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Title: The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells

Abstract

A series of conjugated T2 polymers (PBBF1-T2 and PBBCl1-T2), and T3 polymers (PBBF1-T3, PBBCl1-T3 and PBBCl2-T3) were synthesized using chlorinated/fluorinated benzothiadiazole (BT) and the two-dimensional benzo[1,2-b:4,5-b']dithiophene (BDT) units as the building blocks. When compared to the fluorinated polymer, the performance of the polymer photovoltaic devices showed that these chlorinated polymers gave extended optical absorption spectrum, and lower highest occupied molecular orbital (HOMO) energy levels. The introduction of chlorine atoms increases the twist angle between the polymer backbones, and led to a lower HOMO energy level and resulted in the increase of open circuit voltage (V oc) up to 0.84 V in PBBCl2-T3 based devices with a two chlorine substitution. However, the device based on PBBCl1-T3 with only one chlorine atom exhibited the best power conversion efficiency (PCE) which was as high as 6.87% with a V oc of 0.73 V, and this was about 10% higher than that of its fluorinated analogs. Here, this result indicated that the introduction of chlorine atoms into polymers is not only a simple route to synthesize a large amount of material and which avoids the tedious synthesis steps in widely used fluorinated polymers, but it is also a feasible and effective strategy to finemore » tune the energy level of polymer solar cell with optimized PCE. Furthermore, it is worth noting that the introduction of longer π-conjugation side chains could minimize the influence of chlorine substitution by reducing the twist angle between the polymer backbones, which would reduce the gap of V oc between the chlorinated polymers and their fluorinated analogs.« less

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [1];  [3]; ORCiD logo [4]; ORCiD logo [1]
  1. Southern Univ. of Science and Technology, Shenzhen (China). Dept. of Chemistry
  2. Southern Univ. of Science and Technology, Shenzhen (China). Dept. of Chemistry; Wuhan Univ. (China). Dept. of Chemistry
  3. Wuhan Univ. (China). Dept. of Chemistry
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Univ. of Chicago, IL (United States). Inst. for Molecular Engineering
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). Materials Sciences & Engineering Division; National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1425243
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Polymer Chemistry
Additional Journal Information:
Journal Volume: 9; Journal Issue: 8; Journal ID: ISSN 1759-9954
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Yang, Zhen, Chen, Hui, Wang, Huan, Mo, Daize, Liu, Longzhu, Chao, Pengjie, Zhu, Yulin, Liu, Chuanjun, Chen, Wei, and He, Feng. The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells. United States: N. p., 2017. Web. doi:10.1039/c7py01792h.
Yang, Zhen, Chen, Hui, Wang, Huan, Mo, Daize, Liu, Longzhu, Chao, Pengjie, Zhu, Yulin, Liu, Chuanjun, Chen, Wei, & He, Feng. The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells. United States. doi:10.1039/c7py01792h.
Yang, Zhen, Chen, Hui, Wang, Huan, Mo, Daize, Liu, Longzhu, Chao, Pengjie, Zhu, Yulin, Liu, Chuanjun, Chen, Wei, and He, Feng. Fri . "The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells". United States. doi:10.1039/c7py01792h.
@article{osti_1425243,
title = {The integrated adjustment of chlorine substitution and two-dimensional side chain of low band gap polymers in organic solar cells},
author = {Yang, Zhen and Chen, Hui and Wang, Huan and Mo, Daize and Liu, Longzhu and Chao, Pengjie and Zhu, Yulin and Liu, Chuanjun and Chen, Wei and He, Feng},
abstractNote = {A series of conjugated T2 polymers (PBBF1-T2 and PBBCl1-T2), and T3 polymers (PBBF1-T3, PBBCl1-T3 and PBBCl2-T3) were synthesized using chlorinated/fluorinated benzothiadiazole (BT) and the two-dimensional benzo[1,2-b:4,5-b']dithiophene (BDT) units as the building blocks. When compared to the fluorinated polymer, the performance of the polymer photovoltaic devices showed that these chlorinated polymers gave extended optical absorption spectrum, and lower highest occupied molecular orbital (HOMO) energy levels. The introduction of chlorine atoms increases the twist angle between the polymer backbones, and led to a lower HOMO energy level and resulted in the increase of open circuit voltage (Voc) up to 0.84 V in PBBCl2-T3 based devices with a two chlorine substitution. However, the device based on PBBCl1-T3 with only one chlorine atom exhibited the best power conversion efficiency (PCE) which was as high as 6.87% with a Voc of 0.73 V, and this was about 10% higher than that of its fluorinated analogs. Here, this result indicated that the introduction of chlorine atoms into polymers is not only a simple route to synthesize a large amount of material and which avoids the tedious synthesis steps in widely used fluorinated polymers, but it is also a feasible and effective strategy to fine tune the energy level of polymer solar cell with optimized PCE. Furthermore, it is worth noting that the introduction of longer π-conjugation side chains could minimize the influence of chlorine substitution by reducing the twist angle between the polymer backbones, which would reduce the gap of Voc between the chlorinated polymers and their fluorinated analogs.},
doi = {10.1039/c7py01792h},
journal = {Polymer Chemistry},
number = 8,
volume = 9,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2017},
month = {Fri Dec 15 00:00:00 EST 2017}
}

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Works referenced in this record:

Hierarchical Nanomorphologies Promote Exciton Dissociation in Polymer/Fullerene Bulk Heterojunction Solar Cells
journal, September 2011

  • Chen, Wei; Xu, Tao; He, Feng
  • Nano Letters, Vol. 11, Issue 9, p. 3707-3713
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Polymer Photovoltaic Cells: Enhanced Efficiencies via a Network of Internal Donor-Acceptor Heterojunctions
journal, December 1995