Manipulating Interfacial Performance of TPBi–FAPbI₃ Perovskite Interfaces Based on TPBi Orientations: A Theoretical Perspective

1,3,5-Tris­(1-phenyl-1H-benzimidazol-2-yl)­benzene (TPBi), as a popular functional material, has been applied extensively in electron transport layers (ETL) of perovskite optics. However, revealing the interface morphology and the interaction mechanism via limited experimental measurements is still tough. As is known, the optimization of interfacial properties is imperative for achieving high-performance and stable perovskite devices. In this study, the impact on charge transfer and binding energy of different orientations of TPBi interacting with formamidinium lead iodide (FAPbI₃) perovskite and their influence on the key performance parameters such as mobility and stability are investigated by computational approaches. Our findings reveal that the 15° TPBi orientation ensures strong electronic coupling between TPBi and FAPbI₃ perovskite, which improves the interfacial stability and enhances the charge transfer kinetics, leading to improved photogenerated carrier extraction, decreased recombination, and potentially enhanced device efficiency of both solar cell and electroluminescent devices (PeLEDs). Gaining a deeper understanding of TPBi orientations between charge transfer and binding energy of TPBi–FAPbI₃ perovskite interfaces enlightens future research proceedings in both interface engineering strategies and the design of stable hybrid perovskite materials.