Suppressing deep-trap formation in Cu<sub>2</sub>ZnSnS<sub>4</sub>-based solar cells

ORAL

Abstract

Cu2ZnSnS4 (CZTS) is a cheap, nontoxic, easy-to-synthesize, and stable solar cell absorber material. Despite these advantages over Si, GaAs, CdTe, CuInxGa1-xSe2, and hybrid perovskites, CZTS-based solar cells are plagued by low efficiencies (12.6%) compared to the Shockley-Queisser limit (33.7%). This 21.1% efficiency deficit was suggested recently to be due to the formation of defect clusters involving the SnZn antisite, which induces deep-trap states and therefore promotes carrier recombination. In this talk, we present density functional theory calculations of defect thermodynamics to show that these deep-trap defect clusters can be suppressed in CZTS via Ge- and Se-codoping. Additionally, we will describe an electrostatic mechanism for the suppression of deep defects by Ge that can be readily applied to other kesterite-type absorber materials and therefore used to design next-generation CZTS-inspired solar cells.

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Presenters

  • Robert Wexler

    • Princeton University

Authors

  • Robert Wexler

    • Princeton University

  • Sai Gautam Gopalakrishnan

    • Mechanical and Aerospace Engineering, Princeton University
    • Princeton
    • Princeton University

  • Emily Carter

    • Office of the Chancellor, University of California Los Angeles
    • University of California, Los Angeles
    • UCLA
    • Office of Chancellor, University of California Los Angeles
    • Office of the Chancellor, University of California, Los Angeles