Scientists at Australia's Monash University, with colleagues from the universities of Wollongong and Ulm in Germany, have produced tandem dye-sensitized solar cells with a three-fold increase in energy conversion efficiency compared with previously reported tandem dye-sensitized solar cells.
Lead researcher Dr. Udo Bach, from Monash University, said the breakthrough has the potential to increase the energy generation performance of the cells and make them a viable and competitive alternative to traditional silicon solar cells. The key was the discovery of a new, more efficient type of dye that made the operation of inverse dye-sensitized solar cells much more efficient.
When the research team combined two types of dye-sensitized solar cell - one inverse and the other classic - into a simple stack, they were able to produce for the first time a tandem solar cell that exceeded the efficiency of its individual components.
"The tandem approach - stacking many solar cells together - has been successfully used in conventional photovoltaic devices to maximize energy generation, but there have been obstacles in doing this with dye-sensitized cells because there has not been a method for creating an inverse system that would allow dye molecules to efficiently pass on positive charges to a semiconductor when illuminated with light," explained Dr. Bach.
Although dye-sensitized solar cells have been the focus of research for a number of years because they can be fabricated with relative simplicity and cost-efficiency, their effectiveness has not been on par with high-performance silicon solar cells.
"While this new tandem technology is still in its early infancy, it represents an important first step towards the development of the next generation of solar cells that can be produced at low cost and with energy efficient production methods," stated Dr. Bach.