Solution-processed all-inorganic lead halide perovskite/layered double hydroxides superlattices

Quantum wells and superlattices are key building blocks in the semiconductor industry, normally fabricated using epitaxial growth techniques, such as vapor phase epitaxy, metalorganic chemical vapor deposition and molecular beam epitaxy. However, these complicated preparation processes, as well as their high cost, limit their extensive applications. It is essential to develop a simple solution process for building superstructures. Here, we demonstrate an ion exchange strategy for synthesizing an all-inorganic superlattice cesium lead bromide/layered double hydroxides (CsPbBr₃/LDH) in solution. At room temperature, the perovskite ions diffuse into the interlayer of LDH and assemble into layered perovskite with various thicknesses. Compared with traditional organic-inorganic hybrid perovskite superlattice, the all-inorganic perovskite superlattice CsPbBr₃/LDH has weak quantum confinement, which exhibits narrow emission line-widths of 20 nm, high quantum yields of 55%, and radiative lifetimes of several ns. Our findings offer a new route to synthesize novel perovskite superlattices and enrich the perovskite supercrystal platform for electronics, photonics and optoelectronics devices.