Optical absorbance and ohmic behavior of PANI and PANI/ZnO nanocomposites for solar cell application

Polyaniline (PANI) and its nanocomposite with varying concentration of ZnO were synthesized in the laboratory by direct oxidation and In-Situ polymerization methods respectively. These nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), UV-vis absorption and I-V measurement techniques. The XRD results revealed strong and narrow peak corresponding to ZnO (002) plane with a wurtzite crystal structure. FESEM image revealed that the crystalline ZnO was embedded into the PANI matrix and confirmed the formation of PANI/ZnO composite. The elemental composition was analyzed using energy dispersive X-ray analysis (EDX) confirming the presence of ZnO in its nanocomposite. Various chemical bonds and stretching vibrations, assigned to different peaks, were evaluated using Fourier transform infrared (FTIR) spectroscopy. A remarkable optical enhancement was achieved by observing the decrease in band gap with increase in PANI/ZnO composition. The I-V characterization was used to study the influence of nanocomposite on electrical properties of PANI. The conductive property of nanocomposite thin films was found to be increased with increase in PANI/ZnO nanocomposite concentration.