A team led by Professor Benoît Marsan at the Université du Québec à Montréal say that they have solved some of the problems have been hampering the development of efficient and affordable solar cells.
One of the most promising solar cells designs is the dye-sensitized cell, which was designed in the early ’90s based on the principle of photosynthesis. A dye-sensitized solar cell consists of a porous layer of nanoparticles of a white pigment (titanium dioxide) covered with a molecular dye that absorbs sunlight. The pigment-coated titanium dioxide is immersed in an electrolyte solution with a platinum-based catalyst. Sunlight passes through the platinum-based cathode and the electrolyte, and then withdraws electrons from the titanium dioxide anode.
This type of cell has some problems that have prevented its large-scale commercialisation:
- The electrolyte is extremely corrosive, resulting in a lack of durability
- The titanium oxide is a densely coloured, preventing the efficient passage of light; and
- The cathode is covered with platinum, which is expensive, non-transparent and rare.
Professor Marsan realized that two of the technologies developed for the electrochemical solar cell could also be applied to the dye-sensitized solar cell. Entirely new molecules, created in the laboratory, can be used in a liquid or gel electrolyte which is transparent and non-corrosive – thus improving the cell’s output and stability – and platinum can be replaced by cobalt sulphide, which is far less expensive, more efficient, more stable and more readily available.