Charge Transfer Dynamics at Dye Sensitized ZnO and TiO2 Interfaces Studied by Ultrafast XUV Photoelectron Spectroscopy
| Autor: | Thorsten Kampen, Igor Yu. Kiyan, Emad F. Aziz, Kathrin M. Lange, Martin Wilke, Mario Borgwardt, Manda Xiao, Sven Mähl, Leone Spiccia |
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| Rok vydání: | 2016 |
| Předmět: |
Methods and concepts for material development
Multidisciplinary Materials science Photoemission spectroscopy business.industry Binding energy 02 engineering and technology Electronic structure Electron 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Acceptor Article 0104 chemical sciences Electron transfer Semiconductor Physical chemistry X-ray photoelectron spectroscopy Chemical physics Devices for energy harvesting 0210 nano-technology business |
| Zdroj: | Scientific Reports |
| Popis: | Interfacial charge transfer from photoexcited ruthenium-based N3 dye molecules into ZnO thin films received controversial interpretations. To identify the physical origin for the delayed electron transfer in ZnO compared to TiO2, we probe directly the electronic structure at both dye-semiconductor interfaces by applying ultrafast XUV photoemission spectroscopy. In the range of pump-probe time delays between 0.5 to 1.0 ps, the transient signal of the intermediate states was compared, revealing a distinct difference in their electron binding energies of 0.4 eV. This finding strongly indicates the nature of the charge injection at the ZnO interface associated with the formation of an interfacial electron-cation complex. It further highlights that the energetic alignment between the dye donor and semiconductor acceptor states appears to be of minor importance for the injection kinetics and that the injection efficiency is dominated by the electronic coupling. |
| Databáze: | OpenAIRE |
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