Electrical conduction and dielectric relaxation in p-type PVA/CuI polymer composite

Area of Science:

• Materials Science
• Polymer Science
• Solid State Physics

Background:

• Polymer composites are crucial for advanced material applications.
• Incorporating metal halides into polymers can modify their electrical and thermal properties.
• Understanding charge transport mechanisms in polymer composites is essential for device development.

Purpose of the Study:

• To synthesize and characterize Polyvinyl Alcohol/Copper(I) Iodide (PVA/CuI) polymer composites.
• To investigate the effect of Copper(I) Iodide (CuI) concentration on the structural, thermal, and electrical properties of PVA.
• To elucidate the charge transport and dielectric relaxation mechanisms within the PVA/CuI composites.

Main Methods:

• Fourier Transform Infrared (FT-IR) spectroscopy for structural analysis.
• Differential Scanning Calorimetry (DSC) for thermal property assessment.
• AC and DC conductivity measurements to study electrical transport.
• Dielectric spectroscopy to analyze permittivity and loss.

Main Results:

• FT-IR showed variations in absorption peaks with CuI concentration.
• DSC indicated a slight decrease in glass transition temperature (Tg) and crystallization fraction (χ).
• DC conductivity increased with CuI up to 15 wt%, following Arrhenius behavior with activation energies of 0.54-1.32 eV.
• AC conductivity exhibited a power law (0.33 < s < 0.69), suggesting a hopping conduction mechanism.
• Dielectric permittivity and loss followed Debye dispersion relations.
• Thermally activated dipole relaxation times (0.33-0.87 eV) and hopping distances (1.2-3.4 nm) were determined.

Conclusions:

• PVA/CuI composites demonstrate tunable electrical conductivity and dielectric properties.
• The observed properties are attributed to hopping charge transport and dipole relaxation mechanisms.
• The estimated hopping distance aligns with the Bohr radius of excitons, suggesting potential for exciton-related phenomena.