Research output: Contribution to journal › Article › peer-review
Long-Lived Photocatalysis Centers Created in ZnO via Resonant Exciton Excitation. / Titov, V. V.; Lisachenko, A. A.; Akopyan, I. Kh; Labzovskaya, M.E.; Novikov, B. V.
In: Physics of the Solid State, Vol. 61, No. 11, 01.11.2019, p. 2134-2138.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Long-Lived Photocatalysis Centers Created in ZnO via Resonant Exciton Excitation
AU - Titov, V. V.
AU - Lisachenko, A. A.
AU - Akopyan, I. Kh
AU - Labzovskaya, M.E.
AU - Novikov, B. V.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Abstract: ZnO together with TiO2 is a main photocatalyst for various redox reactions to convert light energy into a chemical one and to purify the environment. Intrinsic surface defects in ZnO—the vacancies in anionic and cationic sublattices (F-type and V-type centers)—allow creation of long-lived (up to 103 s) photocatalysis centers and, therefore, tenfold increase in quantum yield of reactions. Slow surface states—the photocatalysis centers—appear via diffusion of electrons and holes generated during the interband transitions in the bulk of a photoactivated sample. The transfer efficiency, however, decreases sharply because of recombination of charge carriers and losses during overcoming the surface Schottky barrier. Neutral energy carriers—excitons—were used in this work to decrease these losses during the energy transfer to a surface. High exciton binding energy in ZnO (60 meV) allows it to move at room temperature without decay. The exciton energy loss for radiation is effectively decreased in our experiments via formation of a 2D surface structure. The results confirm high efficiency of exciton channel to form surface long-lived photocatalysis F-centers and V‑centers during the photoadsorption and photodesorption processes of oxygen, which simulate full cycle of a redox photocatalytic reaction.
AB - Abstract: ZnO together with TiO2 is a main photocatalyst for various redox reactions to convert light energy into a chemical one and to purify the environment. Intrinsic surface defects in ZnO—the vacancies in anionic and cationic sublattices (F-type and V-type centers)—allow creation of long-lived (up to 103 s) photocatalysis centers and, therefore, tenfold increase in quantum yield of reactions. Slow surface states—the photocatalysis centers—appear via diffusion of electrons and holes generated during the interband transitions in the bulk of a photoactivated sample. The transfer efficiency, however, decreases sharply because of recombination of charge carriers and losses during overcoming the surface Schottky barrier. Neutral energy carriers—excitons—were used in this work to decrease these losses during the energy transfer to a surface. High exciton binding energy in ZnO (60 meV) allows it to move at room temperature without decay. The exciton energy loss for radiation is effectively decreased in our experiments via formation of a 2D surface structure. The results confirm high efficiency of exciton channel to form surface long-lived photocatalysis F-centers and V‑centers during the photoadsorption and photodesorption processes of oxygen, which simulate full cycle of a redox photocatalytic reaction.
KW - 2D structure
KW - excitons
KW - oxygen
KW - photoadsorption
KW - photodesorption
KW - surface long-lived centers
KW - ZnO
UR - http://www.scopus.com/inward/record.url?scp=85074688730&partnerID=8YFLogxK
U2 - 10.1134/S1063783419110398
DO - 10.1134/S1063783419110398
M3 - Article
AN - SCOPUS:85074688730
VL - 61
SP - 2134
EP - 2138
JO - Physics of the Solid State
JF - Physics of the Solid State
SN - 1063-7834
IS - 11
ER -
ID: 51178115