Nikiforov IV, Spassky DA, Krutyak NR, Shendrik RY, Zhukovskaya ES, Aksenov SM, Deyneko DV. Co-Doping Effect of Mn
2+ and Eu
3+ on Luminescence in Strontiowhitlockite Phosphors.
Molecules 2023;
29:124. [PMID:
38202708 PMCID:
PMC10780273 DOI:
10.3390/molecules29010124]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
A new series of Sr-based phosphates, Sr9-xMnxEu(PO4)7, were synthesized using the high-temperature solid-state method in air. It was found that these compounds have the same structure as strontiowhitlockite, which is a β-Ca3(PO4)2 (or β-TCP) structure. The concentration of Mn2+ ions required to form a pure strontiowhitlockite phase was determined. An unusual partial reduction of Eu3+ to Eu2+ in air was observed and confirmed by photoluminescence (PL) and electron spin resonance (ESR) spectra measurements. The PL spectra recorded under 370 nm excitation showed transitions of both 4f5d-4f Eu2+ and 4f-4f Eu3+. The total integral intensity of the PL spectra, monitored at 395 nm, decreased with increasing Mn2+ concentration due to quenching effect of Eu3+ by the Mn2+ levels. The temperature dependence of Eu2+ photoluminescence in a Sr9-xMnxEu(PO4)7 host was investigated. The conditions for the reduction of Eu3+ to Eu2+ in air were discussed.
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