First-principles materials design of high-performing bulk photovoltaics with the LiNbO$_3$ structure

TL;DR

This paper uses first-principles calculations to identify new polar oxides with the LiNbO$_3$ structure that have optimal band gaps and high bulk photovoltaic responses, advancing materials for efficient solar energy conversion.

Contribution

It predicts three new materials with high photovoltaic efficiency based on their electronic structure and band gap properties, expanding the design space for bulk photovoltaics.

Findings

Identified three polar oxides with 1-2 eV band gaps.

Predicted high bulk photovoltaic response, up to an order of magnitude better.

Linked electronic configuration to enhanced photovoltaic performance.

Abstract

The bulk photovoltaic effect is a long-known but poorly understood phenomenon. Recently, however, the multiferroic bismuth ferrite has been observed to produce strong photovoltaic response to visible light, suggesting that the effect has been underexploited as well. Here we present three polar oxides in the LiNbO$_3$ structure that we predict to have band gaps in the 1-2 eV range and very high bulk photovoltaic response: PbNiO$_3$, Mg$_{1/2}$Zn$_{1/2}$PbO$_3$, and LiBiO$_3$. All three have band gaps determined by cations with $d^{10}s^0$ electronic configurations, leading to conduction bands composed of cation $s$-orbitals and O $p$-orbitals. This both dramatically lowers the band gap and increases the bulk photovoltaic response by as much as an order of magnitude over previous materials, demonstrating the potential for high-performing bulk photovoltaics.