دورية
Tunable Ti3+-Mediated Charge Carrier Dynamics of Atomic Layer Deposition-Grown Amorphous TiO2
| العنوان: | Tunable Ti3+-Mediated Charge Carrier Dynamics of Atomic Layer Deposition-Grown Amorphous TiO2 |
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| المؤلفون: | Saari, Jesse, Ali-Löytty, Harri, Kauppinen, Minttu Maria, Hannula, Markku, Khan, Ramsha, Lahtonen, Kimmo, Palmolahti, Lauri, Tukiainen, Antti, Grönbeck, Henrik, Tkachenko, Nikolai V., Valden, Mika |
| المصدر: | The Journal of Physical Chemistry - Part C; March 2022, Vol. 126 Issue: 9 p4542-4554, 13p |
| مستخلص: | Amorphous titania (am.-TiO2) has gained wide interest in the field of photocatalysis, thanks to exceptional disorder-mediated optical and electrical properties compared to crystalline TiO2. Here, we study the effects of intrinsic Ti3+and nitrogen defects in am.-TiO2thin films via the atomic layer deposition (ALD) chemistry of tetrakis(dimethylamido)titanium(IV) (TDMAT) and H2O precursors at growth temperatures of 100–200 °C. X-ray photoelectron spectroscopy (XPS) and computational analysis allow us to identify structural disorder-induced penta- and heptacoordinated Ti4+ions (Ti5/7c4+), which are related to the formation of Ti3+defects in am.-TiO2. The Ti3+-rich ALD-grown am.-TiO2has stoichiometric composition, which is explained by the formation of interstitial peroxo species with oxygen vacancies. The occupation of Ti3+3d in-gap states increases with the ALD growth temperature, inducing both visible-light absorption and electrical conductivity via the polaron hopping mechanism. At 200 °C, the in-gap states become fully occupied extending the lifetime of photoexcited charge carriers from the picosecond to the nanosecond time domain. Nitrogen traces from the TDMAT precursor had no effect on optical properties and only little on charge transfer properties. These results provide insights into the charge transfer properties of ALD-grown am.-TiO2that are essential to the performance of protective photoelectrode coatings in photoelectrochemical solar fuel reactors. |
| قاعدة البيانات: | Supplemental Index |
Find this issue from the American Chemical Society | تدمد: | 19327447 19327455 |
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| DOI: | 10.1021/acs.jpcc.1c10919 |