Transport resistance strikes back: unveiling its impact on fill factor losses in organic solar cells
Abstract
The fill factor (FF) is a critical parameter for solar cell efficiency, but its analytical description is challenging due to the interplay between recombination and charge extraction processes. An often overlooked yet significant factor contributing to FF losses, beyond recombination, is the influence of charge transport. In most state-of-the-art organic solar cells, the primary limitations of the FF arise not just from non-radiative recombination but also from low conductivity. A closer look reveals that even in the highest efficiency cells, performance losses due to transport resistance are significant, highlighting the need for refined models to predict the FF accurately. Here, we extend the analytical model for transport resistance to a more general case. Drawing from a large set of experimental current-voltage and light intensity-dependent open-circuit voltage data, we systematically incorporate crucial details previously omitted in the model. Consequently, we introduce a straightforward set of equations to predict the FF of a solar cell, enabling the differentiation of losses attributed to recombination and transport resistance. Our study provides valuable insights into strategies for mitigating FF losses based on the experimentally validated analytical model, guiding the development of more efficient solar cell designs and optimisation strategies.
- Publication:
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arXiv e-prints
- Pub Date:
- April 2024
- DOI:
- 10.48550/arXiv.2404.06190
- arXiv:
- arXiv:2404.06190
- Bibcode:
- 2024arXiv240406190S
- Keywords:
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- Condensed Matter - Materials Science;
- Physics - Applied Physics
- E-Print:
- 10 pages, 6 figures