Photovoltaics and solar thermal energy
The main research topic in the field of photovoltaics are dye-sensitized solar cells (DSSC). DSSC is a new type of molecular level electrochemical solar cell, where light absorption and current generation occurs in dye molecules attached to a nanostructured TiO2 electrode. This technology is developed for photovoltaic modules for outdoor use as well as for low-power future electronic devices such as smart labels and clothes, displays and electronic paper. It is also suitable for powering portable electronics such as cell phones. The advantages of the DSSCs compared to the conventional photovoltaic technologies are its economic and abundant materials, good energy conversion efficiency at relatively simple manufacturing methods and compatibility with high throughput roll-to-roll production on flexible substrates. The development of the DSSCs calls for multidisciplinary research approach combining several fields of physics and chemistry.
The work with dye-sensitized solar cells was initiated in our laboratory in 2001. Since then research has been done on cell materials and preparation methods, impedance spectroscopy of charge transport in the cells, optical characterization of the cells and identification of factors affecting their long-term stability. Special emphasis is laid on issues related to cell preparation on flexible substrates such as plastic or metal sheets, and is done in collaboration with Finnish industry. The efficiencies obtained with our metal-based DSSCs are amongst the best in the world.
The research on solar thermal energy includes structural characterization, long-term stability and aging issues of selective absorber surfaces for solar thermal collectors. Research has been done also on thin film solar cells (CIS, CdTe), especially on their long-term stability in outdoor operating conditions. In this, module encapsulation materials, especially water penetration into them is an important issue, for which a novel TiO2-based moisture measurement sensor was developed.
- Dye-sensitized solar cells
- Plastic and metal substrates
- Structural optimization and cell modeling
- Characterization of the charge transport processes in the cells
- Cell size upscaling
- Degradation mechanisms and long-term stability
- Selective absorbers for solar thermal energy
- Thin film photovoltaics
- Solar cell encapsulation materials
Janne Halme, Minna Toivola, Professor Peter Lund (firstname.lastname@example.org)