Photochemical sensitisation process at photosynthetic pigments/Q-sized colloidal semiconductor hetero-junctions

Electrodes based on Q-sized ZnO and TiO2, synthesised by non-hydrolytic routes, were prepared and characterised. The nanostructured electrodes were modified with photosynthetic pigments, namely, chlorophyll a, carotenoids and their mixture, to probe the photochemical sensitisation process. The photocurrent response of the hetero-junctions and the current–potential (I–V) characteristics of the sensitised electrodes are presented for different dyes. The Q-sized semiconductor sensitised electrodes showed different behaviour when compared to correspondent commercial oxides. Co-sensitisation acted by chlorophyll a and carotenoids on nanostructured electrodes was found to greatly enhance the photocurrent generation.