Ternary Blend Organic Solar Cells Incorporating Ductile Conjugated Polymers with Conjugation Break Spacers
Ternary Blend Organic Solar Cells Incorporating Ductile Conjugated Polymers with Conjugation Break Spacers
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DOI：
10.1021/acsapm.1c00213
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发表时间：
2021-05-19
影响因子：
5
通讯作者：
Thompson, Barry C.
中科院分区：
文献类型：
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作者：
Kazerouni, Negar;Melenbrink, Elizabeth L.;Thompson, Barry C.
为了确定其对太阳能电池性能的电学指标的影响，将一系列具有8碳烷基偶联断裂间隔（CBS）单元的延展性半随机供体-受体（D-A）共聚物加入到三元共混有机太阳能电池中。本研究的目的是阐明有机太阳能电池的光伏和机械性能的潜在协同优化策略。三元共混活性层是基于两个聚合物给体和受体[6,6]-苯基- c61 -丁酸甲酯（PC61BM）。在所有情况下，大多数聚合物供体组分是先前报道的全共轭半随机聚合物p3hht - ehdpp -10%，由80%的3-己基噻吩，10%的带2-乙基己基（eh）侧链的二酮吡咯（DPP）和10%的噻吩组成。作为第二给体，使用了三种不同类型的CBS聚合物，其中间隔剂长度保持在8个亚甲基单位不变。这些聚合物的力学性能非常显著，模量低至8.54 MPa，断裂应变高达432%。然而，随着延展性的增加，孔洞迁移率降低。在这项研究中，我们观察到，当CBS聚合物的含量增加到总供体分数的15%时，三元活性层的孔迁移率普遍增加。较高的载流子迁移率可能有助于在许多三元器件中观察到较高的J（SC）。铸态三元太阳能电池在正常环境下制造，没有任何前后处理，其性能高达25%的CBS聚合物负载。这项工作表明，引入具有较差电荷迁移率的高可拉伸CBS聚合物不会对太阳能电池性能产生不利影响，为柔性/可拉伸有机太阳能电池的三元策略的发展提供了见解。
A broad family of ductile semirandom donor-acceptor (D-A) copolymers with 8-carbon alkyl conjugation break spacer (CBS) units were incorporated into ternary blend organic solar cells in order to determine their impact on the electrical metrics of solar cell performance. The goal of this study was to elucidate potential co-optimization strategies for photovoltaic and mechanical properties in organic solar cells. The ternary blended active layers were based on two polymer donors and the acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM). In all cases, the majority polymer donor component was the previously reported fully conjugated semirandom polymer P3HTT-ehDPP-10%, comprised of 80% 3-hexylthiophene, 10% diketopyrrolopyrrole (DPP) with 2-ethylhexyl (eh) side chains, and 10% thiophene. As the second donor, three different classes of CBS polymers were used, where the spacer length was kept constant at 8 methylene units. The mechanical properties of these polymers are quite notable with moduli as low as 8.54 MPa and fracture strains as high as 432%. However, it was found that as ductility increased, hole mobility decreased. In this study, we observed that the hole mobilities of the ternary active layers generally increased upon increasing the content of the CBS polymer up to 15% of the overall donor fraction. The higher carrier mobilities likely contribute to the higher J(SC) observed in many of the ternary devices. The as-cast ternary solar cells made in ambient environment without any pre/post treatment gave strong performance up to 25% of CBS polymer loading. This work demonstrates that introducing highly stretchable CBS polymers with poor charge mobility does not adversely affect solar cell performance, offering insights into the development of ternary strategies for flexible/stretchable organic solar cells.