Isomerization of Benzothiadiazole Yields a Promising Polymer Donor and Organic Solar Cells with Efficiency of 19.0

Tao Lin; Yulong Hai; Yongmin Luo; Lingwei Feng; Tao Jia; Jiaying Wu; Ruijie Ma; Top Archie Dela Peña; Yao Li; Zengshan Xing; Mingjie Li; Min Wang; Biao Xiao; Kam Sing Wong; Shengjian Liu; Gang Li

doi:10.1002/adma.202312311

Isomerization of Benzothiadiazole Yields a Promising Polymer Donor and Organic Solar Cells with Efficiency of 19.0

Adv Mater. 2024 Feb 2:e2312311. doi: 10.1002/adma.202312311. Online ahead of print.

Authors

Tao Lin¹, Yulong Hai², Yongmin Luo², Lingwei Feng³, Tao Jia¹, Jiaying Wu², Ruijie Ma⁴, Top Archie Dela Peña^{2

5}, Yao Li², Zengshan Xing⁶, Mingjie Li⁵, Min Wang¹, Biao Xiao⁷, Kam Sing Wong⁶, Shengjian Liu⁸, Gang Li⁴

Affiliations

¹ School of Optoelectronic Engineering, School of Mechanical Engineering, Guangdong Polytechnic Normal University, Guangzhou, 510665, China.
² Advanced Materials Thrust, Function Hub, The Hong Kong University of Science and Technology, Nansha, Guangzhou, 511400, China.
³ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China.
⁴ Department of Electrical and Electronic Engineering, Research Institute for Smart Energy (RISE), Photonic Research Institute (PRI), The Hong Kong Polytechnic University, Hong Kong, 999077, China.
⁵ Faculty of Science, Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, 999077, P. R. China.
⁶ School of Science, Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, P. R. China.
⁷ Key Laboratory of Optoelectronic Chemical Materials and Devices (Ministry of Education), Flexible Display Materials and Technology Co-Innovation Centre of Hubei Province, School of Optoelectronic Materials & Technology, Jianghan University (JHUN), Wuhan, 430056, China.
⁸ School of Chemistry, Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Key Laboratory of Electronic Chemicals for Integrated Circuit Packaging, South China Normal University (SCNU), Guangzhou, 510006, China.

PMID: 38305577
DOI: 10.1002/adma.202312311

Abstract

The exploration of high-performance and low-cost wide-bandgap polymer donors remains critical to achieve high-efficiency nonfullerene organic solar cells (OSCs) beyond current thresholds. Herein, the 1,2,3-benzothiadiazole (iBT), which is an isomer of 2,1,3-benzothiadiazole (BT), is used to design wide-bandgap polymer donor PiBT. The PiBT-based solar cells reach efficiency of 19.0%, which is one of the highest efficiencies in binary OSCs. Systemic studies show that isomerization of BT to iBT can finely regulate the polymers' photoelectric properties including i) increasing the extinction coefficient and photon harvest, ii) downshifting the highest occupied molecular orbital energy levels, iii) improving the coplanarity of polymer backbones, iv) offering good thermodynamic miscibility with acceptors. Consequently, the PiBT:Y6 bulk heterojunction (BHJ) device simultaneously reaches advantageous nanoscale morphology, efficient exciton generation and dissociation, fast charge transportation, and suppressed charge recombination, leading to larger V_OC of 0.87 V, higher J_SC of 28.2 mA cm^-2 , greater fill factor of 77.3%, and thus higher efficiency of 19.0%, while the analog-PBT-based OSCs reach efficiency of only 12.9%. Moreover, the key intermediate iBT can be easily afforded from industry chemicals via two-step procedure. Overall, this contribution highlights that iBT is a promising motif for designing high-performance polymer donors.

Keywords: 1,2,3-benzothiadiazole; 2,1,3-benzothiadiazole; organic solar cells; polymer donor.

Abstract

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