Download file (1.64 MB)
Download as zip (1.61 MB)

Collection

Citation

Description:

Broadband near-infrared-II (NIR-II) covered phosphors are crucial for LED applications such as biological imaging and optical sensing. In this study, Ca5Ga6−xO14: xCr phosphors, where x represents the molar concentration of Cr4+ substituting Ga sites, were synthesized with x values of 0.0001, 0.0005, 0.005, 0.01, 0.02, 0.03, and 0.04 using a conventional solid-state reaction. X-ray diffraction showed that the main targeted phase was predominantly observed for Cr doping levels below x = 0.001. Optical characterizations revealed that the optimized phosphor (x = 0.0005) exhibited the most intense and broad NIR emission (1150–1600 nm, peak at 1330 nm) by 650 nm-excitation, originating from the spin-allowed 3T2 → 3A2 transition of tetrahedrally coordinated Cr4+ ions. Low-temperature photoluminescence further elucidated the energetic and crystal field environment of Cr4+. These findings demonstrate that Ca5Ga6O14 is an efficient host for Cr4+-doped NIR-II phosphors, offering insights for the design of next-generation luminescent materials.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: Cr4+ photoluminescence, NIR phosphors

Date published: 2026-02-06

Publisher: MYU K.K.

Journal:

• Sensors and Materials (ISSN: 09144935) vol. 38 issue. 2 p. 593-602

Funding:

• JSPS JP24K21774 (本研究は一部JSPS科研費の補助を用いて行われました。)
• 安全保障技術研究推進制度 (本研究は、ATLA「データ科学と単粒子診断法を融合した新規赤外蛍光体開発の高速化」を用いて行われました。)

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.18494/sam6005

Related item:

Other identifier(s):

Contact agent:

Updated at: 2026-02-11 08:30:38 +0900

Published on MDR: 2026-02-10 18:03:06 +0900