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Jun Ho Yum

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Related publications (128)

Molecular Design of Unsymmetrical Squaraine Dyes for High Efficiency Conversion of Low Energy Photons into Electrons Using TiO2 Nanocrystalline Films

Michael Graetzel, Mohammad Khaja Nazeeruddin, Thomas Geiger, Jun Ho Yum, Soo-Jin Moon

An optimized unsymmetrical squaraine dye 5-carboxy-2[[3-[(2,3-dihydro-1, 1-dimethyl-3-ethyl-1H-benzo[e]indol-2-ylidene)methyl]-2-hydroxy-4-oxo-2-cyclobuten-1-ylidene]methyl]-3,3-dimethyl-1-octyl-3H-indolium (SQ02) with carboxylic acid as anchoring group is ...

2009

Panchromatic Response in Solid-State Dye-Sensitized Solar Cells Containing Phosphorescent Energy Relay Dyes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Soo-Jin Moon

Running relay: Incorporating an energy-relay dye (ERD) into the hole transporter of a dye-sensitized solar cell increased power-conversion efficiency by 29 % by extending light harvesting into the blue region. In the operating mechanism (see picture), abso ...

Wiley-VCH Verlag GmbH2009

Panchromatic Cross-Substituted Squaraines for Dye-Sensitized Solar Cell Applications

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

2009

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, Filippo de Angelis

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

Unsymmetrical extended pi-conjugated zinc phthalocyanine for sensitization of nanocrystalline TiO2 films

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

We have designed and synthesized a new unsymmetrical zinc phthalocyanine based on 'push-pull' and extended pi-conjugation concept, PCH008. The new sensitizer was fully characterized by CHN anlysis, UV-Vis., fluorescence spectroscopies and cyclic voltammetr ...

2009

Increased light harvesting in dye-sensitized solar cells with energy relay dyes

Pascal Comte, Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

Conventional dye-sensitized solar cells have excellent charge collection efficiencies, high open-circuit voltages and good fill factors. However, dye-sensitized solar cells do not completely absorb all of the photons from the visible and near-infrared doma ...

Nature Publishing Group2009

Di-branched di-anchoring organic dyes for dye-sensitized solar cells

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

The first examples of di-branched di-anchoring organic sensitizers were synthesized and used in dye-sensitized solar cells leading to red-shifted IPCE maxima and increased photocurrent when compared to the corresponding mono-branched mono-anchoring dye, yi ...

2009

Highly Efficient Organic Sensitizers for Solid-State Dye-Sensitized Solar Cells

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

Organic sensitizers comprising of donor, electron-conducting, and anchoring groups are designed and developed for dye-sensitized solar cell applications. A solar cell employing 3-(5'-{4-[bis-(4-hexyloxy-phenyl)-amino]-phenyl}-[2,2']bithiophenyl-5-yl)-2-cya ...

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

Carboxy-1,4-phenylenevinylene- and carboxy-2,6-naphthylene-vinylene unsymmetrical substituted zinc phthalocyanines for dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

Two unsymmetrical Zn(II) phthalocyanines 1 and 2 bearing an anchoring carboxylic function linked to the phthalocyanine ring through different rigid arylenevinylene bridges have been designed for dye-sensitized solar cell (DSSC) applications. The phthalocya ...

2009

A Light-Resistant Organic Sensitizer for Solar-Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Ulf Anders Hagfeldt, Jun Ho Yum, Soo-Jin Moon

Finely tuned: A stable dye-sensitized solar cell that contains a molecularly engineered org. dye was prepd. The efficiency of the cell remains at 90% after 1000 h of light soaking at 60°. The remarkable stability of the cell is also reflected in the open-c ...

Wiley-VCH Verlag GmbH2009

Structure-Function Relationships in Unsymmetrical Zinc Phthalocyanines for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

A series of unsymmetrical zinc phthalocyanines bearing an anchoring carboxylic function linked to the phthalocyanine ring through different spacers were designed for dye-sensitised solar cells (DSSC). The modification of the spacer group allows not only a ...

2009

Cyclometallated iridium complexes for conversion of light into electricity and electricity into light

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

This brief review describes applications of cyclometallated iridium complexes for energy saving organic light-emitting devices (OLED's) and energy generating molecular photovoltaic cells. The first part consists of a short overview of the methods to modula ...

2009

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, Filippo de Angelis

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

Effect of Coadsorbent on the Photovoltaic Performance of Zinc Pthalocyanine-Sensitized Solar Cells

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

2008

Recent Developments in Solid-State Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Peter Chen, Jun Ho Yum

2008

Tri-tert-butylcarboxyphthalocyanines, uses thereof and a process for their preparation

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum

Substituted carboxyphthalocyanines (I), wherein both the tert-butyl and carboxyl groups located in the four isoindole rings are located independently in any of the four positions of the corresponding benzene ring of each isoindole ring, its regioisomers an ...

2008

An Improved Perylene Sensitizer for Solar Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Soo-Jin Moon, Felix Thomas Eickemeyer

1,6-Dithiophenol-substituted perylene organic sensitizer 1 was synthesized, and its photovoltaic properties in dye-sensitized solar cells were assessed. When anchored onto TiO2 film, the dye exhibits an unprecedented incident monochromatic photon-to-curren ...

2008

Electron-rich heteroaromatic conjugated bipyridine based ruthenium sensitizer for efficient dye-sensitized solar cells

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

A novel heteroleptic ruthenium complex carrying a heteroaromatic-4,4'-pi-conjugated 2,2'-bipyridine [Ru(II)LL'(NCS)(2)] (L = 4,4'-bis[(E)-2-(3,4-ethylenedioxythien-2-yl)vinyl]-2,2'-bipyridine, L' = 4,4'-(dicarboxylic acid)-2,2'-bipyridine) was synthesized ...

Royal Society of Chemistry2008

CdSe quantum dot-sensitized solar cells exceeding efficiency 1% at full-sun intensity

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

Colloidal cadmium selenide (CdSe) quantum dots QDs) have been prepared and exploited as inorganic dyes to sensitize a large-band-gap TiO2 layer for QD-sensitized solar cells. The optimized QD-sensitized solar cells exhibited an unprecedented incident photo ...

2008

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