Elevating Q‑PHJ Solar Cell Performance with Selenium-Infused Dimer Acceptors

• Published in: Macromolecules 2024-05, Vol.57 (9), p.4167-4173
• Main Authors: Ou, Meihong, Xiong, Shilong, Shen, Xiangyu, Lai, Hanjian, Lai, Xue, Wang, Yunpeng, Li, Heng, He, Feng
• Format: Article
• Language: English
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/acs.macromol.4c00421

Selenium-containing materials are believed to expand the range of light absorption. The larger and more polarizable selenium atoms enable strong Se–Se interactions between molecules, which enhance both crystallinity and electron mobility. Dimerized acceptor materials linked by end-groups exhibit reduced crystallinity due to the sacrifices of end-groups. To enhance the crystallinity of dimers, we substituted the central core of the Y-series molecules with selenium and used selenophene as the linker unit to synthesize three dimer acceptors. The introduction of selenium atoms led to a noteworthy increase in the absorption coefficient, a significant decrease in the Urbach energy, and an improvement in the crystallinity. The three dimers were used to prepare Q-PHJ solar cell devices with PBQx-H-TF as the donor. It was found that dBSeIC2Cl-Se-OD had the highest power conversion efficiency (PCE) of 17.03%, which is significantly higher than that of dBTIC-Se-HD without selenium substitution of the central core. This improvement was mainly attributed to the significant increase in short-circuit current (J SC) and fill factor (FF). The results suggest that the strategy of selenium substitution in the central core applied to the dimer acceptor can effectively improve the properties of the molecule, which, in turn, affects the performance of the solar cell device.