Screen-Printing of ZnO Nanostructures from Sol-Gel Solutions for Their Application in Dye-Sensitized Solar Cells

Diblock copolymers have been used in sol-gel synthesis to successfully tailor the nanoscale morphology of thin ZnO films. As the fabrication of several-micron-thick mesoporous films such as those required in dye-sensitized solar cells (DSSCs) was difficult with this approach, we exploited the benefits of diblock-copolymer-directed synthesis that made it compatible with screen printing. The simple conversion of the diblock copolymer ZnO precursor sol to a screen-printing paste was not possible as it resulted in poor film properties. To overcome this problem, an alternative route is proposed in which the diblock copolymer ZnO precursor sol is first blade coated and calcined, then converted to a screen-printing paste. This allows the benefits of diblock-copolymer-directed particle formation to be compatible with printing methods. The morphologies of the ZnO nanostructures were studied by SEM and correlated with the current density-voltage characteristics. Screen-printed ZnO nanostructures: Simple routes to produce dye-sensitized solar cells (DSSCs) by just printing the commonly used sol-gel system fail and more elaborated approaches are required. The synthesis of metal oxide nanostructures using the diblock copolymer-assisted sol-gel route can be successfully combined with standard printing methods to fabricate DSSCs, in which ZnO nanostructures emerge as a promising alternative to the usually applied TiO₂.