Crossbreeding Effect of Chalcogenation and Iodination on Benzene Additives Enables Optimized Morphology and 19.68% Efficiency of Organic Solar Cells

Abstract

Volatile solid additives have attracted increasing attention in optimizing the morphology and improving the performance of currently dominated non‐fullerene acceptor‐based organic solar cells (OSCs). However, the underlying principles governing the rational design of volatile solid additives remain elusive. Herein, a series of efficient volatile solid additives are successfully developed by the crossbreeding effect of chalcogenation and iodination for optimizing the morphology and improving the photovoltaic performances of OSCs. Five benzene derivatives of 1,4‐dimethoxybenzene (DOB), 1‐iodo‐4‐methoxybenzene (OIB), 1‐iodo‐4‐methylthiobenzene (SIB), 1,4‐dimethylthiobenzene (DSB) and 1,4‐diiodobenzene (DIB) are systematically studied, where the widely used DIB is used as the reference. The effect of chalcogenation and iodination on the overall property is comprehensively investigated, which indicates that the versatile functional groups provided various types of noncovalent interactions with the host materials for modulating the morphology. Among them, SIB with the combination of sulphuration and iodination enabled more appropriate interactions with the host blend, giving rise to a highly ordered molecular packing and more favorable morphology. As a result, the binary OSCs based on PM6:L8‐BO and PBTz‐F:L8‐BO as well as the ternary OSCs based on PBTz‐F:PM6:L8‐BO achieved impressive high PCEs of 18.87%, 18.81% and 19.68%, respectively, which are among the highest values for OSCs.

Chalcogen Atoms Regulate the Organic Solar Cell Performance of B–N-Based Polymer Donors

“…In recent decades, organic solar cells (OSCs) have attracted considerable attention due to their cost-effectiveness, inherent flexibility, and solution processability. − With the advancement of photoactive materials, single-junction OSCs have achieved power conversion efficiencies (PCEs) exceeding 19%. − Among them, p-type conjugated polymer donors play a pivotal role in further enhancing the performance of organic solar cells. − To engineer high-performance polymer donors, several successful approaches in molecular design have been employed to optimize the performance of OSCs. Among others, boron–nitrogen bond-containing polymer donors have garnered considerable attention due to the distinct physical and chemical properties exhibited by boron and nitrogen atoms compared to carbon atoms. − Devices based on boron–nitrogen bond-containing polymer donors have achieved efficiencies exceeding 19%. , These polymer donors have the potential to enhance the performance of OSCs.…”