Imperial College London

ProfessorThomasAnthopoulos

Faculty of Natural SciencesDepartment of Physics

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 7594 6669thomas.anthopoulos Website

 
 
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Assistant

 

Mrs Carolyn Dale +44 (0)20 7594 7579

 
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Location

 

1111Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

380 results found

Choi HH, Paterson AF, Fusella MA, Panidi J, Solomeshch O, Tessler N, Heeney M, Cho K, Anthopoulos TD, Rand BP, Podzorov Vet al., 2019, Hall Effect in Polycrystalline Organic Semiconductors: The Effect of Grain Boundaries, ADVANCED FUNCTIONAL MATERIALS, ISSN: 1616-301X

Journal article

Tang M-C, Barrit D, Munir R, Li R, Barbe JM, Smilgies D-M, Del Gobbo S, Anthopoulos TD, Amassian Aet al., 2019, Bismuth-Based Perovskite-Inspired Solar Cells: In Situ Diagnostics Reveal Similarities and Differences in the Film Formation of Bismuth- and Lead-Based Films, SOLAR RRL, Vol: 3, ISSN: 2367-198X

Journal article

Chaudhry MU, Wang N, Tetzner K, Seitkhan A, Miao Y, Sun Y, Petty MC, Anthopoulos TD, Wang J, Bradley DDCet al., 2019, Light-Emitting Transistors Based on Solution-Processed Heterostructures of Self-Organized Multiple-Quantum-Well Perovskite and Metal-Oxide Semiconductors, ADVANCED ELECTRONIC MATERIALS, Vol: 5, ISSN: 2199-160X

Journal article

Twyman N, Tetzner K, Anthopoulos T, Payne D, Regoutz Aet al., 2019, Rapid photonic curing of solution-processed In2O3 layers on flexible substrates, Applied Surface Science, Vol: 479, Pages: 974-979, ISSN: 0169-4332

In2O3 is one of the most important semiconducting metal oxides primarily because of its wide band gap, high electron mobility and processing versatility. To this end, high-quality thin films of In2O3 can be prepared using scalable and inexpensive solution-based deposition methods, hence making it attractive for application in a number of emerging electronic applications. However, traditional solution processing often requires high temperature and lengthy annealing steps, making it impossible to use in combination with temperature-sensitive plastic substrates, which would be desired for numerous emerging flexible device applications. Here, rapid photonic curing of In2O3 layers is explored as an alternative to thermal annealing. Oxide thin films are successfully prepared on a range of substrates, including glass, polyimide, and polyethylene naphthalate. The effect of substrate and post-processing treatment on the morphology, surface chemistry, and electronic properties is investigated by atomic force microscopy and X-ray photoelectron spectroscopy. Systematic trends are identified, particularly in the degree of conversion of the precursor and its influence on the electronic structure.

Journal article

He Q, Shahid M, Panidi J, Marsh AV, Huang W, Daboczi M, Kim J-S, Fei Z, Anthopoulos TD, Heeney Met al., 2019, A versatile star-shaped organic semiconductor based on benzodithiophene and diketopyrrolopyrrole, Journal of Materials Chemistry C, Vol: 7, Pages: 6622-6629, ISSN: 2050-7526

We report the synthesis of a new star-shaped π-conjugated oligomer, BDT(DPP)4, containing a benzodithiophene core and four diketopyrrolopyrrole arms. The thermal, electrochemical and optical properties are characterized and the results complemented by computational studies. The utility of the molecule is demonstrated in both solar cell and field-effect transistor devices. In the former, BDT(DPP)4 displays low efficiency when used as an acceptor in blends with poly(3-hexylthiophene) but exhibits promising performance as a donor, in blends with either a fullerene or a non-fullerene acceptor. In field-effect transistors BDT(DPP)4 exhibits typical p-type transistor behavior, which is in accordance with its better donor performance in solar cell devices.

Journal article

Wang K, Neophytou M, Aydin E, Wang M, Laurent T, Harrison GT, Liu J, Liu W, De Bastiani M, Khan JI, Anthopoulos TD, Laquai F, De Wolf Set al., 2019, Triarylphosphine Oxide as Cathode Interfacial Material for Inverted Perovskite Solar Cells, ADVANCED MATERIALS INTERFACES, Vol: 6, ISSN: 2196-7350

Journal article

Paterson AF, Tsetseris L, Li R, Basu A, Faber H, Emwas A-H, Panidi J, Fei Z, Niazi MR, Anjum DH, Heeney M, Anthopoulos TDet al., 2019, Addition of the lewis acid Zn(C6 F5 )2 enables organic transistors with a maximum hole mobility in excess of 20 cm2 V-1 s-1, Advanced Materials, Vol: 31, ISSN: 0935-9648

Incorporating the molecular organic Lewis acid tris(pentafluorophenyl)borane [B(C6 F5 )3 ] into organic semiconductors has shown remarkable promise in recent years for controlling the operating characteristics and performance of various opto/electronic devices, including, light-emitting diodes, solar cells, and organic thin-film transistors (OTFTs). Despite the demonstrated potential, however, to date most of the work has been limited to B(C6 F5 )3 with the latter serving as the prototypical air-stable molecular Lewis acid system. Herein, the use of bis(pentafluorophenyl)zinc [Zn(C6 F5 )2 ] is reported as an alternative Lewis acid additive in high-hole-mobility OTFTs based on small-molecule:polymer blends comprising 2,7-dioctyl[1]benzothieno [3,2-b][1]benzothiophene and indacenodithiophene-benzothiadiazole. Systematic analysis of the materials and device characteristics supports the hypothesis that Zn(C6 F5 )2 acts simultaneously as a p-dopant and a microstructure modifier. It is proposed that it is the combination of these synergistic effects that leads to OTFTs with a maximum hole mobility value of 21.5 cm2 V-1 s-1 . The work not only highlights Zn(C6 F5 )2 as a promising new additive for next-generation optoelectronic devices, but also opens up new avenues in the search for high-mobility organic semiconductors.

Journal article

Firdaus Y, Le Corre VM, Khan JI, Kan Z, Laquai F, Beaujuge PM, Anthopoulos TDet al., 2019, Key Parameters Requirements for Non-Fullerene-Based Organic Solar Cells with Power Conversion Efficiency > 20%, ADVANCED SCIENCE, Vol: 6, ISSN: 2198-3844

Journal article

Sun G, Shahid M, Fei Z, Xu S, Eisner FD, Anthopoulos 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 (vol 3, pg 450, 2019), MATERIALS CHEMISTRY FRONTIERS, Vol: 3, Pages: 955-955

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, Vol: 5, ISSN: 2199-160X

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

Petromichelaki E, Gagaoudakis E, Moschovis K, Tsetseris L, Anthopoulos TD, Kiriakidis G, Binas Vet al., 2019, Highly sensitive and room temperature detection of ultra-low concentrations of O-3 using self-powered sensing elements of Cu2O nanocubes, NANOSCALE ADVANCES, Vol: 1, Pages: 2009-2017, ISSN: 2516-0230

Journal article

Eisner F, Azzouzi M, Fei Z, Hou X, Anthopoulos T, Dennis TJ, Heeney M, Nelson Jet al., 2019, Hybridization of local exciton and charge-transfer states reduces non-radiative voltage losses in organic solar cells, Journal of the American Chemical Society, Vol: 141, Pages: 6362-6374, ISSN: 1520-5126

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

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

Chen M, Yengel E, Zhang J, Zhu C, He X, Zhang C, Huang J-K, Hedhili MN, Anthopoulos T, Zhang Xet al., 2019, One-step growth of reduced graphene oxide on arbitrary substrates, CARBON, Vol: 144, Pages: 457-463, ISSN: 0008-6223

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, ISSN: 2052-1537

We report the optimisation of a semi-transparent solar cell based on a blend of a recently reported high performance donor polymer (PFBDB-T) with a non-fullerene acceptor derivative (C8-ITIC). The performance is shown to strongly depend on the nature of the semi-transparent electrode, and we report the optimal fabrication conditions for a multilayer MoO3/Ag/MoO3 electrode. The effect of deposition rate and layer thickness of both the Ag and the outer MoO3 on transparency and sheet resistance is investigated, and is shown to have a significant impact on the overall device performance. The optimised PFBDB-T:C8-ITIC based devices exhibit an average power conversion efficiency (PCE) of 9.2% with an average visible transmittance (AVT) of 22%.

Journal article

Karuthedath S, Gorenflot J, Firdaus Y, Sit W-Y, Eisner F, Seitkhan A, Ravva MK, Anthopoulos TD, Laquai Fet al., 2019, Charge and Triplet Exciton Generation in Neat PC70BM Films and Hybrid CuSCN:PC70BM Solar Cells, ADVANCED ENERGY MATERIALS, Vol: 9, ISSN: 1614-6832

Journal article

Costa JC, Pouryazdan A, Panidi J, Spina F, Anthopoulos TD, Liedke MO, Schneider C, Wagner A, Munzenrieder Net al., 2019, Flexible IGZO TFTs and Their Suitability for Space Applications, IEEE JOURNAL OF THE ELECTRON DEVICES SOCIETY, Vol: 7, Pages: 1182-1190, ISSN: 2168-6734

Journal article

Cheng F, Verrelli E, Alharthi FA, Kelly SM, O'Neill M, Kemp NT, Kitney SP, Lai KT, Mehl GH, Anthopoulos Tet al., 2019, Lyotropic 'hairy' TiO2 nanorods, NANOSCALE ADVANCES, Vol: 1, Pages: 254-264, ISSN: 2516-0230

Journal article

Paterson AF, Anthopoulos TD, 2018, Enabling thin-film transistor technologies and the device metrics that matter, Nature Communications, Vol: 9, ISSN: 2041-1723

The field-effect transistor kickstarted the digital revolution that propelled our society into the information age. One member of the now large family of field-effect devices is the thin-film transistor (TFT), best known for its enabling role in modern flat-panel displays. TFTs can be used in all sorts of innovative applications because of the broad variety of materials they can be made from, which give them diverse electrical and mechanical characteristics. To successfully utilize TFT technologies in a variety of rapidly emerging applications, such as flexible, stretchable and transparent large-area microelectronics, there are a number of metrics that matter.

Journal article

Han Y, Fei Z, Lin YH, Martin J, Tuna F, Anthopoulos TD, Heeney Met al., 2018, Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors, npj Flexible Electronics, Vol: 2

© 2018, The Author(s). Molecular doping is an important strategy to improve the charge transport properties of organic semiconductors in various electronic devices. Compared to p-type dopants, the development of n-type dopants is especially challenging due to poor dopant stability against atmospheric conditions. In this article, we report the n-doping of the milestone naphthalenediimide-based conjugated polymer P(NDI2OD-T2) in organic thin film transistor devices by soluble anion dopants. The addition of the dopants resulted in the formation of stable radical anions in thin films, as confirmed by EPR spectroscopy. By tuning the dopant concentration via simple solution mixing, the transistor parameters could be readily controlled. Hence the contact resistance between the electrodes and the semiconducting polymer could be significantly reduced, which resulted in the transistor behaviour approaching the desirable gate voltage-independent model. Reduced hysteresis was also observed, thanks to the trap filling by the dopant. Under optimal doping concentrations the channel on-current was increased several fold whilst the on/off ratio was simultaneously increased by around one order of magnitude. Hence doping with soluble organic salts appears to be a promising route to improve the charge transport properties of n-type organic semiconductors.

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

Boufflet P, Bovo G, Occhi L, Fei Z, Han Y, Anthopoulos T, Yuan H, Heeney MJet al., 2018, The influence of backbone fluorination on the dielectric constant of conjugated polythiophenes, Advanced Electronic Materials, Vol: 4, ISSN: 2199-160X

The ability to modify or enhance the dielectric constant of semiconducting polymers can prove valuable for a range of optoelectronic and microelectronic applications. In the case of organic photovoltaics, increasing the dielectric constant of the active layer has often been suggested as a method to control charge generation, recombination dynamics, and ultimately, the power conversion efficiencies. In this contribution, the impact that the degree and pattern of fluorination has on the dielectric constant of poly(3-octylthiophene) (P3OT), a more soluble analogue of the widely studied conjugated material poly(3-hexylthiophene), is explored. P3OT and its backbone-fluorinated analogue, F-P3OT, are compared along with a block and alternating copolymer version of these materials. It is found that the dielectric constant of the polymer thin films increases as the degree of backbone fluorination increases, in a trend consistent with density functional theory calculations of the dipole moment.

Journal article

Xu Y, Ji D, Song H, Zhang N, Hu Y, Anthopoulos TD, Di Fabrizio EM, Xiao S, Gan Qet al., 2018, Light-Matter Interaction within Extreme Dimensions: From Nanomanufacturing to Applications, ADVANCED OPTICAL MATERIALS, Vol: 6, ISSN: 2195-1071

Journal article

Wyatt-Moon G, Georgiadou DG, Zoladek-Lemanczyk A, Castro FA, Anthopoulos TDet al., 2018, Flexible nanogap polymer light-emitting diodes fabricated via adhesion lithography (a-Lith), Journal of Physics: Materials, Vol: 1, ISSN: 2515-7639

We report the development of coplanar green colour organic light-emitting diodes (OLEDs) based on asymmetric nanogap electrodes fabricated on different substrates including glass and plastic. Using adhesion lithography (a-Lith) we pattern Al and Au layers acting as the cathode and anode electrodes, respectively, separated by an inter-electrode distance of <15 nm with an aspect ratio of up to 106. Spin-coating the organic light-emitting polymer poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) on top of the asymmetric Al–Au nanogap electrodes results in green light-emitting nanogap OLEDs with promising operating characteristics. We show that the scaling of the OLED's width from 4 to 200 mm can substantially improve the light output of the device without any adverse effects on the manufacturing yield. Furthermore, it is found that the light-emitting properties in the nanogap area differ from the bulk organic film, an effect attributed to confinement of the conjugated polymer chains in the nanogap channel. These results render a-Lith particularly attractive for low cost facile fabrication of nanoscale light-emitting sources and arrays on different substrates of arbitrary size.

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

Over the past three decades, significant research efforts have focused on improving the charge carrier mobility of organic thin‐film transistors (OTFTs). In recent years, a commonly observed nonlinearity in OTFT current–voltage characteristics, known as the “kink” or “double slope,” has led to widespread mobility overestimations, contaminating the relevant literature. Here, published data from the past 30 years is reviewed to uncover the extent of the field‐effect mobility hype and identify the progress that has actually been achieved in the field of OTFTs. Present carrier‐mobility‐related challenges are identified, finding that reliable hole and electron mobility values of 20 and 10 cm2 V−1 s−1, respectively, have yet to be achieved. Based on the analysis, the literature is then reviewed to summarize the concepts behind the success of high‐performance p‐type polymers, along with the latest understanding of the design criteria that will enable further mobility enhancement in n‐type polymers and small molecules, and the reasons why high carrier mobility values have been consistently produced from small molecule/polymer blend semiconductors. Overall, this review brings together important information that aids reliable OTFT data analysis, while providing guidelines for the development of next‐generation organic semiconductors.

Journal article

Costa JC, Pouryazdan A, Panidi J, Anthopoulos T, Liedke MO, Schneider C, Wagner A, Munzenrieder Net al., 2018, Low Temperature and Radiation Stability of Flexible IGZO TFTs and their Suitability for Space Applications, 48th European Solid-State Device Research Conference (ESSDERC 2018), Publisher: IEEE

Conference paper

Wahyudi W, Cao Z, Kumar P, Li M, Wu Y, Hedhili MN, Anthopoulos TD, Cavallo L, Li L-J, Ming Jet al., 2018, Phase Inversion Strategy to Flexible Freestanding Electrode: Critical Coupling of Binders and Electrolytes for High Performance Li-S Battery, ADVANCED FUNCTIONAL MATERIALS, Vol: 28, ISSN: 1616-301X

Journal article

Heeney MJ, Creamer A, Wood C, Howes P, Casey A, Cong S, Marsh A, Godin R, Panidi J, Anthopoulos T, Burgess C, Wu T, Fei Z, McLachlan M, Stevens Met al., 2018, Post-polymerisation functionalisation of conjugated polymer backbones and its application in multi-functional emissive nanoparticles, Nature Communications, Vol: 9, ISSN: 2041-1723

Backbone functionalisation of conjugated polymers is crucial to their performance in many applications, from electronic displays to nanoparticle biosensors, yet there are limited approaches to introduce functionality. To address this challenge we have developed a method for the direct modification of the aromatic backbone of a conjugated polymer, post-polymerisation. This is achieved via a quantitative nucleophilic aromatic substitution (SNAr) reaction on a range of fluorinated electron deficient comonomers. The method allows for facile tuning of the physical and optoelectronic properties within a batch of consistent molecular weight and dispersity. It also enables the introduction of multiple different functional groups onto the polymer backbone in a controlled manner. To demonstrate the versatility of this reaction, we designed and synthesised a range of emissive poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) based polymers for the creation of mono and multifunctional semiconducting polymer nanoparticles (SPNs) capable of two orthogonal bioconjugation reactions on the same surface.

Journal article

Firdaus Y, Seitkhan A, Eisner F, Sit W-Y, Kan Z, Wehbe N, Balawi AH, Yengel E, Karuthedath S, Laquai F, Anthopoulos TDet al., 2018, Charge Photogeneration and Recombination in Mesostructured CuSCN-Nanowire/PC70BM Solar Cells, SOLAR RRL, Vol: 2, ISSN: 2367-198X

Journal article

Wijeyasinghe N, Eisner F, Tsetseris L, Lin Y-H, Seitkhan A, Li J, Yan F, Solomeshch O, Tessler N, Patsalas P, Anthopoulos TDet al., 2018, p-Doping of Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers for High-Performance Transistors and Organic Solar Cells, ADVANCED FUNCTIONAL MATERIALS, Vol: 28, ISSN: 1616-301X

Journal article

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