Starting from a many-years experience in amorphous thin films for photovoltaics application, the research of the group is now essentially devoted to nanostructured materials and nanotechnologies for energy harvesting devices. The principal subjects under study are: dye sensitized solar cells, advanced nanostructured and polymeric materials for energy devices, membranes and reactors for solar water splitting, microbial fuel cells. All the researches are done in collaboration with CSHR @ Polito.it laboratories.
Dye Sensitized Solar Cells (DSSC):
The standard DSSC fabrication procedure, based on sintered nanostructured TiO2 electrodes deposited by screen printing or tape casting on FTO/glass substrates, is available. Moreover a novel microfluidic architecture has been especially designed for the fabrication of small laboratory test-cells with a high degree of reproducibility and good capability of assembly and disassembly. Flexible DSSC obtained with polymeric electrolyte membranes and metallic grids are under study.
Atomistic calculations permit a successful modelling of the surfaces and interfaces within the cell and give a deeper comprehension of the light harvesting and charge transfer mechanisms.
Advanced materials for energy devices:
Different nanostructured semiconducting materials are fabricated to be employed as higly efficient photoanodes in DSSCs, as electrodes in Li-ion batteries and also as photocatalysts in water splitting devices:
- vertically oriented TiO2 nanotubes by anodic oxidation of Ti foils;
- porous and coral-like ZnO films by room temperature RF magnetron sputtering ;
- flower-like ZnO microstructures by a simple, reproducible and low cost hydrothermal process.
Polymer membrane electrolytes for DSSCs are prepared by a rapid, energy-saving and environment friendly technique of photopolymerization; a remarkably better long-term stability in comparison to liquid-electrolyte cells is obtained.
Solar Water Splitting:
Artiphyicial photosynthesis devices are able to split water and produce hydrogen using sunlight.
- An appositely designed PEM photo-electrolyzer has been fabricated: the chamber has a microfluidic architecture with a drop-like structure which favors the liquid flow and avoids gas accumulation.
- Membranes based on Nafion and carbon nanotubes have been employed for obtaining a mixed proton and electron conduction.
- New transparent and conducting electrodes with laser-drilled holes in a very thin FTO-covered quartz have been proposed.
Microbial Fuel Cells:
Microbial fuel cell (MFC) is a prospective technology that allows oxidizing organic matter to generate current by bacteria activity. Low-cost materials can be employed as support for bacteria growth and proliferation either at the anode or cathode. MFCs prototypes are currently setting-up for studying new substrates from glucose, new cathodes, anodes and electrolytes. High porous conductive (and biocompatible) materials by aerogel synthesis and electrospinning (non woven fibres) and new gel and liquid materials as electrolytes will be employed. Our aim is to investigate portable systems and new cells architectures.