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Michael Graetzel

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Related publications (1,223)

Graphene Nanoplatelets Outperforming Platinum as the Electrocatalyst in Co-Bipyridine-Mediated Dye-Sensitized Solar Cells

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

Graphene nanoplatelets (GNP) in the form of thin semitransparent films on F-doped SnO2 (FTO) exhibit high electrocatalytic activity for the Co(bpy)(3)(3+/2+) redox couple in acetonitrile electrolyte solution. The GNP film is superior to the traditional ele ...

American Chemical Society2011

RETRACTED: Advances in colloidal quantum dot solar cells: The depleted-heterojunction device

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ines Raabe, Xiaoyan Wang

Colloidal quantum dot (CQD) photovoltaics combine low-cost solution processibility with quantum size-effect tunability to match absorption with the solar spectrum. Recent advances in CQD photovoltaics have led to 3.6% AM1.5 solar power conversion efficienc ...

Elsevier2011

Coupled Optical and Electronic Modeling of Dye-Sensitized Solar Cells for Steady-State Parameter Extraction

Michael Graetzel, Guido Rothenberger, Matthias Schmid, Sophie Wenger

The design and development of dye-sensitized solar cells (DSCs) is currently often realized on an empirical basis. In view of assisting in this optimization process, we present the framework of a model which consists in a coupled optical and electrical mod ...

American Chemical Society2011

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

Michael Graetzel, Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Xiaoyu Zhang, Filippo de Angelis

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 ...

2011

Electronic and Optical Properties of the Spiro-MeOTAD Hole Conductor in Its Neutral and Oxidized Forms: A DFT/TDDFT Investigation

Michael Graetzel, Mohammad Khaja Nazeeruddin, Filippo de Angelis

The molecular structures and electronic and optical properties of 2,2'7,7'-tetrakis-(N,N-di-p-methoxyphenyl amine)-9,9'-spirobifluorene (spiro-MeOTAD) in different oxidation states have been investigated by means of DFT/TDDFT methods. Spiro-MeOTAD has been ...

American Chemical Society2011

Effect of Sensitizer Adsorption Temperature on the Performance of Dye-Sensitized Solar Cells

Pascal Comte, Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Jean-David Décoppet, Peng Wang

Employing a mesoscopic titania photoanode whose bilayer structure was judiciously selected to fit the optoelectronic characteristics of the Ru-based heteroleptic complex Na-cis-Ru(4,4'-(5-hexyltiophen-2-yl)-2,2'-bipyridine)(4-carboxylic-acid-4'-carboxylate ...

2011

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

Michael Graetzel, Mohammad Khaja Nazeeruddin, Filippo de Angelis

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 ...

American Chemical Society2011

Plasmonic Dye-Sensitized Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Soo-Jin Moon, Peng Wang

2011

Porphyrin-Sensitized Solar Cells with Cobalt (II/III)-Based Redox Electrolyte Exceed 12 Percent Efficiency

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Aravind Kumar Chandiran, Aswani Yella, Chenyi Yi, Hoi Nok Tsao

The iodide/triiodide redox shuttle has limited the efficiencies accessible in dye-sensitized solar cells. Here, we report mesoscopic solar cells that incorporate a Co((II/III))tris(bipyridyl)-based redox electrolyte in conjunction with a custom synthesized ...

American Association for the Advancement of Science2011

Cyclopentadithiophene Bridged Donor-Acceptor Dyes Achieve High Power Conversion Efficiencies in Dye-Sensitized Solar Cells Based on the tris-Cobalt Bipyridine Redox Couple

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Jun Ho Yum, Thomas Moehl, Chenyi Yi, Hoi Nok Tsao

2011

An Organic D-pi-A Dye for Record Efficiency Solid-State Sensitized Heterojunction Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Robin Humphry-Baker, Soo-Jin Moon, Thomas Moehl, Peng Wang

The high molar absorption coefficient organic D-pi-A dye C220 exhibits more than 6% certified electric power conversion efficiency at AM 1.5G solar irradiation (100 mW cm(-2)) in a solid-state dye sensitized solar cell using 2,2',7,7'-tetrakis(N,N-dimethox ...

American Chemical Society2011

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

Michael Graetzel, Kevin Sivula

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 ...

2011

Panchromatic response composed of hybrid visible-light absorbing polymers and near-IR absorbing dyes for nanocrystalline TiO2-based solid-state solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin

In pursuit of panchromatic sensitizers for mesoporous TiO2-based solid-state solar cells, a near-IR absorbing zinc phthalocyanine dye (coded TT1) was firstly adsorbed over relatively thin (similar to 1 mu m) TiO2 mesoporous films and then a visible-light a ...

Elsevier2011

Design of Dye Acceptors for Photovoltaics from First-Principles Calculations

Michael Graetzel, Mohammad Khaja Nazeeruddin, Efthimios Kaxiras, Sheng Meng

We investigate a set of donor-pi-acceptor (D-pi-A) dyes with new acceptor groups for dye-sensitized solar cells, using time-dependent density-functional-theory calculations of the electronic structure and optical absorption. We considered three types of mo ...

American Chemical Society2011

Extraordinarily efficient conduction in a redox-active ionic liquid

Michael Graetzel, Jacques-Edouard Moser, Guido Rothenberger, Shaik Mohammed Zakeeruddin, Jan Cornelius Brauer, Verner Thorsmolle

Iodine added to iodide-based ionic liquids leads to extraordi- narily efficient charge transport, vastly exceeding that expect- ed for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and visc ...

Wiley-Blackwell2011

Design and Development of Functionalized Cyclometalated Ruthenium Chromophores for Light-Harvesting Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Thomas Baumgartner, Aswani Yella

The syntheses and the electrochemical spectroscopic properties of a suite of asymmetrical bistridentate cyclometalated Ru(II) complexes bearing terminal triphenylamine (TPA) substituents are reported. These complexes, which contain structural design elemen ...

2011

Dye-sensitized solar cells: A brief overview

Michael Graetzel, Mohammad Khaja Nazeeruddin

The aim of this brief review is to give a short and simple overview of the dye-sensitized solar cell technology from the working principles to the first commercial applications. It emphasizes the role of the sensitizer and the strategies to improve the per ...

2011

Fine-Tuning of Triarylamine-Based Photosensitizers for Dye-Sensitized Solar Cells

Michael Graetzel

The synthesis of a series of novel organic photosensitizers based on modified triarylamine motives has been achieved. The new "push-pull" dyes, bearing one to three naphthyl units in place of phenyl rings, have been successfully obtained following original ...

2011

The Role of Cobalt Phosphate in Enhancing the Photocatalytic Activity of alpha-Fe2O3 toward Water Oxidation

Michael Graetzel

Transient absorption spectroscopy was used to probe the dynamics of photogenerated charge carriers in alpha-Fe2O3/CoOx nanocomposite photoelectrodes for water splitting. The addition of cobalt-based electrocatalysts was observed to increase the lifetime of ...

2011

The influence of dye structure on charge recombination in dye-sensitized solar cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Yuhang Liu

Replacing the nonyl groups on the solar cell dye Ru(4,4'-carboxylic acid-2,2'-bipyridine)-( 4,4'-dinonyl-2,2'-bipyridine)(NCS)(2) (Z-907) with amino groups results in a marked decrease in solar cell performance. This is despite the fact that the amino deri ...

2011

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