Nanoporous ZnO Nanoball for Efficient CdS/CdSe Co-Sensitized Quantum Dot Sensitized Solar Cells#

Highly monodispersed, nanoporous ZnO nanoballs (NBs) with a diameter of 120 nm were synthesized by a wet chemical method and successfully applied to photoelectrode of CdS/CdSe co-sensitized quantum dot (QD) sensitized solar cells (QDSSCs). In fabricating the QDSSCs by the successive ionic layer adsorption and reaction (SILAR) method, the optimized CdS and CdSe depositions were obtained by nine and four SILAR cycles, respectively. The ZnO/CdS(9)/CdSe(4)/ZnS(1) cell exhibited a photovoltaic conversion efficiency (PCE) of 2.21%, which is significantly higher than the QDSSC adopting conventional ZnO nanorods (NRs) of 1.33%, indicating that the prepared nanoporous ZnO NB is a highly efficient structure for the deposition of CdS/CdSe quantum dots (QDs) as well as transport of charges.