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Multiple exciton generation in semiconductor nanocrystals: Toward efficient solar energy conversion
Author(s) -
Beard M.C.,
Ellingson R.J.
Publication year - 2008
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.200810013
Subject(s) - multiple exciton generation , semiconductor , exciton , optoelectronics , band gap , materials science , photon , energy conversion efficiency , nanocrystal , absorption (acoustics) , nanotechnology , physics , optics , condensed matter physics , composite material
Abstract Within the range of photon energies illuminating the Earth's surface, absorption of a photon by a conventional photovoltaic semiconductor device results in the production of a single electron‐hole pair; energy of a photon in excess of the semiconductor's bandgap is efficiently converted to heat through interactions between the electron and hole with the crystal lattice. Recently, colloidal semiconductor nanocrystals and nanocrystal films have been shown to exhibit efficient multiple electron‐hole pair generation from a single photon with energy greater than twice the effective band gap. This multiple carrier pair process, referred to as multiple exciton generation (MEG), represents one route to reducing the thermal loss in semiconductor solar cells and may lead to the development of low cost, high efficiency solar energy devices. We review the current experimental and theoretical understanding of MEG, and provide views to the near‐term future for both fundamental research and the development of working devices which exploit MEG.