  We use free-standing TiO2 nanotube membranes that are transferred onto FTO
slides in front-side illuminated dye-sensitized solar cells (DSSCs). We
investigate the key parameters for solar cell arrangement of self-ordered
anodic TiO2 nanotube layers on the FTO substrate and namely the influence of
the annealing procedure on the DSSC light conversion efficiency. The results
show that using an optimal temperature annealing profile can significantly
enhance the DSSC efficiency (in our case 9.8 %), as it leads to a markedly
lower density of trapping states in the tube oxide, and thus to strongly
improved electron transport properties.
