NiO- and MnO-nanoparticle-modified pyrogallol-formaldehyde-derived carbon matrix

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Carbon-based materials are crucial for electronic applications.
• Developing novel nanocomposites with enhanced electrical properties is an active research area.
• Transition metal oxides can significantly influence the electronic behavior of carbon matrices.

Purpose of the Study:

• To synthesize and characterize pyrogallol-formaldehyde-derived carbon matrix (CM) nanocomposites.
• To investigate the effect of nickel oxide (NiO) and manganese oxide (MnO) nanoparticles on the structural and electrical properties of the CM.
• To understand the charge transport mechanisms in these nanocomposites for potential electronic applications.

Main Methods:

• Sol-gel synthesis for creating carbon matrix (CM) and its nanocomposites.
• X-ray diffraction (XRD) for structural analysis.
• Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDX) for morphology and elemental composition.
• X-ray Photoelectron Spectroscopy (XPS) for surface elemental analysis.
• Raman spectroscopy to assess structural disorder.
• Electrical conductivity, impedance, and dielectric measurements to study electronic properties.

Main Results:

• Amorphous carbon matrix (CM) with incorporated NiO and MnO nanoparticles was successfully synthesized.
• SEM revealed a porous structure, facilitating homogeneous nanoparticle dispersion (Ni) or some clustering (MnO).
• Raman spectroscopy indicated increased structural disorder with nanoparticle incorporation, enhancing defect density.
• Electrical measurements showed semiconducting behavior with improved conductance in nanocomposites.
• The CM/MnO nanocomposite exhibited the highest conductance and lowest activation energy (80 meV), attributed to Mn redox activity and chlorine-induced defects.
• Impedance and dielectric studies identified Maxwell-Wagner interfacial polarization and non-Debye relaxation.
• Conduction mechanisms were identified as correlated barrier hopping (CBH) in CM/NiO and small polaron hopping (SPH) in CM/MnO.

Conclusions:

• Transition metal oxides play a critical role in tuning the electrical conduction properties of carbon-based nanocomposites.
• The CM/MnO nanocomposite demonstrates superior electrical performance due to synergistic effects of Mn redox activity and defect engineering.
• These findings offer valuable insights for designing efficient carbon-based nanocomposites for advanced electronic applications.
• Understanding charge transport mechanisms (CBH and SPH) is key to optimizing material design.