Fabrication of polypyrrole/ZnCoO nanohybrid systems for solar cell applications

Hybrid solar cells employing conjugated polymers have revolutionized the photovoltaic industry by offering the prospect for large-scale energy conversion applications through cost-effective fabrication techniques. In this regard, we have demonstrated an experimental approach to fabricate polypyrrole/ZnCoO nanorod hybrid systems, using hydrothermal and electropolymerization techniques. The structural property studies on the hydrothermally synthesized Co-doped ZnO nanocrystallites revealed them to be phase pure with rod-like morphology. Considering the significant enhancement in their absorbance values over the visible spectral range (possibility for extended photon absorption), ZnCoO (Zn(0.95)Co(0.05)O) nanorods were deposited on transparent conducting (FTO) substrates through dip-coating methodology, for the fabrication of working electrodes. Electropolymerization of the pyrrole monomers was then carried out on the fabricated electrodes through cyclic voltammetry. The formation of polymer material was verified using FT-IR spectroscopy. The morphological evolution of polypyrrole deposits and their distribution on the working electrodes were substantially studied using atomic force microscopy and scanning electron microscopy. The flat band potential for the hybrid systems assimilated from the Mott-Schottky plots was observed to shift towards negative direction compared with ZnCoO, presumably due to the presence of the polymer composites, which gives rise to a more negative potential.