High-excited-state splitting and multimode vibrational coupling in Mn4+-activated fluoride phosphor

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2024-03, Vol.67 (3), p.234212, Article 234212
• Main Authors: Zhang, Debao, Ye, Wanggui, Cao, Xuguang, Zhou, Ji, Tang, Fei, Zheng, Changcheng, Ning, Jiqiang, Xu, Shijie
• Format: Article
• Language: English
• Subjects: Astronomy; Classical and Continuum Physics; Coupling; Cryogenic temperature; Excitation; Excitation spectra; Fluorides; Jahn-Teller effect; Lasers; Lattice vibration; Low temperature; Manganese ions; Microcrystals; Observations and Techniques; Phosphors; Photoluminescence; Physics; Physics and Astronomy; Raman spectra; Spectrum analysis; Splitting; Temperature; Vibration mode
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-023-2292-5

Excited-states play a crucial role in the optical absorption and luminescence of solids and hence their accurate information is highly desired. Herein, we attempt to seize the excited-states information of Mn 4+ ions in K 2 SiF 6 microcrystals via measuring and calculating their variable-temperature photoluminescence excitation (PLE) spectra. At cryogenic temperatures, an unpredicted splitting of the high-excited-state is observed. Moreover, the two-split high-excited-state levels are further revealed to primarily couple with the two hyperfine split modes of quasi-localized v 2 vibration in the distorted Mn-F 6 octahedral configuration, whereas the coupling strengths are found to be substantially different from each other. The slightly split vibrational mode is firmly supported by the low-temperature Raman spectra. Jahn-Teller lattice distortion is believed to be responsible for the observed splitting of the electronic high-excited-state and the quasi-localized vibrational mode.