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Title: Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoO x Catalyst

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 >> WO 3. Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likely due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2. Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λmax of the dye, and absorbed photon-to-current efficiency of 13% with H 2Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x alwaysmore » results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2, as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are also discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.« less
 [1] ; ORCiD logo [1]
  1. Colorado State Univ., Fort Collins, CO (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
FG02-04ER15591; CHE-1057723
Published Article
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 9; Journal Issue: 33; Journal ID: ISSN 1944-8244
American Chemical Society (ACS)
Research Org:
Colorado State Univ., Fort Collins, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; dye-sensitized photoelectrochemical cell; perylene diimide; cobalt oxide; water oxidation catalysis; alumina overlayer; tin oxide
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1429611