Optimized Active Layer Morphologies via Ternary Copolymerization of Polymer Donors for 17.6 % Efficiency Organic Solar Cells with Enhanced Fill Factor. (1st December 2020)

• Record Type: Journal Article
• Authors: Guo, Xia; Fan, Qunping; Wu, Jingnan; Li, Guangwei; Peng, Zhongxiang; Su, Wenyan; Lin, Ji; Hou, Lintao; Qin, Yunpeng; Ade, Harald; Ye, Long; Zhang, Maojie; Li, Yongfang
• Is Part Of: Angewandte Chemie. Volume 133:Number 5(2021)
• Page Start: 2352
• Page End: 2359
• Publication Date: 2020-12-01
• Subjects: fill factor -- morphology -- organic solar cells -- power conversion efficiency -- terpolymers; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202010596
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Regulating molecular structure to optimize the active layer morphology is of considerable significance for improving the power conversion efficiencies (PCEs) in organic solar cells (OSCs). Herein, we demonstrated a simple ternary copolymerization approach to develop a terpolymer donor PM6‐Tz20 by incorporating the 5, 5′‐dithienyl‐2, 2′‐bithiazole (DTBTz, 20 mol%) unit into the backbone of PM6 (PM6‐Tz00). This method can effectively tailor the molecular orientation and aggregation of the polymer, and then optimize the active layer morphology and the corresponding physical processes of devices, ultimately boosting FF and then PCE. Hence, the PM6‐Tz20: Y6‐based OSCs achieved a PCE of up to 17.1% with a significantly enhanced FF of 0.77. Using Ag (220 nm) instead of Al (100 nm) as cathode, the champion PCE was further improved to 17.6%. This work provides a simple and effective molecular design strategy to optimize the active layer morphology of OSCs for improving photovoltaic performance. Abstract : A terpolymer donor PM6‐Tz20 was developed by incorporating the third 5, 5′‐dithienyl‐2, 2′‐bithiazole (DTBTz) unit into the PM6 backbone. The introduction of DTBTz can tailor the molecular ordering, orientation, and aggregation properties, and then optimize the morphology and electrical properties of devices, ultimately improving fill factor (0.77) and thus device efficiency (17.6 %).