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Morphology Control for Fully Printable Organic–Inorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer
Published on: January 10, 2017
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Molecular Oriented Charge Accumulation in High-Efficiency Polymer Solar Cells as Revealed by Operando Spin Analysis
Vanadian AstariSuci Atina Rachmat1, Takaya Kubodera1, Donghyun Son1
1Division of Materials Science , University of Tsukuba , Tsukuba , Ibaraki 305-8573 , Japan.
ACS Applied Materials & Interfaces
|August 3, 2019
Summary
High-efficiency polymer solar cells degrade due to internal charge accumulation. This study used operando electron spin resonance (ESR) to identify charge buildup in PTB7-Th cells, linking it to performance loss.
Area of Science:
- Materials Science
- Organic Electronics
- Photovoltaics
Background:
- PTB7-Th is a high-efficiency p-type semiconductor used in polymer solar cells.
- Polymer solar cells achieve over 10% power conversion efficiency but suffer from internal deterioration.
- The exact molecular-level degradation mechanisms remain under investigation.
Purpose of the Study:
- To elucidate the internal deterioration mechanism of PTB7-Th polymer solar cells at a molecular level.
- To investigate charge accumulation phenomena within these devices.
- To correlate charge accumulation with observed performance decline.
Main Methods:
- Operando electron spin resonance (ESR) spectroscopy was employed.
- Light-induced ESR was used to observe charge accumulation under simulated solar irradiation.
- Density functional theory (DFT) calculations were performed to identify charge accumulation sites.
Main Results:
- Direct observation of ambipolar charge accumulation with a face-on molecular orientation in PTB7-Th:PC71BM solar cells.
- A clear correlation was established between charge accumulation and cell performance deterioration.
- ESR analysis and DFT calculations pinpointed specific sites of charge accumulation.
Conclusions:
- Ambipolar charge accumulation is a key factor in the deterioration of high-efficiency PTB7-Th polymer solar cells.
- Understanding and preventing charge accumulation is crucial for the commercialization of these devices.
- Operando ESR spectroscopy provides valuable molecular-level insights into degradation pathways.
Keywords:
PTB7-Thcharge accumulationdensity functional theory calculationlight-induced electron spin resonance spectroscopymolecular orientationorganic photovoltaicsMore Related Videos
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