Piranha etching, nanowire solar cells, and the photovoltaic holy grail

“Piranha Etching” Could Push Nanowire Solar Cells Way Past Theoretical Limits – research in Holland is showing how to dramatically increase the efficiency of nanowire solar cells using ‘piranha etching’, a method of chemically cleaning the surface of the wires.  The large surface area of nanowire tends to have imperfections, causing a level of energy loss which until now has been a major weakness of nanowire photovoltaics.

While the researchers have demonstrated an increase to 11.1 percent efficiency with their technique, it is the long-term prospects of the method that appear the most promising with estimates for the conversion efficiency ultimately reaching 65 percent.

The potential for nanowire-based photovoltaics to reach extremely high conversion efficiencies was demonstrated earlier this year when researchers at the Nano-Science Center at the Niels Bohr Institut in Denmark and the Ecole Polytechnique Fédérale de Lausanne in Switzerland suggested that nanowire photovoltaic cells could surpass the Shockley-Queisser limit. The Shockley-Queisser limit is a theory established in 1960 that suggested among other things that that only 33.7 percent of all the sun’s energy could be converted into electricity for solar cells with a single p-n junction. To surpass this limit has been a  Holy Grail quest of sorts for photovoltaics.

Saw this item on the Advanced Energy Economy LinkedIn discussion group, posted by Lewis Perelman.