13.4 % Efficiency from All-Small-Molecule Organic Solar Cells Based on a Crystalline Donor with Chlorine and Trialkylsilyl Substitutions

Wenyan Su; Yang Wang; Zhihong Yin; Qunping Fan; Xia Guo; Liyang Yu; Yuxiang Li; Lintao Hou; Maojie Zhang; Qiang Peng; Yongfang Li; Ergang Wang

doi:10.1002/cssc.202100860

13.4 % Efficiency from All-Small-Molecule Organic Solar Cells Based on a Crystalline Donor with Chlorine and Trialkylsilyl Substitutions

ChemSusChem. 2021 Sep 6;14(17):3535-3543. doi: 10.1002/cssc.202100860. Epub 2021 Jun 19.

Authors

Wenyan Su^{1

2}, Yang Wang³, Zhihong Yin³, Qunping Fan², Xia Guo³, Liyang Yu⁴, Yuxiang Li⁵, Lintao Hou¹, Maojie Zhang³, Qiang Peng⁴, Yongfang Li³, Ergang Wang^{2

6}

Affiliations

¹ Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China.
² Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, 412 96, Sweden.
³ Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China.
⁴ School of Chemical Engineering, and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China.
⁵ School of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an, 710054, P. R. China.
⁶ School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, P. R. China.

Abstract

How to simultaneously achieve both high open-circuit voltage (V_oc ) and high short-circuit current density (J_sc ) is a big challenge for realising high power conversion efficiency (PCE) in all-small-molecule organic solar cells (all-SM OSCs). Herein, a novel small molecule (SM)-donor, namely FYSM-SiCl, with trialkylsilyl and chlorine substitutions was designed and synthesized. Compared to the original SM-donor FYSM-H, FYSM-Si with trialkylsilyl substitution showed a decreased crystallinity and lower highest occupied molecular orbital (HOMO) level, while FYSM-SiCl had an improved crystallinity, more ordered packing arrangement, significantly lower HOMO level, and predominant "face-on" orientation. Matched with a SM-acceptor Y6, the FYSM-SiCl-based all-SM OSCs exhibited both high V_oc of 0.85 V and high J_sc of 23.7 mA cm^-2 , which is rare for all-SM OSCs and could be attributed to the low HOMO level of FYSM-SiCl donor and the delicate balance between high crystallinity and suitable blend morphology. As a result, FYSM-SiCl achieved a high PCE of 13.4 % in all-SM OSCs, which was much higher than those of the FYSM-H- (10.9 %) and FYSM-Si-based devices (12.2 %). This work demonstrated a promising method for the design of efficient SM-donors by a side-chain engineering strategy via the introduction of trialkylsilyl and chlorine substitutions.

Keywords: crystalline donor; organic solar cells; photovoltaics; power conversion efficiency; side chain engineering.

Abstract

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