Mapping the energetics of defect states in Cu2ZnSnS4 films and the impact of Sb doping

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Tiwari, Devendra and Yakushev, Michael V. and Koehler, Tristan and Cattelan, Mattia and Fox, Neil and Martin, Robert W. and Klenk, Reiner and Férmin, David J. (2022) Mapping the energetics of defect states in Cu2ZnSnS4 films and the impact of Sb doping. ACS Applied Energy Materials, 5 (4). pp. 3933-3940. ISSN 2574-0962 (https://doi.org/10.1021/acsaem.1c03729)

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Abstract

The sub-bandgap levels associated with defect states in Cu2ZnSnS4 (CZTS) thin films are investigated by correlating the temperature dependence of the absorber photoluminescence (PL) with the device admittance spectroscopy. CZTS thin films are prepared by thermolysis of molecular precursors incorporating chloride salts of the cations and thiourea. Na and Sb are introduced as dopants in the precursor layers to assess their impact on Cu/Zn and Sn site disorder, respectively. Systematic analysis of PL spectra as a function of excitation power and temperature show that radiative recombination is dominated by quasi-donor–acceptor pairs (QDAP) with a maximum between 1.03 and 1.18 eV. It is noteworthy that Sb doping leads to a transition from localized to delocalized QDAP. The activation energies obtained associated with QDAP emission closely correlate with the activation energies of the admittance responses in a temperature range between 150 K and room temperature in films with or without added dopants. Admittance data of CZTS films with no added dopants also have a strong contribution from a deeper state associated with Sn disorder. The ensemble of PL and admittance data, in addition to energy-filtered photoemission of electron microscopy (EF-PEEM), shows a detailed picture of the distribution of sub-bandgap states in CZTS and the impact of doping on their energetics and device performance.

ORCID iDs

Tiwari, Devendra, Yakushev, Michael V., Koehler, Tristan, Cattelan, Mattia, Fox, Neil, Martin, Robert W. ORCID logoORCID: https://orcid.org/0000-0002-6119-764X, Klenk, Reiner and Férmin, David J.;
  • Item type:Article
    ID code:80163
    Dates:
    Date
    Event
    25 April 2022
    Published
    22 March 2022
    Published Online
    7 February 2022
    Accepted
    Notes:Published in the special issue 'Early Career Forum'
    Subjects:Science > Physics
    Science > Chemistry
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:11 Apr 2022 13:52
    Last modified:12 Dec 2024 13:00
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/80163
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