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Chemical and Electrochemical Behavior of Graphene-Covered Silicon Photoanodes

Citation

Nielander, Adam Christopher (2016) Chemical and Electrochemical Behavior of Graphene-Covered Silicon Photoanodes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z92R3PNB. https://resolver.caltech.edu/CaltechTHESIS:03042016-133215131

Abstract

This dissertation describes efforts over the last five years to develop protective layers for semiconductor photoelectrodes based on monolayer or few-layer graphene sheets. Graphene is an attractive candidate for a protective layer because of its known chemical inertness, transparency, ease of deposition, and limited number of electronic states. Monolayer graphene was found to effectively inhibit loss of photocurrent over 1000 seconds at n-Si/aqueous electrolyte interfaces that exhibit total loss over photocurrent over 100 seconds. Further, the presence of graphene was found to effect only partial Fermi level pinning at the Si/graphene interface with respect to a range of nonaqueous electrolytes. Fluorination of graphene was found to extend the stability imparted on n-Si by the monolayer sheet in aqueous Fe(CN)63-/4- electrolyte to over 100,000 seconds. It was demonstrated that the stability of the photocurrent of n-Si/fluorinated graphene/aqueous electrolyte interfaces relative to n-Si/aqueous electrolyte interfaces is likely attributable to the inhibition of oxidation of the silicon surface.

This dissertation also relates efforts to describe and define terminology relevant to the field of photoelectrochemistry and solar fuels production. Terminology describing varying interfaces employed in electrochemical solar fuels devices are defined, and the research challenges associated with each are discussed. Methods for determining the efficiency of varying photoelectrochemical and solar-fuel-producing cells from the current-voltage behavior of the individual components of such a device without requiring the device be constructed are described, and a range of commonly employed performance metrics are explored.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Photoelectrochemistry; Graphene; Solar Energy Conversion; Solar Fuels
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Lewis, Nathan Saul
Thesis Committee:
  • Gray, Harry B. (chair)
  • Okumura, Mitchio
  • Brunschwig, Bruce S.
  • Lewis, Nathan Saul
Defense Date:11 January 2016
Non-Caltech Author Email:ANieland (AT) gmail.com
Record Number:CaltechTHESIS:03042016-133215131
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:03042016-133215131
DOI:10.7907/Z92R3PNB
ORCID:
AuthorORCID
Nielander, Adam Christopher0000-0002-3639-2427
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9603
Collection:CaltechTHESIS
Deposited By: Adam Nielander
Deposited On:18 Mar 2016 20:53
Last Modified:04 Oct 2019 00:12

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PDF (Thesis - Part 1/13; Title Page ) - Final Version
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PDF (Thesis - Part 10/13; Chapter 4 - Single Layer Graphene) - Final Version
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