Regulating Phase Distribution of Dion–Jacobson Perovskite Colloidal Multiple Quantum Wells Toward Highly Stable Deep‐Blue Emission

Abstract

AbstractMetal halide perovskite colloidal quantum wells (CQWs) hold great promise for modern photonics and optoelectronics. However, current studies focus on Ruddlesden–Popper (R–P) phase perovskite CQWs that contain bilayers of monovalent long‐chain alkylamomoniums between the separated perovskite octahedra layers. The bilayers are packed back‐to‐back via weak van der Waals interaction, resulting in inferior charge carrier transport and easier decomposition of perovskite. This report first creates a new type of perovskite colloidal multiple QWs (CMQWs) in the form of Dion–Jacobson (D–J) structure by introducing an asymmetric diammonium cation. Furthermore, the phase distribution is optimized by the synergistic effect of valeric acid and zwitterionic lecithin, finally achieving pure deep‐blue emission at 435 nm with narrow full width at half maximum. The diammonium layer in D–J perovskite CMQWs features extremely short width of only ≈0.6 nm, thereby contributing to more effective charge carrier transport and higher stability. Through the continuous photoluminescence (PL) measurement and corresponding theoretical calculation, the higher stability of D–J perovskite CMQWs than that of R–P structural CMQWs is confirmed. This work reveals the inherent superior stability of D–J structural CMQWs, which opens a new direction for fabricating stable perovskite optoelectronics.