Modulation Spectroscopy of Subbandgap Light in Reduced TiO2 Electrodes
| Autor: | Kazutaka Hongo, Lucia Avalle, Suehiro Ohkubo, Gyoichi Nogami |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Photocurrent
Renewable Energy Sustainability and the Environment business.industry Band gap Chemistry Amplifier Photoelectrochemistry Doping Analytical chemistry Condensed Matter Physics Laser Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Semiconductor law Electrode Materials Chemistry Electrochemistry Optoelectronics business |
| Zdroj: | Journal of The Electrochemical Society. 143:3600-3606 |
| ISSN: | 1945-7111 0013-4651 |
| Popis: | The charge-transfer dynamics across a TiO 2 -aqueous electrolyte interface was studied by modulation spectroscopy of subbandgap light. A chopped light from a He-Ne laser was illuminated, and the resultant signals were detected by a phase-sensitive detector (a lock-in amplifier). Although light energy (∼1.97 eV) is too small to generate electron-hole pairs by a band-to-band transition of TiO 2 with a bandgap energy of 3.05 eV, photocurrent could be detected by the lock-in amplifier. The real and imaginary parts of the photocurrent could be well characterized by an arc plot similar to the Cole-Cole plot, from the analysis of which it is concluded that the electron transfer takes place from the valence band via midgap states to the semiconductor bulk. It is also concluded that the defect doping under a hydrogen atmosphere introduces deep levels, penetrating deep into the TiO 2 bulk |
| Databáze: | OpenAIRE |
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