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Title: Metal-free organic sensitizers for use in water-splitting dye-sensitized photoelectrochemical cells

Solar fuel generation requires the efficient capture and conversion of visible light. In both natural and artificial systems, molecular sensitizers can be tuned to capture, convert, and transfer visible light energy. We demonstrate that a series of metal-free porphyrins can drive photoelectrochemical water splitting under broadband and red light (λ > 590 nm) illumination in a dye-sensitized TiO2 solar cell. Here, we report the synthesis, spectral, and electrochemical properties of the sensitizers. Despite slow recombination of photoinjected electrons with oxidized porphyrins, photocurrents are low because of low injection yields and slow electron self-exchange between oxidized porphyrins. As a result, the free-base porphyrins are stable under conditions of water photoelectrolysis and in some cases photovoltages in excess of 1 V are observed.
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Pennsylvania State Univ., University Park, PA (United States)
  2. Arizona State Univ., Tempe, AZ (United States)
Publication Date:
OSTI Identifier:
1235499
Grant/Contract Number:
FG02-07ER15911; SC0001016; DGE1255832; ECS-0335765
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 112; Journal Issue: 6; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Arizona State Univ., Tempe, AZ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; artificial photosynthesis; metal-free porphyrins; photoelectrochemical; visible light; water-splitting