Role of Intrinsic Dipoles in the Evaporation‐Driven Assembly of Perovskite Nanocubes into Energy‐Harvesting Composites

Abstract

Efficient ambient energy scavenging exploiting piezoelectric properties of ferroelectric perovskites is an attractive green strategy to power low‐energy devices. In turn, the colloidal processing of the nearly monodisperse and highly crystalline single‐domain nanocubes of BaTiO3 is a promising route to produce oriented, high‐performance thin films for integration into nanostructured‐ferroelectric devices. Controlling the local behavior of nanocrystals is imperative for fabricating highly ordered assemblies, whereas the current picture of nanoscale polarization suggests a potential presence of significant electrodipolar interaction in ferroelectric nanoparticles. However, its role in the condensation of perovskite nanocubes remains unknown. The results of simulated self‐assembly and characterization of osmotically densified ensembles of dipolar nanocubes are reported. It is shown that in fact for solubilized BaTiO3 nanocubes, the polarization screening must be complete without appreciable dipole moment (below a few kBT), whereas stray interactions from incompletely screened surface charges are likely the major sources of disorder in self‐assembled architectures of SrTiO3.