Publications by Julien Edouard Frey

Synthesis, characterization and ab initio investigation of a panchromatic ullazine–porphyrin photosensitizer for dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ursula Röthlisberger, Basile Curchod, Magdalena Anna Marszalek, Negar Ashari Astani, Julien Edouard Frey, Simon Mathew

An ullazine unit was employed as a donor moiety in a donor-pi-acceptor (D-p-A) motif, employing the porphyrin macrocycle as a pi-system. Synthesis of this ullazine-porphyrin dyad containing sensitizer (SM63) was achieved and an investigation of the electro ...

Royal Society of Chemistry2016

Investigation of electrodeposited cobalt sulphide counter electrodes and their application in next-generation dye sensitized solar cells featuring organic dyes and cobalt-based redox electrolytes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Thomas Moehl, Julien Edouard Frey, Simon Mathew

Cobalt sulphide (CoS) films are potentiodynamically deposited on fluorine-doped tin oxide (FTO) coated glass substrates employing one, three and five sweep cycles (CoS-I, CoS-III and CoS-V respectively). Analysis of the CoS-III film by impedance spectrosco ...

Elsevier Science Bv2015

Structure-property relationships based on Hammett constants in cyclometalated iridium(III) complexes: their application to the design of a fluorine-free FIrPic-like emitter

Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Julien Edouard Frey

While phosphorescent cyclometalated iridium(III) complexes have been widely studied, only correlations between oxidation potential EOX and Hammett constant sigma, and between the redox gap (Delta E-REDOX = E-OX-E-RED) and emission or absorption wavelength ...

2014

Solid-state carbon-13 NMR and computational characterization of the N719 ruthenium sensitizer adsorbed on TiO2 nanoparticles

Michael Graetzel, Geoffrey Bodenhausen, Nicola Salvi, Julien Edouard Frey, Diego Carnevale

The ruthenium-containing sensitizing dye N719 grafted on TiO2 nanoparticles was investigated by solidstate NMR. The carbon resonances are assigned by means of 13C cross-polarized dipolar dephasing experiments. DFT calculations of the carbon magnetic shield ...

Royal Society of Chemistry2014

Charged Bis-Cyclometalated Iridium(III) Complexes with Carbene-Based Ancillary Ligands

Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Julien Edouard Frey

Charged cydometalated (CN) iridium(III) complexes with carbene-based ancillary ligands are a promising family of deep-blue phosphorescent compounds. Their emission properties are controlled primarily by the main CN ligands, in contrast to the classic ...

American Chemical Society2013

Towards Compatibility between Ruthenium Sensitizers and Cobalt Electrolytes in Dye-Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Joël Teuscher, Rosario Scopelliti, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Negar Ashari Astani, Aswani Yella, Julien Edouard Frey, Peng Gao, Simon Mathew, Lauren Elizabeth Polander

Wiley-Blackwell2013

Low Current Density Driving Leads to Efficient, Bright, and Stable Green Electroluminescence

Mohammad Khaja Nazeeruddin, Julien Edouard Frey

Electroluminescent devices have the potential to reshape lighting and display technologies by providing low-energy consuming solutions with great aesthetic features, such as flexibility and transparency. In particular, light-emitting electrochemical cells ...

Wiley-VCH Verlag Berlin2013

Correlating the Lifetime and Fluorine Content of Iridium(III) Emitters in Green Light-Emitting Electrochemical Cells

Mohammad Khaja Nazeeruddin, Julien Edouard Frey

In light-emitting electrochemical cells, the lifetime of the device is intrinsically linked to the stability of the phosphorescent emitter. In this study, we present a series of ionic iridium(III) emitters based on cyclometalating phenylpyridine ligands wh ...

American Chemical Society2013

Molecular Engineering of a Fluorene Donor for Dye-Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Joël Teuscher, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Negar Ashari Astani, Aswani Yella, Julien Edouard Frey, Simon Mathew, Lauren Elizabeth Polander

To improve their efficiency beyond the state-of-the-art, D-pi-A dyes must display increased spectral breadth and account for the physical limitations observed in the dye. sensitized solar cells. In particular, they should be designed to control the electro ...

Amer Chemical Soc2013

Unravelling the Potential for Dithienopyrrole Sensitizers in Dye-Sensitized Solar Cells

Michael Graetzel, Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Joël Teuscher, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Negar Ashari Astani, Aswani Yella, Julien Edouard Frey, Peng Gao, Lauren Elizabeth Polander

Two D−π−A dyes based on the dithieno[3,2-b:2′,3′-d]pyrrole π-bridge (DTP) were synthesized, characterized using UV−vis absorption spectroscopy and electrochemistry, modeled using quantum chemical calculations, and used as sensitizers in dye-sensitized sola ...

Amer Chemical Soc2013

A new generation of platinum and iodine free efficient dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Takeru Bessho, Chenyi Yi, Julien Edouard Frey

We report a series of cobalt complexes with various polypyridyl ligands, where the oxidation potential is tuned from 0.17 to 0.34 V vs. ferrocene. The highest occupied molecular orbitals (HOMO) of the cobalt complexes were stabilized by adding electron acc ...

2012

Acid-Induced Degradation of Phosphorescent Dopants for OLEDs and Its Application to the Synthesis of Tris-heteroleptic Iridium(III) Bis-cyclometalated Complexes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Julien Edouard Frey

Investigations of blue phosphorescent organic light emitting diodes (OLEDs) based on [Ir(2-(2,4-difluorophenyl)pyridine)(2)(picolinate)] (FIrPic) have pointed to the cleavage of the picolinate as a possible reason for device instability. We reproduced the ...

2012

Stable Green Electroluminescence from an Iridium Tris-Heteroleptic Ionic Complex

Mohammad Khaja Nazeeruddin, Julien Edouard Frey

An ionic tris-heteroleptic iridium complex gives green light-emitting electrochemical cells (LECs) with unprecedented performances for this part of the visible spectrum. The devices are very bright (>1000 cd m(-2)), efficient (similar to 3%), and stable (> ...

American Chemical Society2012