NREL achieves 114% external quantum efficiency with quantum dots

KW51
NREL states that it has reached an external quantum efficiency of 114% with sub-microscopic semiconductor crystals, also called quantum dots, photo-excited with photons from high-energy light. The results of the organization's research have been originally published in the December 16th, 2011 issue of Science Magazine [co-authored by Octavi E. Semonin, Joseph M. Luther, Sukgeun Choi, Hsiang-Yu Chen, Jianbo Gao, Arthur J. Nozik and Matthew C. Beard.](...) Researchers constructed the 114% external quantum efficiency cell from a layered PV cell consisting of anti-reflection coated glass, a thin layer of transparent conductor, a nano-structured zinc oxide layer, a quantum dot layer of lead selenide treated with ethanedithol and hydraizine, and a thin gold top electrode layer.
NREL states that the mechanism for producing a quantum efficiency greater than 100% is based on a process called Multiple Exciton Generation (MEG). In this process, a single high energy absorbed photon can produce more than one electron-hole pair per absorbed photon.
Here is the full article (for those with a Science subscription).