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Title: Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells

Abstract

Here, halogenation is an effective way to tune the energy levels of organic semiconducting materials. To date, fluorination of organic semiconducting materials to fabricate polymer solar cells (PSCs) has been used far more than chlorination; however, fluorine exchange reactions suffer from low yields and the resulting fluorinated polymer always comes with higher price, which will greatly hinder their commercial applications. Herein, we designed and synthesized a series of chlorinated donor-acceptor (D-A) type polymers, in which benzo[1,2-b:4,5- b]dithiophene and chlorinated benzothiadiazole units are connected by thiophene π-bridges with an asymmetric alkyl chain. These chlorinated polymers showed deep highest occupied molecular orbital energy levels, which promoted the efficiency of their corresponding PSCs by increasing the device open circuit voltage. The asymmetric alkyl chain on the thiophene moieties gave the final polymer sufficient solubility for solution processing and strong π-π stacking in films allowed for high mobility. Although the introduction of a large chlorine atom increased the torsion angle of the polymer backbone, the chlorinated polymers maintained high crystallinity and a favorable backbone orientation in the blended films. These factors contributed to respectable device performances from thick-film devices, which showed PCEs as high as 9.11% for a 250 nm-thick active layer. These resultsmore » demonstrate that chlorination is a promising method to fine tune the energy levels of conjugated polymers, and chlorinated benzothiadiazole may be a versatile building block in materials for efficient solar energy conversion.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1];  [2];  [3];  [3]; ORCiD logo [4]; ORCiD logo [1]
  1. South Univ. of Science and Technology of China, Shenzhen (People's Republic of China)
  2. Argonne National Lab. (ANL), Lemont, IL (United States)
  3. State Key Lab. of Supramolecular Structure and Materials College of Chemistry Jilin Univ., Changchun (People's Republic of China)
  4. Argonne National Lab. (ANL), Lemont, IL (United States); The Univ. of Chicago, Chicago, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1352927
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 7; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Mo, Daize, Wang, Huan, Chen, Hui, Qu, Shiwei, Chao, Pengjie, Yang, Zhen, Tian, Leilei, Su, Yu -An, Gao, Yu, Yang, Bing, Chen, Wei, and He, Feng. Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells. United States: N. p., 2017. Web. doi:10.1021/acs.chemmater.6b04828.
Mo, Daize, Wang, Huan, Chen, Hui, Qu, Shiwei, Chao, Pengjie, Yang, Zhen, Tian, Leilei, Su, Yu -An, Gao, Yu, Yang, Bing, Chen, Wei, & He, Feng. Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells. United States. doi:10.1021/acs.chemmater.6b04828.
Mo, Daize, Wang, Huan, Chen, Hui, Qu, Shiwei, Chao, Pengjie, Yang, Zhen, Tian, Leilei, Su, Yu -An, Gao, Yu, Yang, Bing, Chen, Wei, and He, Feng. Wed . "Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells". United States. doi:10.1021/acs.chemmater.6b04828. https://www.osti.gov/servlets/purl/1352927.
@article{osti_1352927,
title = {Chlorination of low-band-gap polymers: Toward high-performance polymer solar cells},
author = {Mo, Daize and Wang, Huan and Chen, Hui and Qu, Shiwei and Chao, Pengjie and Yang, Zhen and Tian, Leilei and Su, Yu -An and Gao, Yu and Yang, Bing and Chen, Wei and He, Feng},
abstractNote = {Here, halogenation is an effective way to tune the energy levels of organic semiconducting materials. To date, fluorination of organic semiconducting materials to fabricate polymer solar cells (PSCs) has been used far more than chlorination; however, fluorine exchange reactions suffer from low yields and the resulting fluorinated polymer always comes with higher price, which will greatly hinder their commercial applications. Herein, we designed and synthesized a series of chlorinated donor-acceptor (D-A) type polymers, in which benzo[1,2-b:4,5- b]dithiophene and chlorinated benzothiadiazole units are connected by thiophene π-bridges with an asymmetric alkyl chain. These chlorinated polymers showed deep highest occupied molecular orbital energy levels, which promoted the efficiency of their corresponding PSCs by increasing the device open circuit voltage. The asymmetric alkyl chain on the thiophene moieties gave the final polymer sufficient solubility for solution processing and strong π-π stacking in films allowed for high mobility. Although the introduction of a large chlorine atom increased the torsion angle of the polymer backbone, the chlorinated polymers maintained high crystallinity and a favorable backbone orientation in the blended films. These factors contributed to respectable device performances from thick-film devices, which showed PCEs as high as 9.11% for a 250 nm-thick active layer. These results demonstrate that chlorination is a promising method to fine tune the energy levels of conjugated polymers, and chlorinated benzothiadiazole may be a versatile building block in materials for efficient solar energy conversion.},
doi = {10.1021/acs.chemmater.6b04828},
journal = {Chemistry of Materials},
number = 7,
volume = 29,
place = {United States},
year = {2017},
month = {3}
}

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Works referencing / citing this record:

Influence of Backbone Chlorination on the Electronic Properties of Diketopyrrolopyrrole (DPP)‐Based Dimers
journal, February 2019

  • Xue, Ning; Wei, Yuan; Zhang, Guowei
  • Chemistry – An Asian Journal, Vol. 14, Issue 7
  • DOI: 10.1002/asia.201900142

Chlorine Effects of Heterocyclic Ring‐Based Donor Polymer for Low‐Cost and High‐Performance Nonfullerene Polymer Solar Cells
journal, May 2019


Over 14% Efficiency in Polymer Solar Cells Enabled by a Chlorinated Polymer Donor
journal, March 2018


Short-axis substitution approach on ladder-type benzodithiophene-based electron acceptor toward highly efficient organic solar cells
journal, June 2018


Over 14% Efficiency in Polymer Solar Cells Enabled by a Chlorinated Polymer Donor
journal, March 2018


Influence of Backbone Chlorination on the Electronic Properties of Diketopyrrolopyrrole (DPP)‐Based Dimers
journal, February 2019

  • Xue, Ning; Wei, Yuan; Zhang, Guowei
  • Chemistry – An Asian Journal, Vol. 14, Issue 7
  • DOI: 10.1002/asia.201900142

Chlorine Effects of Heterocyclic Ring‐Based Donor Polymer for Low‐Cost and High‐Performance Nonfullerene Polymer Solar Cells
journal, May 2019


Short-axis substitution approach on ladder-type benzodithiophene-based electron acceptor toward highly efficient organic solar cells
journal, June 2018