Efficient Carrier Multiplication in Colloidal CuInSe2 Nanocrystals.
Transient absorption spectroscopy (TAS) was used to study carrier multiplication (CM) (also called multiexciton generation (MEG)) in solvent-dispersed colloidal CuInSe2 nanocrystals with diameters as small as 4.5 nm. Size-dependent carrier cooling rates, absorption cross sections, and Auger lifetimes were also determined. The energy threshold for CM in the CuInSe2 nanocrystals was found to be 2.4 ± 0.2 times the nanocrystal energy gap (Eg) and the CM efficiency was 36 ± 6% per unit Eg. This is similar to other types of nanocrystal quantum dot materials.
†McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712, United States.
C Jackson
CJ
Stolle
‡Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.|§Center for Nanoscale Materials, Argonne National Laboratories, Argonne, Illinois 60439, United States.
Richard D
RD
Schaller
†McKetta Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712, United States.
Brian A
BA
Korgel
CuInSe2; carrier multiplication; multiple exciton generation; nanocrystals; photovoltaics; solar cells; transient absorption spectroscopy