Synthesis of zinc oxide/titanium dioxide (ZnO/TiO2) nanocomposites by wet incipient wetness impregnation method and preparation of ZnO/TiO2 paste using poly(vinylpyrrolidone) for efficient dye-sensitized solar cells

The overall objective of this study is to enhance the power conversion efficiency of dye-sensitized solar cells (DSSCs) by employing nanocomposite photoanodes. Nanocomposites of TiO2 with ZnO were synthesized by impregnation method. ZnO nanoparticles were impregnated on TiO2 in different concentrations and then characterized by Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD) and scanning electron microscopy- energy-dispersive X-ray (SEM-EDX) analyses. Thin film photoanodes were prepared using composite paste with poly(vinylpyrrolidone) as a binder. Solar cells fabricated with ZnO/TiO2 nanocomposites photoanodes were characterized by photocurrent-voltage characteristic, Incident photon-to-current efficiency, and electrochemical impedance spectroscopy measurements. The results show that the DSSC based on ZnO/TiO2 film with an optimum concentration of ZnO (3 wt%) shows power conversion efficiency of 8.10%, improved by 28% compared to that of pure TiO2 based solar cell. The increase in efficiency can be attributed to fast electron transport, improve light harvesting efficiency, and enhanced electron collection at photoanodes.