Molecular Bridge on Buried Interface for Energy Level Alignment in Inverted Perovskite Solar Cell with Efficiency over 25%
Yinyan Xu, Canjie Wang, Urasawadee Amornkitbamrung, Hyeon Jun Jeong, Ryan Rhee, Yongjae In, Aedan Gibson, Tomoya Nakamura, Minh Anh Truong, Atsushi Wakamiya, Hyunjung Shin
Abstract
Defect management and energy-level alignment at buried interfaces are challenging but crucial for further improvements of inverted perovskite solar cells ( i PSCs). Herein, an anchorable molecule, [[5 H -diindolo[3,2- a:3′,2′- c ]carbazole-5,10,15-triyl]tris(propane-3,1-diyl)]tris(phosphonic acid) (3PATAT), is developed to optimize the film morphology and energy level alignment at the buried interface between atomic layer deposition (ALD)-NiO and perovskite. By employing ALD-NiO, a conformal deposition can be achieved on rough substrates, in particular, fluorine-doped tin oxide (FTO), thus overcoming the limitation of traditional sol–gel and nanoparticle methods that are difficult to achieve the uniform coating, i.e., conformality. Meanwhile, the functional 3PATAT can synchronously coordinate with nickel ion in NiO and lead ion in perovskite, respectively. These interactions facilitate the interface carrier extraction and reduce interface-driven energy losses, thereby realizing a balanced charge carrier transport. Consequently, the optimal i PSCs achieve a champion power conversion efficiency of 25.1, 23.0, and 22.1% with a cell size of 0.06, 0.25, and 1 cm 2, respectively. Meanwhile, the 3PATAT bridged buried interface significantly enhances the device thermal stability.