Strain-driven optimization of bulk WSe2 for photovoltaic, photocatalytic, and thermoelectric applications: First-Principles insights

Abstract

This study examines how biaxial tensile strain affects the performance of bulk WSe 2 for solar energy conversion through photovoltaic, photocatalytic, and thermoelectric applications. This work investigates the structural, dynamic, electronic, optical, photovoltaic, transport, and photocatalytic properties for hydrogen production and CO 2 photoreduction. WSe 2 remains stable under strain, with formation energy consistently negative. The bandgap decreases from 1.40 eV to 1.23 eV at 4% strain. Optical properties show enhanced light absorption and reduced bandgap with increased strain. For the photovoltaic response, the optical absorbance increases, accompanied by a corresponding decrease in transmittance, leading to an improvement in the power conversion efficiency from 31.83 % to 33.35%. Due to favorable redox potential alignment, WSe 2 efficiently splits water into hydrogen and oxygen. Biaxial tensile strain further optimizes this process by aligning the conduction band minimum and valence band maximum closer to redox potentials, improving photocatalytic performance. The thermoelectric properties were also analyzed, showing that WSe 2 maintains its transport characteristics under strain, indicating its potential for multifunctional applications. • The material is thermodynamically and dynamically stable with and without strain. • Calculated results closely match experimental data. • Strain increases the photovoltaic efficiency from 31.8% to 33.3%. • Water-splitting and thermoelectric efficiencies are enhanced. • The material shows potential for CO 2 reduction.