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Das C, Roy R, Kedia M, Kot M, Zuo W, Félix R, Sobol T, Flege JI, Saliba M. Unraveling the Role of Perovskite in Buried Interface Passivation. ACS Appl Mater Interfaces 2023; 15:56500-56510. [PMID: 37991727 DOI: 10.1021/acsami.3c13085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Interfaces in perovskite solar cells play a crucial role in their overall performance, and therefore, detailed fundamental studies are needed for a better understanding. In the case of the classical n-i-p architecture, TiO2 is one of the most used electron-selective layers and can induce chemical reactions that influence the performance of the overall device stack. The interfacial properties at the TiO2/perovskite interface are often neglected, owing to the difficulty in accessing this interface. Here, we use X-rays of variable energies to study the interface of (compact and mesoporous) TiO2/perovskite in such a n-i-p architecture. The X-ray photoelectron spectroscopy and X-ray absorption spectroscopy methods show that the defect states present in the TiO2 layer are passivated by a chemical interaction of the perovskite precursor solution during the formation of the perovskite layer and form an organic layer at the interface. Such passivation of intrinsic defects in TiO2 removes charge recombination centers and shifts the bands upward. Therefore, interface defect passivation by oxidation of Ti3+ states, the organic cation layer, and an upward band bending at the TiO2/perovskite interface explain the origin of an improved electron extraction and hole-blocking nature of TiO2 in the n-i-p perovskite solar cells.
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Affiliation(s)
- Chittaranjan Das
- Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
- Helmholtz Young Investigator Group, IEK5-Photovoltaik, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rajarshi Roy
- Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
| | - Mayank Kedia
- Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
- Helmholtz Young Investigator Group, IEK5-Photovoltaik, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Małgorzata Kot
- Chair of Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Straße 1, 03046 Cottbus, Germany
| | - Weiwei Zuo
- Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
| | - Roberto Félix
- Department Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Tomasz Sobol
- SOLARIS National Synchrotron Radiation Centre, Jagiellonian University, 31-007 Krakow, Poland
| | - Jan Ingo Flege
- Chair of Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Straße 1, 03046 Cottbus, Germany
| | - Michael Saliba
- Institute for Photovoltaics (ipv), University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany
- Helmholtz Young Investigator Group, IEK5-Photovoltaik, Forschungszentrum Jülich, 52425 Jülich, Germany
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