Efficient steplike carrier multiplication in percolative networks of epitaxially connected PbSe nanocrystals

Kulkarni, A ORCID: 0000-0002-5840-8768, Evers, WH, Tomic, S ORCID: 0000-0003-3622-6960, Beard, MC ORCID: 0000-0002-2711-1355, Vanmaekelbergh, D ORCID: 0000-0002-3535-8366 and Siebbeles, LDA ORCID: 0000-0002-4812-7495 2017, 'Efficient steplike carrier multiplication in percolative networks of epitaxially connected PbSe nanocrystals' , ACS Nano, 12 (1) , pp. 378-384.

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Abstract

Carrier multiplication (CM) is a process in which a single photon excites two or more electrons. CM is of interest to enhance the efficiency of a solar cell. Until now, CM in thin films and solar cells of semiconductor nanocrystals (NCs) has been found at photon energies well above the minimum required energy of twice the band gap. The high threshold of CM strongly limits the benefits for solar cell applications. We show that CM is more efficient in a percolative network of directly connected PbSe NCs. The CM threshold is at twice the band gap and increases in a steplike fashion with photon energy. A lower CM efficiency is found for a solid of weaker coupled NCs. This demonstrates that the coupling between NCs strongly affects the CM efficiency. According to device simulations, the measured CM efficiency would significantly enhance the power conversion efficiency of a solar cell.

Item Type: Article
Uncontrolled Keywords: carrier multiplication, charge carrier mobility, nanocrystal networks, solar cell efficiency, terahertz spectroscopy
Schools: Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre (SIRC)
Journal or Publication Title: ACS Nano
Publisher: ACS Publications
ISSN: 1936-086X
Related URLs:
Funders: Foundation for Fundamental Research on Matter (FOM)
SWORD Depositor: Publications Router
Depositing User: Publications Router
Date Deposited: 03 Jan 2018 12:44
Last Modified: 28 Mar 2018 19:01
URI: http://usir.salford.ac.uk/id/eprint/44806

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