Author Archives: Catherine Heyer

A core/shell approach that utilizes a high-surface area conducting core and an outer semiconductor shell is exploited to prepare p-type dye-sensitized solar energy cells that operate with a minimal applied bias. Photocathodes were prepared by coating thin films of nanocrystalline … Read more

The mechanism for interfacial electron transfer (ET) from a metal oxide core|shell nanostructure to a [RuIII(2,2′-bipyridine)2(4,4′-(PO3H2)2-2,2′-bipyridine)]3+ sensitizer was probed through spectroscopic quantification of the ET kinetics over a 70 °C temperature range in an aqueous 0.1 M HClO4 solution. Mesoporous thin films … Read more

The power conversion efficiency of tandem dye-sensitized photoelectrosynthesis cells is limited by the number of p-type metal oxide semiconductors and chromophores available for the photocathode. Here, a new class of donor–acceptor–donor organic chromophores is introduced with deep highest occupied molecular … Read more

Recent advances in our mechanistic understanding of dye-sensitized electron transfer reactions occurring at metal oxide interfaces are described. These advances were enabled by the advent of mesoporous thin films, comprised of anatase TiO2 nanocrystallites, that are amenable to spectroscopic and … Read more

Energy transfer was explored in a series of poly(phenylene ethynylene) (PPE) polymers with increasing lengths that were end-capped with thiophene-benzothiadiazole (TBT) groups to form fully conjugated donor–acceptor polymers. For the polymers in solution, ultrafast transient absorption and time-resolved fluorescence spectroscopy … Read more

Two osmium(II) photocatalysts bearing a dicationic 4,4′-bis-(trimethylaminomethyl)-2,2′-bipyridine (tmam) ligand and 2,2′-bipyridine {[Os(bpy)2(tmam)]4+} or 4,4′-(CF3)2-2,2′-bipyridine {[Os((CF3)2bpy)2(tmam)]4+} ancillary ligands were synthesized and characterized for application in HX splitting. Iodide titration studies in acetone solutions provided evidence for an in situ formed terionic complex with two iodide … Read more

Maximizing the efficiency of solar energy conversion using dye assemblies rests on understanding where the energy goes following absorption. Transient spectroscopies in solution are useful for this purpose, and the time-resolved data are usually analyzed with a sum of exponentials. … Read more

The performance of dye sensitized solar cells (DSSCs) depends on the properties and interactions of three fundamental components: the semiconductor, chromophore, and electrolyte. For the electrolyte, the dependence of DSSC performance on the identity and valence state of the spectator … Read more

The synthesis, characterization, electrochemical and photophysical properties of the phosphonate-derivatized Carbazole (CBZ) and boron dipyrromethene (BODIPY) chromophores in the dyes, BODIPY(CBZ)2PO3H2 [8] and BODIPY(Tol)2PO3H2 [7], are described. The oxide-bound dyes have been explored as light absorbers in dye-sensitized photoelectrosynthesis cell … Read more

The total reorganization energy, λ, for interfacial electron transfer, ET, from a conductive electrode to redox-active molecules at fixed positions within the electric double layer, EDL, has been determined experimentally. Conductive indium–tin-oxide (ITO, In2O3:Sn) mesoporous films were functionalized with 4-[N,N-di(p-tolyl)-amino]benzylphosphonic … Read more

A new approach is described for the preparation of water oxidation photoanodes in a Dye-Sensitized Photoelectrosynthesis Cell (DSPEC) for water splitting. It is based on a chromophore (C) – catalyst (Cat) assembly prepared by a self-assembled bilayer (SAB) on a … Read more

Congratulations to Eric Assaf, 3rd year graduate student in the Miller group and member of the AMPED EFRC Catalysis Team, who has been accepted to the editorial board of the DOE EFRC quarterly newsletter Frontiers in Energy Research. This newsletter … Read more

Molecular excited states at conductive and semiconductive interfaces were found to transfer an electron to the oxide (injection) or accept an electron from the oxide (hole transfer). The direction of this electron transfer was determined by the metal oxide electronic … Read more

In the development of photoelectrochemical cells for water splitting or CO2 reduction, a major challenge is O2 evolution at photoelectrodes that, in behavior, mimic photosystem II. At an appropriate semiconductor electrode, a water oxidation catalyst must be integrated with a visible … Read more

A study of SnO2/TiO2 core/shell films was undertaken to investigate the influence of shell thickness and post deposition sintering on electron localization and transport properties. Electrochemical reduction of the materials resulted in the appearance of a broad visible –near IR … Read more