Predicted bulk photovoltaic effect in hydrogenated Zintl compounds

TL;DR

This study predicts hydrogenated Zintl compounds exhibit a strong bulk photovoltaic effect with potential for efficient solar energy conversion, outperforming some existing materials like BiFeO3, especially at lower photon energies.

Contribution

The paper introduces hydrogenated Zintl compounds as promising materials for bulk photovoltaic effect applications, with calculated responses exceeding known materials.

Findings

Maximum shift current up to eight times greater than BiFeO3.

Significant photovoltaic response at low photon energies.

Some compounds stable in air up to 770 K.

Abstract

The bulk photovoltaic effect (BPVE) is a phenomenon which creates a net electrical current from sunlight in a polar noncentrosymmetric material possessing a moderate band gap. This effect is being explored as an alternative to traditional pn-junction solar cells to convert solar energy into electricity. This paper assesses the possibility that hydrogenated Zintl-phase compounds consisting only of metal, metalloid, and hydrogen atoms, may be able to provide a BPVE response. Towards this end, the magnitude of the BPVE shift current is calculated for each of the compounds AeTrTtH (Ae = Ca, Sr, and Ba; Tr = Al and Ga; and Tt = Si, Ge, and Sn). For this family of hydogenated Zintl compounds, maximum shift current responses are predicted that are up to eight times greater than that calculated for BiFeO3, and have a significant response down to much lower photon energies than BiFeO3 as well. With band gaps below 1 eV, and with some members of this family of compounds exhibiting stability in air up to 770 K, some of these compounds may find use in photovoltaic devices.