Imperial College London

ProfessorMartinHeeney

Faculty of Natural SciencesDepartment of Chemistry

Professor of Organic Materials
 
 
 
//

Contact

 

+44 (0)20 7594 1248m.heeney Website

 
 
//

Location

 

401GMolecular Sciences Research HubWhite City Campus

//

Summary

 

Publications

Publication Type
Year
to

289 results found

Eisner FD, Azzouzi M, Fei Z, Hou X, Anthopoulos TD, Dennis TJS, Heeney M, Nelson Jet al., 2019, Hybridization of Local Exciton and Charge-Transfer States Reduces Nonradiative Voltage Losses in Organic Solar Cells., J Am Chem Soc

A number of recent studies have shown that the nonradiative voltage losses in organic solar cells can be suppressed in systems with low energetic offsets between donor and acceptor molecular states, but the physical reasons underpinning this remain unclear. Here, we present a systematic study of 18 different donor/acceptor blends to determine the effect that energetic offset has on both radiative and nonradiative recombination of the charge-transfer (CT) state. We find that, for certain blends, low offsets result in hybridization between charge-transfer and lowest donor or acceptor exciton states, which leads to a strong suppression in the nonradiative voltage loss to values as low as 0.23 V associated with an increase in the luminescence of the CT state. Further, we extend a two-state CT-state recombination model to include the interaction between CT and first excited states, which allows us to explain the low nonradiative voltage losses as an increase in the effective CT to ground state oscillator strength due to the intensity borrowing mechanism. We show that low nonradiative voltage losses can be achieved in material combinations with a strong electronic coupling between CT and first excited states and where the lower band gap material has a high oscillator strength for transitions from the excited state to the ground state. Finally, from our model we propose that achieving very low nonradiative voltage losses may come at a cost of higher overall recombination rates, which may help to explain the generally lower FF and EQE of highly hybridized systems.

JOURNAL ARTICLE

Ye L, Xiong Y, Chen Z, Zhang Q, Fei Z, Henry R, Heeney M, O'Connor BT, You W, Ade Het al., 2019, Sequential Deposition of Organic Films with Eco-Compatible Solvents Improves Performance and Enables Over 12%-Efficiency Nonfullerene Solar Cells., Adv Mater

Casting of a donor:acceptor bulk-heterojunction structure from a single ink has been the predominant fabrication method of organic photovoltaics (OPVs). Despite the success of such bulk heterojunctions, the task ofcontrolling the microstructure in a single casting process has been arduous and alternative approaches are desired. To achieve OPVs with a desirable microstructure, a facile and eco-compatible sequential deposition approach is demonstrated for polymer/small-molecule pairs. Using a nominally amorphous polymer as the model material, the profound influence of casting solvent is shown on the molecular ordering of the film, and thus the device performance and mesoscale morphology of sequentially deposited OPVs can be tuned. Static and in situ X-ray scattering indicate that applying (R)-(+)-limonene is able to greatly promote the molecular order of weakly crystalline polymers and form the largest domain spacing exclusively, which correlates well with the best efficiency of 12.5% in sequentially deposited devices. The sequentially cast device generally outperforms its control device based on traditional single-ink bulk-heterojunction structure. More crucially, a simple polymer:solvent interaction parameter χ is positively correlated with domain spacing in these sequentially deposited devices. These findings shed light on innovative approaches to rationally create environmentally friendly and highly efficient electronics.

JOURNAL ARTICLE

Reichsoellner E, Creamer A, Cong S, Casey A, Eder S, Heeney M, Glocklhoefer Fet al., 2019, Fast and Selective Post-polymerization Modification of Conjugated Polymers Using Dimethyldioxirane, FRONTIERS IN CHEMISTRY, Vol: 7, ISSN: 2296-2646

JOURNAL ARTICLE

Sun G, Shahid M, Fei Z, Xu S, Eisner FD, Anthopolous TD, McLachlan MA, Heeney Met al., 2019, Highly-efficient semi-transparent organic solar cells utilising non-fullerene acceptors with optimised multilayer MoO3/Ag/MoO3 electrodes, MATERIALS CHEMISTRY FRONTIERS, Vol: 3, Pages: 450-455

JOURNAL ARTICLE

Rimmele M, Ableidinger K, Marsh AV, Cheetham NJ, Taublaender MJ, Buchner A, Prinz J, Froehlich J, Unterlass MM, Heeney M, Gloecklhofer Fet al., 2019, Thioalkyl- and sulfone-substituted poly(p-phenylene vinylene)s, POLYMER CHEMISTRY, Vol: 10, Pages: 738-750, ISSN: 1759-9954

JOURNAL ARTICLE

Paterson AF, Mottram AD, Faber H, Niazi MR, Fei Z, Heeney M, Anthopoulos TDet al., 2019, Impact of the Gate Dielectric on Contact Resistance in High-Mobility Organic Transistors, Advanced Electronic Materials

© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The impact of the gate dielectric on contact resistance in organic thin-film transistors (OTFTs) is investigated using electrical characterization, bias-stress stability measurements, and bandgap density of states (DOS) analysis. Two similar dielectric materials, namely Cytop and poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene] (Teflon AF2400), are tested in top-gate bottom-contact OTFTs. The contact resistance of Cytop-based OTFTs is found to be greater than that of the AF2400-based devices, even though the metal/OSC interface remains identical in both systems. The Cytop devices are also found to perform worse in bias-stress stability tests which, along with the DOS calculations, suggests that charge trapping at the OSC/dielectric interface is more prevalent with Cytop than AF2400. This increased charge trapping at the Cytop OSC/dielectric interface appears to be associated with the higher contact resistance in Cytop OTFTs. Differences in the molecular structure between Cytop and AF2400 and the large difference in the glass transition temperature of the two polymers may be responsible for the observed difference in the transistor performance. Overall, this study highlights the importance of the gate dielectric material in the quest for better performing OTFTs and integrated circuits.

JOURNAL ARTICLE

Krauspe P, Tsokkou D, Causa M, Buchaca-Domingo E, Fei Z, Heeney M, Stingelin N, Banerji Net al., 2018, Terahertz short-range mobilities in neat and intermixed regions of polymer: fullerene blends with controlled phase morphology, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 6, Pages: 22301-22309, ISSN: 2050-7488

JOURNAL ARTICLE

Rimmele M, Ableidinger K, Marsh A, Cheetham N, Taublaender J, Buchner A, Prinz J, Fröhlich J, Unterlass M, Heeney M, Glöcklhofer Fet al., 2018, Thioalkyl- and Sulfone-Substituted Poly(p-Phenylene Vinylene)s

Poly(p-phenylene vinylene)s (PPVs) have been studied for decades, but research on this interesting class of conjugated polymers is far from being completed. New applications like in bioimaging keep emerging and even simple structural variations are still waiting to be explored. Surprisingly, not even dithioalkyl-substituted PPVs (S-PPVs) have been reported in the peer-reviewed literature, although the corresponding dialkoxy-substituted PPVs (O-PPVs) like MEH-PPV or MDMO-PPV are most frequently used and although thioalkyl substituents can improve the material properties significantly. We herein report the development of a highly efficient, scalable two-step synthesis of Gilch monomers for S-PPVs starting from low-cost 1,4-diiodobenzene. A low-temperature polymerization protocol has been developed for these monomers, affording high-molecular weight S-PPVs in excellent yields. The thermal, electrochemical, and photophysical properties of S-PPVs are reported to highlight the potential of these polymers. Furthermore, treatment with dimethyldioxirane is demonstrated to result in rapid conversion into sulfone-substituted PPVs (SO<sub>2</sub>-PPVs), introducing a route to high-molecular weight SO<sub>2</sub>-PPVs with exceptional stability and solid-state photoluminescence quantum yields of up to 0.46.

WORKING PAPER

Boufflet P, Bovo G, Occhi L, Yuan H-K, Fei Z, Han Y, Anthopoulos TD, Stavrinou PN, Heeney Met al., 2018, The Influence of Backbone Fluorination on the Dielectric Constant of Conjugated Polythiophenes, ADVANCED ELECTRONIC MATERIALS, Vol: 4, ISSN: 2199-160X

JOURNAL ARTICLE

Paterson AF, Lin Y-H, Mottram AD, Fei Z, Niazi MR, Kirmani AR, Amassian A, Solomeshch O, Tessler N, Heeney M, Anthopoulos TDet al., 2018, The Impact of Molecular p-Doping on Charge Transport in High-Mobility Small-Molecule/Polymer Blend Organic Transistors, ADVANCED ELECTRONIC MATERIALS, Vol: 4, ISSN: 2199-160X

JOURNAL ARTICLE

Paterson AF, Singh S, Fallon KJ, Hodsden T, Han Y, Schroeder BC, Bronstein H, Heeney M, McCulloch I, Anthopoulos TDet al., 2018, Recent Progress in High-Mobility Organic Transistors: A Reality Check, ADVANCED MATERIALS, Vol: 30, ISSN: 0935-9648

JOURNAL ARTICLE

Patra D, Lee J, Dey S, Lee J, Kalin AJ, Putta A, Fei Z, McCarthy-Ward T, Bazzi HS, Fang L, Heeney M, Yoon M-H, Al-Hashimi Met al., 2018, Chalcogen Bridged Thieno- and Selenopheno[2,3-d:5,4-d ']bisthiazole and Their Diketopyrrolopyrrole Based Low-Bandgap Copolymers, MACROMOLECULES, Vol: 51, Pages: 6076-6084, ISSN: 0024-9297

JOURNAL ARTICLE

Marsh AV, Cheetham NJ, Little M, Dyson M, White AJP, Beavis P, Warriner CN, Swain AC, Stavrinou PN, Heeney Met al., 2018, Carborane-Induced Excimer Emission of Severely Twisted Bis-o-Carboranyl Chrysene, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 57, Pages: 10640-10645, ISSN: 1433-7851

JOURNAL ARTICLE

Creamer A, Wood CS, Howes PD, Casey A, Cong S, Marsh AV, Godin R, Panidi J, Anthopoulos TD, Burgess CH, Wu T, Fei Z, Hamilton I, McLachlan MA, Stevens MM, Heeney Met al., 2018, Post-polymerisation functionalisation of conjugated polymer backbones and its application in multifunctional emissive nanoparticles, NATURE COMMUNICATIONS, Vol: 9, ISSN: 2041-1723

JOURNAL ARTICLE

Rodriquez D, Kohl JG, Morel P, Burrows K, Favaro G, Root SE, Ramirez J, Alkhadra MA, Carpenter CW, Fei Z, Boufflet P, Heeney M, Lipomi DJet al., 2018, Measurement of Cohesion and Adhesion of Semiconducting Polymers by Scratch Testing: Effect of Side-Chain Length and Degree of Polymerization, ACS MACRO LETTERS, Vol: 7, Pages: 1003-1009, ISSN: 2161-1653

JOURNAL ARTICLE

Nieuwendaal RC, DeLongchamp DM, Richter LJ, Snyder CR, Jones RL, Engmann S, Herzing A, Heeney M, Fei Z, Sieval AB, Hummelen JCet al., 2018, Characterization of Interfacial Structure in Polymer-Fullerene Bulk Heterojunctions via C-13 {H-2} Rotational Echo Double Resonance NMR, PHYSICAL REVIEW LETTERS, Vol: 121, ISSN: 0031-9007

JOURNAL ARTICLE

Eisner F, Seitkhan A, Han Y, Khim D, Yengel E, Kirmani AR, Xu J, de Arquer FPG, Sargent EH, Amassian A, Fei Z, Heeney M, Anthopoulos TDet al., 2018, Solution-Processed In2O3/ZnO Heterojunction Electron Transport Layers for Efficient Organic Bulk Heterojunction and Inorganic Colloidal Quantum-Dot Solar Cells, SOLAR RRL, Vol: 2, ISSN: 2367-198X

JOURNAL ARTICLE

Datko BD, Walwark DJ, Fei Z, Heeney MJ, Grey JKet al., 2018, Resolving Anomalous Heavy Atom Effects from Discrete Triplet Mediated Photochemistry Events on Single Conjugated Polymer Chains, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 122, Pages: 9718-9725, ISSN: 1932-7447

JOURNAL ARTICLE

Squeo BM, Gregoriou VG, Han Y, Palma-Cando A, Allard S, Serpetzoglou E, Konidakis I, Stratakis E, Avgeropoulos A, Anthopoulos TD, Heeney M, Scherf U, Chochos CLet al., 2018, alpha,beta-Unsubstituted meso-positioning thienyl BODIPY: a promising electron deficient building block for the development of near infrared (NIR) p-type donor-acceptor (D-A) conjugated polymers, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 6, Pages: 4030-4040, ISSN: 2050-7526

JOURNAL ARTICLE

Taroni PJ, Santagiuliana G, Wan K, Calado P, Qiu M, Zhang H, Pugno NM, Palma M, Stingelin-Stutzman N, Heeney M, Fenwick O, Baxendale M, Bilotti Eet al., 2018, Toward Stretchable Self-Powered Sensors Based on the Thermoelectric Response of PEDOT:PSS/Polyurethane Blends, ADVANCED FUNCTIONAL MATERIALS, Vol: 28, ISSN: 1616-301X

JOURNAL ARTICLE

Wijeyasinghe N, Tsetseris L, Regoutz A, Sit W-Y, Fei Z, Du T, Wang X, McLachlan MA, Vourlias G, Patsalas PA, Payne DJ, Heeney M, Anthopoulos TDet al., 2018, Copper (I) Selenocyanate (CuSeCN) as a Novel Hole-Transport Layer for Transistors, Organic Solar Cells, and Light-Emitting Diodes, ADVANCED FUNCTIONAL MATERIALS, Vol: 28, ISSN: 1616-301X

JOURNAL ARTICLE

Datko B, Fei Z, Heeney M, Grey Jet al., 2018, Effect of conformational changes on triplet formation in a heavy heteroatom conjugated polymer: Single polymer molecules and molecular aggregates, 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

CONFERENCE PAPER

Charlton RJ, Fogarty RM, Bogatko S, Zuehlsdorff TJ, Hine NDM, Heeney M, Horsfield AP, Haynes PDet al., 2018, Implicit and explicit host effects on excitons in pentacene derivatives, JOURNAL OF CHEMICAL PHYSICS, Vol: 148, ISSN: 0021-9606

JOURNAL ARTICLE

Fei Z, Eisner FD, Jiao X, Azzouzi M, Rohr JA, Han Y, Shahid M, Chesman ASR, Easton CD, McNeill CR, Anthopoulos TD, Nelson J, Heeney Met al., 2018, An Alkylated Indacenodithieno[3,2-b]thiophene-Based Nonfullerene Acceptor with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies Greater than 13% with Low Voltage Losses, ADVANCED MATERIALS, Vol: 30, ISSN: 0935-9648

JOURNAL ARTICLE

Lu R, Han Y, Zhang W, Zhu X, Fei Z, Hodsden T, Anthopoulos TD, Heeney Met al., 2018, Alkylated indacenodithieno[3,2-b] thiophene-based all donor ladder-type conjugated polymers for organic thin film transistors, Journal of Materials Chemistry C, Vol: 6, Pages: 2004-2009, ISSN: 2050-7534

We report the synthesis of a series of indacenodithieno[3,2-b]thiophene (IDTT) based conjugated polymers by copolymerization with three different electron rich co-monomers [thiophene (T), thieno[3,2-b] thiophene (TT) and dithieno[3,2-b:2′,3′-d]thiophene (DTT)] under Stille coupling conditions. The resulting all-donor polymers show very good solubility in common solvents and exhibit similar optical, thermal and electronic properties. However, the performance of these semiconductors in thin film transistor devices varied and was highly dependent on the nature of the co-monomer. All polymers exhibited unipolar p-type charge transport behaviour, with the mobility values following the trend of IDTT-TT > IDTT-DTT > IDTT-T. The peak saturation mobility value of IDTT-TT was extracted to be 1.1 cm 2 V -1 s -1 , amongst the highest mobility for all-donor conjugated polymers reported to date.

JOURNAL ARTICLE

Panidi J, Paterson AF, Khim D, Fei Z, Han Y, Tsetseris L, Vourlias G, Patsalas PA, Heeney M, Anthopoulos TDet al., 2018, Remarkable Enhancement of the Hole Mobility in Several Organic Small-Molecules, Polymers, and Small-Molecule:Polymer Blend Transistors by Simple Admixing of the Lewis Acid p-Dopant B(C6F5)(3), ADVANCED SCIENCE, Vol: 5, ISSN: 2198-3844

JOURNAL ARTICLE

Datko BD, Thomas AK, Fei Z, Heeney M, Grey JKet al., 2017, Effect of a heavy heteroatom on triplet formation and interactions in single conjugated polymer molecules and aggregates, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 19, Pages: 28239-28248, ISSN: 1463-9076

JOURNAL ARTICLE

Wade J, Wood S, Collado-Fregoso E, Heeney M, Durrant J, Kim J-Set al., 2017, Impact of Fullerene Intercalation on Structural and Thermal Properties of Organic Photovoltaic Blends, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 121, Pages: 20976-20985, ISSN: 1932-7447

JOURNAL ARTICLE

Wijeyasinghe N, Regoutz A, Eisner F, Du T, Tsetseris L, Lin Y-H, Faber H, Pattanasattayavong P, Li J, Yan F, McLachlan MA, Payne DJ, Heeney M, Anthopoulos TDet al., 2017, Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers Processed from Aqueous Precursor Solutions and Their Application in Thin-Film Transistors and Highly Efficient Organic and Organometal Halide Perovskite Solar Cells, ADVANCED FUNCTIONAL MATERIALS, Vol: 27, ISSN: 1616-301X

JOURNAL ARTICLE

Green JP, Cryer SJ, Marafie J, White AJP, Heeney Met al., 2017, Synthesis of a Luminescent Arsolo[2,3-d:5,4-d']bis(thiazole) Building Block and Comparison to Its Phosphole Analogue, ORGANOMETALLICS, Vol: 36, Pages: 2632-2636, ISSN: 0276-7333

JOURNAL ARTICLE

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: limit=30&amp%3bid=00606985&amp%3brespub-action=search.html&amp%3bperson=true&amp%3bpage=5&respub-action=search.html&id=00606985&person=true