Effects of polyaniline thickness on photovoltaic properties of PANI/tio2 photovoltaic cells

Abstract

Polyaniline (PANI) is a cheap conducting polymer that exhibits p-type properties with high conductivity and unique redox properties. In this work, PANI was synthesized directly on TiO2/FTO substrates by electropolymerisation from acidic aqueous solutions of aniline to form PANI/TiO2 p-n junctions with photovoltaic properties. The thickness of the PANI layer was varied by varying electrodeposition time: 15, 30, and 45 min at the same current density of 2 mA cm-2. The thicknesses of the deposited PANI layers were examined with Scanning Electron Microscope (SEM). Short-circuit currents (ISC) and open-circuit voltages (VOC) of fabricated Pt/PANI/TiO2/FTO cells are investigated. It was found that the PANI electrodeposition time at least 30 min corresponding to a PANI thickness of 399 nm was required for the cell to exhibit significant photovoltaic properties. Furthermore, the TiO2 nanorods that is a remarkable morphology of the n-type TiO2 was synthesized by electrochemical anodization of titanium in a fluoride-based electrolyte with varying anodization times: 45 and 60 min at the constant potential of 60 V. It was found that the anodization time at 60 min is the sufficient condition for the PANI electrodeposition at 45 min to exhibit photovoltaic properties.