Indirect band gap semiconductors for thin-film photovoltaics: High-throughput calculation of phonon-assisted absorption

TL;DR

This study introduces a computationally efficient method to evaluate phonon-assisted absorption in indirect band gap semiconductors, screening 127 materials and identifying 28 promising candidates for thin-film photovoltaic applications, including many previously unexplored compounds.

Contribution

The paper presents a novel high-throughput computational approach to assess phonon-assisted absorption in indirect band gap semiconductors for photovoltaics, expanding the pool of potential PV materials.

Findings

Identified 28 candidate materials for thin-film PV, including 20 indirect band gap semiconductors.

Discovered new promising compounds such as TiS₃, Ga₂Te₅, PdP₂, and others.

Most candidates are chalcogenides and phosphides with homoelemental bonds.

Abstract

Discovery of high-performance materials remains one of the most active areas in photovoltaics (PV) research. Indirect band gap materials form the largest part of the semiconductor chemical space, but predicting their suitability for PV applications from first principles calculations remains challenging. Here we propose a computationally efficient method to account for phonon assisted absorption across the indirect band gap and use it to screen 127 experimentally known binary semiconductors for their potential as thin film PV absorbers. Using screening descriptors for absorption, carrier transport, and nonradiative recombination, we identify 28 potential candidate materials. The list, which contains 20 indirect band gap semiconductors, comprises both well established (3), emerging (16), and previously unexplored (9) absorber materials. Most of the new compounds are anion rich chalcogenides (TiS$_3$, Ga$_2$Te$_5$) and phosphides (PdP$_2$, CdP$_4$, MgP$_4$, BaP$_3$) containing homoelemental bonds, and represent a new frontier in PV materials research. Our work highlights the previously underexplored potential of indirect band gap materials for optoelectronic thin-film technologies.