Shape-Controlled NaTaO3 by Flux-Mediated Synthesis

NaTaO3 is a stable and wide bandgap n-type semiconductor material with many different applications. Here, a flux-mediated synthesis method is presented for NaTaO3 resulting in highly distinctive, substrate covering shapes via precursor chemistry variation at comparatively low temperatures. It is found that the microstructure of the resulting NaTaO3 films can be varied from nanocubes to smooth thin films. These shapes and surface chemistries can be correlated by employing density functional theory calculations and surface sensitive X-ray photoemission spectroscopy. This study provides guidance on how to synthesize the material and tailor its shape and surface termination for different applications. Finally, as a proof of concept of one possible application, NaTaO3 is applied to perovskite solar cells as the electron transport layer, resulting in conversion efficiencies of >19%. This study provides a new strategy for designing ternary oxide thin films for renewable energy applications.