Sharp-Line Near-Infrared Emission from Tetrahedron-Occupied Ni2+ in Ca2GeO4

Wenjing Huang; Jiahui Zhang; Jiaqi Fan; Peican Chen; Qi Pang; Liya Zhou; Zhan-Chao Wu; Yunrui Hu; Xinguo Zhang

doi:10.1021/acs.inorgchem.3c01706

Sharp-Line Near-Infrared Emission from Tetrahedron-Occupied Ni²⁺ in Ca₂GeO₄

Inorg Chem. 2023 Aug 21;62(33):13370-13377. doi: 10.1021/acs.inorgchem.3c01706. Epub 2023 Aug 10.

Authors

Wenjing Huang¹, Jiahui Zhang¹, Jiaqi Fan¹, Peican Chen², Qi Pang², Liya Zhou², Zhan-Chao Wu³, Yunrui Hu¹, Xinguo Zhang¹

Affiliations

¹ Key Laboratory of Drug Metabolism Research and Evaluation of the State Drug Administration, Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
² School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
³ Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Key Laboratory of Biochemical Analysis, Shandong Province, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.

PMID: 37560992
DOI: 10.1021/acs.inorgchem.3c01706

Abstract

As far as we are concerned, the phenomenon of Ni²⁺ luminescence in tetrahedral coordination has not been reported. For the first time, a new NIR phosphor Ca₂GeO₄:Ni²⁺ is developed in this work. It is found that the NIR emission from this phosphor is a sharp peak attributed to the unusual Ni²⁺-occupied GeO₄ site in the lattice, instead of the conventional broadband luminescence of Ni²⁺ in the octahedrally coordinated site. Crystal-field analysis has been applied, and the parameters Dq, B, and Δ are calculated to reveal the relationship between the emission profile and the crystal field strength. The optimal Ni²⁺ doping concentration is found to be 1%. Ca₂GeO₄:Ni²⁺ provides an efficient sharp-line (fwhm = 16 nm) emission centered at 1164 nm which originates from the ¹T₂ → ³T₁ transition with an internal quantum efficiency of 23.1% and a decay lifetime of about 300 μs. This work could provide some new insights to explore novel NIR luminescent materials based on transition-metal elements.