Zhang Hao, Tian Qingwen, Gu Xiaojing, Zhang Shiang, Wang Zhiteng, Zuo Xuejiao, Liu Yali, Zhao Kui, Liu Shengzhong Frank
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, No. 620, West Chang'an Avenue, Xi'an, 710119, P. R. China.
Dalian National Laboratory for Clean Energy, iChEM, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457, Zhongshan Road, Dalian, Liaoning, 116023, P. R. China.
Small. 2022 Aug;18(33):e2202690. doi: 10.1002/smll.202202690. Epub 2022 Jul 20.
The nonradiative charge recombination caused by surface defects and inferior crystalline quality are major roadblocks to further enhancing the performance of CsPbI Br perovskite solar cells (PSCs). Theoretical calculations indicate that sodium diethyldithiocarbamate (NaDDTC), a popular bacteriostatic benign material, can initiate multiple interactions with the CsPbI Br perovskite surface to effectively passivate the defects. The experimental results reveal that the NaDDTC can indeed passivate the electron trap states and lock active sites for charge traps and water adsorption. In addition, it is found that a solid-state reaction is triggered for perovskite crystal regrowth by the NaDDTC post-treatment, which not only enlarges grain size for reducing the density of grain boundary defects but also compensates some surface defects induced by the primary film growth. Consequently, the power conversion efficiency (PCE) of the CsPbI Br PSC is increased to as high as 20.40%, with significant improvement in fill factor and open-circuit voltage (V ), making it one of the highest for this type of solar cell. Furthermore, the optimized devices exhibit better environmental stability. Overall, this robust synchronous strategy provides efficient surface reconstruction and defect passivation for achieving both high PCE and stable inorganic perovskite.
由表面缺陷和较差的晶体质量引起的非辐射电荷复合是进一步提高CsPbI Br钙钛矿太阳能电池（PSC）性能的主要障碍。理论计算表明，二乙基二硫代氨基甲酸钠（NaDDTC），一种常用的抑菌良性材料，可与CsPbI Br钙钛矿表面发生多种相互作用，有效钝化缺陷。实验结果表明，NaDDTC确实可以钝化电子陷阱态，并锁定电荷陷阱和水吸附的活性位点。此外，发现通过NaDDTC后处理引发了钙钛矿晶体再生长的固态反应，这不仅增大了晶粒尺寸以降低晶界缺陷密度，还补偿了由初级膜生长引起的一些表面缺陷。因此，CsPbI Br PSC的功率转换效率（PCE）提高到高达20.40%，填充因子和开路电压（V）有显著改善，使其成为这类太阳能电池中效率最高的之一。此外，优化后的器件表现出更好的环境稳定性。总体而言，这种稳健的同步策略为实现高PCE和稳定的无机钙钛矿提供了有效的表面重构和缺陷钝化。
