Li Dan, Li Yong, Liu Lidan, Liu Zhike, Yuan Ningyi, Ding Jianning, Wang Dapeng, 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, Xi'an 710119, China.
School of Materials Science and Engineering Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering Jiangsu Province Cultivation Base for State Key Laboratory of Photovoltaic Science and Technology, Changzhou University, Changzhou 213164, China.
ACS Omega. 2021 May 17;6(21):13766-13773. doi: 10.1021/acsomega.1c01074. eCollection 2021 Jun 1.
Compact TiO films are one of the most widely used electron transport layers (ETLs) in planar perovskite solar cells (PSCs). However, the performance of the PSC device is controlled by the comprehensive qualities of the functional layers and their bilateral surfaces. In this work, the alkali metal halide of RbBr as the interfacial modifier is introduced into the interface of the TiO ETL and perovskite absorber. By spin-coating the proper content of RbBr, the surface of the TiO film consisting of smooth morphology and low density of oxygen-deficiency defect is readily obtained. The perovskite layer successively fabricated on the RbBr-modified TiO film demonstrates large grain size, low surface roughness, and low bulk defect density, which enhances the electron extraction and decreases nonradiation recombination. By virtue of the modulation of the perovskite crystal quality and the passivation of the interfacial defects, the light-harvesting efficiency of the corresponding device is increased to 21.15 from 19.21% for the PSC without a RbBr insertion layer. More importantly, the passivation strategy enables impressive device stability by retaining 90% of its initial efficiency in an ambient environment for 500 h. This study provides a promising and feasible strategy to regulate surface passivation engineering and simultaneously facilitate the perovskite crystal growth for the achievement of efficient and stable perovskite photovoltaics.
致密TiO薄膜是平面钙钛矿太阳能电池（PSC）中应用最广泛的电子传输层（ETL）之一。然而，PSC器件的性能受功能层及其两侧表面综合质量的控制。在本工作中，将卤化碱金属RbBr作为界面改性剂引入TiO ETL与钙钛矿吸收体的界面。通过旋涂适当含量的RbBr，可轻松获得由光滑形貌和低密度缺氧缺陷组成的TiO薄膜表面。在RbBr改性的TiO薄膜上依次制备的钙钛矿层具有大晶粒尺寸、低表面粗糙度和低体缺陷密度，这增强了电子提取并减少了非辐射复合。借助于对钙钛矿晶体质量的调制和界面缺陷钝化，相应器件的光捕获效率从不含RbBr插入层的PSC的19.21%提高到21.15%。更重要的是，钝化策略通过在环境条件下500小时内保持其初始效率的90%，实现了令人印象深刻的器件稳定性。本研究提供了一种有前景且可行的策略，用于调控表面钝化工程并同时促进钙钛矿晶体生长，以实现高效稳定的钙钛矿光伏器件。
