Oriented Grains with Preferred Low-Angle Grain Boundaries in Halide Perovskite Films by Pressure-Induced Crystallization

A general methodology is reported to create organic-inorganic hybrid metal halide perovskite films with enlarged and preferred-orientation grains. Simply pressing polyurethane stamps with hexagonal nanodot arrays on partially dried perovskite intermediate films can cause pressure-induced perovskite crystallization. This pressure-induced crystallization allows to prepare highly efficient perovskite solar cells (PSCs) because the preferred-orientation and enlarged grains with low-angle grain boundaries in the perovskite films exhibit suppressed nonradiative recombination. Consequently, the photovoltaic response is dramatically improved by the uniaxial compression in both inverted-planar PSCs and normal PSCs, leading to power conversion efficiencies of 19.16%.