Synergetic effects of electrochemical oxidation of Spiro-OMeTAD and Li+ ion migration for improving the performance of n–i–p type perovskite solar cells
| Autor: | Liangping Zhang, Changzeng Ding, Dongyu Zhang, Fangsen Li, Chang-Qi Ma, Ronald Österbacka, Rong Huang, Qun Luo, Jian Lin, Christian Ahläng |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment Energy conversion efficiency 02 engineering and technology General Chemistry Conductivity 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Cathode 0104 chemical sciences law.invention Anode Secondary ion mass spectrometry Chemical engineering law Solar cell General Materials Science 0210 nano-technology Perovskite (structure) |
| Zdroj: | Journal of Materials Chemistry A. 9:7575-7585 |
| ISSN: | 2050-7496 2050-7488 |
| Popis: | n–i–p Type perovskite solar cells generally require air oxidation of the Spiro-OMeTAD layer to achieve high power conversion efficiency (PCE). However, the detailed oxidation mechanism is still not fully understood. In this paper, oxidation of Spiro-OMeTAD was demonstrated via a non-contact electrochemical route using UV-Vis absorption, laser beam induced current (LBIC) imaging and secondary ion mass spectrometry (SIMS) profiling of the Spiro-OMeTAD films. At the cathode, oxygen is reduced to form OH− with the help of H2O, while the anodic reaction is the oxidation of Spiro-OMeTAD to form Spiro-OMeTAD+. Diffusion of Li+ towards the surface of the Ag electrode completes the electrochemical cycle and increases the conductivity of the hole-transporting layer. SIMS analyses of the completed devices demonstrate that the oxidation of Spiro-OMeTAD also leads to migration of Li+ through the perovskite layer into SnO2, which supposedly leads to an increase of the built-in voltage. We verify these results by incorporation of the experimentally measured Li+ concentration into a numerical drift-diffusion simulation, to replicate solar cell J–V-curves. This work provides a new insight into the oxidation of Spiro-OMeTAD in perovskite solar cells, and demonstrates that Li+ migration is involved in the oxidation of Spiro-OMeTAD. |
| Databáze: | OpenAIRE |
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