Broader contextExcitonic solar cells (organic, hybrid and dye sensitized) are the best examples of efficient and environmental friendly energy-conversion devices. The possibility of being fabricated by low-cost and easy-scalable solution processing techniques has driven the technology into the marketplace. Nanostructured materials are key constituents of these solar cells. The improvement in photovoltaic efficiency is achievable by the application of advanced structures built at a nanoscale: nanoparticles, nanorods, nanocables, nanosheets, core-shell, among many others. ZnO has become a promising semiconductor oxide when applied as an electron transport material. It presents properties closely related to the best semiconductor oxide used up to date, TiO2, but contrary to the former, it is possible to obtain ZnO in a wide variety of nano-forms by low-cost and scalable synthesis methods. Yet another breakthrough in ZnO-based photovoltaics seems possible if nanostructures could be obtained in a controlled, well-ordered and reproducible manner. This review describes the evolution and future potential for the application of nanostructured ZnO in next-generation excitonic solar cells.