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Surface Passivation and Positive Band-Edge Shift of p-Si(111) Surfaces Functionalized with Mixed Methyl/Trifluoromethylphenylacetylene Overlayers

Cabán-Acevedo, Miguel and Papadantonakis, Kimberly M. and Brunschwig, Bruce S. and Lewis, Nathan S. (2020) Surface Passivation and Positive Band-Edge Shift of p-Si(111) Surfaces Functionalized with Mixed Methyl/Trifluoromethylphenylacetylene Overlayers. Journal of Physical Chemistry C, 124 (30). pp. 16338-16349. ISSN 1932-7447. https://resolver.caltech.edu/CaltechAUTHORS:20200630-105347382

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[img] PDF (Data analysis equations, characterization data for CH3-Si(111) surfaces prepared using methylzinc chloride and for methyl/TFMPA-terminated Si surfaces, Bode plot comparison for H- and methyl-terminated p-Si(111) in contact with Hg, and Mott–Schottky...) - Supplemental Material
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Abstract

Chemical functionalization of semiconductor surfaces can provide high-efficiency photoelectrochemical devices through molecular-level control of the energetics, surface dipole, surface electronic defects, and chemical reactivity at semiconductor/electrolyte junctions. We describe the covalent functionalization by nucleophilic addition chemistry of p-Si(111) surfaces to produce mixed overlayers of trifluoromethylphenylacetylene (TFMPA) and methyl moieties. Functionalization of Cl-terminated Si(111) surfaces with TFMPA moieties introduced a positive surface molecular dipole that in contact with CH₃CN or Hg produced a positive band-edge shift of the semiconductor relative to junctions with CH₃-Si(111) surfaces. Methylation of the Cl/TFMPA surfaces using methylmagnesium chloride resulted in the degradation of the TFMPA moieties, whereas methylation using methylzinc chloride allowed controlled production of mixed TFMPA/methyl-terminated surfaces and permitted reversal of the order of the functionalization steps so that nucleophilic addition of TFMPA could be accomplished after methylation of Cl–Si(111) surfaces. Mixed TFMPA/methyl functionalization resulted in a Si(111) surface with surface recombination velocities of 2 × 10² cm s⁻¹ that exhibited an ∼150 mV positive band-edge shift relative to CH₃–Si(111) surfaces.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.jpcc.0c02017DOIArticle
ORCID:
AuthorORCID
Papadantonakis, Kimberly M.0000-0002-9900-5500
Brunschwig, Bruce S.0000-0002-6135-6727
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2020 American Chemical Society. Received: March 9, 2020; Revised: June 29, 2020; Published: June 30, 2020. M.C. acknowledges support from the Ford Foundation under the Postdoctoral Scholar Fellowship program. B.S.B. and M.C. acknowledge support from the National Science Foundation CCI Solar Fuels Program under grant no. CHE-1305124. N.S.L. and M.C. acknowledges support from the National Science Foundation under grant no. CHE-1808599. Instrumentation support was provided by the Molecular Materials Resource Center of the Beckman Institute at the California Institute of Technology. The authors declare no competing financial interest.
Group:CCI Solar Fuels
Funders:
Funding AgencyGrant Number
Ford FoundationUNSPECIFIED
NSFCHE-1305124
NSFCHE-1808599
Issue or Number:30
Record Number:CaltechAUTHORS:20200630-105347382
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200630-105347382
Official Citation:Surface Passivation and Positive Band-Edge Shift of p-Si(111) Surfaces Functionalized with Mixed Methyl/Trifluoromethylphenylacetylene Overlayers. Miguel Cabán-Acevedo, Kimberly M. Papadantonakis, Bruce S. Brunschwig, and Nathan S. Lewis. The Journal of Physical Chemistry C 2020 124 (30), 16338-16349; DOI: 10.1021/acs.jpcc.0c02017
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104162
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:30 Jun 2020 18:54
Last Modified:31 Jul 2020 16:35

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