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Jun Ho Yum

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Related publications (128)

Subphthalocyanines: Active molecules for molecular photovoltaics

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Aswani Yella, Olga Trukhina

Amer Chemical Soc2014

Peripherally and Axially Carboxylic Acid Substituted Subphthalocyanines for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Aswani Yella

A series of subphthalocyanines (SubPcs) bearing a carboxylic acid group either at the peripheral or axial position have been designed and synthesized to investigate the influence of the COOH group positions on the dye-sensitized solar cell (DSSC) performan ...

Wiley-Blackwell2014

Sterically Hindered Phthalocyanines for Dye-Sensitized Solar Cells: Influence of the Distance between the Aromatic Core and the Anchoring Group

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Aravind Kumar Chandiran

A new phthalocyanine (Pc) bearing bulky peripheral substituents and a carboxylic anchoring group directly attached to the macrocycle has been prepared and used as a sensitizer in DSSCs, reaching 5.57% power conversion efficiency. In addition, an enhanced p ...

Wiley-Blackwell2014

Graphene-based cathodes for liquid-junction dye sensitized solar cells: Electrocatalytic and mass transport effects

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

The optimization of mediator/cathode in a dye sensitized solar cell (DSC) requires detailed knowledge about their electrochemical properties. Particularly, the kinetics of mediator's turnover on the cathode and the mass transport of mediator in the electro ...

Pergamon-Elsevier Science Ltd2014

Toward Higher Photovoltage: Effect of Blocking Layer on Cobalt Bipyridine Pyrazole Complexes as Redox Shuttle for Dye-Sensitized Solar Cells

Michael Graetzel, Jun Ho Yum, Paul Gratia, Aravind Kumar Chandiran, Thomas Moehl, Junghyun Yoon

Fluorine-doped tin-oxide (FTO) transparent conducting substrates, for use in cobalt bis(bipyridine pyrazole) complex based dye-sensitized solar cells (DSCs), were compared using the conventional TiCl4 treatment with conformal TiO2 blocking layers formed by ...

American Chemical Society2014

Panchromatic symmetrical squaraines: a step forward in the molecular engineering of low cost blue-greenish sensitizers for dye-sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Guido Viscardi, Davide Di Censo, Jun Ho Yum, Elisa Dell'Orto

Two novel symmetrical blue squaraine sensitizers were synthesized, which exhibit panchromatic light harvesting and a record efficiency over 6% with J(sc) exceeding 14 mA cm(-2), and V-oc over 620 mV under 1 sun. Their color, low cost, easiness of synthesis ...

Royal Soc Chemistry2014

Molecular Engineering of Phthalocyanine Sensitizers for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Simon Mathew, Yongjoo Kim

A series of novel near-infrared-absorbing zinc phthalocyanines bearing donor-chromophore-acceptor/anchoring groups have been synthesized to investigate their influence on solar cell performance. With the aim of extending the absorption spectra while mainta ...

American Chemical Society2014

Facile synthesis of a bulky BPTPA donor group suitable for cobalt electrolyte based dye sensitized solar cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Peng Gao, Thomas Wesley Holcombe, Yongjoo Kim

An efficient synthesis of N-(2 ',4 '-bis(hexyloxy)-[1,1 '-biphenyl]-4-yl)-N-(4-bromophenyl)-2 ',4 '-bis(hexyloxy)-[ 1,1 '-biphenyl]-4-amine (BPTPA donor, 5) was developed based on a new 4-step synthetic route. The BPTPA donor is used to quickly access two ...

Royal Society of Chemistry2013

Nanofibrous TiO2 improving performance of mesoporous TiO2 electrode in dye-sensitized solar cell

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

A method of direct coating of conducting glass by electrospinning was developed. Electrospun fibrous TiO2 consisting of closely packed anatase nanocrystals of 40-50 nm in size was incorporated into mesoporous TiO2 thin film stabilized by phosphorus. The me ...

Springer Verlag2013

Electrodes for dye-sensitized solar cells: A case of graphene-based materials

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

Amer Chemical Soc2013

Blue-Coloured Highly Efficient Dye-Sensitized Solar Cells by Implementing the Diketopyrrolopyrrole Chromophore

Michael Graetzel, Mohammad Khaja Nazeeruddin, Joël Teuscher, Jun Ho Yum, Thomas Moehl, Thomas Wesley Holcombe, Kasparas Rakstys, Yongjoo Kim

The paradigm shift in dye sensitized solar cells (DSCs) - towards donor-pi bridge-acceptor (D-pi-A) dyes - increases the performances of DSCs and challenges established design principles. Framed by this shifting landscape, a series of four diketopyrrolopyr ...

Nature Publishing Group2013

Highly soluble energy relay dyes for dye-sensitized solar cells

Michael Graetzel, Jun Ho Yum

High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, char ...

Royal Society of Chemistry2013

The Role of p Bridges in High-Efficiency DSCs Based on Unsymmetrical Squaraines

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

A series of squaraine-based sensitizers with various p bridges and anchors were prepared and examined in dye-sensitized solar cells. The carboxylic anchor group was attached onto a squaraine dye through p bridges with and without an ethynyl spacer. DFT stu ...

Wiley-Blackwell2013

Diketopyrrolopyrrole-based sensitizers for dye-sensitized solar cell applications: anchor engineering

Michael Graetzel, Jun Ho Yum, Thomas Wesley Holcombe, Kasparas Rakstys, Yongjoo Kim

A series of donor-chromophore-anchor (D-C-A) sensitizers comprising the diketopyrrolopyrrole (DPP) chromophore were synthesized and tested in both I-3(-)/I- and Co(bpy) redox shuttle DSC devices. The dye series was strategically designed to elucid ...

Royal Society of Chemistry2013

Application of graphene-based nanostructures in dye-sensitized solar cells

Michael Graetzel, Ladislav Kavan, Jun Ho Yum

The paper reviews recent advances in the application of graphene and related materials, viz. graphene nanoplatelets (GNP), functionalized graphene sheets (FGS), graphene oxide (GO), and reduced graphene oxide (rGO) as electrode building materials in dye-se ...

Wiley-Blackwell2013

A Simple Synthetic Route to Obtain Pure Trans-Ruthenium(II) Complexes for Dye-Sensitized Solar Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Guido Viscardi, Davide Di Censo, Jun Ho Yum, Filippo de Angelis

We report a facile synthetic route to obtain functionalized quaterpyridine ligand and its trans-dithiocyanato ruthenium complex, based on a microwave-assisted procedure. The ruthenium complex has been purified using a silica chromatographic column by prote ...

Wiley-VCH Verlag Berlin2013

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

Bodipy dyes as a potential sentisizer for dye sensitized solar cells

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

Amer Chemical Soc2013

Towards high-performance DPP-based sensitizers for DSC applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Thomas Wesley Holcombe, Junghyun Yoon, Kasparas Rakstys, Yongjoo Kim

A novel, asymmetric DPP bridge/core was synthesized and tested in DSC devices. By desymmetrising the DPP core/bridge, a remarkable IPCE of >80% and a maximum power conversion efficiency of 7.7% were achieved. With the use of a wide-bandgap co-sensitizer, 8 ...

Royal Society of Chemistry2012

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

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

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

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