Molecular engineering of conjugated polymers for efficient hole transport and defect passivation in perovskite solar cells
Molecular engineering of conjugated polymers for efficient hole transport and defect passivation in perovskite solar cells
复制标题
用于钙钛矿太阳能电池中高效空穴传输和缺陷钝化的共轭聚合物的分子工程
DOI：
10.1016/j.nanoen.2017.12.028
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发表时间：
2018-03-01
期刊：
影响因子：
17.6
通讯作者：
Wang, Tao
中科院分区：
文献类型：
--
作者：
Cai, Feilong;Cai, Jinlong;Wang, Tao
有机-无机混合钙钛矿太阳能电池是下一代光伏技术的杰出候选者。然而，钙钛矿晶体中存在的表面缺陷限制了钙钛矿太阳能电池的性能和稳定性。我们采用了一系列基于咔唑和苯并噻二唑（BT）的供体-受体共聚物，它们在BT单元上接枝了不同长度的烷氧基侧链，作为钙钛矿太阳能电池的无掺杂空穴传输材料（HTM）。我们证明，虽然这些侧链可以降低这些共聚物的 pi-pi 堆积结构顺序从而影响空穴传输性能，但甲氧基单元引入了所需的缺陷钝化效应。与基于Spiro-OMeTAD的器件相比，BT单元上带有甲氧基侧链的共聚物（即PCDTBT1）作为HTM由于有效的空穴传输和抑制陷阱诱导的降解而实现了优异的功率转换效率和稳定性，而BT单元上带有辛氧基侧链的共聚物（即PCDTBT8）作为HTM导致性能和稳定性较差。
Organic-inorganic hybrid perovskite solar cells represent an exceptional candidate for next-generation photovoltaic technology. However, the presence of surface defects in perovskite crystals limits the performance as well as the stability of perovskite solar cells. We have employed a series of carbazole and benzothiadiazole (BT) based donor-acceptor copolymers, which have different lengths of alkoxy side-chains grafted on the BT unit, as the dopant-free hole transport materials (HTMs) for perovskite solar cells. We demonstrate that although these side-chains can reduce the pi-pi stacking structural order of these copolymers to affect the hole transport properties, the methoxy unit introduces a desired defect passivation effect. Compared to the Spiro-OMeTAD-based device, the copolymer with methoxy side-chains on the BT unit (namely PCDTBT1) as the HTM achieved superior power conversion efficiency and stability due to efficient hole transport and the suppression of trap-induced degradation, whilst the copolymer with octyloxy side-chains on the BT unit (namely PCDTBT8) as the HTM lead to poor performance and stability.