The research team led by Prof. Wang Dan at the State Key Laboratory of Multi-Phase Complex System, Institute of Process Engineering, Chinese Academy of Sciences (IPE-CAS), has designed a new nanostructured ZnO DSSCs material with different shell structures. This work may open up new opportunities for fabricating high efficiency DSSCs based on structural design and manipulation of hollow microspheres.

Hollow micro/nanoscale metal oxides are of great interest because of their unique structures enable physical properties that make them attractive materials for such applications as photonic devices, catalysis, chemical sensors, drug delivery, and energy conversion and storage systems. Among those applications, hollow structures of ZnO with micron sized features are particularly attractive as the photoanodes for dye-sensitized solar cells due to their high surface area to adsorb dye molecules, relatively large size for scattering incident light, high electron mobility and low production cost compared with TiO2. Here, we demonstrate controllable synthesis of several structures of multi-shelled ZnO hollow microspheres. By using carbonaceous microsphere as templates, via a simple programmable heating process, we have prepared ZnO hollow microspheres with well-defined structures, in which not only the number of shells but also the inter-shell spacings can be controlled. Interestingly, ZnO hollow microspheres with different shell structures show obvious differences in energy conversion efficiency when used in the dye-sensitized solar cells.

The work was supported by National Natural Science Foundation of China (No. 20971125, 21031005, 21006116, 21050110428 and 91122014), Beijing Municipal Natural Science Foundation (No. 2082022) and the Foundation for State Key Laboratory of Multi-phase Complex Systems (No. MPCS-2011-D-15) and State Key Laboratory of Biochemical Engineering (No. 2010KF-09). More results of the research have been published on Adv. Mater. 2012, 24, 1046-1049.