Photovoltaics/Nanotechnology 040816

 (July 2004) University of California scientists (Richard Schaller and Victor Klimov)  at Los Alamos National Laboratory demonstrate in their experiment, a phenomenon in which semiconductor nanocrystals respond to photons by producing multiple electrons.  The potential application would be a new generation of solar cells that could produce possibly as much as 35 percent more electrical output than current solar cells.  

The Los Alamos scientists have demonstrated the use of nanoscale semiconductor particles which can greatly improve the efficiency of a carrier multiplication through a significant enhancement of the effect called impact ionization - a process where an exciton, created in a semiconductor by absorbing a photon, transfers the excess energy , which is  normally lost, as heat to another electron.  Thus, two excitons are formed for one absorbed photon as a result of this energy transfer.