Photoelectrodes with titanate nanotubes sensitized by mesoporphyrin derivative from cashew nut shell

Abstract

Titanate nanotubes (TiNTs) with the chemical composition Na 2 Ti 3 O 7 .nH 2 O (NaTiNT) were obtained through a hydrothermal method in highly alkaline medium. Protonated titanates nanotubes (H-TiNTs), with the composition H 2 Ti 3 O 7 .nH 2 O, were prepared by ion exchange reaction through a suspension of Na 2 Ti 3 O 7 nH 2 O nanotubes in HCl medium, promoting the exchange of Na + ions by H +. Both Na 2 Ti 3 O 7 .nH 2 O and H 2 Ti 3 O 7 .nH 2 O products, as well the TiO 2 used as raw material for the nanotubes processing, were used as starting material for the solar cells photoelectrodes sensitized using mesoporphyrin extracted from a precursor of cashew nut shell. Exposing the NaTiNT sample to solar radiation of 1258 W/m 2 , a short-circuit current density (I SC) of 13 A/cm 2 and an open-circuit voltage (V OC) of 370 mV were registered and, a current density of 7.6 A/cm 2 and a voltage of 256 mV for the prototype cell based on H-TiNTs. A current density of 1.1 A/cm 2 and an open-circuit voltage of 1.6 mV were obtained for the cell using TiO 2 as electrode.