Self-assembled atomically thin hybrid conjugated polymer perovskites with two-dimensional structure

Abstract

We show that self-assembly of protonated polymer chains and metal halide network gives rise to formation of two-dimensional (2D) hybrid perovskites, which incorporate protonated polyaniline as the conjugated organic cation component and PbI₆ octahedra as the inorganic component. Single- and few-unit-cell-thick layers of these perovskites are obtained by mechanical exfoliation. Owing to the semiconducting behaviour of conjugated compounds, the atomically thin hybrid conjugated polymer perovskites reported here are expected to be considerably different from the quantum well systems based on unconjugated organic cation incorporating hybrid perovskites, in which the insulating organic layers act as potential barriers and the semiconducting inorganic layers act as potential wells. Besides, these materials are highly flexible in terms of chemical composition unlike conventional inorganic 2D materials, such as graphene, transition metal chalcogenides, transition metal oxides, boron nitride and black phosphorus. Different functional polymers/macromolecules could be self-assembled with a metal halide network in the same manner for the design of novel 2D hybrid perovskites for target applications. We also demonstrate that the conjugated polymer perovskites have tunable optical band gaps and they are highly stable against humidity.