Simultaneous mechanical and chemical synthesis of long-range-ordered perovskites

Abstract

Combining mechanical and chemical effects during the synthesis of crystals can lead to unexpected material attributes. The role of mechanical effects during the wet chemical synthesis of halide perovskite remains insufficiently explored, mainly due to its temporal asynchronization with the typical slower solvent evaporation-motivated chemical changes. Here we introduce stress from mechanical shearing into a short temporal window of crystal synthesis by using a fast-crystallizing precursor ink, which causes mechanical shearing effects to occur simultaneously with the atomic assembly of perovskite. This protocol allows macroscopic dynamic shearing to impact the atomic lattice rearrangement, growth and facet orientation. Such an effect is consistently observed across atomic to centimetre scales, culminating in films with long-range uniformity. These perovskite films exhibit exceptional crystalline orientation and structural uniformity, demonstrating a Herman’s orientation factor of −0.3135 and leading to a remarkable power conversion efficiency of 25.90% on small-area cells and exceeding 21% in a 70 cm2 solar module. This synthetic approach exemplifies the use of mechanical shearing to foster the assembly of long-range-ordered crystallographic lattices, thereby providing a scalable synthesis for high-quality perovskite films. Controlling crystal growth in perovskite syntheses that rely solely on chemical processes is challenging. Now, a synthesis protocol that integrates mechanical and chemical effects achieves enhanced crystalline orientation and uniformity.