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High-Efficiency Solar Fuel Devices: Protection and Light Management Utilizing TiO2


Verlage, Erik A. (2017) High-Efficiency Solar Fuel Devices: Protection and Light Management Utilizing TiO2. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9MC8X2P.


Global climate change coupled with increasing global energy consumption drives the need for renewable and carbon-neutral alternatives to fossil fuels. Photoelectrochemical devices store solar energy in chemical bonds, and have the potential to provide cost-effective fuel for grid-scale energy storage as well as to serve as a feedstock for the production of carbon-neutral transportation fuels. A widely recognized goal is the demonstration of a monolithically-integrated solar-fuels system that is simultaneously efficient, stable, intrinsically safe, and scalably manufacturable. This thesis presents the development of three separate high-efficiency solar fuel devices protected by thin films of amorphous TiO2, and develops light management strategies to increase the performance of these devices.

First, high-efficiency monolithic cells were designed to perform solar water-splitting and CO2 reduction. These designs are driven by high-quality single-crystalline III-V semiconductors that are unstable when placed in direct contact with aqueous electrolytes but can be protected against corrosion by hole-conducting amorphous films. Experimental fabrication and characterization of this tandem device was realized in the form of a fully-integrated water-splitting prototype with a solar-to-hydrogen efficiency of 10% showing stability for over 80 hours of operation. This was followed by the demonstration of water-splitting and CO2 reduction devices enabled by bipolar membranes, which increased stability and alleviated materials-compatibility constraints by creating a pH difference between the anolyte and catholyte, maintained at steady-state. Finally, universal light management strategies were developed using high-aspect-ratio TiO2 nanocones, resulting in an increase in catalyst loading with ultrahigh broadband transmission.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Artificial Photosynthesis, Solar Fuels, Solar, Hydrogen, III-V, Silicon, Energy, Energy Storage
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Atwater, Harry Albert
Thesis Committee:
  • Atwater, Harry Albert (chair)
  • Lewis, Nathan Saul
  • Goddard, William A., III
  • Gray, Harry B.
Defense Date:9 May 2017
Non-Caltech Author Email:everlage88 (AT)
Record Number:CaltechTHESIS:06012017-152250262
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Ch. 1, 2, and 3. adapted for Ch. 4. adapted for Ch. 4.
Verlage, Erik A.0000-0001-5940-0859
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10245
Deposited By: Erik Verlage
Deposited On:02 Jun 2017 21:51
Last Modified:08 Nov 2023 18:46

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