Ternary Strategy Enables Non‐Halogenated Solvent‐Processed All‐Polymer Solar Cells with High Efficiency Over 18

• Published in: Advanced functional materials Vol. 34; no. 21
• Main Authors: Zhang, Jiabin, Zhou, Qiuman, Xie, Juxuan, Zhao, Ju, Yu, Jiangkai, Zhang, Kai, Jia, Tao, Huang, Fei, Cao, Yong
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.05.2024
• Subjects: Absorptivity; all‐polymer solar cell; Efficiency; Energy conversion efficiency; Energy harvesting; Energy transfer; Excitons; Miscibility; Molecular orbitals; morphology; Open circuit voltage; Photovoltaic cells; Polymers; power conversion efficiency; Short circuit currents; Solar cells; Solvents; ternary strategy
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202313722

Herein, efficient ternary all‐polymer solar cells (all‐PSCs) are fabricated by employing PDEDTQ that possesses down‐shifted highest occupied molecular orbital (HOMO) level and blue‐shifted absorption with higher maximum absorption coefficients compared with the host donor JD40‐BDD20 as a guest donor into the JD40‐BDD20:PA‐5 host blend. The enhanced light‐harvesting and the energy transfer from PDEDTQ to JD40‐BDD20 can be observed in the ternary device, which conduces to improving the short circuit current density (JSC). Additionally, the PDEDTQ shows relatively weak crystalline and well miscibility with the JD40‐BDD20, meaning that the morphology can be tuned using the PDEDTQ. Subsequently, a more uniform and fine‐divided network with slightly weakened crystalline occurs in the ternary blend film, implying that a more intermixing domain with a higher density of donor/acceptor (D/A) interfaces may be formed. Thus, compared with JD40‐BDD20:PA‐5, the ternary device obtained enhanced exciton dissociation and charge extraction, reducing charge recombination and energy loss (Eloss). Ultimately, in addition to guaranteeing outstanding fill factor (FF), the higher JSC and improve open circuit voltage (VOC) are achieved and then boosted the power conversion efficiency (PCE) from 17.39% to 18.47%, which is one of the highest PCEs for the all‐PSCs. Overall, this work provides guidance on forming a high‐quality network with uniform distribution of D/A using ternary strategy, and then obtaining high‐efficiency all‐PSCs processed using non‐halogenated solvent. The PDEDTQ is introduced as the third component into the JD40‐BDD20:PA‐5 host blend to fabricate the high‐performance ternary all‐polymer solar cells (all‐PSCs) with a power conversion efficiency (PCE) of 18.47%. It can not only transfer energy to JD40‐BDD20 and form extra exciton dissociation channels, but also regulate the miscibility between JD40‐BDD20 and PA‐5 to form a high‐quality network with uniform distribution on the micron scale.