Metastable Multi-centered Polarons in BiVO$_{4}$

TL;DR

This paper uses first-principles calculations to reveal the existence of multi-centered polarons in BiVO4, showing their anisotropic nature and impact on charge transport, which advances understanding of its photocatalytic properties.

Contribution

It uncovers the formation of multi-centered polarons in BiVO4 and characterizes their anisotropic behavior, providing new insights into charge-lattice interactions in this material.

Findings

Multi-centered polarons are present in BiVO4.

Electron polarons are anisotropic, holes are isotropic.

Multi-centered polarons create new charge transport channels.

Abstract

Polarons, quasiparticles formed through interactions between lattice and charge carriers (electrons and holes), strongly influence the electronic and optical properties of functional materials. In nanostructured BiVO$_{4}$, polaron formation and dynamics govern photocatalytic efficiency and charge transport, yet the microscopic nature remains not fully resolved. Here, using first-principles calculations, we report the formation of multi-centered polarons, in contrast to the more common single-centered states. Moreover, electron polarons exhibit pronounced anisotropy compared to the isotropic hole counterpart, reflecting a distinct character in charge-lattice coupling. These theoretical insights offer a direct interpretation of optical and spectroscopic experiments, providing strong evidence of anisotropic multi-centered polaronic behavior in BiVO$_{4}$. The presence of multiple in-gap states, especially from multi-centered polarons, introduces new channels for charge transport and recombination, possibly offering opportunities to control carrier dynamics in nanoscale photocatalytic and optoelectronic devices.