Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Christian J. Mueller is active.

Publication


Featured researches published by Christian J. Mueller.


Journal of Materials Chemistry | 2016

EDOT–diketopyrrolopyrrole copolymers for polymer solar cells

Chao Wang; Christian J. Mueller; Eliot Gann; Amelia C. Y. Liu; Mukundan Thelakkat; Christopher R. McNeill

The photovoltaic properties of a series of diketopyrrolo[3,4-c]pyrrole (DPP) copolymers containing 3,4-ethylenedioxythiophene (EDOT) as a comonomer are reported. With use of different aryl flanking units on the DPP core, namely thiophene, pyridine or phenyl, optical gaps ranging from 1.91 eV to 1.13 eV are achieved. When blended with the fullerene derivative [6,6]-phenyl C71-butyric acid methyl ester (PC71BM), the thiophene-flanked copolymer PDPP[T]2-EDOT with an optical gap of 1.13 eV was found to have the best photovoltaic performance, with an efficiency of 2.5% in an inverted device architecture. Despite having the lowest open circuit voltage of the three polymers studied, PDPP[T]2-EDOT-based devices were able to achieve superior efficiencies due to the high short circuit current of up to ∼15 mA cm−2. PDPP[T]2-EDOT-based devices also exhibit higher external quantum efficiencies which are associated with a superior microstructure – as revealed by transmission electron microscopy (TEM) and grazing incidence wide-angle X-ray scattering (GIWAXS) – which is associated with the enhanced aggregation tendency of PDPP[T]2-EDOT chains. In particular PDPP[T]2-EDOT : PC71BM blends were found to have a finer phase separated morphology with superior thin-film crystallinity. Surface morphology was also investigated with atomic force microscopy and near-edge X-ray absorption fine-structure spectroscopy.


Journal of Materials Chemistry C | 2015

Influence of fluorination in π-extended backbone polydiketopyrrolopyrroles on charge carrier mobility and depth-dependent molecular alignment

Christian J. Mueller; Eliot Gann; Christopher R. McNeill; Mukundan Thelakkat

A series of π-extended polydiketopyrrolo[3,4-c]pyrroles with a varying degree of fluorination on the thiophene–phenyl–thiophene comonomer was synthesized by Stille polycondensation. The influence of the degree of fluorination was studied with regard to the polymer properties, such as absorption, electrochemical redox potentials, the solid state structure as well as depth-dependent molecular alignment in thin films. Additionally, their performance in organic field effect transistors was evaluated. Whereas fluorination slightly increases the alkyl lamella and shrinks the π–π spacings, the coherence lengths were found to improve significantly in both directions. All polymers were found to be p-type materials when employed in organic field effect transistors (OFET). These devices can be tuned towards ambipolarity in the case of the tetrafluorinated copolymer upon thermal annealing.


Journal of Materials Chemistry C | 2017

Fluorination in thieno[3,4-c]pyrrole-4,6-dione copolymers leading to electron transport, high crystallinity and end-on alignment

Tina Weller; M. Breunig; Christian J. Mueller; Eliot Gann; Christopher R. McNeill; Mukundan Thelakkat

A series of copolymers based on thieno[3,4-c]pyrrole-4,6-dione and thiophene-phenyl-thiophene with varying degrees of fluorination on the phenyl unit was synthesized by Stille polycondensation. The influence of the degree of fluorination on the optical, thermal and electrochemical properties of these polymers is systematically studied. Additionally, the charge transport in organic field effect transistors (OFETs) as well as the thin film alignment are investigated. After thermal annealing the non-fluorinated as well as difluorinated polymers show ambipolar charge transport in OFETs. In contrast, tetrafluorination results in exclusively n-type behaviour with an electron mobility of 3.7 × 10−4 cm2 V−1 s−1. GIWAXS measurements of as-cast and annealed films reveal a very interesting structural alignment in thin films. All polymers show the rarely observed “end-on” orientation, where the polymer chains stand on the substrate. This may be explained by the low molecular weights of these polymers in relation to the film thickness. Fluorination does not influence the microstructural properties, only the propensity of crystallization is increased.


Macromolecules | 2010

Understanding the Influence of Morphology on Poly(3-hexylselenothiophene):PCBM Solar Cells

Amy M. Ballantyne; Toby A. M. Ferenczi; Mariano Campoy-Quiles; Tracey M. Clarke; Andrea Maurano; Kien Hon Wong; Weimin Zhang; Natalie Stingelin-Stutzmann; Ji-Seon Kim; Donal D. C. Bradley; James R. Durrant; Iain McCulloch; Martin Heeney; Jenny Nelson; Steve Tierney; Warren Duffy; Christian J. Mueller; Paul Smith


Advanced Functional Materials | 2015

High Bulk Electron Mobility Diketopyrrolopyrrole Copolymers with Perfluorothiophene

Christian J. Mueller; Chetan R. Singh; Martina Fried; Sven Huettner; Mukundan Thelakkat


Chemistry of Materials | 2016

Control of Molecular Orientation in Polydiketopyrrolopyrrole Copolymers via Diffusive Noncovalent Interactions

Christian J. Mueller; Eliot Gann; Chetan R. Singh; Mukundan Thelakkat; Christopher R. McNeill


Advanced Energy Materials | 2015

Diketopyrrolopyrroles with a Distinct Energy Level Cascade for Efficient Charge Carrier Generation in Organic Solar Cells

Christian J. Mueller; Michael Brendel; Pia Ruckdeschel; Jens Pflaum; Mukundan Thelakkat


Journal of Polymer Science Part B | 2016

EDOT‐diketopyrrolopyrrole copolymers for high bulk hole mobility and near infrared absorption

Christian J. Mueller; Chetan R. Singh; Mukundan Thelakkat


Macromolecules | 2016

Azido-Functionalized Thiophene as a Versatile Building Block To Cross-Link Low-Bandgap Polymers

Christian J. Mueller; Tobias Klein; Eliot Gann; Christopher R. McNeill; Mukundan Thelakkat


Advanced Materials Interfaces | 2016

Influence of Electron Extracting Interface Layers in Organic Bulk‐Heterojunction Solar Cells

Chetan R. Singh; Cheng Li; Christian J. Mueller; Sven Hüttner; Mukundan Thelakkat

Collaboration


Dive into the Christian J. Mueller's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Eliot Gann

Australian Synchrotron

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Cheng Li

University of Bayreuth

View shared research outputs
Top Co-Authors

Avatar

Jens Pflaum

University of Würzburg

View shared research outputs
Top Co-Authors

Avatar

M. Breunig

University of Bayreuth

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge