Space charge and conductivity

Pulsed Electro-Acoustic Method

• Non-destructive technique for profiling space charge accumulation in polymeric materials.
• Permits the derivation of the total absolute stored charge density along with trap-controlled mobility of charges and trap depths.

TSDC – Thermally Stimulated Depolarization currents

This is a relaxation technique for investigation of molecular mobility in the solid state with sensitivity comparable to DMA.

Materials: semiconductors, polymers, polymer-clay composites.

Provides information on

• trap centers and corresponding thermal activation energies
• trap concentrations.

Operating principle: Thermal detrapping of carriers from defects causes peaks in the leakage current at certain temperatures corresponding to specific trapping centers.

Sensitivity: Densities of electronically active traps as low as 10⁹ cm⁻³ can easily be detected in high resistivity materials.

DC conductivity

• Conductivity is a fundamental property of a material and it represents a material’s ability to conduct electric current.
• Standards: ASTM D257-14 and IEC 62631-3-1:2016.

Facilities for adequate experimental setup:

• HVDC generator (provides the voltage to the sample)
• Pico-amperometer (acquires the current flowing through the material)
• Cell (defines the electrodes configuration)