Zhao Wenyan, Shi Jiangjian, Tian Chuanjin, Wu Jionghua, Li Hongshi, Li Yusheng, Yu Bingcheng, Luo Yanhong, Wu Huijue, Xie Zhipeng, Wang Changan, Duan Defang, Li Dongmei, Meng Qingbo
Key Laboratory for Renewable Energy (CAS), Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190, China.
School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, China.
ACS Appl Mater Interfaces. 2021 Mar 3;13(8):9771-9780. doi: 10.1021/acsami.0c18311. Epub 2021 Feb 20.
In perovskite solar cells, the halide vacancy defects on the perovskite film surface/interface will instigate charge recombination, leading to a decrease in cell performance. In this study, cadmium sulfide (CdS) has been introduced into the precursor solution to reduce the halide vacancy defects and improve the cell performance. The highest efficiency of the device reaches 21.62%. Density functional theory calculation reveals that the incorporated Cd ions can partially replace Pb ions, thus forming a strong Cd-I bond and effectively reducing iodide vacancy defects (V); at the same time, the loss of the charge recombination is significantly reduced because V is filled by S ions. Besides, the substitution of Cd for Pb could increase the generation of PbI, which can further passivate the grain boundary. Therefore, the stability of the cells, together with the efficiency of the power conversion efficiencies (PCEs), is also improved, maintaining 87.5% of its initial PCEs after being irradiated over 410 h. This work provides a very effective strategy to passivate the surface/interface defects of perovskite films for more efficient and stable optoelectronic devices.
在钙钛矿太阳能电池中，钙钛矿薄膜表面/界面上的卤化物空位缺陷会引发电荷复合，导致电池性能下降。在本研究中，已将硫化镉（CdS）引入前驱体溶液中，以减少卤化物空位缺陷并提高电池性能。该器件的最高效率达到21.62%。密度泛函理论计算表明，掺入的Cd离子可以部分取代Pb离子，从而形成强Cd-I键并有效减少碘化物空位缺陷（V）；同时，由于V被S离子填充，电荷复合损失显著降低。此外，用Cd替代Pb可以增加PbI的生成，这可以进一步钝化晶界。因此，电池的稳定性以及功率转换效率（PCE）也得到了提高，在超过410小时的光照后仍保持其初始PCE的87.5%。这项工作为钝化钙钛矿薄膜的表面/界面缺陷以制备更高效、稳定的光电器件提供了一种非常有效的策略。
