TY - JOUR
T1 - Effect of main and side chain chlorination on the photovoltaic properties of benzodithiophene-
T2 - Alt -benzotriazole polymers
AU - Bin, Haijun
AU - Angunawela, Indunil
AU - Ma, Ruijie
AU - Nallapaneni, Asritha
AU - Zhu, Chenhui
AU - Leenaers, Pieter J.
AU - Saes, Bart W.H.
AU - Wienk, Martijn M.
AU - Yan, He
AU - Ade, Harald
AU - Janssen, René A.J.
PY - 2020/11/21
Y1 - 2020/11/21
N2 - In developing organic semiconductor polymers for photovoltaic applications, chlorine substitution has become an effective strategy in replacing fluorine substitution to overcome the drawbacks of low yield and high cost, commonly associated with fluorination. In general, several molecular positions are available for chlorination. To obtain a clear understanding of the impact of chlorine substitution on the intrinsic polymer properties, an investigation of structure-property relationships is necessary. Herein, four donor-acceptor type polymers with the same conjugated backbone and flexible alkyl chains, but with chlorine atoms in different positions, are employed to systematically investigate the effect of the site of chlorination on the optoelectronic properties and photovoltaic performance. Substitution of fluorine by chlorine in the backbone slightly increases open circuit voltage (Voc) and fill factor (FF) of the solar cells but causes a loss of short-circuit current density (Jsc). The introduction of chlorine in the conjugated side chains, however, significantly improves Voc, FF, and power conversion efficiency, benefiting from a lower HOMO energy level, efficient and well-balanced transport properties, and superior nanoscale morphology.
AB - In developing organic semiconductor polymers for photovoltaic applications, chlorine substitution has become an effective strategy in replacing fluorine substitution to overcome the drawbacks of low yield and high cost, commonly associated with fluorination. In general, several molecular positions are available for chlorination. To obtain a clear understanding of the impact of chlorine substitution on the intrinsic polymer properties, an investigation of structure-property relationships is necessary. Herein, four donor-acceptor type polymers with the same conjugated backbone and flexible alkyl chains, but with chlorine atoms in different positions, are employed to systematically investigate the effect of the site of chlorination on the optoelectronic properties and photovoltaic performance. Substitution of fluorine by chlorine in the backbone slightly increases open circuit voltage (Voc) and fill factor (FF) of the solar cells but causes a loss of short-circuit current density (Jsc). The introduction of chlorine in the conjugated side chains, however, significantly improves Voc, FF, and power conversion efficiency, benefiting from a lower HOMO energy level, efficient and well-balanced transport properties, and superior nanoscale morphology.
UR - http://www.scopus.com/inward/record.url?scp=85096221170&partnerID=8YFLogxK
U2 - 10.1039/d0tc03095c
DO - 10.1039/d0tc03095c
M3 - Article
AN - SCOPUS:85096221170
SN - 2050-7526
VL - 8
SP - 15426
EP - 15435
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
IS - 43
ER -