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Jun Ho Yum

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Publications associées (128)

Page 3 sur 7

Evaluation of a Ruthenium Oxyquinolate Architecture for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Chenxu Zhao

Synthesis of the Ru(dcbpy)(2)(OQN) complex is reported in which dcbpy and OQN(-) are the bidentate 4,4'-dicarboxy-2,2'-bipyridyl and 8-oxyquinolate ligands, respectively. Spectroscopic, electrochemical, and theoretical analyses are indicative of exten ...

2012

Graphene Nanoplatelet Cathode for Co(III)/(II) Mediated Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ladislav Kavan, Jun Ho Yum

Graphene nanoplatelets (GNP) in the form of thin semitransparent film on F-doped SnO2 (FTO) exhibit high electrocatalytic activity for Co(L)(2); where L is 6-(1H-pyrazol-1-yl)-2,2'-bipyridine. The exchange current densities for the Co(2+/)3(+)(L)(2) redox ...

American Chemical Society2011

Crown Ether Modulation Enables over 23% Efficient Formamidinium-Based Perovskite Solar Cells

Michael Graetzel, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Ursula Röthlisberger, Ulf Anders Hagfeldt, Jun Ho Yum, Kevin Sivula, Marko Mladenovic, David Lyndon Emsley, Farzaneh Jahanbakhshi, Jovana Milic, Dan Ren, Aditya Mishra, Felix Thomas Eickemeyer, Hong Zhang, Michael Allan Hope, Jun Li, Anurag Krishna, Olivier Ouellette, Zhiwen Zhou

The use of molecular modulators to reduce the defect density at the surface and grain boundaries of perovskite materials has been demonstrated to be an effective approach to enhance the photovoltaic performance and device stability of perovskite solar cell ...

2020

Phenomenally High Molar Extinction Coefficient Sensitizer with "Donor- Acceptor” Ligands for Dye-Sensitized Solar Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Jun Ho Yum

A phenomenally high molar extinction coefﬁcient heteroleptic ruthenium(II) complex [Ru(4,4′-carboxylic acid-2,2′- bipyridine)(4,4′-(4-{4-methyl-2,5-bis[3-methylbutoxy]styryl}-2,5-bis[3- methylbutoxy]-2,2′-bipyridine)(NCS)2] (DCSC13) was synthesized by inco ...

2008

Molecular Engineering of Organic Sensitizers for Dye-Sensitized Solar Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Ulf Anders Hagfeldt, Jun Ho Yum

Novel unsym. org. sensitizers comprising donor, electron-conducting and anchoring groups were engineered at a mol. level and synthesized for sensitization of mesoscopic TiO2 injection solar cells. The unsym. org. sensitizers 3-(5-(4-(diphenylamino)styryl)t ...

2008

Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells

Jun Ho Yum

Mesoscopic solar cells based on nanostructured oxide semiconductors are considered as a promising candidates to replace conventional photovoltaics employing costly materials. However, their overall performances are below the sufficient level required for p ...

Wiley-V C H Verlag Gmbh2017

Optically Transparent Cathode for Dye-Sensitized Solar Cells Based on Graphene Nanoplatelets

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

Commercial graphene nanoplatelets in the form of optically transparent thin films on F-doped SnO2 (FTO) exhibited high electrocatalytic activity toward I-3(-)/I- redox couple, particularly in electrolyte based on, ionic liquid (Z952). The charge-transfer r ...

American Chemical Society2011

Complex Refractive Index Spectra of CH3NH3PbI3 Perovskite Thin Films Determined by Spectroscopic Ellipsometry and Spectrophotometry

Christophe Ballif, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

The complex refractive index (dielectric function) of planar CH3NH3PbI3 thin films at room temperature is investigated by variable angle spectroscopic ellipsometry and spectrophotometry. Knowledge of the complex refractive index is essential for designing ...

Amer Chemical Soc2015

High Open-Circuit Voltage Solid-State Dye-Sensitized Solar Cells with Organic Dye

Michael Graetzel, Mohammad Khaja Nazeeruddin, Robin Humphry-Baker, Peter Chen, Jun Ho Yum, Soo-Jin Moon

Solid-state dye-sensitized solar cells were fabricated using an organic dye, 2-cyanoacrylic acid-4-(bis-dimethylfluoreneaniline)dithiophene (JK2), which exhibits more than 1 V open-circuit potential (V-oc). To scrutinize the origin of high voltage in these ...

American Chemical Society (ACS)2009

Facile preparation of large aspect ratio ellipsoidal anatase TiO2 nanoparticles and their application to dye-sensitized solar cell

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

A simple one-step heat-treatment of peroxotitanate complex aqueous solution at around 100 degrees C was resulted in the formation of ellipsoidal anatase TiO2 nanoparticles having a high aspect ratio with no branches. The length of these ellipsoidal TiO2 fa ...

Elsevier2009

A cobalt complex redox shuttle for dye-sensitized solar cells with high open-circuit potentials

Michael Graetzel, Jacques-Edouard Moser, Mohammad Khaja Nazeeruddin, Arianna Marchioro, Takeru Bessho, Jun Ho Yum, Elham Ghadiri, Thomas Moehl, Chenyi Yi

Dye-sensitized solar cells are a promising alternative to traditional inorganic semiconductor- based solar cells. Here we report an open-circuit voltage of over 1,000 mV in mesoscopic dye- sensitized solar cells incorporating a molecularly engineered cobal ...

Nature Research2012

Cobalt Electrolyte/Dye Interactions in Dye-Sensitized Solar Cells: A Combined Computational and Experimental Study

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

We report a combined experimental and computational investigation to understand the nature of the interactions between cobalt redox mediators and TiO2 surfaces sensitized by :ruthenium and organic dyes, and their impact on. the performance of the correspon ...

American Chemical Society2012

High Molar Extinction Coefficient Organic Sensitizers for Efficient Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ines Raabe, Jun Ho Yum

We have designed and synthesized highly efficient organic sensitizers with a planar thienothiophene-vinylene-thienothiophene linker. Under standard global AM 1.5 solar conditions, the JK-113-sensitized cell gave a short circuit photocurrent density (J(sc)) ...

2010

Polypyridyl Ru(II)-sensitizers with extended pi-system enhances the performance of dye sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

New polypyridyl ruthenium(II) complexes "cis-Ru(4,4'-dimesity1-2,2'-bipyridine) (Ln) (NCS)(2) H102" and "cis-Ru(4,4'-bis(2,3,6-tri-isopropylphenyl)-2,2'-bipyridine) (Ln) (NCS)(2) H105", where Ln = 4,4'-dicarboxylic acid-2,2'-bipyridine; were synthesized an ...

Elsevier2011

The Many Faces of Mixed Ion Perovskites: Unraveling and Understanding the Crystallization Process

Mohammad Khaja Nazeeruddin, Jun Ho Yum, Kevin Sivula, Paul Gratia, Iwan Zimmermann

Understanding the crystallization process of organic-inorganic halide perovskites is of paramount importance for fabrication of reproducible and efficient perovskite solar cells. We report for the first time on the discovery and interplay of ubiquitous hex ...

Amer Chemical Soc2017

Iron Oxide Photoelectrode with Multidimensional Architecture for Highly Efficient Photoelectrochemical Water Splitting

Jun Ho Yum

Nanostructured metal oxide semiconductors have shown outstanding performances in photoelectrochemical (PEC) water splitting, but limitations in light harvesting and charge collection have necessitated further advances in photo-electrode design. Herein, we ...

Wiley-VCH Verlag GmbH2017

Convergent Synthesis of Near-Infrared Absorbing, "Push-Pull", Bisthiophene-Substituted, Zinc(II) Phthalocyanines and their Application in Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

Zinc(II) phthalocyanine dyes that contain triarylamine-terminated bisthiophene and hexylbisthiophene groups have been synthesized by a convergent approach by using carboxytriiodoZnPc as a precursor. Further transformation of the iodo groups by a Pd-catalyz ...

2012

Cyclometallated Iridium Complexes as Sensitizers for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Il Jung

Wiley-Blackwell2010

Surface Passivation of FAPbI3-Rich Perovskite with Cesium Iodide Outperforms Bulk Incorporation

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Mounir Driss Mensi, Jun Ho Yum, Kevin Sivula, Thomas Paul Baumeler, Essa Awadh R Alharbi, Brian Irving Carlsen, Jing Gao, George Cameron Fish, Felix Thomas Eickemeyer, Lukas Pfeifer, Georgios Kakavelakis

Metal halide perovskites (MHPs) have shown an incredible increase in efficiency, reaching as high as 25.7%, which now competes with traditional photovoltaic technologies. Herein, we excluded CsX and RbX (X = I–, Br–, Cl–), the most commonly used cations to ...

2023

Carbon-graphene nanocomposite cathodes for improved Co(II/III) mediated dye-sensitized solar cells

Michael Graetzel, Jun Ho Yum, Yelin Hu, Morgan Mertens Stefik

Cobalt-based electrolytes have significantly advanced the tunability and performance of dye-sensitized solar cells. The typically used platinum cathodes are expensive and non-optimal for cobalt complexes, motivating the search for replacements. Graphene na ...

Royal Society of Chemistry2013