Performance of ZnO dye-sensitized solar cells with various nanostructures as anodes

Several types of ZnO nanostructured films, including nanoparticle films, ordered porous films, nanorod films, nanotube films and porous nanosheet films, were fabricated and used as photoanodes in dyesensitized solar cells (DSSCs). Their performance was described and compared in detail. DSSCs based on ordered porous films presented relatively higher conversion efficiency (0.7%) than that of DSSCs based on nanoparticle films (0.2%). DSSCs based on nanorod films showed the maximal efficiency up to 1.3%, mainly attributed to the c-axis oriented structure which could provide the faster conduction pathway for charge transport. Although nanotube films with large surface area could absorb more dyes, the efficiency of DSSCs based on nanotube films was only 1.2% and wasn't as high as that of nanorod DSSCs, which may be caused by the charge-carrier recombination losses at the defects formed in the etching. Moreover, the porous ZnO nanosheets photoanode showed an improved efficiency by 2.5 times as compared to ZnO nanosheets samples due to increase the dye loading and light harvesting. (C) 2011 Elsevier Masson SAS. All rights reserved.