Epitaxial growth of horizontally aligned single-crystal arrays of perovskite

Well-aligned single-crystal nanowire arrays of CH3NH3PbI3 have shown potentials in laser sources and photovoltaic applications. Here we developed a solution based epitaxial method to grow CH3NH3 PbI3 nanowire arrays. By confining the precursor solution between a silicon wafer and ST-cut quartz, the evaporation rate of the solvent was slowed down which brings a more stable and controllable solution environment. Relying on the lattice match between CH3NH3PbI3 and ST-cut quartz, arrays of single-crystal nanowires of CH3NH3PbI3 have been grown epitaxially. The densities and lengths of CH3NH3PbI3 nanowires can be tuned. The lengths of the resultant crystals range from several microns to over one millimeter. Such CH3NH3PbI3 arrays with good alignment and crystallinity were then applied to fabricate photovoltaic devices with good performances.