Comparison of different vertically-aligned ZnO nanostructures in excitonic solar cells: Nanorods, Nanocore-shells and Nanotrees.

In this work we present the synthesis and photovoltaic application of four different vertically-aligned ZnO nanostructured electrodes: ZnO nanorods prepared by the a) low-temperature hydrothermal method (LT-HM) and the b) autoclave method (A-HM), c) ZnO nanotrees (NTs) and d) ZnO core-shell NRs with an indium sulfide layer as the shell (CS). The electrodes have been applied in Dye sensitized solar cells (DSCs) and Polymer solar cells (PSCs). The photovoltaic properties of each type of nanostructured electrode were optimized separately. Our results show that the optimal power conversion efficiency depends in great extent on NR dimensions (length and diameter) and the final ZnO nanostructure. In this respect, we have observed an increase in power conversion efficiency when the NR nanostructure is modified as follows: ZnO NRs LT-HM < A-HM < NT < CS for Dye semnsitized solar cells. In the case of PSCs the best power conversion efficiency was obtained for the CS sample