A group of researchers from the Universidad Pablo de Olavide, in Seville, Spain, led by Juan Antonio Anta, are working on optimizing Grätzel solar cells by incorporating ionic salts, known as green solvents, with a view to preventing evaporation of the liquid compounds and the consequent reduction in efficiency.
Grätzel (dye-sensitized) cells work by using the interaction of a structured semiconductor less than nanometer in size and an organic dye acting as a solar collector. Many tweaks to the Grätzel cells are done at the dye level, but this one is different.
Studies revealed that ionic salts are less volatile, and professor Anta is looking to exploit just that. “Notwithstanding its liquid state, these types of solvents have high viscosity levels and, therefore, during the coming months we will continue our study, working on different alternatives within ionic liquids, their synthesis, etc.,” comments Elena Guillén.
“If you use an organic dye, it can be degraded by the action of sunlight, with the consequent reduction in useful life compared to silicon cells. On the other hand,” the researcher highlights, “our group is working on one of the key aspect for improving cell stability – elimination of the need to use liquids that can present problems with evaporation, etc. and for which, as already mentioned, our focus is on the use of ionic salts.”
The maximum efficiency obtained by Grätzel cells is 11%, so they don’t excel in that. The Grätzel cells’ strong point is price vs efficiency, because they don’t use precious metals or expensive fabrication processes.