Voltage Losses in Organic Solar Cells: Understanding the Contributions of Intramolecular Vibrations to Nonradiative Recombinations
KAUST DepartmentLaboratory for Computational and Theoretical Chemistry of Advanced Materials
Physical Sciences and Engineering (PSE) Division
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AbstractThe large voltage losses usually encountered in organic solar cells significantly limit the power conversion efficiencies (PCEs) of these devices, with the result that the current highest PCE values in single-junction organic photovoltaic remain smaller than for other solar cell technologies, such as crystalline silicon or perovskite solar cells. In particular, the nonradiative recombinations to the electronic ground state from the lowest-energy charge-transfer (CT) states at the donor-acceptor interfaces in the active layer of organic devices, are responsible for a significant part of the voltage losses. Here, to better comprehend the nonradiative voltage loss mechanisms, a fully quantum-mechanical rate formula is employed within the framework of time-dependent perturbation theory, combined with density functional theory. The objective is to uncover the specific contributions of intramolecular vibrations to the CT-state nonradiative recombinations in several model systems, which include small-molecule and polymer donors as well as fullerene and nonfullerene acceptors.
CitationChen X-K, Brédas J-L (2017) Voltage Losses in Organic Solar Cells: Understanding the Contributions of Intramolecular Vibrations to Nonradiative Recombinations. Advanced Energy Materials: 1702227. Available: http://dx.doi.org/10.1002/aenm.201702227.
SponsorsThe authors acknowledge the financial support from the King Abdullah University of Science and Technology and, at the Georgia Institute of Technology, from the Office of Naval Research (Award No. N00014-17-1-2208). The authors are grateful to the KAUST IT Research Computing Team and Supercomputing Laboratory for providing continuous assistance as well as computational and storage resources.
JournalAdvanced Energy Materials