SINGLE WALL TIO2 NANOTUBES FOR SENSITIZED SOLAR CELLS

Abstract

TiO2 nanotubes (NTs) from the most common solvent ethylene glycol (EG), consist of a double shell wall; a compact thin outside shell, and a surplus spongy inside shell. In the present thesis it is firstly shown that the nanotubes from EG are highly contaminated by carbon from the degradation of EG during the anodization. Afterward, an approach to suppress the formation of the inside wall of the tubes to gain high aspect ratio single wall (SW) nanotubes is proposed. It is then shown that SW NTs have a higher conductivity and less carbon content compared to the common double wall (DW) NTs. Dye sensitized solar cells (DSSCs) made from SW and TiCl4 treated SW tubes show better photocurrent and photo-conversion efficiency, faster carrier transport and higher charge collection efficiency than DW-DSSCs. In CdSe sensitized solar cells, the IPCE measurement showed better incident photon to current efficiency for SW-SSSCs than DW-SSSCs.