Abstract :
TiO2/ZnO and ZnO/TiO2 nanolayer thin films were synthesized using sol–gel method. Optical analysis revealed high transmittance of
the films in the visible range with almost the same bandgap energy for the both systems. XPS technique shows stoichiometric formation
of TiO2 and ZnO on the surface of TiO2/ZnO and ZnO/TiO2 layers, respectively. According to AFM observations and its data analysis,
the TiO2/ZnO films exhibited a higher surface roughness and more effective interfaces with electrolyte during redox reactions. Based on
photoelectrochemical measurements, TiO2/ZnO nanolayer photoanode possesses a lower charge transfer resistance and higher transient
time for charge carriers (e and h+) and hence a higher photocurrent density under visible light irradiation as compared with the ZnO/
TiO2 nanolayer system.
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