First-Principles Calculations on Electronic, Optical, and Phonon Properties of γ-Bi₂MoO₆

Area of Science:

• Materials Science
• Solid State Physics
• Photocatalysis

Background:

• Wide band gap materials are crucial for emergent solar harvesting technologies.
• Gamma-Bi2MoO6 (BMO) exhibits significant potential due to its properties.

Purpose of the Study:

• To investigate the physical properties of BMO relevant to light sensitivity using a combined experimental and DFT approach.
• To synthesize phase-pure BMO and analyze its structural, dynamical, and electronic characteristics.
• To evaluate the photocatalytic efficiency of BMO for dye degradation.

Main Methods:

• Solvothermal synthesis of BMO at different pH values.
• First-principles density functional theory (DFT) calculations, including HSE06, vdW, and SOC corrections.
• Elastic tensor simulations for structural stability.
• Phonon band structure calculations for dynamical stability.
• Diffuse reflectance spectroscopy (DRS) for band gap determination.
• Raman and infrared spectroscopy for vibrational modes.
• Photocatalytic degradation of methylene blue dye.

Main Results:

• Phase-pure BMO with a wide band gap (≳3 eV) was successfully synthesized.
• DFT calculations accurately predicted structural stability, dynamical stability, and vibrational modes (Raman and IR).
• The calculated band gap using HSE06+SOC+vdW corrections closely matched experimental DRS data.
• Optical absorption spectra from DFT aligned well with experimental observations.
• BMO demonstrated approximately 43% photocatalytic efficiency in degrading methylene blue under illumination.

Conclusions:

• The combined DFT-experimental approach provides a comprehensive understanding of BMO's properties for solar energy applications.
• BMO exhibits promising characteristics for light harvesting and photocatalysis.
• Further research into BMO-based materials could advance solar energy technologies.