Polymerized Small‐Molecule Acceptor as an Interface Modulator to Increase the Performance of All‐Small‐Molecule Solar Cells

• Published in: Advanced energy materials Vol. 12; no. 3
• Main Authors: Zhang, Ziqi, Deng, Dan, Li, Yi, Ding, Jianwei, Wu, Qiong, Zhang, Lili, Zhang, Guangjie, Iqbal, Muhammad Junaid, Wang, Rui, Zhang, Jianqi, Qiu, Xiaohui, Wei, Zhixiang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-01-2022
• Subjects: Additives; all‐small‐molecule OSCs; Charge transfer; Charge transport; Circuits; Domains; Energy conversion efficiency; Excitons; interface modulators; Molecular interactions; Morphology; Photovoltaic cells; Polymerization; polymerized small‐molecule acceptors; Short circuit currents; Solar cells
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202102394

Modulating the morphology of all‐small‐molecule organic solar cells (ASM‐OSCs) has proved to be a considerable challenge in the context of efficient exciton dissociation and charge transport. Regulating the morphology of ASM‐OSCs is a great challenge due to the low viscosity of the small molecules, which tend to form large domain sizes and loose molecular packing, especially in the interfacial region. Here, a polymerized small‐molecule acceptor (PJ1) is introduced as an interface modulator to strengthen the interfacial molecular interactions in a high‐efficiency system, consisting of a novel small molecule donor (ZR‐TT) and a widely used acceptor (Y6). Optimized ASM‐OSCs exhibit a power conversion efficiency (PCE) of 14.33% without any additives. A small amount of PJ1 effectively condenses the morphology, enhances the crystallinity of the blend, and decreases the domain sizes. Upon 3% PJ1 addition in the blends, the accelerated hole transfer and the enhanced charge transport ultimately lead to an increased PCE of 15.54% with improved short circuit current and fill factor. Notably, the generality of this interfacial modulator strategy is proved by using PJ1 in three other ASM‐OSCs and using another polymerized host acceptor, PYT‐F‐o.
To modulate the morphology of all‐small‐molecule organic solar cells, a polymerized small‐molecule acceptor PJ1 is introduced into a high‐efficiency system ZR‐TT: Y6 as an interface modulator. By accelerating hole transfer and enhancing charge transport, the more condensed and uniform morphology contribute to an enhanced power conversion efficiency of 15.54% in 3% PJ1 added devices. This strategy shows good generality.