Journal ArticleDOI
Ultrafast Electron Injection: Implications for a Photoelectrochemical Cell Utilizing an Anthocyanin Dye-Sensitized TiO2 Nanocrystalline Electrode
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TLDR
In this article, the photovoltaic cells were shown to convert sunlight to electrical power at an efficiency of 0.56% under full sun at the peak of the visible absorption band of the anthocyanin dye.Abstract:
colloidal TiO2 powder, is shown to convert sunlight to electrical power at an efficiency of 0.56% under full sun. Fluorescence quenching is observed for the excited state of the TiO2-adsorbed anthocyanin dye, cyanin, and the photocurrent spectrum correlates well with the optical absorption of the cyanin-sensitized TiO 2 nanocrystalline film. The incident photon-to-current efficiency of 19% at the peak of the visible absorption band of the dye, the open-circuit voltages of 0.5-0.4 V, and short-circuit photocurrents of 1.5-2.2 mA/cm 2 are remarkable for such a simple system and suggest efficient charge carrier injection. The ultrafast excitedstate dynamics of cyanin in solution are compared with those of surface-adsorbed cyanin on TiO2 and ZrO2 colloids, as well as complexed with Al(III) ions. A transient absorption signal with a risetime of <100 fs for cyanin-sensitized TiO2 nanoparticles is assigned to electrons injected from the dye to TiO 2. This signal is fit to a double-exponential decay with time constants of 0.52 and 67 ps. The 0.52 ps component is due to trapping of conduction band electrons or to fast direct recombination with the dye cation, while the 67 ps decay is attributed to trap state mediated indirect recombination. In contrast, stimulated emission with a 2.6 ps decay time is observed for cyanin in solution, cyanin on ZrO2, and cyanin complexed with Al(III) ions. When compared to the photon-to-current efficiency measured for the solar cell, the efficiency estimated from the injection and recombination rate constants suggests that electron recapture by the redox mediator and light screening mechanisms may limit the efficiency of the cell.read more
Citations
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Journal ArticleDOI
Chemistry and properties of nanocrystals of different shapes.
TL;DR: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties are equally important.
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A surface science perspective on TiO2 photocatalysis
TL;DR: The field of surface science provides a unique approach to understand bulk, surface and interfacial phenomena occurring during TiO2 photocatalysis as mentioned in this paper, including photon absorption, charge transport and trapping, electron transfer dynamics, adsorbed state, mechanisms, poisons and promoters, and phase and form.
Journal ArticleDOI
Applications of functionalized transition metal complexes in photonic and optoelectronic devices
TL;DR: A review of the recent applications of transition metal-to-ligand charge transfer (MLCT) and ligand-centered (π −π*) excited states of these complexes is given in this article.
Journal ArticleDOI
Anchoring Groups for Dye-Sensitized Solar Cells
TL;DR: This review focuses especially on the structural aspects of these novel dye anchors for TiO2-based DSSCs, including pyridine, phosphonic acid, tetracyanate, perylene dicarboxylic acid anhydride, 2-hydroxylbenzonitrile, 8-Hydroxylquinoline, pyrsidine-N-oxide, hydroxylpyridium, and salicylic acid substituents.
Journal ArticleDOI
Ultrafast Electron Transfer Dynamics from Molecular Adsorbates to Semiconductor Nanocrystalline Thin Films
TL;DR: Using femtosecond mid-IR spectroscopy, a series of studies designed to understand how the interfacial electron transfer dynamics depends on the properties of the adsorbates, semiconductors, and their interaction are presented in this paper.
References
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Journal ArticleDOI
A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films
TL;DR: In this article, the authors describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency.
Journal ArticleDOI
Conversion of light to electricity by cis-X2bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) charge-transfer sensitizers (X = Cl-, Br-, I-, CN-, and SCN-) on nanocrystalline titanium dioxide electrodes
Mohammad Khaja Nazeeruddin,Andreas Kay,I. Rodicio,Robin Humphry-Baker,E. Mueller,Paul Liska,Nick Vlachopoulos,Michael Graetzel +7 more
TL;DR: Cis-X 2 Bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) complexes were prepared and characterized with respct to their absorption, luminescence, and redox behavior.
Journal ArticleDOI
Light-Induced Redox Reactions in Nanocrystalline Systems
Anders Hagfeldt,Michael Graetzel +1 more
TL;DR: A review with 156 refs on interfacial electron transfer reactions in colloidal semiconductor solns and thin films and their application for solar light energy conversion and photocatalytic water purifn is presented in this paper.