Two-dimensional (2D) metal halide perovskite-like quantum wells can be obtained by slicing the inorganic perovskite lattices with large organic molecules, where the number of consecutive inorganic slabs (n) determines the quantum confinement. Synthesizing large-area and ultrathin 2D perovskite sheets is crucial to achieving heterostructures for future thin-sheet optoelectronic devices. In this work, we demonstrate a synthesis method in which perovskite precursor solutions are introduced on an antisolvent liquid surface. Well-defined n = 1 sheets with sub-10 nm thickness and up to 50 μm lateral size are obtained in a scalable manner. This is achieved through careful engineering of subphase and spreading phase compositions to encourage controlled perovskite crystallization at the antisolvent–air interface. Structural and spectroscopic characterizations reveal a high phase purity and a clean excitonic emission, with their overall optical properties comparable to those of the highly crystalline films fabricated by blade coating, highlighting the clear potential of this liquid surface synthesis strategy.
Li et al. (Thu,) studied this question.