MrSeb writes: "After more than 20 years of continued research, electrochemist Michael Gratzel of the Swiss Federal Institute of Technology has cracked it: He has created a cheap photovoltaic cell that uses an organic, printed dye to absorb sunlight. This builds on his initial, dye-based photovoltaic discovery way back in 1991 which required ruthenium, an incredibly rare and expensive element. These new dye-sensitized nanocrystal cells (DSCs) are basically slabs of ceramic titanium dioxide (titania) — the same, very cheap material that makes up the pigment in white paint. The organic dye, which is simply printed onto the titania, is a molecule with three distinct characteristics: It has a group of atoms that readily gains electrons, a group that loses electrons, and a light-absorbing bridge that’s similar to the chlorophyll found in plant cells. Basically, sunlight hits the dye, which then fires electrons into the titania, where electrodes pick them up to create a current." Link to Original Source
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