Electrical conduction in pure and iodine-doped polyvinyl acetate thick films

The electrical conductivity (σ) of polyvinyl acetate (PVAc) films as a function of the iodine (I2) concentration, temperature (T), and voltage (U) is studied and an increase of about four orders of magnitude in σ is observed due to the doping of I2 in PVAc at room temperature. For pure PVAc, σ increases exponentially with T, whereas in the case of PVAc: I2 films, σ first increases with T, reaches a maximum and then decreases and the maxima in σ vs. T curves, shift towards lower temperatures with the increase in I2 concentration. It appears from the I—U—T characteristics of pure and iodine doped PVAc films that the Poole-Frenkel effect is the dominant charge transfer mechanism. On doping I2 in PVAc, an optical absorption band peaking at ≈ 370 nm, is observed and is attributed to charge transfer complexes.