Pseudo-bulk heterojunction(BHJ)fabricated by sequential casting of donor and acceptor layers has been recently demonstrated as a superior structure to prepare organic solar cells(OSCs)with enhanced efficiency compared to the conventional BHJ OSCs cast from a common solution of donors and acceptors.However,molecular diffusion and aggregation within the pseudo-BHJ layer bring great challenges to fully realize the advantage of pseudo-BHJ structure.Herein,a solution-incubated pre-aggregation strategy is employed to tune the nanoscale aggregates of non-fullerene acceptor(NFA)BTP-eC11 and N3 to substantially enhance device power-conversion efficiency(PCE).NFA pre-aggregates are incubated in solutions via aging or adding anti-solvent,and then sequentially cast onto D18 fibrillar network,which then penetrate to form a pseudo-BHJ structure with appropriate domain sizes to ensure superior charge mobilities.While the conventional pseudo-BHJ OSCs obtain inferior PCEs below 17％compared with normal BHJ OSCs,NFA pre-aggregates help to achieve remarkable PCEs of 17.7％and 17.5％for D18/BTP-eC11 and D18/N3 pseudo-BHJ OSCs.This work demonstrates that the solution-incubated nanoscale pre-aggregation is an efficient approach to regulate molecular diffusion and aggregation to guarantee high performance pseudo-BHJ OSCs.

Donghui Li;Chuanhang Guo;Xue Zhang;Baocai Du;Cong Yu;Pang Wang;Shili Cheng;Liang Wang;Jinlong Cai;Hui Wang;Dan Liu;Huifeng Yao;Yanming Sun;Jianhui Hou;Tao Wang

School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China;State Key Laboratory of Polymer Physics and Chemistry,Beijing National Laboratory for Molecular Sciences,CAS Research/Education Center for Excellence in Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Chemistry,Beihang University,Beijing 100191,China

中国科学:化学（英文版）

[1]Donghui Li;Chuanhang Guo;Xue Zhang;Baocai Du;Cong Yu;Pang Wang;Shili Cheng;Liang Wang;Jinlong Cai;Hui Wang;Dan Liu;Huifeng Yao;Yanming Sun;Jianhui Hou;Tao Wang-.Non-fullerene acceptor pre-aggregates enable high efficiency pseudo-bulk heterojunction organic solar cells)[J].中国科学:化学（英文版）,2022(02):373-381

eC11

Non,fullerene,aggregates,enable,high,efficiency,pseudo,bulk,heterojunction,organic,solar,cells,Pseudo,BHJ,fabricated,by,casting,layers,has,been,recently,demonstrated,superior,structure,prepare,OSCs,enhanced,compared,conventional,from,common,donors,acceptors,However,molecular,diffusion,aggregation,within,bring,great,challenges,fully,realize,advantage,Herein,incubated,strategy,employed,tune,nanoscale,NFA,BTP,N3,substantially,device,power,conversion,solutions,via,aging,adding,solvent,then,sequentially,onto,D18,fibrillar,network,which,penetrate,appropriate,domain,sizes,ensure,charge,mobilities,While,obtain,inferior,PCEs,below,normal,help,achieve,remarkable,This,demonstrates,that,efficient,approach,regulate,guarantee,performance

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