The spray-deposition technique is an effective and scalable method to deposit zinc oxide nanostructures, which are used as active layers for dye-sensitized solar cells (DSSCs) in the present study. The dynamics of structural evolution are studied with grazing incidence small-angle X-ray scattering during in situ spraying. Nanostructured films obtained through multiple spray shots provide suitable structural length scales, morphologies, and film thicknesses; this leads to reasonable performance in a DSSC with the highest short-circuit current density reported so far.

A low temperature route to crystalline titania nanostructures in thin films is presented. The synthesis is performed by the combination of sol-gel processes, using a novel precursor for this kind of application, an ethylene glycol-modified titanate (EGMT), and the structure templating by micro-phase separation of a di-block copolymer. Different temperatures around 100 °C are investigated. The nanostructure morphology is examined with scanning electron microscopy, whereas the crystal structure and thin film compositions are examined by scattering methods. Optoelectronic measurements reveal the band-gap energies and sub-band states of the titania films. An optimum titania thin film is created at temperatures not higher than 90 °C, regarding sponge-like morphology with pore sizes of 25-30 nm, porosity of up to 71% near the sample surface, and crystallinity of titania in the rutile phase. The low temperature during synthesis is of high importance for photovoltaic applications and renders the resulting titania films interesting for future energy solutions.

Incorporation of spray-deposited zinc titanate films in the active layer of dye-sensitized solar cells showing promising device performance.