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DOE OSTI · 2328531

Layer-by-Layer-Processed Organic Solar Cells with 18.02% Efficiency Enabled by Regulating the Aggregation of Bottom Polymers

Wu, Xing·Wu, Yixuan·Peng, Shichu·Xiao, Liangang·Xiao, Zijie·Zhang, Wei·Ren, Guoxing·Min, Yonggang·Liu, Yi
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Abstract

The fabrication of organic solar cells (OSCs) by a layer-by-layer (LBL) method has attracted growing attention in recent years. As already known, the pre-aggregates of conjugated polymers in solution have a profound impact on their microstructure morphology in films. Herein, by simply controlling the solution temperature and annealing processes, the pre-aggregation behavior of D18 polymer in solution can be fine-tuned and the microstructure of D18 bottom layer is well manipulated. The optimized D18 bottom layer can effectively regulate L8-BO upper-layer-forming suitable networks for efficient charge transportation. In addition, a vertical phase separation with a special D/D:A/A structure (P-i-N-type component distribution) is also formed. As a result, compared to the 16.43% power conversion efficiency (PCE) of the bulk heterojunction devices, such control enables bilayer OSC devices based on the polymer D18 and L8-BO to deliver an enhanced PCE of 18.02% with simultaneously improved short-circuit current density, open-circuit voltage, and fill factor. Importantly, it is also demonstrated in these results that the LBL deposition process utilizing the pre-aggregation of polymer and its fiber-network-forming ability is a very promising approach to improve charge dynamics, suppress carrier recombination, and fabricate highly efficient OSCs.

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14 SOLAR ENERGYlayer-by-layermolecular stackingorganic solar cellspre-aggregationvertical phase separation

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Wu, Xing, Wu, Yixuan, Peng, Shichu, Xiao, Liangang, Xiao, Zijie, Zhang, Wei, Ren, Guoxing, Min, Yonggang, Liu, Yi. 2023-03-27. Layer-by-Layer-Processed Organic Solar Cells with 18.02% Efficiency Enabled by Regulating the Aggregation of Bottom Polymers. https://doi.org/10.1002/solr.202300136

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