Dong Yujing, Guo Yuan, Wang Mengru, Zhu Rui, Ma Dongwei, Jia Yu
Key Laboratory for Special Functional Materials of Ministry of Education, and School of Materials, Center for Topological Functional Materials, and School of Physics and Electronic, Henan University, Kaifeng 475001, China.
School of Science and Technology, Xinyang College, Xinyang 464000, China.
Inorg Chem. 2022 Jun 27;61(25):9469-9479. doi: 10.1021/acs.inorgchem.2c00394. Epub 2022 Jun 13.
High-density and multitype surface defects of CsPbIBr perovskite induce charge recombination and accumulation, hindering its device efficiency and stability. However, the surface defect types of CsPbIBr perovskite are still unclear, and conventional organic molecules only passivate one specific defect and cannot achieve good overall passivation. Here, density functional theory is used to explore surface defect types and properties of CsPbIBr with calculating the defect formation energy and electronic structure. Results show that the dominant deep-level defects are cationic defects (Pb) under Br-poor conditions and anionic defects (I and Br) under moderate and Br-rich conditions, originating from Pb-Pb bonding and I-I bonding. Multifunctional organic molecules containing donor and acceptor groups are used to passivate both cationic and anionic defects simultaneously. It turns out that the deep-level defects are effectively decreased by forming strong interaction of N-Pb, O-Pb, and halide-Pb bonds. Moreover, the electron and hole transfers from perovskite to molecules increase dramatically to -9.06 × 10 and 2.60 × 10 /cm and maybe improve the efficiency of power conversion. Our findings not only reveal the surface defect properties of CsPbIBr, but also offer an approach for designing new multifunctional passivators for perovskite solar cells with high conversion efficiency.
CsPbIBr钙钛矿的高密度和多类型表面缺陷会引发电荷复合和积累，阻碍其器件效率和稳定性。然而，CsPbIBr钙钛矿的表面缺陷类型仍不明确，传统有机分子仅能钝化一种特定缺陷，无法实现良好的整体钝化效果。在此，利用密度泛函理论，通过计算缺陷形成能和电子结构来探究CsPbIBr的表面缺陷类型和性质。结果表明，在Br贫条件下，主要的深能级缺陷是阳离子缺陷（Pb），而在中等和Br富条件下是阴离子缺陷（I和Br），它们分别源于Pb - Pb键合和I - I键合。使用含有供体和受体基团的多功能有机分子同时钝化阳离子和阴离子缺陷。结果表明，通过形成N - Pb、O - Pb和卤化物 - Pb键的强相互作用，深能级缺陷有效减少。此外，从钙钛矿到分子的电子和空穴转移显著增加至 - 9.06×10和2.60×10/cm，这可能提高功率转换效率。我们的研究结果不仅揭示了CsPbIBr的表面缺陷性质，还为设计用于高转换效率钙钛矿太阳能电池的新型多功能钝化剂提供了一种方法。
