THE INFLUENCE OF HEAT TREATMENT IN THE DIFFERENT GASEOUS MEDIA ON THE OPTICAL PROPERTIES OF FROZEN MELTS EuS AND EuIn2S4IN NaCl-KCl

• Published in: Vìsnik Odesʹkogo Nacìonalʹnogo Unìversitetu: Hìmìâ Vol. 20; no. 2(54); pp. 16 - 26
• Main Authors: Nechyporenko, G. V., Zinchenko, V. F., Dyshleva, L. F., Timukhin, I. V., Meshkova, S. B., Stoianova, I. V.
• Format: Journal Article
• Language: English
• Published: Odessa I. I. Mechnikov National University 18.11.2015
• Subjects: сульфіди європію (II), люмінесценція, оптичні властивості
• ISSN: 2304-0947; 2414-5963
• DOI: 10.18524/2304-0947.2015.2(54).50625

Influence of medium (inert gas, air) is studied at heat treatment of molten solutions of EuS and EuIn2S4 in NaCl-KCl of equimolar composition on optical properties. Unlike initial Europium (II) sulphides, stiffened melts exhibit an intensive luminescence in spectral interval of 420-450 nanometers due to 5d-4f electronic transitions in Eu2+ions. At transition from EuS to EuIn2S4 the sharp increase in intensity of a luminescence because of solubility increase is observed.Heat treatment in the air medium results in similar result that is especially revealed in case of EuS. Spectral curve of diffuse reflectance lies in the field of negative values of absorption that is caused by luminescence processes, and correlation in their change with increase in intensity of a luminescence is observed. On IR spectra of sample EuS in NaCl-KCl, processed in the air medium, there is a band of high intensity in interval nearby 1360 cm-1, and in case of sample EuIn2S4in NaCl-KCl – in the field of 2900-3000 cm-1. Their occurrence is caused by valence oscillations in SO42-and H-Cl, accordingly. Thermodynamic calculations have shown that solubility of EuSO4 in the NaCl-KCl melt is more than in 4 times above in comparison with EuS. Possibility of management of a luminescence of stiffened melts of Europium (II) compounds in saline melts both by change of medium and compound composition is shown.