Achieving Broadband NIR Emission in Fe<sup>3+</sup>‐Activated ALaBB′O<sub>6</sub> (A = Ba, Sr, Ca; B–B′ = Li–Te, Mg–Sb) Phosphors via Multi‐Site Ionic Co‐Substitutions
Shikun Su, Chen Hu, Shaolei Ding, Yutong Sun, Lijie Sun, Yanfei Zou, Ronghui Liu, Zonghao Lei, Bing Teng, Degao Zhong
Abstract
Phosphor‐converted near‐infrared (NIR) LEDs are becoming increasingly demanded as miniature, portability, and broad emission spectrum. In this work, a class of Fe 3+ ‐activated double perovskite structured is reported ALaBB′O 6 (A = Ba, Sr, Ca; B–B′ = Li–Te, Mg–Sb) phosphors. Through the co‐substitution strategy at the A‐site and B‐B' sites, the emission spectral intensity and position of Fe 3+ ions can be tuned. Finally, by utilizing Ca 2+ at the A‐site and Mg–Sb co‐substitution for Li–Te, long‐wave NIR emission centered at 995 nm in CaLaMgSbO 6 : 0.6%Fe 3+ with a full width at half maximum of 147 nm and internal quantum efficiency of 54.05% is achieved. The effects of the double perovskite crystal structure on Fe 3+ photoluminescence properties are comprehensively analyzed. NIR LEDs are fabricated by encapsulating UV chips with the synthetic CaLaMgSbO 6 : 0.6%Fe 3+ phosphors, and their application value in night vision, nondestructive biological monitoring, and NIR detection is evaluated.