الفهرس 
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Abstract
Polyaniline doped with dodecylbenzene sulfonic acid (PANI-DBSA) was prepared by emulsion polymerization technique and treated by ammonia solution to obtain the undoped polyaniline. The PANI obtained by the emulsion polymerization showed good solubility, and high electrical conductivity. The emulsion polymerization parameters such as polymerization duration, oxidant, dopant, and solvent concentrations are investigated to determine the optimum preparation conditions. UV-Vis spectra and conductivity measurements have been performed for all prepared samples. The polyaniline base is more crystalline than polyaniline salt. The particle sizes of polyaniline salt and polyaniline base are in the nanorange. The degradation temperature of the polyaniline base form is higher than that of the polyaniline salt form.
The heterojunction photovoltaic devices of Au/PANI/n-Si/Al are characterized by using current-voltage, capacitance-voltage and impedance measurements under both dark and illumination conditions. Polyaniline base can be acted as a p-type layer for n-type Si to complete the heterojunction solar cells. Different solvents (Tetrahydrofuran, N, N-dimethyl formamide, and N-methyl-2-pyrrolidinone) are used to produce solutions of PANI base in order to fabricate photovoltaic cells. The use of THF as a solvent produces a heterojunction solar cell with efficiency equal to 0.38%. This type of solar cell has open circuit voltage, short circuit current density, and fill factor equal to 0.2 V, 3.11 mA/cm2, and 0.2 respectively at illumination intensity of 0.05 W/cm2.
The carrier concentration can be determined from the slope of C’2 versus V curve. It is found that the carrier concentrations have the same value of about 1013 /cm3 for EB dissolved in the (THF and NMP) solvents.
Impedance analysis method enables determination of series resistance and shunt resistance of the p-n junctions. The value of series resistance for the cell (Al/n-Si/EB/Au) with EB dissolved in THF is lower than those dissolved in DMF and NMP. The same trend is observed for the value of series resistance measured using J-V characterization.