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Jun Ho Yum

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Related publications (128)

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

A structural study of DPP-based sensitizers for DSC applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Davide Di Censo, Jun Ho Yum, Magdalena Anna Marszalek, Peng Gao, Thomas Wesley Holcombe, Junghyun Yoon, Kasparas Rakstys

Four D-pi-A sensitizers comprising a thienyl-diketopyrrolopyrrole (ThDPP) bridge were synthesized and tested in iodide/triiodide liquid electrolyte DSC devices. The dye series was strategically designed to develop a structure-property relationship. The bes ...

Royal Society of Chemistry2012

Optically Transparent Cathode for Co(III/II) Mediated Dye-Sensitized Solar Cells Based on Graphene Oxide

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

Thin semitransparent films were fabricated on F-doped SnO2 (FTO) from single-layer graphene oxide (GO) either pure or in a composite with graphene nanoplatelets. Electrocatalytic activity of prepared films was tested for the Co(bpy)(3)(3+/2+) redox couple ...

Amer Chemical Soc2012

Successful demonstration of an efficient I-/(SeCN)(2) redox mediator for dye-sensitized solar cells

Jun Ho Yum

A new I-/(SeCN)(2) redox mediator has favorable properties for dye-sensitized solar cells (DSCs) such as less visible light absorption, higher ionic conductivity, and downward shift of redox potential than I-/I-3(-). It was then applied for DSCs towards in ...

2012

Highly efficient water splitting by a dual-absorber tandem cell

Michael Graetzel, Maurin Cornuz, Jun Ho Yum, Kevin Sivula, Jérémie Minh-Châu Brillet, Takashi Hisatomi

Photoelectrochemical water-splitting devices, which use solar energy to convert water into hydrogen and oxygen, have been investigated for decades. Multijunction designs are most efficient, as they can absorb enough solar energy and provide sufficient free ...

Nature Publishing Group2012

Carboxyethynyl Anchoring Ligands: A Means to Improving the Efficiency of Phthalocyanine-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Davide Di Censo, Jun Ho Yum

Wiley-VCH Verlag GmbH2012

Lead Iodide Perovskite Sensitized All-Solid-State Submicron Thin Film Mesoscopic Solar Cell with Efficiency Exceeding 9%

Michael Graetzel, Jacques-Edouard Moser, Robin Humphry-Baker, Arianna Marchioro, Jun Ho Yum, Soo-Jin Moon, Thomas Moehl, Jeong-Hyeok Im

We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH3NH3)PbI3 as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI2 and deposited onto ...

2012

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

Anthocyanins and betalains as light-harvesting pigments for dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Alessandro Sinopoli, Jun Ho Yum

We present the photoelectrochemical properties of dye-sensitized solar cells using natural pigments containing betalains and anthocyanins as sensitizers. The dyes extracted from grape, mulberry, blackberry, red Sicilian orange, Sicilian prickly pear, eggpl ...

2012

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

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Yu-Ting Huang, 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

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

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

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 ...

2012

Improved redox couple for electrochemical and optoelectronic devices

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Aswani Yella, Hoi Nok Tsao

The present invention provides an improved redox couple for electrochemical and optoelectronic devices. The redox couple is based on a complex of a first row transition metal, said complex containing at least one mono-, bi-, or tridentate ligand comprising ...

2012

Towards flexibility: metal free plastic cathodes for dye sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Elisa Dell'Orto

We report herein lightweight, and economical dye-sensitized solar cells fabrication facilitated by an all plastic, metal free cathode consisting of poly(3,4-ethylenedioxythiophene). ...

Royal Society of Chemistry2012

High-voltage (1.8 V) tandem solar cell system using a GaAs/AlXGa(1-X)As graded solar cell and dye-sensitised solar cells with organic dyes having different absorption spectra

Pascal Comte, Michael Graetzel, Paul Liska, Péter Kalman Péchy, Jun Ho Yum

Stacked multijunction (tandem) solar cells have been prepared by mechanically stacking dye-sensitised solar cells (DSCs) and a GaAs/AlXGa(1-X)As graded solar cell (GGC) as the top and bottom cells, respectively. Three organic dyes with different absorption ...

2011

Optimization of distyryl-Bodipy chromophores for efficient panchromatic sensitization in dye sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Jun Ho Yum, Magdalena Anna Marszalek

Versatility of Bodipy (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) dyes was further expanded in recent dye-sensitized solar cell applications. Here we report a series of derivatives designed to address earlier problems in Bodipy sensitized solar cells. In ...

2011

Incorporating Multiple Energy Relay Dyes in Liquid Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Jun Ho Yum

Panchromatic response is essential to increase the light-harvesting efficiency in solar conversion systems. Herein we show increased light harvesting from using multiple energy relay dyes inside dye-sensitized solar cells. Additional photoresponse from 400 ...

2011

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

Panchromatic engineering for dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Sophie Wenger

The dye-sensitized mesoscopic solar cell has been intensively investigated as a promising photovoltaic cell. Its ecological and economical fabrication processes make it attractive and credible alternative to conventional photovoltaic systems. In contrast t ...

2011

Effect of anchoring groups in zinc phthalocyanine on the dye-sensitized solar cell performance and stability

Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Robin Humphry-Baker, Péter Kalman Péchy, Jun Ho Yum

We have designed and developed an unsymmetrical zinc phthalocyanine (TT9) sensitizer that consists of three tert-butyl and two carboxylic acid groups that act as "push'' and "pull'', respectively. The two carboxylic acid groups graft the sensitizer onto th ...

2011

Bis-Donor-Bis-Acceptor Tribranched Organic Sensitizers for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Filippo de Angelis

A new class of tribranched dye-sensitized solar cell (DSC) sensitizers carrying two conjugated donors and two acceptor/anchoring groups is introduced. The approach leads to significantly different optical properties and enhanced stability with respect to r ...

Wiley-Blackwell2011

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