Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review
During the last two decades, various pathways describing photoexcitation of small molecules’ surface reactions at the wide band gap metal oxides and halides (Eg>3 eV) have been recognized. Photogeneration of excitons and free charge carriers may occur in bands of: i) fundamental absorption; ii) e...
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| Language: | English |
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Wiley
2004-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/S1110662X04000145 |
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| author | Vladimir Ryabchuk |
| author_facet | Vladimir Ryabchuk |
| author_sort | Vladimir Ryabchuk |
| collection | DOAJ |
| description | During the last two decades, various pathways describing photoexcitation of small molecules’
surface reactions at the wide band gap metal oxides and halides (Eg>3 eV) have been recognized. Photogeneration
of excitons and free charge carriers may occur in bands of: i) fundamental absorption; ii) extrinsic
and intrinsic defect absorption, including those related to surface states; and iii) in UV-induced color centers.
Considerable red shifts relative to the fundamental absorption threshold of wide band gap solids have
been observed for the spectral limits of surface photoreactions induced in extrinsic absorption bands. This
allows thinking about the wide band gap solids as a potential competitors for the relatively narrow band gap
photocatalysts. This review discusses the concept of surface photoadsorption (photocatalytic) center while
differentiating active and inactive states of the center. Electronically excited defect, surface self-trapped or
bound exciton, and the surface defect with trapped photo carrier are considered as the active states of photoadsorption
(photocatalytic) centers of different types. The decay pathway of active state determines the
lifetime of a photocatalytic center, and in this connection the Langmuir-Hinshelwood kinetic approach is
discussed. |
| format | Article |
| id | doaj-art-6374f554bed84ff6bdb13a4583e3d119 |
| institution | OA Journals |
| issn | 1110-662X |
| language | English |
| publishDate | 2004-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Photoenergy |
| spelling | doaj-art-6374f554bed84ff6bdb13a4583e3d1192025-08-20T02:35:13ZengWileyInternational Journal of Photoenergy1110-662X2004-01-01639511310.1155/S1110662X04000145Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A reviewVladimir Ryabchuk0Department of Photonics, V. A. Fok Institute of Physics, St. Petersburg State University, Ulyanovskaia 1, St. Petersburg 198504, RussiaDuring the last two decades, various pathways describing photoexcitation of small molecules’ surface reactions at the wide band gap metal oxides and halides (Eg>3 eV) have been recognized. Photogeneration of excitons and free charge carriers may occur in bands of: i) fundamental absorption; ii) extrinsic and intrinsic defect absorption, including those related to surface states; and iii) in UV-induced color centers. Considerable red shifts relative to the fundamental absorption threshold of wide band gap solids have been observed for the spectral limits of surface photoreactions induced in extrinsic absorption bands. This allows thinking about the wide band gap solids as a potential competitors for the relatively narrow band gap photocatalysts. This review discusses the concept of surface photoadsorption (photocatalytic) center while differentiating active and inactive states of the center. Electronically excited defect, surface self-trapped or bound exciton, and the surface defect with trapped photo carrier are considered as the active states of photoadsorption (photocatalytic) centers of different types. The decay pathway of active state determines the lifetime of a photocatalytic center, and in this connection the Langmuir-Hinshelwood kinetic approach is discussed.http://dx.doi.org/10.1155/S1110662X04000145 |
| spellingShingle | Vladimir Ryabchuk Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review International Journal of Photoenergy |
| title | Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review |
| title_full | Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review |
| title_fullStr | Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review |
| title_full_unstemmed | Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review |
| title_short | Photophysical processes related to photoadsorption and photocatalysis on wide band gap solids: A review |
| title_sort | photophysical processes related to photoadsorption and photocatalysis on wide band gap solids a review |
| url | http://dx.doi.org/10.1155/S1110662X04000145 |
| work_keys_str_mv | AT vladimirryabchuk photophysicalprocessesrelatedtophotoadsorptionandphotocatalysisonwidebandgapsolidsareview |