Structural, diffuse reflectance and luminescence study of t-Mg₂B₂O₅ nanostructures

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Magnesium diboride (Mg2B2O5) is a material with known mechanical and thermal properties.
• Previous reports suggested Mg2B2O5 has an indirect band gap, limiting its optical applications.
• Efficient synthesis methods for nanostructured Mg2B2O5 are crucial for exploring its potential.

Purpose of the Study:

• To synthesize Mg2B2O5 nanostructures at lower temperatures using an optimized combustion method.
• To characterize the structural, optical, and thermoluminescent properties of the synthesized Mg2B2O5.
• To investigate the band gap nature and potential applications of Mg2B2O5 nanostructures.

Main Methods:

• Combustion synthesis for Mg2B2O5 nanostructures.
• X-ray diffraction (XRD) with Rietveld refinement for structural analysis.
• Diffuse reflectance spectroscopy (DRS) to determine the band gap.
• First-principles calculations (FPLAPW method) to elucidate band gap nature.
• Photoluminescence (PL) and thermoluminescence (TL) spectroscopy for optical properties.
• Anti-biofilm activity assay using Pseudomonas aeruginosa.

Main Results:

• Single-phase triclinic Mg2B2O5 nanoparticles were successfully synthesized.
• Experimentally determined direct band gap of 5.23 eV, supported by theoretical calculations (5.10 eV).
• Observed yellow-reddish photoluminescence peaking at 588 nm, attributed to defect states.
• UV (254 nm) responsive thermoluminescence with peaks indicating trapping sites.
• Demonstrated significant anti-biofilm activity (91% inhibition) against Pseudomonas aeruginosa.

Conclusions:

• Combustion synthesized Mg2B2O5 nanostructures possess a direct wide band gap and UV-responsive thermoluminescence.
• The material's properties suggest suitability for luminescence-based applications and UV dosimetry.
• Mg2B2O5 nanoparticles show promise as an antimicrobial agent against P. aeruginosa biofilms.