High-Speed Slot-Die Coating with Donor-Priority Rapid Aggregation Kinetics for Improved Morphology and Efficiency in Ecofriendly Organic Solar Cells

Solution-processable organic solar cells (OSCs) represent a promising renewable photovoltaic technology with significant potential for eco-compatible production. While high power conversion efficiencies (PCEs) have been achieved in OSCs, scaling this technology for high-throughput manufacturing remains challenging. Key reason lies in the lack of efficient control strategies for the complex and long-duration morphology evolution during high-speed coating process with ecofriendly solvents. Here, a donor-priority rapid aggregation process (DP-RAP) scheme is proposed to solve this issue by adjusting the aggregation kinetics of donor and acceptor components. DP-RAP enables blends with a nanoscale fiber network structure and favorable crystallinity, which contributes to balanced carrier transport and reduced recombination losses. As a result, the PCE is improved from 14.3% (reference) to 17.4% (DP-RAP) for ultra-high speed coated PM6:BTP-eC9 devices in atmosphere, which is one of the highest values for non-halogenated solvent-processed solar cells at coating speeds of 500 mm s⁻¹. Moreover, the DP-RAP based devices remain a stable PCE of approximately 17.4% across a broad range of coating speeds (20–500 mm s⁻¹), illustrating its tolerance to the varied manufacturing conditions. This work highlights a promising avenue for the high-speed, ecofriendly production of efficient OSCs, pushing the boundaries of practical manufacturing in renewable energy technologies.