Print Email Facebook Twitter Asymmetric Optical Transitions Determine the Onset of Carrier Multiplication in Lead Chalcogenide Quantum Confined and Bulk Crystals Title Asymmetric Optical Transitions Determine the Onset of Carrier Multiplication in Lead Chalcogenide Quantum Confined and Bulk Crystals Author Spoor, F.C.M. (TU Delft ChemE/Opto-electronic Materials; TU Delft Science Education and Communication) Grimaldi, G. (TU Delft ChemE/Opto-electronic Materials) Delerue, Christophe (IEMN Institut d'Electronique de Microelectronique et de Nanotechnologie) Evers, W.H. (TU Delft BN/Technici en Analisten) Crisp, R.W. (TU Delft ChemE/Opto-electronic Materials) Geiregat, P.A. (TU Delft ChemE/Opto-electronic Materials; Universiteit Gent) Hens, Zeger (Universiteit Gent) Houtepen, A.J. (TU Delft ChemE/Opto-electronic Materials) Siebbeles, L.D.A. (TU Delft ChemE/Opto-electronic Materials) Date 2018 Abstract Carrier multiplication is a process in which one absorbed photon excites two or more electrons. This is of great promise to increase the efficiency of photovoltaic devices. Until now, the factors that determine the onset energy of carrier multiplication have not been convincingly explained. We show experimentally that the onset of carrier multiplication in lead chalcogenide quantum confined and bulk crystals is due to asymmetric optical transitions. In such transitions most of the photon energy in excess of the band gap is given to either the hole or the electron. The results are confirmed and explained by theoretical tight-binding calculations of the competition between impact ionization and carrier cooling. These results are a large step forward in understanding carrier multiplication and allow for a screening of materials with an onset of carrier multiplication close to twice the band gap energy. Such materials are of great interest for development of highly efficient photovoltaic devices. Subject carrier coolingcarrier multiplicationquantum dotthreshold energytight-binding calculationstransient absorption spectroscopy To reference this document use: http://resolver.tudelft.nl/uuid:f357a5f6-a40e-4768-9134-c6882e729f21 DOI https://doi.org/10.1021/acsnano.8b01530 ISSN 1936-0851 Source ACS Nano (online), 12 (5), 4796-4802 Part of collection Institutional Repository Document type journal article Rights © 2018 F.C.M. Spoor, G. Grimaldi, Christophe Delerue, W.H. Evers, R.W. Crisp, P.A. Geiregat, Zeger Hens, A.J. Houtepen, L.D.A. Siebbeles Files PDF acsnano.8b01530.pdf 2.07 MB Close viewer /islandora/object/uuid:f357a5f6-a40e-4768-9134-c6882e729f21/datastream/OBJ/view