Dye-sensitized mesoscopic solar cells have recently demonstrated their potential for large scale applications and mass production for building integrated photovoltaics. However, efforts are still needed to boost their efficiency in order to further expand their attractiveness for consumers and to favor the spreading of this technology. To enhance the efficiency of such solar cells, the design of new organic dyes that reveal a high absorption of photons is a promising strategy, but the preparation of nanostructured metal oxides electrodes with a high porosity is also a lane to explore.
With that respect, porous three-dimensional inverse opal (3D-IO) oxides are very appealing nanostructures to be integrated into the photoelectrodes. Due to their periodic interconnected pore network with a high pore volume fraction, they facilitate electrolyte infiltration and enhance light scattering.
In this work, a versatile method to synthesize mesoporous 3D-IO TiO2 nanostructures and to incorporate them in photoelectrodes suitable for application in DSSCs has been developed. Their specific surface area and porosity can be strongly increased by adding a small amount of silica precursor during the synthesis and subsequent removal of the formed SiO2 domains. After removal from the growing substrate the obtained 3D-IO mesoporous nanostructures have been integrated into conventional dye solar cells photoelectrodes while preserving locally their structural properties. These mesoporous layers, containing locally ordered mesoporous 3D-IO nanostructures, have been sensitized with a new organic dye and the resulting solar cells employing iodine-based liquid electrolyte reached a maximum value of 10.35%.
This study paves the way for new works aiming at the development of more efficient photoelectrodes fabricated with various metal oxides and applicable in dye solar cells, perovskite solar cells or photocatalytic devices.
This work was done in collaboration with researchers from the Institute of Chemical Research of Catalonia (ICIQ) and some characterizations were carried out using the Hybriden and PFNC facilities.