| Popis: |
Bismuth vanadate has attracted much attention as one of the most promising materials for photoelectrochemical (PEC) water splitting. This Master Thesis is aimed at understanding BiVO4 films growth to use it as photoanodes. We fabricate samples by spin- coating method modifying BiVO4 thickness up to ∼ 40 nm and adding a thin (∼ 5 nm) SnO2 hole blocking layer. Morphological characterization with scanning electron microscopy have confirmed the formation of BiVO4 layers on FTO and have shown an increase on the grain sizes from 64 nm to 98 nm for increasing film thickness. Electrochemical experiments are performed on thin films to characterize its electrical parameters, showing an increase of the photocurrent density with increasing number of layers up to 0.72 mA · cm−2 at 1.23 VRHE for the thicker sample. Moreover, it is demonstrated an optimization of the fill factor for the samples that include a intermediate SnO2 layer, confirmed by Mott-Schottky analysis, obtaining a shift of 80 mV of the flat band potential, improving photogenerated voltage and thus, performance of the photoanode. We have proposed and demonstrated a method to obtain sample thicknesses by a linear relation with the incident photon to current conversion efficiency value at 400 nm. |
