Dye-Sensitized Solar Cell

A dye-sensitized solar cell, also known as a Grätzel cell, is a low cost solar cell belonging to the thin film group of photovoltaic technologies, built as a photoelectrochemical system with a semiconductor formed between a photosensitized anode and an electrolyte. Its modern form was co-invented in 1988 by Brian O'Regan and Michael Grätzel at UC Berkeley and then refined at the École Polytechnique Fédérale de Lausanne, with the first high efficiency prototype published in 1991; Grätzel received the 2010 Millennium Technology Prize for the work. Sunlight passes through a transparent electrode and excites electrons in a dye layer coating titanium dioxide nanoparticles, and those electrons travel through the semiconductor to an external circuit to power a device, while an electrolyte solution containing iodide ions restores electrons to the oxidized dye molecules to complete the circuit; separating the light absorbing role, carried by the dye, from the charge transporting role, carried by the semiconductor, is what distinguishes the dye-sensitized design from a conventional silicon solar cell.