Benzotriazole‐Based Nonfused Ring Acceptors for Efficient and Thermally Stable Organic Solar Cells

• Published in: Macromolecular rapid communications. Vol. 43; no. 22; pp. e2200530 - n/a
• Main Authors: Han, Daehee, Lim, Chulhee, Phan, Tan Ngoc‐Lan, Kim, Youngkwon, Kim, Bumjoon J.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2022; Wiley
• Subjects: Benzotriazole; Carrier mobility; Charge transport; Chemical synthesis; chlorination; Circuits; Cold crystallization; Crystallization; Current carriers; Energy conversion efficiency; High temperature; Infrared absorption; Near infrared radiation; nonfused ring acceptors; organic solar cells; Photovoltaic cells; Polymer Science; Polymers; Solar cells; Thermal stability; Triazoles
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.202200530

Nonfused ring acceptors (NFRAs) have attracted significant attention for nonfullerene organic solar cells (OSCs) owing to their chemical tunability and facile synthesis. In this study, a benzotriazole‐based NFRA with chlorinated end groups (Triazole‐4Cl) is developed to realize highly efficient and thermally stable NFRA‐based OSCs; an analogous NFRA with nonchlorinated end groups (Triazole‐H) is synthesized for comparison. Triazole‐4Cl film exhibits the high‐order packing structure and the near‐infrared absorption capability, which are advantageous in charge transport and light harvesting of the resulting OSCs. In particular, the strong crystalline behavior of Triazole‐4Cl results in enhanced self‐aggregation, leading to high charge carrier mobility. Owing to these properties, a PBDB‐T (polymer donor):Triazole‐4Cl OSC demonstrates a high short‐circuit current, fill factor, and power conversion efficiency (PCE = 10.46%), outperforming a PBDB‐T:Triazole‐H OSC (PCE = 7.65%). In addition, the thermal stability of a PBDB‐T:Triazole‐4Cl OSC at an elevated temperature of 120 °C exceeds that of a PBDB‐T:Triazole‐H OSC. This is mainly attributed to the significantly higher cold crystallization temperature of Triazole‐4Cl (205.9 °C). This work provides useful guidelines for the design of NFRAs to achieve efficient and thermally stable NFRA‐based OSCs. Benzotriazole‐based nonfused ring acceptors (NFRAs) with chlorinated end groups for achieving efficient and thermally stable organic solar cells (OSCs) is developed. Incorporating chlorine atoms onto the end groups of benzotriazole‐based NFRA effectively tunes its opto‐electrical properties, crystallinity, and intermolecular interactions with the polymer donor. This design strategy provides useful guidelines for the realization of efficient and thermally stable NFRA‐based OSCs.