Abstract

Gamma radiation-induced changes in the conduction mechanisms in prepared PVA/Lithium chloride

Author(s): S.Albayoumy

The electrical conductivity, current-voltage (I-V) and current–time (I – T) characteristics of pure PVA and different Wt % of LiCl -doped polyvinyl alcohol (PVA) films have been studied under different conditions. The electrical conductivity increased with increasing dopant concentration up to 60 % of weight and then showed a decrease beyond this concentration. The increase in conductivity is attributed to formation of charge transfer complexes while the decrease beyond 60 wt. % may be due to segregation. The variation of electrical conductivity with temperature showed two regions of activation energies for undoped films and three regions for doped films. I-V characteristics indicated that Schottky emission is the dominant charge transportmechanismin both undoped and LiCl -doped films. The effect of gamma irradiation at different radiation doses (20 and 50 kGy) on pure polyvinyl alcohol films and PVAloaded with differentWt%of LiCl was investigated. Measurements of I-V characteristics have been carried out at temperature range of 30-140C. Therefore, the charge carrier’s concentration in each of the conduction bands, the trapping parameter , the trap density Nt is determined as a function of different Wt % of LiCl is determined, leading to the electronmobility 0, effective electron driftmobility e, aswell as electrical transport properties and trapping energy calculation. The change that occurred in the dielectric constant values at different temperatures after irradiation can be attributed mainly to the changes in the intra- and intermolecular interactions.