Origin of Efficient Inverted Nonfullerene Organic Solar Cells: Enhancement of Charge Extraction and Suppression of Bimolecular Recombination Enabled by Augmented Internal Electric Field Yiwen Wang Bo Wu Zhenghui Wu Zhaojue Lan Yongfang Li Maojie Zhang Furong Zhu 10.1021/acs.jpclett.7b02308.s001 https://acs.figshare.com/articles/journal_contribution/Origin_of_Efficient_Inverted_Nonfullerene_Organic_Solar_Cells_Enhancement_of_Charge_Extraction_and_Suppression_of_Bimolecular_Recombination_Enabled_by_Augmented_Internal_Electric_Field/5496997 We report our effort to unravel the origin of efficient operation of nonfullerene organic solar cells (OSCs), based on a poly­[4,8-bis­(5-(2-ethylhexyl) thiophen-2-yl)­benzo­[1,2-b;4,5-b′]­dithiophene-2,6-diyl-<i>alt</i>-(4-(2-ethylhexyl)-3-fluorothieno­[3,4-<i>b</i>]­thiophene-)-2-carboxylate-2-6-diyl)]­(PTB7-Th):3,9-bis­(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis­(4-hexylphenyl)-dithieno­[2,3-d:2′,3′-d′]-s-indaceno [1,2-b:5,6-b′]­dithiophene (ITIC) blend system. The effects of buildup of space charges, charge extraction, and bimolecular recombination processes on the performance and the stability of PTB7-Th:ITIC-based regular and reverse configuration OSCs are analyzed. It is found that the high-performing inverted PTB7-Th:ITIC OSCs benefit from the combined effects of (1) suppression of bimolecular recombination enabled by an augmented effective internal electric field and (2) improvement of charge extraction by avoiding the holes passing through ITIC-rich region, which would otherwise occur in a regular configuration cell. The inverted PTB7-Th:ITIC OSCs possess a significant improvement in the cell stability and a high power conversion efficiency of ∼8.0%, which is >29% higher than that of an optimized regular configuration control cell (6.1%). 2017-10-13 00:00:00 PTB 7-Th OSCs benefit stability power conversion efficiency Augmented Internal Electric Field configuration Efficient Inverted Nonfullerene Organic Solar Cells PTB 7-Th OSCs charge extraction ITIC Bimolecular Recombination Enabled recombination