Sequential deposition method processed ternary organic solar cells with efficiency of 17.92%

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Bulk heterojunction (BHJ) organic solar cells (OSCs) have developed rapidly in recent years. However, the problems of BHJ OSCs such as difficulty in regulating morphology have limited its further development. Combining sequential deposition (SD) method and ternary strategy is an effective way to solve the above problems as well as achieve high-performance OSCs. Herein, we prepared SD devices based on D18-Cl/Y6 system, which possess a vertical distribution structure facilitating charge transmission and inhibiting bimolecular recombination. Compared with BHJ OSCs, the highest power conversion efficiency (PCE) of SD OSCs is increased from 16.54% to 17.16%. Moreover, highly crystalline small molecule BTR-Cl was introduced to the active layer, which further broadened the absorption spectrum of the main system, enhanced the crystallinity of molecules and improved the morphology of films. Ultimately, ternary OSCs based on SD structure obtain a best efficiency of 17.92%, with an open-circuit voltage ( V o c ) of 0.886 V, short-circuit current density ( J s c ) of 26.97 m A c m − 2 , and fill factor (FF) of 75.11%. This work demonstrates that the ternary strategy combined with SD approach is an effective method to overcome the difficulty to regulate morphology and realize high-performance OSCs. • Combining sequential deposition (SD) method and ternary strategy is an effective way to regulate the morphology of films, which achieves high-performance OSCs. • SD processing can form a vertical distribution structure inhibiting the charge recombination and facilitating the charge collection. • The introduction of BTR-Cl can further broaden the absorption spectrum of the main system, improve the morphology of films and enhance the crystallinity of molecules. • Adopting the SD structure substitutes for the BHJ structure, D18-Cl/Y6 system-based OSCs achieved an improved PCE from 16.54% to 17.16%. With the addition of BTR-Cl, the efficiency of SD OSCs based on ternary system was further increased to 17.92%.