The Study of Carbon Nano-particles (CNPs) & Film Thickness & Temperature Effect on the Electrical Properties of Poly (3-hexylthiophene-2,5-diyl)

Abstract

A thin films of a neat and a doped of P3HT in (1%, 2%, 3%, 4%, 5%) CNPs concentrations were fabricated by a spin coating method in multi revolution speeds (1000, 1500, 2000, 2500, 3000)rpm on glass substrate for thin film thickness measurement, and other films were fabricated on aluminum interdigitated finger electrodes of ceramic substrates for I-V characteristics measurement. The film thickness of the fabricated thin films of neat and doped P3HT was found in direct proportional to CNPs concentration in every revolution speed, and in reciprocal proportional to the revolution speed for every CNPs concentration. I-V characteristics were measured at (303, 313, 323, 333, 343)ᴼK temperature for all thin films in the voltage range to equal or less than (10 V), which presents an ohmic behavior of all samples. The surface electrical conductivity (σ_s) of samples was calculated from a slope of ohmic lines, the results shows an electrical semiconductor behavior for all neat and doped P3HT deposited films. On the other hand, an increasing of a surface conductivity of samples with an increase of CNPs doping concentration from (0%) to (5%) in every temperature and revolution speed. Its observed from the results that the electrical conductivity was decreased with film thickness increasing for neat and doped P3HT films in any one of temperature range. An activation energy (E_a) of the fabricated thin films was calculated from the slope of linear relation between conductivity an inverse of temperature, its observed that the activation energy decreasing for doped case P3HT in comparison with neat polymer, and its decreasing with an increase of the CNPs doping ratio. Also its clear that activation energy, increasing with increasing film thickness of the neat and doped P3HT.