High-throughput computational characterization of two-dimensional compositionally complex transition-metal chalcogenide alloys

TL;DR

This study develops a high-throughput VCA-DFT workflow to predict properties of 2D compositionally complex transition-metal chalcogenide alloys, enabling efficient computational design of materials for light adsorption and photovoltaic applications.

Contribution

It introduces a VCA-DFT based high-throughput method for predicting properties of 2D complex alloys, validated against traditional DFT calculations, facilitating accelerated materials discovery.

Findings

VCA-DFT results are comparable to traditional DFT with some inaccuracies.

2D CCTMCAs can form type II heterostructures suitable for photovoltaics.

Certain alloys exhibit high electrical conductivities at room temperature.

Abstract

Two-dimensional (2D) binary transition-metal chalcogenides (TMCs) like molybdenum disulfide exhibits excellent properties as materials for light adsorption devices. Alloying binary TMCs can form 2D compositionally complex TMC alloys (CCTMCAs) that possess remarkable properties from the constituent TMCs. We adopt a high-throughput workflow performing density functional theory (DFT) calculations based on the virtual crystal approximation (VCA) model (VCA-DFT). We test the workflow by predicting properties including in-plane lattice constants, band gaps, effective masses, spin-orbit coupling (SOC), and band alignments of the Mo-W-S-Se, Mo-W-S-Te, and Mo-W-Se-Te 2D CCTMCAs. We validate the VCA-DFT results by computing the same properties using unit cells and supercells of selected compositions. The VCA-DFT results of the abovementioned five properties are comparable to that of DFT calculations, with some inaccuracies in several properties of MoSTe and WSTe. Moreover, 2D CCTMCAs can form type II heterostructures as used in photovoltaics. Finally, we use Mo0.5W0.5SSe, Mo0.5W0.5STe, and Mo0.5W0.5SeTe 2D CCTMCAs to demonstrate the room-temperature entropy-stabilized alloys. They also exhibit high electrical conductivities at 300K, promising for light adsorption devices. Our work shows that the high-throughput workflow using VCA-DFT calculations provides a tradeoff between efficiency and accuracy, opening up opportunities in the computational design of other 2D CCTMCAs for various applications.