr displacements for the narrow emission in Sr[Li$_2$Al$_2$O$_2$N$_2$]:Eu$^{2+}$ phosphor
最近发现的Sr[Li $_2$ Al $_2$ O $_2$ N $_2$ ]：Eu $^{2+}$红色磷光体，下一代生态高效白光发光二极管的候选者，表现出优异的发射光谱位置和异常小的线宽。它属于UCr $_4$ C $_4$ -结构的磷光体家族，包含许多潜在的候选商业磷光体，其小线宽，暂时归因于掺杂位点的高对称性立方体环境，在过去五年中引起了研究人员的注意。我们使用密度泛函理论，$Δ$ SCF方法和组态坐标模型（CCM）提供了一个完整的表征这种材料。利用多维CCM，得到了电子5d $\rightarrow$ 4f跃迁与振动结构耦合的精确描述，包括部分Huang-Rhys因子和主模的频率.我们发现，除了第一配位壳长方体变形模式，低频声子模式涉及链的锶原子沿四轴形状的发射线宽在Sr[Li $_2$ Al $_2$ O $_2$ N $_2$ ]：Eu $^{2+}$。这一发现揭示了UCr $_4$ C $_4$结构荧光粉的发光特性，具有类似的Ca/Sr/Ba通道。我们的方法提供了一个强大的理论框架，系统地研究这种Eu掺杂的荧光粉的发射光谱，并预测候选人与预期的相似或甚至更尖锐的线宽。
Machine Learning a Phosphor's Excitation Band Position
University of Houston（休斯顿大学）；Texas Center for Superconductivity, University of Houston（休斯顿大学超导中心）；Harvard University Center for the Environment（哈佛大学环境中心）；Pohang Accelerator Laboratory, POSTECH（浦项工科大学波哈克加速器实验室）；School of Chemistry, University of Birmingham（伯明翰大学化学学院）
