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Title: The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells

Abstract

Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) solar cells typically exhibit high short-circuit current density (J{sub sc}), but have reduced cell efficiencies relative to other thin film technologies due to a deficit in the open-circuit voltage (V{sub oc}), which prevent these devices from becoming commercially competitive. Recent research has attributed the low V{sub oc} in CZTSSe devices to small scale disorder that creates band tail states within the absorber band gap, but the physical processes responsible for this V{sub oc} reduction have not been elucidated. In this paper, we show that carrier recombination through non-mobile band tail states has a strong voltage dependence and is a significant performance-limiting factor, and including these effects in simulation allows us to simultaneously explain the V{sub oc} deficit, reduced fill factor, and voltage-dependent quantum efficiency with a self-consistent set of material parameters. Comparisons of numerical simulations to measured data show that reasonable values for the band tail parameters (characteristic energy, capture rate) can account for the observed low V{sub oc}, high J{sub sc}, and voltage dependent collection efficiency. These results provide additional evidence that the presence of band tail states accounts for the low efficiencies of CZTSSe solar cells and further demonstrates that recombination through non-mobile bandmore » tail states is the dominant efficiency limiting mechanism.« less

Authors:
 [1];  [2];  [3];  [4]; ; ;  [3]
  1. Naval Research Laboratory, Washington, DC 20375 (United States)
  2. (United States)
  3. Purdue University, West Lafayette, Indiana 47907 (United States)
  4. (Germany)
Publication Date:
OSTI Identifier:
22590585
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CAPTURE; COMPUTERIZED SIMULATION; CURRENT DENSITY; CURRENTS; ELECTRIC POTENTIAL; ELECTRICAL FAULTS; FILL FACTORS; PERFORMANCE; QUANTUM EFFICIENCY; RECOMBINATION; SOLAR CELLS; THIN FILMS

Citation Formats

Moore, James E., Purdue University, West Lafayette, Indiana 47907, Hages, Charles J., Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Agrawal, Rakesh, Lundstrom, Mark S., and Gray, Jeffery L. The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells. United States: N. p., 2016. Web. doi:10.1063/1.4955402.
Moore, James E., Purdue University, West Lafayette, Indiana 47907, Hages, Charles J., Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Agrawal, Rakesh, Lundstrom, Mark S., & Gray, Jeffery L. The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells. United States. doi:10.1063/1.4955402.
Moore, James E., Purdue University, West Lafayette, Indiana 47907, Hages, Charles J., Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Agrawal, Rakesh, Lundstrom, Mark S., and Gray, Jeffery L. Mon . "The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells". United States. doi:10.1063/1.4955402.
@article{osti_22590585,
title = {The importance of band tail recombination on current collection and open-circuit voltage in CZTSSe solar cells},
author = {Moore, James E. and Purdue University, West Lafayette, Indiana 47907 and Hages, Charles J. and Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin and Agrawal, Rakesh and Lundstrom, Mark S. and Gray, Jeffery L.},
abstractNote = {Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) solar cells typically exhibit high short-circuit current density (J{sub sc}), but have reduced cell efficiencies relative to other thin film technologies due to a deficit in the open-circuit voltage (V{sub oc}), which prevent these devices from becoming commercially competitive. Recent research has attributed the low V{sub oc} in CZTSSe devices to small scale disorder that creates band tail states within the absorber band gap, but the physical processes responsible for this V{sub oc} reduction have not been elucidated. In this paper, we show that carrier recombination through non-mobile band tail states has a strong voltage dependence and is a significant performance-limiting factor, and including these effects in simulation allows us to simultaneously explain the V{sub oc} deficit, reduced fill factor, and voltage-dependent quantum efficiency with a self-consistent set of material parameters. Comparisons of numerical simulations to measured data show that reasonable values for the band tail parameters (characteristic energy, capture rate) can account for the observed low V{sub oc}, high J{sub sc}, and voltage dependent collection efficiency. These results provide additional evidence that the presence of band tail states accounts for the low efficiencies of CZTSSe solar cells and further demonstrates that recombination through non-mobile band tail states is the dominant efficiency limiting mechanism.},
doi = {10.1063/1.4955402},
journal = {Applied Physics Letters},
number = 2,
volume = 109,
place = {United States},
year = {Mon Jul 11 00:00:00 EDT 2016},
month = {Mon Jul 11 00:00:00 EDT 2016}
}