Nonstoichiometric Strategy for Enhancing Luminescence Performance of Cr 3+ ‐Activated Ca 3 Ga 2 G
Jing Zhang, Weijie Li, Jianjun Zhao, Yang Zheng, Feiyu Wang, Zhixiang Zhang, Naicen Xu, Xiaoming Shen, Quan LiuABSTRACT
Near‐infrared (NIR) emitting phosphors with broadband emission enable their promising application in various fields. In this work, a series of Ca 3 Ga 2 Ge 3‐ x O 12‐δ :Cr 3+ NIR phosphors were synthesized to investigate the influence of Ge 4+ vacancies on the structural and luminescent properties. X‐ray diffraction analysis confirms that the main garnet phase is retained at low vacancy concentrations, whereas minor impurity phases appear at higher x values. X‐ray photoelectron spectroscopy analysis reveals the presence of both GaO 6 and GeO 6 octahedrons in this garnet. Under 458 nm excitation, all samples exhibit a broad NIR emission band centered at 752 nm. The integrated emission intensity increases with Ge 4+ vacancy concentration, reaching a maximum at x = 0.4. The optimized phosphor shows exceptional thermal stability, retaining 91.4% of its room‐temperature intensity at 423 K. This study demonstrates that Ge 4+ vacancy engineering is an effective strategy for enhancing the NIR luminescence of Cr 3+ ‐doped garnet phosphors.