Readily Accessible Benzo[d]thiazole Polymers for Nonfullerene Solar Cells with >16% Efficiency and Potential Pitfalls

Published

May 4, 2020

Author(s)

Liang-Wen Feng, Jianhua Chen, Subhrangsu Mukherjee, Yao Chen, Ding Zheng, Joseph Strzalka, Gang Wang, Dean DeLongchamp, Antonio Facchetti, Tobin Marks

Abstract

Here we report facile, high-yield synthetic access to the difluoro BTA building block, 4,7-bis(5-bromo-4-(2-hexyl-decyl)-thiophen-2-yl)-5,6-difluoro-2-(pentadecan-7-yl)-benzo[d]thiazole (BTAT-2f), for use in donor (D)–acceptor 1 (A1)–D–acceptor 2 (A2) polymers [D = bithiophene; A1 = BTA-2f; A2 = benzothiadiazole (BT) derivative] for organic solar cells (OSCs). Fine tuning of polymer optical and electronic properties is achieved by incrementally varying the A2 fluorination level. Bulk-heterojunction (BHJ) PBTATBT-4f:Y6 solar cells deliver a noteworthy power conversion (PCE) efficiency of 16.08% (Voc = 0.81 V; Jsc = 27.25 mAcm–2; FF = 72.70%) without processing additives. In contrast, PBTATBT-2f:Y6 exhibits an irregular morphology and low PCE, ascribable to cocrystal formation-induced recombination, which is unprecedented for nonfullerene (NFA) OSCs. This result should be of guiding significance for future NFA design.

Citation

ACS Energy Letters

Pub Type

Journals

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DOI Link

Citation

Feng, L. , Chen, J. , Mukherjee, S. , Chen, Y. , Zheng, D. , Strzalka, J. , Wang, G. , DeLongchamp, D. , Facchetti, A. and Marks, T. (2020), Readily Accessible Benzo[d]thiazole Polymers for Nonfullerene Solar Cells with >16% Efficiency and Potential Pitfalls, ACS Energy Letters, [online], https://doi.org/10.1021/acsenergylett.0c00691 (Accessed October 14, 2024)