Polymer bridging towards ion migration suppression in lateral 2D perovskite heterostructure

Two-dimensional (2D) halide perovskites have garnered significant interest owing to their facile solution processing, high quantum yield, and tunable photoelectronic properties. The formation of lateral heterostructures by 2D halide perovskites offers exceptional electronic and photoelectronic characteristics. However, the stability of 2D halide perovskite lateral heterostructures is compromised by the substantial intrinsic ion migration within the perovskite structure. Consequently, the suppression of ion diffusion at the interface is crucial to enable the growth of stable 2D halide perovskite heterostructures. In this study, we present an innovative polymer bridging strategy for the preparation of 2D halide perovskite lateral heterostructures with enhanced stability. We selected a linear polymer with cyano as the polymer bridge. The Polymers contain a significant number of binding sites that can effectively coordinate with the uncoordinated lead atoms at the in-plane edge of the 2D halide perovskite, thereby providing protection against perovskite decomposition. Additionally, the coordination of the polymer results in a heightened binding energy of Pb, leading to stronger halide ion binding and subsequent inhibition of halide ion migration. As a result, we demonstrate highly thermal stability of the heterostructure. Furthermore, the heterostructure exhibits the biexciton luminescence behaviors without the high energy excitation light. These findings present an effective approach for fabricating robust 2D halide perovskite lateral heterostructures. This research contributes to the advancement of the field by providing a new concept for fabricating stable 2D halide perovskite lateral heterostructures, and by offering significant insights into anionic behavior within such heterostructures.