Toward High Efficiency Polymer Solar Cells: Influence of Local Chemical Environment and Morphology
Toward High Efficiency Polymer Solar Cells: Influence of Local Chemical Environment and Morphology
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DOI：
10.1002/aenm.201601081
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发表时间：
2017
影响因子：
27.8
通讯作者：
Cheng Zhou;Guichuan Zhang;Chengmei Zhong;Xiao’e Jia;P. Luo;Rongguo Xu;Ke Gao;Xiao-Fang Jiang;Feng Liu;T. P. Russell;F. Huang;Yong Cao
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文献类型：
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作者：
Cheng Zhou;Guichuan Zhang;Chengmei Zhong;Xiao’e Jia;P. Luo;Rongguo Xu;Ke Gao;Xiao-Fang Jiang;Feng Liu;T. P. Russell;F. Huang;Yong Cao
共轭聚合物的化学结构在决定其物理性质方面起着重要作用，而物理性质反过来又决定了它们在光伏器件中的性能。5-氟-2，1，3-苯并噻二唑是一种不对称单元，它被引入到基于噻吩基的聚合物主链上，形成具有可控区域规整性的空穴导电聚合物。在区域规则聚合物中可以看到高偶极矩，这种聚合物具有更紧密的链间堆积，促进了体相异质结共混物中形态的形成，并提高了功率转换效率。系统地改变了脂肪族侧链取代度，以了解侧链长度和对称性对产物形态和合成性能的影响。这种侧链修饰影响了晶体的取向和相分离形态。采用具有主链区域规整性的非对称侧链替代，获得了9.06%的优化功率转换效率，开路电压为0.72V，短路电流为19.63 mA cm−2，填充因子大于65%。这些结果表明，局部化学环境可以显著影响所生成材料的物理性质。
The chemical structure of conjugated polymers plays an important role in determining their physical properties that, in turn, dictates their performance in photovoltaic devices. 5‐Fluoro‐2,1,3‐benzothiadiazole, an asymmetric unit, is incorporated into a thiophene‐based polymer backbone to generate a hole conducting polymers with controlled regioregularity. A high dipole moment is seen in regioregular polymers, which have a tighter interchain stacking that promotes the formation of a morphology in bulk heterojunction blends with improved power conversion efficiencies. Aliphatic side chain substitution is systematically varied to understand the influence of side chain length and symmetry on the morphology and resultant performance. This side chain modification is found to influence crystal orientation and the phase separated morphology. Using the asymmetric side chain substitution with regioregularity of the main chain, an optimized power conversion efficiency of 9.06% is achieved, with an open circuit voltage of 0.72 V, a short circuit current of 19.63 mA cm−2, and a fill factor over 65%. These results demonstrate that the local chemical environment can dramatically influence the physical properties of the resultant material.