Unraveling the Remarkable Influence of Square Antiprism Geometry on Highly Efficient Far‐Red Emission of Eu3+ in Borotellurate Phosphors for Versatile Utilizations

• Published in: Laser & photonics reviews 2024-12, Vol.18 (12), p.n/a
• Main Authors: Li, Hong, Niu, Yingfan, Liu, Conglin, Jiang, Hongming, Li, Junpeng, Wu, Jianze, Huang, Shuping, Zhang, Hongzhi, Zhu, Jing
• Format: Article
• Language: English
• Subjects: borotellurate; compositional engineering; Effectiveness; Emission spectra; Europium; far‐red emission; Gadolinium; Lighting; Luminous efficacy; Phosphors; security ink; solid‐state lighting; Thermal stability
• ISSN: 1863-8880; 1863-8899
• DOI: 10.1002/lpor.202400843

Eu3+‐activated red‐emitting inorganic phosphors have been favored highly for their classical 5D0→7FJ (J = 0, 1, 2, 3, 4) emissions. However, the fatal drawbacks of poor luminous efficacy and weak 5D0→7F4 transition persist, resulting in the ongoing challenge of achieving far‐red emission. This research reports series of highly efficient far‐red phosphors LnTeBO5 (Ln = La3+, Y3+, Gd3+):Eu3+ with anomalously strong 5D0→7F4 transition, resulting from the distorted square antiprism [Ln/EuO8]. Both the luminous efficacy and thermal stability can be greatly enhanced via the simple composition variation. [Ln/EuO8] square antiprism‐triggered 5D0→7F2,4 transitions are elucidated in depth, acquiring ultra‐high luminous efficacy (IQE = 95%, EQE = 40%, and AE = 42%) and near‐zero thermal quenching (99%@150°C and 98%@200°C). Subsequently, the versatile utilizations in indoor lighting, plant growth lighting, and security ink are illustrated. This finding establishes a deep understanding for constructing high‐quality far‐red phosphors via the Eu3+‐centered structural units of square antiprism. Anomalously strong 5D0→7F4 transitions are obtained in LnTeBO5 (Ln = La3+, Y3+, Gd3+):Eu3+ owing to the distorted square antiprism [Ln/EuO8]. The optimal phosphor GTBO:45%Eu3+ exhibits ultra‐high luminous efficacy (IQE = 95%, EQE = 40%, and AE = 42%) via tuning 5D0→7F2,4 transitions. Meanwhile, GTBO:45%Eu3+ exhibits near‐zero thermal quenching luminescence via simple composition variation. The versatile utilizations are illustrated.