Arrays of ZnO/AZO (Al-doped ZnO) nanocables: A higher open circuit voltage and remarkable improvement of efficiency for CdS-sensitized solar cells

Photoelectrode of nanocables (NCs) structure of ZnO nanowires (NWs) coated with Al-doped ZnO (AZO) shells was investigated for CdS quantum dots sensitized solar cells (QDSSCs). ZnO NWs serve as the frame for the preparation of AZO shells, in which elec-tron transport more rapidly due to the more higher electron mobility of AZO (n-ZnO) than that of i-ZnO. AZO shells were assembled onto the surface of ZnO NWs via a spin-coating method. Optical band-gap of the ZnO/AZO films varies from 3.19 eV for pure ZnO to 3.25 eV for AZO (15%) depending on the Al-doping concentration. The PL intensity of AZO/ZnO, eta of the cells first increased and then decreased with the increase in the AI-doping (from 0% to 20%) and post-annealed temperature. Remarkably, the value of V, can achieve above 0.8 V after Al-doping. The dark current and absorption spectrum provided direct evidence of the increase in J(sc) and V proportional to, respectively. Moreover, we discussed the effect of Al-doping On optical band-gap of the samples and the transfer of electron. Crown Copyright (C) 2013 Published by Elsevier Inc. All rights reserved.