With that in mind a team from Helsinki University of Technology, Finland, tested the performance of dye solar cells on stainless steel substrates.
"We showed that rather high efficiencies can be gained with dye solar cells on stainless steel substrates even without additional coatings such as recombination blocking layers," researcher Kati Miettunen told environmentalresearchweb. "The fewer coatings required, the cheaper the manufacturing."
Miettunen and colleagues chose stainless steel as it is one of the cheapest metals that has been shown to be stable in electrolyte soaking tests. Many other metals have suffered from corrosion under these conditions.
As well as cutting costs, the use of a flexible metal substrate could enhance roll-to-roll mass production.
Dye solar cells – also known as Grätzel cells after co-inventor Michael Grätzel – use a layer of photosensitive dye on a nanomaterial scaffold, typically TiO2. The nanomaterial serves to increase the number of dye molecules available for a given surface area and also acts as a semiconductor. Unlike conventional solar cells, where the semiconductor both creates free photoelectrons in response to light and provides a potential barrier to separate electrons and holes and create a current, in a dye solar cell it’s the dye that creates photoelectrons while charge separation is provided by the semiconductor and an electrolyte.
As well as being relatively cheap to manufacture, dye solar cells are able to work under cloudy conditions.
The team used photovoltaic characterization, electrochemical impedance spectroscopy, open circuit voltage decay and substrate polarization measurements to test their cells. The use of a stainless steel substrate appeared to have some effect on the electrochemical function of the TiO2 layer.
"Since the initial performance of these cells is satisfactory, further studies on the long term effects are called for," said Miettunen.
The researchers reported their work in J. Phys. Chem. C.