Publications de Michael Graetzel

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Hematite is a semiconducting mineral with a role in natural photoelectrochemical processes, and has been studied from the viewpoint of solar energy utilization. Hematite is an anisotropic conductor, with faster conduction parallel to (001) planes. Flatband ...

Perhaps the largest challenge for our global society is to find ways to replace the slowly but inevitably vanishing fossil fuel supplies by renewable resources and, at the same time, avoid negative effects from the current energy system on climate, environ ...

Electrochemical oxidation of hematite (alpha-Fe2O3) nanoparticulate films at 600 mV vs Ag+/AgCl in KOH electrolyte forms a species at the hematite surface which causes a new transition in the upper Hubbard band between the Fe(3d)-O(2p) state region and the ...

Electrochemical reduction of carbon dioxide (CO2) to multi-carbon products such as ethylene, ethanol and n-propanol offers a promising path for utilization of excessive CO2 and energy storage. Oxide-derived Cu electrodes are among the best electrocatalysts ...

A Spiro fluorene-based dopant-free hole-transporting material denoted as Spiro-IA has been designed and developed from inexpensive starting materials with high yield via a simple synthetic approach for application in perovskite solar cells (PSCs). The unit ...

Surface and bulk molecular modulators are the key to improving the efficiency and stability of hybrid perovskite solar cells. However, due to their low concentration, heterogeneous environments, and low sample mass, it remains challenging to characterize t ...

Water oxidation is the key kinetic bottleneck of photoelectrochemical devices for fuel synthesis. Despite advances in the identification of intermediates, elucidating the catalytic mechanism of this multi-redox reaction on metal-oxide photoanodes remains a ...

The performance of perovskite solar cells is under direct control of the perovskite film quality and controlling the crystalinity and orientation of solution-processed perovskite film is a fundamental challenge. In this study, we present a scalable fabrica ...

Competition between charge recombination and the forward reactions required for water splitting limits the efficiency of metal-oxide photocatalysts. A key requirement for the photochemical oxidation of water on both nanostructured alpha-Fe2O3 and TiO2 is t ...

Membrane electrode assembly (MEA) electrolyzers offer a means to scale up CO2-to-ethylene electroconversion using renewable electricity and close the anthropogenic carbon cycle. To date, excessive CO2 coverage at the catalyst surface with limited active si ...

Dion-Jacobson (DJ) iodoplumbates based on 1,4-phenylenedimethanammonium (PDMA) have recently emerged as promising light absorbers for perovskite solar cells. While PDMA is one of the simplest aromatic spacers potentially capable of forming a DJ structure b ...

Two novel heteroleptic ruthenium sensitizers, TT204 and TT205, containing bulky substituents at the 4,4-positions of the ancillary 2,2-bipyridine ligand, were synthesized and characterized. They exhibit absorption maxima in the visible region at 520-530 nm ...

Tandem solar cells using different bandgap absorbers allow efﬁcient photovoltaic conversion in a wide range of the solar spectrum. The optical gaps of the dye-sensitized solar cell and the Cu(In,Ga)Se2 solar cell are ideal for application in double-junctio ...

Dye-sensitized solar cells (DSCs) convert light into electricity by using photosensitizers adsorbed on the surface of nanocrystalline mesoporous titanium dioxide (TiO2) films along with electrolytes or solid charge-transport materials(1-3). They possess ma ...

Sustainable hydrogen production through photoelectrochemical water splitting using hematite (alpha-Fe2O3) is a promising approach for the chemical storage of solar energy, but is complicated by the material's nonoptimal optoelectronic properties. Nanostruc ...

Carbon-based perovskite solar cells (C-PSCs) are widely accepted as stable, cost-effective photovoltaics. However, C-PSCs have been suffering from relatively low power conversion efficiencies (PCEs) due to severe electrode-related energy loss. Herein, we r ...

We have investigated the absorption spectrum and the alignment of ground and excited state energies for the prototypical N719 Ru(II) sensitizer adsorbed on an extended TiO2 model by means of high level DFT/TDDFT calculations. The calculated and experimenta ...

We report a new class of molecular insulators that electronically passivate the surface of nanocrystalline titania films for high performance dye sensitized solar cells (DSC). Using electrical impedance measurements we demonstrate that co-adsorption of din ...

Phenyl-imidazole-based ligands with various substitution patterns have been used as the main ligand for heteroleptic bis-cyclometalated Iridium complexes. Two series of complexes have been prepared and their photophysical and electrochemical properties wer ...

Given the intermittent nature of solar radiation, the large-scale use of solar energy requires an efficient energy storage solution. So far, the only practical way to store such large amounts of energy is in the form of a chemical energy carrier, i.e., a f ...

Michael Graetzel

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Anisotropic photocatalytic properties of hematite

Recent Advances in Sensitized Mesoscopic Solar Cells

Evolution of an Oxygen Near-Edge X-ray Absorption Fine Structure Transition in the Upper Hubbard Band in alpha-Fe2O3 upon Electrochemical Oxidation

Sequential catalysis enables enhanced C-C coupling towards multi-carbon alkenes and alcohols in carbon dioxide reduction: a study on bifunctional Cu/Au electrocatalysts

Facile and low-cost synthesis of a novel dopant-free hole transporting material that rivals Spiro-OMeTAD for high efficiency perovskite solar cells

Dynamic Nuclear Polarization Enables NMR of Surface Passivating Agents on Hybrid Perovskite Thin Films

Multihole water oxidation catalysis on haematite photoanodes revealed by operando spectroelectrochemistry and DFT

Solution-based heteroepitaxial growth of stable mixed cation/anion hybrid perovskite thin film under ambient condition via a scalable crystal engineering approach

Activation Energies for the Rate-Limiting Step in Water Photooxidation by Nanostructured alpha-Fe2O3 and TiO2

Silica-copper catalyst interfaces enable carbon-carbon coupling towards ethylene electrosynthesis

Multi-Length Scale Structure of 2D/3D Dion-Jacobson Hybrid Perovskites Based on an Aromatic Diammonium Spacer

Effect of bulky groups in ruthenium heteroleptic sensitizers on dye sensitized solar cell performance

Fabrication and performance of a monolithic dye-sensitized TiO2/Cu(In,Ga)Se2 thin film tandem solar cell

Hydroxamic acid pre-adsorption raises the efficiency of cosensitized solar cells

Photoelectrochemical Water Splitting with Mesoporous Hematite Prepared by a Solution-Based Colloidal Approach

Ti-1-graphene single-atom material for improved energy level alignment in perovskite solar cells

Absorption Spectra and Excited State Energy Levels of the N719 Dye on TiO2 in Dye-Sensitized Solar Cell Models

Passivation of nanocrystalline TiO2 junctions by surface adsorbed phosphinate amphiphiles enhances the photovoltaic performance of dye sensitized solar cells

Cyclometalated Iridium(III) Complexes Based on Phenyl-Imidazole Ligand

On the stability enhancement of cuprous oxide water splitting photocathodes by low temperature steam annealing