Fig. 4: Lattice-matching defined crystal orientation.

a Illustration of the one-dimensional PDS crystals lying on solution surface; b the edge-sharing Pb-I octahedra chains in one-dimensional PDS crystal. c Illustration of the conversion of edge-sharing Pb-I octahedra chains into corner-sharing octahedral chains (see detailed process in supplementary movie 1), in which the I⁻ ions at the exposed corners are low-coordinated I^- ions (blue colored). d Illustration of the corner-sharing PbI₆ octahedra in the (0 1 0) plane of RP perovskites and the low-coordinated I⁻ ions (blue colored) at the edge of crystal sheet along the \([10\bar 1]\) direction. e Illustration of the templated downward growing layered perovskite crystals on 3D-like perovskites, in which the dominating orientation is defined by the lattice matching shown in (c) and (d). f XRD spectra of BA-based RP perovskite film (<n> = 4), PEA-based RP perovskite film (<n> = 4), and PPD-based DJ perovskite film (<n> = 4) with OP orientation, in which the dominating diffraction peaks are all (1 1 1) and (2 0 2) peaks.