Efficient Defect Passivation for Perovskite Solar Cells by Controlling the Electron Density Distribution of Donor-pi-Acceptor Molecules
Efficient Defect Passivation for Perovskite Solar Cells by Controlling the Electron Density Distribution of Donor-pi-Acceptor Molecules
复制标题
通过控制供体-受体分子的电子密度分布有效钝化钙钛矿太阳能电池的缺陷
DOI：
10.1002/aenm.201803766
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发表时间：
2019
影响因子：
27.8
通讯作者：
Han Liyuan
中科院分区：
文献类型：
--
作者：
Wu Tianhao;Wang Yanbo;Li Xing;Wu Yongzhen;Meng Xiangyue;Cui Danyu;Yang Xudong;Han Liyuan
有机-无机杂化钙钛矿太阳能电池（PSCs）是近年来发展迅速的一种极具发展前景的光伏技术。然而，钙钛矿吸收剂内部的大量离子缺陷可以作为非辐射复合中心，限制了聚苯乙烯复合材料的性能。本文采用具有不同电子密度分布的有机施主- π -受体（D - π - A）分子有效钝化钙钛矿薄膜中的缺陷。X射线光电子能谱（XPS）分析表明，分子中N，N -二丁基氨基苯基的强供电子性导致钝化位点（羧酸基）的电子密度增加，从而更好地与缺配Pb2+阳离子的缺陷结合。通过时间分辨光致发光光谱测量的钙钛矿薄膜中的载流子寿命也随着D - π - A分子供体能力的增加而延长。因此，这些优点有助于器件的开路电压增加80 mV，使最大功率转换效率（PCE）达到20.43%，而控制器件的PCE为18.52%。作者的发现提供了一种基于控制钝化分子电子构型的钙钛矿太阳能电池有效缺陷钝化的新策略。
Organic–inorganic hybrid perovskite solar cells (PSCs) are a promising photovoltaic technology that has rapidly developed in recent years. Nevertheless, a large number of ionic defects within perovskite absorber can serve as non‐radiative recombination center to limit the performance of PSCs. Here, organic donor‐π‐acceptor (D‐π‐A) molecules with different electron density distributions are employed to efficiently passivate the defects in the perovskite films. The X‐ray photoelectron spectroscopy (XPS) analysis shows that the strong electron donating N,N‐dibutylaminophenyl unit in a molecule causes an increase in the electron density of the passivation site that is a carboxylate group, resulting in better binding with the defects of under‐coordinated Pb2+cations. Carrier lifetime in the perovskite films measured by the time‐resolved photoluminescence spectrum is also prolonged by an increase in donation ability of the D‐π‐A molecules. As a consequence, these benefits contribute to an increase of 80 mV in the open circuit voltage of the devices, enabling a maximum power conversion efficiency (PCE) of 20.43%, in comparison with PCE of 18.52% for the control device. The authors' findings provide a novel strategy for efficient defect passivation in the perovskite solar cells based on controlling the electronic configuration of passivation molecules.