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Information × Registration Number 0221U100654, 0120U100133 , R & D reports Title The effect of redox reactions on the photoluminescence of lanthanides in different valence states in oxide-halide crystals and complexes popup.stage_title Head Dotsenko Volodymyr P., Доктор хімічних наук Registration Date 08-01-2021 Organization Physico-Chemical Institute O. Bogatsky National Academy of Sciences of Ukraine popup.description2 The object of research is redox processes in lanthanide fluoride systems of variable valence and their influence on spectral properties, in particular, luminescence. The aim of the work is to develop ideas about the chemistry of redox reactions in lanthanide fluoride systems with variable valence in the presence of alkali metal chlorides. Research methods - thermodynamic calculations of processes, analysis of available data of X-ray phase analysis, high-temperature synthesis in an inert medium, spectroscopic methods: IR transmission spectroscopy, diffuse reflection spectroscopy, fluorescence spectroscopy. The influence of high-temperature treatment on the composition of LnF3-Ln'F3 systems (Ln = Sm, Eu, Tm, Yb; Ln'= Ce, Pr, Tb) is determined. Based on the data of X-ray phase analysis, new phases based on LnF2 compounds were found, the content of which is the highest in the EuF3-CeF3 system. Thermodynamic calculations confirmed the possibility of redox reactions in these systems. The occurrence of Ln(II) fluoride phases in all studied systems was established by the method of diffuse reflection spectroscopy, especially in the UV range of the spectrum, as well as by luminescent spectroscopy. Evaluation of the solubility of the initial components of the systems in the salt melt NaCl-KCl gave a value of 0.2÷0.6%wt., which is beyond the sensitivity of the method of X-ray phase analysis. In contrast, in UV range in the diffuse reflection spectra of the melts, sharp changes were detected, indicating the possibility of intense luminescence. The luminescence intensity was much higher than in the melts of individual fluorides - components of the studied systems or binary crystal systems. In the case of the EuF3-CeF3-NaCl-KCl system, the melt practically contains only Eu2+ ions and, possibly, Ce3+, Ce4+ ions in a commensurate amount. This system can be considered promising for the development and application in detectors and dosimeters.  Product Description popup.authors Ieriomin Oleh G. Iefriushina Ninel’ Р. Antonovych Valeriy P. Berezovska Iryna V. Volchak Ganna V. Doha Pavlo G. Dotsenko Volodymyr P. Zinchenko Viktor F. Korovin Andriy Yu. Magunov Igor R. Rusakova Natalia V. Sadkovska Liudmyla V. Semenyshyn Mykola Oleksandrovych Smola Serhiy S. Stamikosto Olena V. Stoyanova Irina V. Fadieiev Yevhen M. Khomenko Olena V. Chivireva Natalia О. popup.nrat_date 2021-03-17 Close