| Autor: |
Vlasov MI; Institute of High Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences, 620990 Yekaterinburg, Russia. maxim.vlsv@yandex.ru., Zainullina VM, Korotin MA, Farlenkov AS, Ananyev MV |
| Jazyk: |
angličtina |
| Zdroj: |
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2019 Apr 21; Vol. 21 (15), pp. 7989-7995. Date of Electronic Publication: 2019 Mar 29. |
| DOI: |
10.1039/c9cp00539k |
| Abstrakt: |
Features of the energy levels in the band-gap of La 1-x Sr x ScO 3-x/2 and the effect on those levels of proton uptake from H 2 and H 2 O atmospheres were studied by diffuse reflectance spectroscopy and coherent potential approximation (CPA) calculations. It was shown that oxygen vacancies appearing due to acceptor doping with Sr form energy levels near the bottom of the conduction band that are strongly hybridized with the states of the nearest atoms. Excitation of electrons from the valence band to these vacancy levels gives rise to an additional absorption band which overlaps with the fundamental absorption edge. Proton incorporation from both H 2 and H 2 O atmospheres leads to formation of proton levels below the valence band. However, during H 2 uptake, electrons from hydrogen atoms occupy oxygen vacancy levels, and as a result additional absorption in the red-IR range appears due to electronic transitions from these levels to the conduction band. On the other hand, H 2 O uptake leads to the disappearance of oxygen vacancy levels. Experimental results obtained are similar to literature data on the optical absorption properties of some other proton-conducting perovskites, allowing the conclusion that findings from these CPA calculations on the nature of the energy levels could be extrapolated to some extent to those oxides. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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