Publications de Thomas Wesley Holcombe

Efficient Blue-Colored Solid-State Dye-Sensitized Solar Cells: Enhanced Charge Collection by Using an in Situ Photoelectrochemically Generated Conducting Polymer Hole Conductor

Michael Graetzel, Nikolaos Vlachopoulos, Ulf Anders Hagfeldt, Thomas Wesley Holcombe, Jiahuan Zhang, Yan Hao

A high power conversion efficiency (PCE) of 5.5% was achieved by efficiently incorporating a diketopyrrolopyrrole-based dye with a conducting polymer poly(3,4-ethylenediothiophene) (PEDOT) hole-transporting material (HTM) that was formed in situ, compared ...

Wiley-V C H Verlag Gmbh2016

Diketopyrrolopyrole (dpp)-based sensitizers for electrochemical or optoelectronic devices

Michael Graetzel, Mohammad Khaja Nazeeruddin, Jun Ho Yum, Thomas Wesley Holcombe

The present invention relates to compounds of formula (I) based on DPP moiety being useful as metal-free organic sensitizers or dyes of type D-Pi-A in electrochemical or optoelectronic devices, their use as sensitizer or dye and an electrochemical or optoe ...

2015

Unravel the Impact of Anchoring Groups on the Photovoltaic Performances of Diketopyrrolopyrrole Sensitizers for Dye-Sensitized Solar Cells

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Peng Gao, Thomas Wesley Holcombe, Paramaguru Ganesan

Two D-pi-A dyes, one with a strong electron withdrawing cyanoacrylic acid DPP 20 and one with a weak acceptor carboxylic acid DPP 21 have been synthesized and characterized for their application in dye-sensitized solar cells. This allows us to understand t ...

Amer Chemical Soc2015

Influence of the Donor Size in D-pi-A Organic Dyes for Dye-Sensitized Solar Cells

Pascal Comte, Michael Graetzel, Mohammad Khaja Nazeeruddin, Shaik Mohammed Zakeeruddin, Joël Teuscher, Thomas Moehl, Chenyi Yi, Thomas Wesley Holcombe, Yongjoo Kim, Paramaguru Ganesan, Jiabao Yang

We report two new molecularly engineered push-pull dyes, i.e., YA421 and YA422, based on substituted quinoxaline as a pi-conjugating linker and bulky-indoline moiety as donor and compared with reported IQ4 dye. Benefitting from increased steric hindrance w ...

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

The Molecular Engineering of Organic Sensitizers for Solar-Cell Applications

Michael Graetzel, Mohammad Khaja Nazeeruddin, Aswani Yella, Thomas Wesley Holcombe

Wiley-Blackwell2013

Position-Dependent Extension of π-Conjugation in D-π-A Dye Sensitizers and the Impact on the Charge-Transfer Properties

Michael Graetzel, Jacques-Edouard Moser, Shaik Mohammed Zakeeruddin, Thomas Wesley Holcombe, Mateusz Barnaba Wielopolski, Yuxiang Yu, Jinhyun Kim

A series of five organic donor-π-bridge-acceptor (D-π-A) sensitizers is investigated within the context of their photoinduced charge-transfer properties. Thereby, the focus is set on the impact of structural modifications of the molecular architecture on t ...

American Chemical Society2013

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

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

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

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