Cr 3+ -Sphere Effect on the Whitlockite-Type NIR Phosphor Sr 9 Sc(PO 4 ) 7 with High Heat Dissipation for Digital Medical Applications

• Published in: Inorganic chemistry Vol. 61; no. 5; pp. 2530 - 2537
• Main Authors: Lu, Chun-Han, Tsai, Yi-Ting, Tsai, Tzong-Liang, Chan, Ting-Shan, Zhang, Xuejie, Lin, Chun Che
• Format: Journal Article
• Language: English
• Published: United States 07.02.2022
• Subjects: Calcium Phosphates; Chromium - chemistry; Hot Temperature; Humans; Infrared Rays; Luminescent Agents - chemical synthesis; Luminescent Agents - chemistry; Minerals - chemistry; Phosphates - chemistry; Scandium - chemistry; Strontium - chemistry
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.1c03377

The analysis of human body composition and food composition requires high-efficiency broadband near-infrared (NIR) lighting sources to achieve a portable, appropriately sized equipment. Herein, we develop a whitlockite-type NIR phosphor Sr Sc(PO ) :Cr with an emission centered at 860 nm and full width at half-maximum of 147 nm. Due to the structural characteristics of the matrix, the 60 mol % Cr substitution at the Sc sites gives an internal quantum efficiency up to 56.5%. By replacing Sr with Ba and Ca, we observe a nontypical spectral shift phenomenon and discuss the influence of the second-sphere effect on octahedral Cr ions. To evaluate the diagnostic application, we design a NIR ceramic device with a high optical power of 27.38 mW and high heat dissipation, which can decrease surface working temperature by nearly 50 °C for digital intraoral application. This study provides the research of the second-sphere coordination effect for selective octahedral sites such as Ca, Sr, and Ba coordinated by O atoms on a whitlockite-type crystal. Furthermore, the device promotes a nonionizing solution for detecting dental caries, tooth calcification, and diagnostic application.