Imperial College London

ProfessorMartinHeeney

Faculty of Natural SciencesDepartment of Chemistry

Professor of Organic Materials
 
 
 
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Contact

 

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

 
 
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Location

 

401GMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Publication Type
Year
to

358 results found

Jacoutot P, Scaccabarozzi AD, Zhang T, Qiao Z, Anies F, Neophytou M, Bristow H, Kumar R, Moser M, Nega AD, Schiza A, Dimitrakopoulou-Strauss A, Gregoriou VG, Anthopoulos TD, Heeney M, McCulloch I, Bakulin AA, Chochos CL, Gasparini Net al., 2022, Infrared organic photodetectors employing ultralow bandgap polymer and non-fullerene acceptors for biometric monitoring, Small, Vol: 18, Pages: 1-10, ISSN: 1613-6810

Recent efforts in the field of organic photodetectors (OPD) have been focused on extending broadband detection into the near-infrared (NIR) region. Here, two blends of an ultralow bandgap push–pull polymer TQ-T combined with state-of-the-art non-fullerene acceptors, IEICO-4F and Y6, are compared to obtain OPDs for sensing in the NIR beyond 1100 nm, which is the cut off for benchmark Si photodiodes. It is observed that the TQ-T:IEICO-4F device has a superior IR responsivity (0.03 AW-1 at 1200 nm and −2 V bias) and can detect infrared light up to 1800 nm, while the TQ-T:Y6 blend shows a lower responsivity of 0.01 AW-1. Device physics analyses are tied with spectroscopic and morphological studies to link the superior performance of TQ-T:IEICO-4F OPD to its faster charge separation as well as more favorable donor–acceptor domains mixing. In the polymer blend with Y6, the formation of large agglomerates that exceed the exciton diffusion length, which leads to high charge recombination, is observed. An application of these devices as biometric sensors for real-time heart rate monitoring via photoplethysmography, utilizing infrared light, is demonstrated.

Journal article

Scaccabarozzi AD, Basu A, Anies F, Liu J, Zapata-Arteaga O, Warren R, Firdaus Y, Nugraha MI, Lin Y, Campoy-Quiles M, Koch N, Mueller C, Tsetseris L, Heeney M, Anthopoulos TDet al., 2022, Doping Approaches for Organic Semiconductors, CHEMICAL REVIEWS, Vol: 122, Pages: 4420-4492, ISSN: 0009-2665

Journal article

Azzouzi M, Nelson J, Eisner F, Gallop N, Yan J, Zheng X, Cha H, He Q, Fei Z, Heeney M, Bakulin Aet al., 2022, Reconciling models of interfacial state kinetics and device performance in organic solar cells: Impact of the energy offsets on the power conversion efficiency, Energy and Environmental Science, Vol: 15, Pages: 156-1270, ISSN: 1754-5692

Achieving the simultaneous increases in the open circuit voltage (Voc), short circuit current (Jsc) and fill factor (FF) necessary to further increase the power conversion efficiency (PCE) of organic photovoltaics (OPV) requires a unified understanding of how molecular and device parameters affect all three characteristics. In this contribution, we introduce a framework that for the first time combines different models that have been used separately to describe the different steps of the charge generation and collection processes in OPV devices: a semi-classical rate model for charge recombination processes in OPV devices, zero-dimensional kinetic models for the photogeneration process and exciton dissociation and one-dimensional semiconductor device models. Using this unified multi-scale model in conjunction with experimental techniques (time-resolved absorption spectroscopy, steady-state and transient optoelectronic measurements) that probe the various steps involved in charge generation we can shed light on how the energy offsets in a series of polymer: non-fullerene devices affect the charge carrier generation, collection, and recombination properties of the devices. We find that changing the energy levels of the donor significantly affects not only the transition rates between local-exciton (LE) and charge-transfer (CT) states, but also significantly changes the transition rates between CT and charge-separated (CS) states, challenging the commonly accepted picture of charge generation and recombination. These results show that in order to obtain an accurate picture of charge generation in OPV devices, a variety of different experimental techniques under different conditions in conjunction with a comprehensive model of processes occurring at different time-scales are required.

Journal article

Aniés F, Qiao Z, Nugraha MI, Basu A, Anthopoulos TD, Gasparini N, Heeney Met al., 2022, N-type polymer semiconductors incorporating para, meta, and ortho-carborane in the conjugated backbone, Polymer, Vol: 240, Pages: 124481-124481, ISSN: 0032-3861

We report on three novel n-type conjugated polymer semiconductors incorporating carborane in the polymer backbone and demonstrate their applicability in optoelectronic devices. Comparing the optoelectronic properties of para-, meta-, and ortho-carborane isomers revealed similar energetic characteristics between the different polymers, with the carborane unit acting as a “conjugation breaker”, confining electron delocalisation to the conjugated moieties. The fabrication of all-polymer organic photovoltaic (OPV) devices and thin-film transistors (TFTs) revealed some differences in device performance between the polymers, with the meta-carborane based polymer exhibiting superior performance in both OPV and TFT devices.

Journal article

Hernandez FJ, Fei Z, Osborne C, Crespo-Otero R, Heeney M, Dimitrov SD, Hernandez FJ, Fei Z, Osborne C, Crespo-Otero R, Heeney M, Dimitrov SDet al., 2022, Triplet Generation Dynamics in Si- and Ge-Bridged Conjugated Copolymers, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 126, Pages: 1036-1045, ISSN: 1932-7447

Journal article

Liang X, Chen Y, Jiao X, Heeney M, McNeill CR, Dong L, Zhou C, Liu Z, Tan L, Liang X, Chen Y, Jiao X, Heeney M, McNeill CR, Dong L, Zhou C, Liu Z, Tan Let al., 2022, Vinylene Flanked Naphtho[1,2-c:5,6-c ']bis[1,2,5]thiadiazole Polymer for Low-Crystallinity Ambipolar Transistors, MACROMOLECULES, Vol: 55, Pages: 331-337, ISSN: 0024-9297

Journal article

Kim Y, Kim G, Ding B, Jeong D, Lee I, Park S, Kim BJ, McCulloch I, Heeney M, Yoon M-Het al., 2022, High-current-density organic electrochemical diodes enabled by asymmetric active layer design, Advanced Materials, ISSN: 0935-9648

Owing to their outstanding electrical/electrochemical performance, operational stability, mechanical flexibility, and decent biocompatibility, organic mixed ionic–electronic conductors have shown great potential as implantable electrodes for neural recording/stimulation and as active channels for signal switching/amplifying transistors. Nonetheless, no studies exist on a general design rule for high-performance electrochemical diodes, which are essential for highly functional circuit architectures. In this work, generalizable electrochemical diodes with a very high current density over 30 kA cm−2 are designed by introducing an asymmetric active layer based on organic mixed ionic–electronic conductors. The underlying mechanism on polarity-sensitive balanced ionic doping/dedoping is elucidated by numerical device analysis and in operando spectroelectrochemical potential mapping, while the general material requirements for electrochemical diode operation are deduced using various types of conjugated polymers. In parallel, analog signal rectification and digital logic processing circuits are successfully demonstrated to show the broad impact of circuits incorporating organic electrochemical diodes. It is expected that organic electrochemical diodes will play vital roles in realizing multifunctional soft bioelectronic circuitry in combination with organic electrochemical transistors.

Journal article

Loganathan K, Scaccabarozzi AD, Faber H, Ferrari F, Bizak Z, Yengel E, Naphade DR, Gedda M, He Q, Solomeshch O, Adilbekova B, Yarali E, Tsetseris L, Salama KN, Heeney M, Tessler N, Anthopoulos TDet al., 2022, 14 GHz schottky diodes using a p-doped organic polymer., Advanced Materials, Pages: e2108524-e2108524, ISSN: 0935-9648

The low carrier mobility of organic semiconductors and the high parasitic resistance and capacitance often encountered in conventional organic Schottky diodes, hinder their deployment in emerging radio frequency (RF) electronics. Here we overcome these limitations by combining self-aligned asymmetric nanogap electrodes (∼25 nm) produced by adhesion-lithography, with a high mobility organic semiconductor and demonstrate RF Schottky diodes able to operate in the 5G frequency spectrum. We used C16 IDT-BT, as the high hole mobility polymer, and studied the impact of p-doping on the diode performance. Pristine C16 IDT-BT-based diodes exhibit maximum intrinsic and extrinsic cutoff frequencies (fC ) of >100 and 6 GHz, respectively. This extraordinary performance is attributed primarily to the planar nature of the nanogap channel and the diode's small junction capacitance (< 2 pF). Doping of C16 IDT-BT with the molecular p-dopant C60 F48 , improves the diode's performance further by reducing the series resistance resulting to intrinsic and extrinsic fC of >100 and ∼14 GHz respectively, while the DC output voltage of a RF rectifier circuit increases by a tenfold. Our work highlights the importance of the planar nanogap architecture and paves the way for the use of organic Schottky diodes in large-area radio frequency electronics of the future. This article is protected by copyright. All rights reserved.

Journal article

Kafourou P, Nugraha MI, Nikitaras A, Tan L, Firdaus Y, Aniés F, Eisner F, Ding B, Wenzel J, Holicky M, Tsetseris L, Anthopoulos TD, Heeney Met al., 2021, Near-IR absorbing molecular semiconductors incorporating cyanated benzothiadiazole acceptors for high performance semi-transparent n-type organic field-effect transistors, ACS Materials Letters, Vol: 4, Pages: 165-174, ISSN: 2639-4979

Small band gap molecular semiconductors are of interest for the development of transparent electronics. Here we report two near-infrared (NIR), n-type small molecule semiconductors, based upon an acceptor-donor-acceptor (A-D-A) approach. We show that the inclusion of molecular spacers between the strong electron accepting end group, 2,1,3-benzothiadiazole-4,5,6-tricarbonitrile, and the donor core affords semiconductors with very low band gaps down to 1 eV. Both materials were synthesised by a one-pot, sixfold nucleophilic displacement of a fluorinated precursor by cyanide. Significant differences in solid-state ordering and charge carrier mobility are observed depending on the nature of the spacer, with a thiophene spacer resulting in solution processed organic field-effect transistors (OFETs) exhibiting excellent electron mobility up to 1.1 cm2 V-1s-1. The use of silver nanowires as the gate electrodes enables the fabrication of semi-transparent OFET device with average visible transmission of 71% in the optical spectrum.

Journal article

Allen JDW, Adlem K, Heeney M, 2021, The synthesis and application of novel benzodithiophene based reactive mesogens with negative wavelength dispersion birefringence, Journal of Materials Chemistry C, Vol: 9, Pages: 17419-17426, ISSN: 2050-7526

Optical corrective retardation films are widely used in the display industry to compensate for a variety of imperfections such as off-axis contrast reduction, grey-scale inversion and colour shifts in LCDs and backplane reflections in OLEDs. A wide variety of these films have been produced by multiple methods, however, obtaining ideal wavelength dispersion remains difficult and costly to achieve in thin, single-layer systems. In this work, we report the synthesis of a novel series of reactive mesogen materials designed to exhibit negative wavelength dispersion birefringence. This series of photopolymerisable materials based on a benzodithiophene core exhibiting either an ‘X’-shaped or ‘T’-shaped geometry were synthesised. Their negative wavelength dispersion birefringence properties were investigated in aligned films prepared from photo-polymerised reactive mesogen host mixtures. The nature of the substituents on the BDT core was found to have a significant impact on performance, and materials with an X-shaped geometry were found to exhibit much higher performance than those with a T-shape.

Journal article

Lin Y-H, Han Y, Sharma A, AlGhamdi WS, Liu C-H, Chang T-H, Xiao X-W, Lin W-Z, Lu P-Y, Seitkhan A, Mottram AD, Pattanasattayavong P, Faber H, Heeney M, Anthopoulos TDet al., 2021, A tri-channel oxide transistor concept for the rapid detection of biomolecules including the SARS-CoV-2 spike protein, Advanced Materials, Pages: 1-14, ISSN: 0935-9648

Solid-state transistor sensors that can detect biomolecules in real time are highly attractive for emerging bioanalytical applications. However, combining upscalable manufacturing with the required performance remains challenging. Here, an alternative biosensor transistor concept is developed, which relies on a solution-processed In2O3/ZnO semiconducting heterojunction featuring a geometrically engineered tri-channel architecture for the rapid, real-time detection of important biomolecules. The sensor combines a high electron mobility channel, attributed to the electronic properties of the In2O3/ZnO heterointerface, in close proximity to a sensing surface featuring tethered analyte receptors. The unusual tri-channel design enables strong coupling between the buried electron channel and electrostatic perturbations occurring during receptor–analyte interactions allowing for robust, real-time detection of biomolecules down to attomolar (am) concentrations. The experimental findings are corroborated by extensive device simulations, highlighting the unique advantages of the heterojunction tri-channel design. By functionalizing the surface of the geometrically engineered channel with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody receptors, real-time detection of the SARS-CoV-2 spike S1 protein down to am concentrations is demonstrated in under 2 min in physiological relevant conditions.

Journal article

Pletzer M, Plasser F, Rimmele M, Heeney M, Glöcklhofer Fet al., 2021, [2.2.2.2]Paracyclophanetetraenes (PCTs): cyclic structural analogues of poly(p‑phenylene vinylene)s (PPVs), Open Research Europe, Vol: 1, Pages: 1-12, ISSN: 2732-5121

Background: Poly(p-phenylene vinylene)s (PPVs) and [2.2.2.2]paracyclophanetetraene (PCT) are both composed of alternating π-conjugated para-phenylene and vinylene units. However, while the former constitute a class of π-conjugated polymers that has been used in organic electronics for decades, the latter is a macrocycle that only recently revealed its potential for applications such as organic battery electrodes. The cyclic structure endows PCT with unusual properties, and further tuning of these may be required for specific applications. Methods: In this article, we adopt an approach often used for tuning the properties of PPVs, the introduction of alkoxy (or alkylthio) substituents at the phenylene units, for tuning the optoelectronic properties of PCT. The resulting methoxy- and methylthio-substituted PCTs, obtained by Wittig cyclisation reactions, are studied by UV-vis absorption, photoluminescence, and cyclic voltammetry measurements, and investigated computationally using the visualisation of chemical shielding tensors (VIST) method. Results: The measurements show that substitution leads to slight changes in terms of absorption/emission energies and redox potentials while having a pronounced effect on the photoluminescence intensity. The computations show the effect of the substituents on the ring currents and chemical shielding and on the associated local and global (anti)aromaticity of the macrocycles, highlighting the interplay of local and global aromaticity in various electronic states. Conclusions: The study offers interesting insights into the tuneability of the properties of this versatile class of π-conjugated macrocycles.

Journal article

Allen TG, Kafourou P, Larson BW, Heeney M, Reid OG, Rumbles Get al., 2021, Reconciling the Driving Force and the Barrier to Charge Separation in Donor-Nonfullerene Acceptor Films, ACS ENERGY LETTERS, Vol: 6, Pages: 3572-3581, ISSN: 2380-8195

Journal article

Huang Y, Lukito Tjhe DH, Jacobs IE, Jiao X, He Q, Statz M, Ren X, Huang X, McCulloch I, Heeney M, McNeill C, Sirringhaus Het al., 2021, Design of experiment optimization of aligned polymer thermoelectrics doped by ion-exchange, APPLIED PHYSICS LETTERS, Vol: 119, ISSN: 0003-6951

Journal article

Ding B, Kim G, Kim Y, Eisner FD, GutiérrezFernández E, Martín J, Yoon M, Heeney Met al., 2021, Influence of backbone curvature on the organic electrochemical transistor performance of glycolated donor–acceptor conjugated polymers, Angewandte Chemie, Vol: 133, Pages: 19831-19836, ISSN: 0044-8249

Two new glycolated semiconducting polymers PgBT(F)2gT and PgBT(F)2gTT of differing backbone curvatures were designed and synthesised for application as p-type accumulation mode organic electrochemical transistor (OECT) materials. Both polymers demonstrated stable and reversible oxidation, accessible within the aqueous electrochemical window, to generate polaronic charge carriers. OECTs fabricated from PgBT(F)2gT featuring a curved backbone geometry attained a higher volumetric capacitance of 170 F cm−3. However, PgBT(F)2gTT with a linear backbone displayed overall superior OECT performance with a normalised peak transconductance of 3.00×104 mS cm−1, owing to its enhanced order, expediting the charge mobility to 0.931 cm2 V−1 s−1.

Journal article

Dey S, Attar S, Manley EF, Moncho S, Brothers EN, Bazzi HS, Bronstein H, Marks TJ, Heeney M, Schroeder BC, Al-Hashimi Met al., 2021, Transition-Metal-Free Homopolymerization of Pyrrolo[2,3-d:5,4-d']bisthiazoles via Nucleophilic Aromatic Substitution, ACS APPLIED MATERIALS & INTERFACES, Vol: 13, Pages: 41094-41101, ISSN: 1944-8244

Journal article

Brabec CJ, Heeney M, Kim Y, Luscombe CKet al., 2021, Preface to the Special Issue of ChemSusChem on Advanced Organic Solar Cells, CHEMSUSCHEM, Vol: 14, Pages: 3426-3427, ISSN: 1864-5631

Journal article

Ding B, Kim G, Kim Y, Eisner FD, Gutierrez-Fernandez E, Martin J, Yoon M-H, Heeney Met al., 2021, Influence of backbone curvature on the organic electrochemical transistor performance of glycolated donor-acceptor conjugated polymers, Angewandte Chemie International Edition, Vol: 60, Pages: 19679-19684, ISSN: 1433-7851

Two new glycolated semiconducting polymers PgBT(F)2gT and PgBT(F)2gTT of differing backbone curvatures were designed and synthesised for application as p-type accumulation mode organic electrochemical transistor (OECT) materials. Both polymers demonstrated stable and reversible oxidation, accessible within the aqueous electrochemical window, to generate polaronic charge carriers. OECTs fabricated from PgBT(F)2gT featuring a curved backbone geometry attained a higher volumetric capacitance of 170 F cm−3. However, PgBT(F)2gTT with a linear backbone displayed overall superior OECT performance with a normalised peak transconductance of 3.00×104 mS cm−1, owing to its enhanced order, expediting the charge mobility to 0.931 cm2 V−1 s−1.

Journal article

Rimmele M, Nogala W, Seif-Eddine M, Roessler M, Heeney M, Plasser F, Glöcklhofer Fet al., 2021, Functional group introduction and aromatic unit variation in a set of π‑conjugated macrocycles: revealing the central role of local and global aromaticity, Organic Chemistry Frontiers, Vol: 8, Pages: 4730-4745, ISSN: 2052-4110

π-Conjugated macrocycles are molecules with unique properties that are increasingly exploited for applications and the question of whether they can sustain global aromatic or antiaromatic ring currents is particularly intriguing. However, there are only a small number of experimental studies that investigate how the properties of π‑conjugated macrocycles evolve with systematic structural changes. Here, we present such a systematic experimental study of a set of [2.2.2.2]cyclophanetetraenes, all with formally Hückel antiaromatic ground states, and combine it with an in-depth computational analysis. The study reveals the central role of local and global aromaticity for rationalizing the observed optoelectronic properties, ranging from extremely large Stokes shifts of up to 1.6 eV to reversible fourfold reduction, a highly useful feature for charge storage/accumulation applications. A recently developed method for the visualization of chemical shielding tensors (VIST) is applied to provide unique insight into local and global ring currents occurring in different planes along the macrocycle. Conformational changes as a result of the structural variations can further explain some of the observations. The study contributes to the development of structure–property relationships and molecular design guidelines and will help to understand, rationalize, and predict the properties of other π‑conjugated macrocycles.

Journal article

Rimmele M, Nogala W, Seif-Eddine M, Roessler MM, Heeney M, Plasser F, Glöcklhofer Fet al., 2021, Functional Group Introduction and Aromatic Unit Variation in a Set of π-Conjugated Macrocycles: Revealing the Central Role of Local and Global Aromaticity, Publisher: American Chemical Society (ACS)

<jats:p>π-Conjugated macrocycles are molecules with unique properties that are increasingly exploited for applications and the question of whether they can sustain global aromatic or antiaromatic ring currents is particularly intriguing. However, there are only a small number of experimental studies that investigate how the properties of π-conjugated macrocycles evolve with systematic structural changes. Here, we present such a systematic experimental study of a set of [2.2.2.2]cyclophanetetraenes, all with formally Hückel antiaromatic ground states, and combine it with an in-depth computational analysis. The study reveals the central role of local and global aromaticity for rationalizing the observed optoelectronic properties, ranging from extremely large Stokes shifts of up to 1.6 eV to reversible fourfold reduction, a highly useful feature for charge storage/accumulation applications. A recently developed method for the visualization of chemical shielding tensors (VIST) is applied to provide unique insight into local and global ring currents occurring in different planes along the macrocycle. Conformational changes as a result of the structural variations can further explain some of the observations. The study contributes to the development of structure–property relationships and molecular design guidelines and will help to understand, rationalize, and predict the properties of other π-conjugated macrocycles.</jats:p>

Working paper

Yoo D-J, Heeney M, Glocklhofer F, Choi JWet al., 2021, Tetradiketone macrocycle for divalent aluminium ion batteries, Nature Communications, Vol: 12, Pages: 1-9, ISSN: 2041-1723

Contrary to early motivation, the majority of aluminium ion batteries developed to date do not utilise multivalent ion storage; rather, these batteries rely on monovalent complex ions for their main redox reaction. This limitation is somewhat frustrating because the innate advantages of metallic aluminium such as its low cost and high air stability cannot be fully taken advantage of. Here, we report a tetradiketone macrocycle as an aluminium ion battery cathode material that reversibly reacts with divalent (AlCl2+) ions and consequently achieves a high specific capacity of 350 mAh g−1 along with a lifetime of 8000 cycles. The preferred storage of divalent ions over their competing monovalent counterparts can be explained by the relatively unstable discharge state when using monovalent AlCl2+ ions, which exert a moderate resonance effect to stabilise the structure. This study opens an avenue to realise truly multivalent aluminium ion batteries based on organic active materials, by tuning the relative stability of discharged states with carrier ions of different valence states.

Journal article

Adamczak D, Perinot A, Komber H, Illy A, Hultmark S, Passarella B, Tan WL, Hutsch S, Becker-Koch D, Rapley C, Scaccabarozzi AD, Heeney M, Vaynzof Y, Ortmann F, McNeill CR, Mueller C, Caironi M, Sommer Met al., 2021, Influence of synthetic pathway, molecular weight and side chains on properties of indacenodithiophene-benzothiadiazole copolymers made by direct arylation polycondensation, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 9, Pages: 4597-4606, ISSN: 2050-7526

Journal article

Paterson AF, Li R, Markina A, Tsetseris L, MacPhee S, Faber H, Emwas A-H, Panidi J, Bristow H, Wadsworth A, Baran D, Andrienko D, Heeney M, McCulloch I, Anthopoulos TDet al., 2021, N-Doping improves charge transport and morphology in the organic non-fullerene acceptor O-IDTBR, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 9, Pages: 4486-4495, ISSN: 2050-7526

Journal article

Heeney M, Kafourou P, Park B, Luke J, Luxi T, Panidi J, Glöcklhofer F, Kim J, Anthopoulos TD, Kim J-S, Lee K, Kwon Set al., 2021, One-step six-fold cyanation of benzothiadiazole acceptor Units for air-stable high-performance n-type organic field-effect transistors, Angewandte Chemie International Edition, Vol: 60, Pages: 5970-5977, ISSN: 1433-7851

We report a new high electron affinity acceptor end group for organic semiconductors, 2,1,3-benzothiadiazole-4,5,6-tricarbonitrile (TCNBT). An n-type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a six-fold nucleophilic substitution with cyanides on a fluorinated precursor, itself prepared by a direct arylation approach. This one-step chemical modification was found to significantly impact the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n-type semiconductor. The highly electron-deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n-type organic field-effect transistors (OFETs). Solution-processed OFETs based on TCNBT IDT exhibited a charge carrier mobility of up to µ e ≈ 0.15 cm 2 V -1 s -1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.

Journal article

Kafourou P, Park B, Luke J, Tan L, Panidi J, Glöcklhofer F, Kim J, Anthopoulos TD, Kim J, Lee K, Kwon S, Heeney Met al., 2021, One‐step sixfold cyanation of benzothiadiazole acceptor units for air‐stable high‐performance n‐type organic field‐effect transistors, Angewandte Chemie, Vol: 133, Pages: 6035-6042, ISSN: 0044-8249

Reported here is a new high electron affinity acceptor end group for organic semiconductors, 2,1,3‐benzothiadiazole‐4,5,6‐tricarbonitrile (TCNBT). An n‐type organic semiconductor with an indacenodithiophene (IDT) core and TCNBT end groups was synthesized by a sixfold nucleophilic substitution with cyanide on a fluorinated precursor, itself prepared by a direct arylation approach. This one‐step chemical modification significantly impacted the molecular properties: the fluorinated precursor, TFBT IDT, a poor ambipolar semiconductor, was converted into TCNBT IDT, a good n‐type semiconductor. The electron‐deficient end group TCNBT dramatically decreased the energy of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO) compared to the fluorinated analogue and improved the molecular orientation when utilized in n‐type organic field‐effect transistors (OFETs). Solution‐processed OFETs based on TCNBT IDT exhibited a charge‐carrier mobility of up to μe≈0.15 cm2 V−1 s−1 with excellent ambient stability for 100 hours, highlighting the benefits of the cyanated end group and the synthetic approach.

Journal article

Hodsden T, Thorley KJ, Basu A, White AJP, Wang C, Mitchell W, Glocklhofer F, Anthopoulos TD, Heeney Met al., 2021, The influence of alkyl group regiochemistry and backbone fluorination on the packing and transistor performance of N-cyanoimine functionalised indacenodithiophenes, Materials Advances, Vol: 2, Pages: 1706-1714

The synthesis of two novel n-type molecular organic semiconductors based on a fluorinated indacenodithiophene core in combination with an electron withdrawing N-cyanoimine group is reported, and the influence of the regiochemistry of the solubilizing sidechain is investigated. The N-cyanoimine is confirmed to be a strongly electron accepting group, which in combination with the core fluorination resulted in high electron affinities for both materials. Single crystal analysis demonstrated that whilst both materials arrange in ordered slipped stacks with close π–π stacking distances (∼3.40 Å), significant differences in electron transfer integrals for the two regioisomers were observed, relating to differences in relative molecular displacement along the π-stacking direction. Organic thin-film transistors fabricated via blade-coating displayed electron mobility up to 0.13 cm2 V−1 s−1 for the isomer with the larger transfer integral.

Journal article

Rodriguez-Martinez X, Pascual-San-Jose E, Fei Z, Heeney M, Guimera R, Campoy-Quiles Met al., 2021, Predicting the photocurrent-composition dependence in organic solar cells, ENERGY & ENVIRONMENTAL SCIENCE, Vol: 14, Pages: 986-994, ISSN: 1754-5692

Journal article

Marsh AV, Little M, Cheetham NJ, Dyson MJ, Bidwell M, White AJP, Warriner CN, Swain AC, McCulloch I, Stavrinou PN, Heeney Met al., 2020, Highly Deformed o-Carborane Functionalised Non-linear Polycyclic Aromatics with Exceptionally Long C-C Bonds, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 27, Pages: 1970-1975, ISSN: 0947-6539

Journal article

Lin Y, Nugraha MI, Firdaus Y, Scaccabarozzi AD, Anies F, Emwas A-H, Yengel E, Zheng X, Liu J, Wahyudi W, Yarali E, Faber H, Bakr OM, Tsetseris L, Heeney M, Anthopoulos TDet al., 2020, A Simple n-Dopant Derived from Diquat Boosts the Efficiency of Organic Solar Cells to 18.3%, ACS ENERGY LETTERS, Vol: 5, Pages: 3663-3671, ISSN: 2380-8195

Journal article

Basu A, Niazi MR, Scaccabarozzi AD, Faber H, Fei Z, Anjum DH, Paterson AF, Boltalina O, Heeney M, Anthopoulos TDet al., 2020, Impact of p-type doping on charge transport in blade-coated small-molecule:polymer blend transistors, JOURNAL OF MATERIALS CHEMISTRY C, Vol: 8, Pages: 15368-15376, ISSN: 2050-7526

Journal article

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