Journal article
The Importance of Quantifying the Composition of the Amorphous Intermixed Phase in Organic Solar Cells.
- Marina S POLYMAT, University of the Basque Country UPV/EHU, Av. de Tolosa 72, San Sebastián, 20018, Spain.
- Kaufmann NP Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, Zurich, 8093, Switzerland.
- Karki A Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA.
- Gutiérrez-Meza E School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- Gutiérrez-Fernández E POLYMAT, University of the Basque Country UPV/EHU, Av. de Tolosa 72, San Sebastián, 20018, Spain.
- Vollbrecht J Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA.
- Solano E ALBA Synchrotron Light Source, NCD-SWEET Beamline, Cerdanyola del Valles, 08290, Spain.
- Walker B Centre for Plastic Electronics and Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- Bannock JH Centre for Plastic Electronics and Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- de Mello J Centre for Plastic Electronics and Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- Silva C School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- Nguyen TQ Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA.
- Cangialosi D Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, San Sebastián, 20018, Spain.
- Stingelin N School of Materials Science & Engineering and School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA, 30332, USA.
- Martín J POLYMAT, University of the Basque Country UPV/EHU, Av. de Tolosa 72, San Sebastián, 20018, Spain.
- 2020-10-22
Published in:
- Advanced materials (Deerfield Beach, Fla.). - 2020
English
The relation of phase morphology and solid-state microstructure with organic photovoltaic (OPV) device performance has intensely been investigated over the last twenty years. While it has been established that a combination of donor:acceptor intermixing and presence of relatively phase-pure donor and acceptor domains is needed to get an optimum compromise between charge generation and charge transport/charge extraction, a quantitative picture of how much intermixing is needed is still lacking. This is mainly due to the difficulty in quantitatively analyzing the intermixed phase, which generally is amorphous. Here, fast scanning calorimetry, which allows measurement of device-relevant thin films (<200 nm thickness), is exploited to deduce the precise composition of the intermixed phase in bulk-heterojunction structures. The power of fast scanning calorimetry is illustrated by considering two polymer:fullerene model systems. Somewhat surprisingly, it is found that a relatively small fraction (<15 wt%) of an acceptor in the intermixed amorphous phase leads to efficient charge generation. In contrast, charge transport can only be sustained in blends with a significant amount of the acceptor in the intermixed phase (in this case: ≈58 wt%). This example shows that fast scanning calorimetry is an important tool for establishing a complete compositional characterization of organic bulk heterojunctions. Hence, it will be critical in advancing quantitative morphology-function models that allow for the rational design of these devices, and in delivering insights in, for example, solar cell degradation mechanisms via phase separation, especially for more complex high-performing systems such as nonfullerene acceptor:polymer bulk heterojunctions.
- Language
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- English
- Open access status
- closed
- Identifiers
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- DOI 10.1002/adma.202005241
- PMID 33089554
- Persistent URL
- https://sonar.ch/global/documents/66719
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