2020 Fiscal Year Research-status Report
Frequency Domain Characterization of Optically Controlled Processes in Perovskite Materials
| Project/Area Number |
20K15028
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| Research Institution | Kyushu University |
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Principal Investigator |
Klotz Dino 九州大学, カーボンニュートラル・エネルギー国際研究所, 助教 (00814849)
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Keywords | perovskite materials / impedance spectroscopy / ionic conductivity / photo-effect / opto-ionics |
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| Outline of Annual Research Achievements |
For conductivity in perovskite materials, more general in ceramic materials, the grain boundaries play a major role. In this project, it could already be demonstrated that light above the band-gap can significantly increase the grain boundary conductivity. Thin films consisting 3mol% Gd doped CeO2 were compared, one epitaxial without grain boundaries, one polycrystalline with grain sizes around 50-100nm. Only in the polycrystalline film, the light increased the conductivity by a factor of around 3.5. That is an exceptional result. Further, a model was developed to explain the photo-effect on the ceramic material. For the characterization under light, two new measurement techniques have been adapted: intensity-modulated photocurrent spectoscopy (IMPS) and single-frequency impedance transients (SFIT). A publication summarizing the results, the methods and the model to explain the observed behavior has been submitted to Nature Materials and is currently in the second round of revisions. Furthermore, for perovskite materials as used in solar cells, new strategies for characterization have been developed based on electrochemical impedance spectroscopy. Measurements have been performed and the impact of interfaces is currently examined.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The measurements and modelling are progressing smoothly. Online-meetings could mostly substitute the collaborative work with co-workers. The review process of the first publication reporting this work has been delayed by the pandemic.
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| Strategy for Future Research Activity |
As planned, additional measurements on ceramic materials (oxygen ion conductors) and perovskite materials for solar cells will be conducted. Further progress regarding the development of new measurement techniques and the establishment of respective guidelines is expected in the first half of the second year of the project.
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| Causes of Carryover |
Additional features (option) for the used measurement devices are necessary to conduct all planned measurements. Consumables are required for sample production. If possible one trip to MIT will be made for discussions and planning of further experiments and model development. It is also planned to present the work on international conferences if possible, in order to promote the work for future collaborations.
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