This is a 3D illustration of FDT molecules on the surface of perovskite crystals. Image: Sven M. Hein; Copyright: EPFL.Scientists at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in France have developed a solar cell material that can cut down on photovoltaic costs while achieving a competitive power-conversion efficiency of more than 20%.
Some of the most promising solar cells today use light-harvesting films made from perovskites – a group of materials that share a characteristic molecular structure. However, perovskite-based solar cells require expensive ‘hole-transporting’ materials, whose function is to transport the positive charges generated when light hits the perovskite film. There are currently only two hole-transporting materials available for perovskite-based solar cells; both types are quite costly to synthesize, adding to the overall expense of the solar cell.
In a paper in Nature Energy, an international team of scientists now report their development of a considerably cheaper hole-transporting material that costs only a fifth of existing ones while keeping the efficiency of the solar cell above 20%. Led by Mohammad Nazeeruddin at EPFL, the scientists developed a fluorine-based hole-transporting material called fluorine dithiophene (FDT) that can bring costs down while keeping efficiency up to competitive levels.
Tests showed that the efficiency of FDT rose to 20.2% – higher than other two more expensive hole-transporting materials. And because FDT can be easily modified, it can act as a blueprint for an entire generation of new low-cost hole-transporting materials.
"The best performing perovskite solar cells use hole transporting materials, which are difficult to make and purify, and are prohibitively expensive, costing over €300 per gram, preventing market penetration," says Nazeeruddin. "By comparison, FDT is easy to synthesize and purify, and its cost is estimated to be a fifth of that for existing materials – while matching, and even surpassing their performance."
This story is adapted from material from EPFL, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.