Physical Models for Charge Transfer at Single Crystal Oxide Semiconductor Surfaces as Revealed by the Doping Density Dependence of the Collection Efficiency of Dye Sensitized Photocurrents
| Autor: | Bruce A. Parkinson, M. T. Spitler, Kevin J. Watkins |
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| Rok vydání: | 2015 |
| Předmět: |
Photocurrent
Materials science business.industry Schottky barrier Doping Physics::Optics Chromophore Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Molecular physics Surfaces Coatings and Films Condensed Matter::Materials Science Depletion region Condensed Matter::Superconductivity Electrode Materials Chemistry Optoelectronics Physical and Theoretical Chemistry business Single crystal Quantum tunnelling |
| Zdroj: | The Journal of Physical Chemistry B. 119:7579-7588 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp511438j |
| Popis: | The doping density dependence of photocurrents has been experimentally measured at single crystal rutile TiO2 electrodes sensitized with the N3 chromophore and a trimethine dye. As the doping density of the electrodes was varied from 10(15) to 10(20) cm(-3), three different regimes of behavior were observed for the magnitude and shape of the dye sensitized current-voltage curves. Low-doped crystals produced current-voltage curves with a slow rise of photocurrent with potential. At intermediate doping levels, Schottky barrier behavior was observed producing a photocurrent plateau at electrode bias in the depletion region. At highly doped electrodes, tunneling currents played a significant role especially in the recombination processes. These different forms of the current-voltage curves could be fit to an Onsager-based model for charge collection at a semiconductor electrode. The fitting revealed the role of the various physical parameters that govern photoinduced charge collection in sensitized systems. |
| Databáze: | OpenAIRE |
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