Junction formation and current transport mechanisms in hybrid n-Si/PEDOT:PSS solar cells

Jaeckle S, Mattiza M, Liebhaber M, Broenstrup G, Rommel M, Lips K, Christiansen S (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Scientific Reports Nature Publishing Group: Open Access Journals - Option B

Book Volume: 5

Article Number: 13008

DOI: 10.1038/srep13008

Abstract

We investigated hybrid inorganic-organic solar cells combining monocrystalline n-type silicon (n-Si) and a highly conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). The build-in potential, photo- and dark saturation current at this hybrid interface are monitored for varying n-Si doping concentrations. We corroborate that a high build-in potential forms at the hybrid junction leading to strong inversion of the n-Si surface. By extracting work function and valence band edge of the polymer from ultraviolet photoelectron spectroscopy, a band diagram of the hybrid n-Si/PEDOT:PSS heterojunction is presented. The current-voltage characteristics were analyzed using Schottky and abrupt pn-junction models. The magnitude as well as the dependence of dark saturation current on n-Si doping concentration proves that the transport is governed by diffusion of minority charge carriers in the n-Si and not by thermionic emission of majorities over a Schottky barrier. This leads to a comprehensive explanation of the high observed open-circuit voltages of up to 634 mV connected to high conversion efficiency of almost 14%, even for simple planar device structures without antireflection coating or optimized contacts. The presented work clearly shows that PEDOT:PSS forms a hybrid heterojunction with n-Si behaving similar to a conventional pn-junction and not, like commonly assumed, a Schottky junction.

Additional Organisation(s)

Exzellenz-Cluster Engineering of Advanced Materials

Involved external institutions

Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE) Fraunhofer-Institut für Integrierte Schaltungen (IIS) DE Germany (DE)

How to cite

APA:

Jaeckle, S., Mattiza, M., Liebhaber, M., Broenstrup, G., Rommel, M., Lips, K., & Christiansen, S. (2015). Junction formation and current transport mechanisms in hybrid n-Si/PEDOT:PSS solar cells. Scientific Reports, 5. https://dx.doi.org/10.1038/srep13008

MLA:

Jaeckle, Sara, et al. "Junction formation and current transport mechanisms in hybrid n-Si/PEDOT:PSS solar cells." Scientific Reports 5 (2015).

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