Environmentally Printing Efficient Organic Tandem Solar Cells with High Fill Factors: A Guideline Towards 20% Power Conversion Efficiency |
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Authors: | Ning Li Derya Baran George D. Spyropoulos Hong Zhang Stephane Berny Mathieu Turbiez Tayebeh Ameri Frederik C. Krebs Christoph J. Brabec |
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Affiliation: | 1. Institute of Materials for Electronics and Energy Technology (i‐MEET), Friedrich‐ Alexander‐University Erlangen‐Nuremberg, Erlangen, Germany;2. Bavarian Center for Applied Energy Research (ZAE Bayern), Erlangen, Germany;3. Erlangen Graduate School in Advanced Optical Technologies (SAOT), Erlangen, Germany;4. Merck Chemicals Ltd., Chilworth Technical Centre, University Parkway, Southampton, UK;5. BASF Schweiz AG, Basel, Switzerland;6. Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde, Denmark |
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Abstract: | The tandem concept involves stacking two or more cells with complementary absorption spectra in series or parallel connection, harvesting photons at the highest possible potential. It is strongly suggested that the roll‐to‐roll production of organic solar cells will employ the tandem concept to enhance the power conversion efficiency (PCE). However, due to the undeveloped deposition techniques, the challenges in ink formulation as well as the lack of commercially available high performance active materials, roll‐to‐roll fabrication of highly efficient organic tandem solar cells currently presents a major challenge. The reported high PCE values from lab‐scale spin‐coated devices are, of course, representative, but not helpful for commercialization. Here, organic tandem solar cells with exceptionally high fill factors and PCE values of 7.66% (on glass) and 5.56% (on flexible substrate), which are the highest values for the solution‐processed tandem solar cells fabricated by a mass‐production compatible coating technique under ambient conditions, are demonstrated. To predict the highest possible performance of tandem solar cells, optical simulation based on experimentally feasible values is performed. A maximum PCE of 21% is theoretically achievable for an organic tandem solar cell based on the optimized bandgaps and achieved fill factors. |
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Keywords: | organic photovoltaics solution processing large‐scale production flexible electronics organic solar cells |
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