title: Electric and Photoelectric Properties of 3,4-Ethylenedioxythiophene-Functionalized n-Si/PEDOT:PSS Junctions.
abstract: Organic/inorganic solid-state junctions play a critical role in tandem artificial photosynthetic devices supported by conducting polymer membranes. Recent work with n-Si/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (
  PSS) hybrid junctions has shown that the electrical behavior is dominated by the passivating groups present on the silicon surface. In this work, the photovoltaic behavior of n-Si/
  PSS was investigated with methyl, thiophene, and 3,4-ethylenedioxythiophene (EDOT) groups covalently attached to the Si(111) surface. X-ray photoelectron spectroscopy results demonstrated that complete monolayer coverage was achieved in 3 h and that the organic passivating groups were retained over two months of exposure to ambient conditions with minimal silicon oxidation. All surfaces investigated exhibited similar light-limited photocurrents and bulk-limited open-circuit voltages, and thiophene produced a dramatic reduction of the fill factor attributed to the formation of trap states at the interface. Furthermore, shunt behavior observed near the power-producing regions for the thiophene and EDOT surfaces is indicative of increased recombination events under forward bias and suggests that hole transport across the interface is enhanced. Thus, thiophene- and EDOT-functionalized Si(111) offer similar stabilities and efficiencies to those of methylated surfaces as well as enhanced hole transport to the
  PSS interface from the n-Si surfaces.
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
authors.forename: Patrick K
authors.initials: PK
authors.lastname: Giesbrecht
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.|Department of Chemistry, University of California, Irvine, CA, 92697, USA.
authors.forename: Jared P
authors.identifier: http://orcid.org/0000-0003-1660-1305
authors.initials: JP
authors.lastname: Bruce
authors.affiliation: Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada. michael.freund@umanitoba.ca.|Department of Chemistry, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL, 32901, USA. michael.freund@umanitoba.ca.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Freund
mesh_terms: D004553:Electric Conductivity; D011211:Electric Power Supplies; D004566:Electrodes; D008027:Light; D053770:Nanowires / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011137:Polystyrenes / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D013876:Thiophenes / Q000737:chemistry*
chemical_list: C000601652:3,4-ethylenedioxythiophene; D011137:Polystyrenes; D013876:Thiophenes; C533756:poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate); D012825:Silicon
keywords: conducting materials; photoelectron spectroscopy; photophysics; semiconductors; silicon