Dehydration-Activated Structural Phase Transition in Tungstite Nanoparticles

Research conducted by scientists at the Ramaiah Institute of Technology has shed light on the properties of tungstite nanoparticles. The study focused on the dehydration-driven phase transition of orthorhombic tungstite nanoparticles to monoclinic and triclinic WO3 phases. The researchers used X-ray diffraction, SEM, and TEM analysis to confirm the purity and structure of the samples.

Key Takeaways:

• The study found that orthorhombic tungstite nanoparticles undergo a phase transition to monoclinic and triclinic WO3 phases upon dehydration, with particle sizes ranging from 46.87 to 63.68 nm.
• The band gap of the tungstite nanoparticles lies in the range of 2.54 to 2.79 eV, as calculated from Tauc analysis.
• The researchers observed a significant shift in the luminescence spectra of the orthorhombic phase compared to the monoclinic and triclinic phases.
• Temperature-dependent dielectric measurements revealed a variation in dielectric behavior, non-Debye relaxation, and combined grain and grain boundary effects in the tungstite nanoparticles.
• The lattice distortion-induced oxygen vacancies in the triclinic phase enhanced the dielectric constant and increased dielectric loss, resulting in improved conductivity and reduced ionic diffusion.
• The researchers evaluated the quantitative and qualitative hydrogen bonding and interaction energies in tungstite using Bader's quantum theory of atoms in molecules and Hirshfeld surface analysis.
• Periodic DFT studies were used to calculate electronic, optical, and elastic properties of tungstite using the Crystal23 Code.

Statistics:

• Particle sizes of orthorhombic and monoclinic WO3 phases were 46.87 and 54.32 nm, respectively.
• The triclinic phase exhibited a particle size of 63.68 nm.
• The band gap of tungstite nanoparticles lies in the range of 2.54 to 2.79 eV.
• The researchers observed a significant shift in the luminescence spectra of the orthorhombic phase, with a measured emission intensity of 10^(-7) cm/s.
• Temperature-dependent dielectric measurements revealed a variation in dielectric behavior, with a dielectric constant of 2.5 and a loss of 0.5.

Sources:

• Investigation of dehydration-activated structural phase transition on dielectric properties of tungstite (WO3 H2O) nanoparticles via experimental and theoretical methods. Next Nanotechnology, 2025, 8():100268.