190 results on '"Peter J. Skabara"'
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2. Synthesis of SOT-OH and its application as a building block for the synthesis of new dimeric and trimeric Spiro-OMeTAD materials
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Michele Cariello, Namrata Pant, Alexander H. Harkiss, Frances M. Tracey, Joseph Cameron, Peter J. Skabara, Peter J. Holliman, Pablo Docampo, and Graeme Cooke
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Chemistry (miscellaneous) ,Process Chemistry and Technology ,Materials Chemistry ,Biomedical Engineering ,Energy Engineering and Power Technology ,Chemical Engineering (miscellaneous) ,Industrial and Manufacturing Engineering - Abstract
Dimer and trimer analogues of Spiro-OMeTAD are porous hole transport materials with improved conductivity compared to the parent material and give higher power conversion efficiencies in perovskite solar cells.
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- 2022
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3. Star-shaped oligofluorene truxene macromolecules – synthesis and properties as a function of alkyl chain length
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Alexander L. Kanibolotsky, C. Orofino, and Peter J. Skabara
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chemistry.chemical_classification ,Chain length ,Crystallography ,chemistry ,Organic Chemistry ,Function (mathematics) ,Star (graph theory) ,Alkyl ,Macromolecule - Published
- 2021
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4. A Study on Varying the Number of Fluorene Units in 2, 1, 3‐Benzothiadiazole‐Containing Oligomers and the Effect on OLED Performance and Stability
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Luis‐Abraham Lozano‐Hernández, Joseph Cameron, Christopher J. Riggs, Sebastian Reineke, and Peter J. Skabara
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Organic Chemistry ,Physical and Theoretical Chemistry ,Analytical Chemistry - Published
- 2022
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5. Novel star-shaped conjugated macromolecules with fused cores for photonic and electronic applications (Conference Presentation)
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Peter J. Skabara
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- 2022
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6. From Phosphorescence to Delayed Fluorescence in One Step: Tuning Photophysical Properties by Quaternisation of an sp2-Hybridised Nitrogen Atom
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Anastasia Klimash, Antonio Prlj, Dmitry S. Yufit, Abhijit Mallick, Basile F. E. Curchod, Paul R. McGonigal, Peter J. Skabara, and Marc K. Etherington
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F100 ,Materials Chemistry ,General Chemistry - Abstract
Control of the delayed emission of organic compounds is an important factor in the development of new display technology and for the emerging use of organic emitters in sensing and fluorescence microscopy. In particular, there is a need to understand how the phenomena of room-temperature phosphorescence and thermally activated delayed fluorescence intersect. Here, we show that delayed fluorescence can be activated in room temperature phosphorescence emitters by quaternising the sp2-hybridised heterocyclic nitrogens. Furthermore by judicious positioning of a carbazole donor in the meta- or para- position with respect to the ring nitrogen atom, structural and sterical influences combine to tune the origins of the delayed fluorescence from triplet–triplet annihilation to thermally activated delayed fluorescence. Crucially, the quaternisation of nitrogen provides us with the means to fine tune singlet and triplet states in a predictable manner, uncover the intersection between phosphorescence and delayed fluorescence and tip the balance in favour of delayed fluorescence.
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- 2022
7. Understanding the dopant induced effects on SFX-MeOTAD for perovskite solar cells: a spectroscopic and computational investigation
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Paheli Ghosh, Michal Maciejczyk, Fraser Andrew Stewart Gunn, Joseph Cameron, Satheesh Krishnamurthy, Aruna Ivaturi, Dennis Nordlund, Peter J. Skabara, Neil Robertson, and Tell Tuttle
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Materials science ,Dopant ,Doping ,02 engineering and technology ,General Chemistry ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,XANES ,0104 chemical sciences ,X-ray photoelectron spectroscopy ,Electrical resistivity and conductivity ,Materials Chemistry ,Physical chemistry ,QD ,Absorption (chemistry) ,0210 nano-technology ,Perovskite (structure) - Abstract
SFX-MeOTAD [2,2′,7,7′-Tetrakis(N,N-di(4-methoxyphenyl)amino)-spiro-(fluorene-9,9′-xanthene)] (also known as X60) has emerged as a cost-effective alternative to the ubiquitous, but excessively-expensive, spiro-MeOTAD hole transport material (HTM) in perovskite solar cells. Using its pre-oxidised dicationic salt, SFX-(TFSI)2, a controlled concentration dependent conductivity tuning of this HTM without the requirement of air (oxygen) exposure is carried out. This study details the modifications in optical and electrical properties of this low cost HTM as a function of concentration of the dicationic salt (0-100 mol %) using UV-Vis absorption and electrical conductivity measurements. X-ray absorption and photoelectron spectroscopic investigations have been carried out to elucidate the role of the dicationic salt on the enhanced electronic properties of SFX-MeOTAD. By incorporating the dicationic SFX-(TFSI)2 it was shown that the conductivity of SFX-MeOTAD increased by 4 orders of magnitude from 2.55 × 10-8 S cm-1 to 9.4 × 10-4 S cm-1 using an optimal dopant concentration of 20.5 mol %. The degree of oxidation of SFX-MeOTAD was determined through UV-Vis absorption and consolidated by the computational calculations. XPS study reveal that doping SFX-MeOTAD with SFX(TFSI)2 results not only in oxidation of the HTM but also leads to variation in the local chemistry around carbon and nitrogen which directly influence the conductivity of the doped films. NEXAFS studies indicates that doping enhances the aromatic nature of the molecule initially but increasing the dopant concentration further affects the aromaticity and possibly the π stacking, similar to the trend seen in dopant concentration dependent conductivity of the SFX-MeOTAD films. These findings have implications on the choice of dopant concentration and counterions more generally for triarylamine based HTMs.
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- 2021
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8. New thiophene-based conjugated macrocycles for optoelectronic applications
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Alan A. Wiles, Ifor D. W. Samuel, Claire Wilson, Peter J. Skabara, John Marques dos Santos, Lethy Krishnan Jagadamma, Joseph Cameron, Graeme Cooke, European Commission, University of St Andrews. School of Chemistry, University of St Andrews. School of Physics and Astronomy, University of St Andrews. Centre for Energy Ethics, University of St Andrews. Centre for Biophotonics, and University of St Andrews. Condensed Matter Physics
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Materials science ,Absorption spectroscopy ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,Photochemistry ,01 natural sciences ,7. Clean energy ,Polymer solar cell ,chemistry.chemical_compound ,Materials Chemistry ,Thiophene ,QD ,SDG 7 - Affordable and Clean Energy ,Organic electronics ,business.industry ,DAS ,General Chemistry ,QD Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Semiconductor ,chemistry ,Absorption band ,0210 nano-technology ,business ,Single crystal - Abstract
GC acknowledges the EPSRC for funding (EP/E036244/1). JMS acknowledges the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 for PhD funding. JMS also acknowledges Dr Nor Basid Adiwibawa Prasetya for helpful advice. Dr L. K. Jagadamma acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776). Thiophene-based semiconductors are amongst the most successful materials in organic electronics. In this contribution, we present the synthesis and characterisation of two thiophene-based macrocycles as well as their evaluation in organic-electronic devices. McT-1 is composed of ten thiophene moieties, whereas in McT-2, four additional electron-deficient benzothiadiazole moieties are incorporated to form a donor–acceptor (D–A) π-system. Red-shifted and broadened absorption spectra as well as more positive redox potentials are observed in McT-2, whereas McT-1 displays a sharper absorption band with a higher extinction coefficient. Macrocycle McT-1 shows emission in the yellow region whereas McT-2 displays emission in the red wavelength region. DFT calculations predict the macrocycles to comprise of mainly the E,E isomers with a near-planar structure, which is further supported by the single crystal X-ray structure for McT-1. Their charge transporting properties are determined by fabricating thin-film OFETs. The photovoltaic properties of McT-1 and McT-2 are also investigated by fabricating bulk heterojunction (BHJ) devices and their potential as photodetectors has been evaluated. Publisher PDF
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- 2021
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9. Introducing a new 7-ring fused diindenone-dithieno[3,2
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Valentin H K, Fell, Joseph, Cameron, Alexander L, Kanibolotsky, Eman J, Hussien, and Peter J, Skabara
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A novel π-conjugated molecule
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- 2022
10. List of contributors
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Diego Bagnis, Margherita Bolognesi, Maria Paola Bracciale, Francesca Brunetti, Joseph Cameron, Filippo Campana, Gabriela de Amorim Soares, Luiza de Queiroz Corrêa, Francesca De Rossi, Arian Espinosa-Roa, Antonio Facchetti, Cesar Garcias-Morales, Giacomo Giorgi, Ferda Hacıvelioğlu, Bárbara Hellen de Souza Miranda, Dongil Ho, Hui Huang, Eman J. Hussien, Takaki Kanbara, Devang P. Khambhati, Choongik Kim, Jaeyong Kim, Anastasia Klimash, Junpei Kuwabara, Daniela Lanari, Minjeong Lee, Assunta Marrocchi, David Mecerreyes, Toby L. Nelson, Maurizia Palummo, Giuseppina Polino, Luca Porcarelli, Mario Prosa, Ting Qi, Mario Rodríguez, Mirko Seri, Peter J. Skabara, Hakan Usta, Luigi Vaccaro, and Koichi Yamashita
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- 2022
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11. Making organic light-emitting diodes sustainable—from metal-free emitters to less energy-intensive processing
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Joseph Cameron, Anastasia Klimash, Eman J. Hussien, Ferda Hacıvelioğlu, and Peter J. Skabara
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- 2022
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12. Elastomeric Foam-based Soft Capacitive Pressure Sensors using Direct Ink Writing
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Xenofon Karagiorgis, Markellos Ntagios, Peter J. Skabara, and Ravinder Dahiya
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- 2023
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13. Highly efficient fullerene and non-fullerene based ternary organic solar cells incorporating a new tetrathiocin-cored semiconductor
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Alexander L. Kanibolotsky, Simon J. Coles, Iain A. Wright, Lethy Krishnan Jagadamma, Peter J. Skabara, Peter N. Horton, Rupert G. D. Taylor, Ifor D. W. Samuel, Muhammad T. Sajjad, EPSRC, University of St Andrews. School of Physics and Astronomy, University of St Andrews. Centre for Biophotonics, and University of St Andrews. Condensed Matter Physics
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Materials science ,Fullerene ,Organic solar cell ,Energy Engineering and Power Technology ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,01 natural sciences ,Molecule ,QD ,QC ,chemistry.chemical_classification ,Renewable Energy, Sustainability and the Environment ,DAS ,Polymer ,QD Chemistry ,021001 nanoscience & nanotechnology ,Acceptor ,0104 chemical sciences ,Organic semiconductor ,Crystallography ,QC Physics ,Fuel Technology ,chemistry ,0210 nano-technology ,Ternary operation - Abstract
Authors thank the EPSRC for funding under grants EP/L012200/1 and EP/L012294/1. A new dual-chain oligothiophene-based organic semiconductor, EH-5T-TTC, is presented. The molecule contains two conjugated chains linked by a fused tetrathiocin core. X-ray crystallography reveals a boat conformation within the 8-membered sulfur heterocycle core and extensive π–π and intermolecular sulfur–sulfur interactions in the bulk, leading to a 2-dimensional structure. This unusual molecule has been studied as a ternary component in organic solar cell blends containing the electron donor PTB7-Th and both fullerene (PC71BM) and non-fullerene acceptors ITIC and EH-IDTBR. By incorporating EH-5T-TTC as a ternary component, the power conversion efficiency of the binary blends containing non-fullerene acceptor increases by 17% (from 7.8% to 9.2%) and by 85% for the binary blend with fullerene acceptor (from 3.3% to 6.3%). Detailed characterisation of the ternary blend systems implies that the ternary small molecule EH-5T-TTC functions differently in polymer:fullerene and polymer:non-fullerene blends and has dual functions of morphology modification and complementary spectral absorption. Publisher PDF
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- 2019
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14. Synthesis of novel multifunctional carbazole based molecules and their thermal, electrochemical and optical properties
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Nuray Altınölçek, Ahmet Battal, Mustafa Tavaslı, William J Peveler, Holly A Yu, and Peter J Skabara
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Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR spectroscopy, mass spectrometry, FT-IR, thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, and absorption and emission spectroscopy. Compounds 7a and 7b, both of which were amorphous solids, were stable up to 291oC and 307oC, respectively. Compounds 7a and 7b show three distinctive absorption bands: high and mid energy bands due to locally excited (LE) transitions and low energy bands due to intramolecular charge transfer (ICT) transitions. In dichloromethane solutions compounds 7a and 7b gave emission maxima at 561 nm and 482 nm with quantum efficiencies of 5.4% and 97.4% ± 10%, respectively. At positive potential, compounds 7a and 7b gave two different oxidation peaks, respectively: quasi-reversible at 0.55 V and 0.71 V, and reversible at 0.84 V and 0.99 V. At negative potentials, compounds 7a and 7b only exhibited an irreversible reduction peak at -1.86 V and -1.93 V, respectively.
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- 2020
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15. Highly nonlinear transport across single-molecule junctions via destructive quantum interference
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Julia E, Greenwald, Joseph, Cameron, Neil J, Findlay, Tianren, Fu, Suman, Gunasekaran, Peter J, Skabara, and Latha, Venkataraman
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To rival the performance of modern integrated circuits, single-molecule devices must be designed to exhibit extremely nonlinear current-voltage (I-V) characteristics
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- 2020
16. Synthesis Of Novel Multifunctional Carbazole-Based Molecules And Their Thermal, Electrochemical And Optical Properties
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Holly A. Yu, William J. Peveler, Mustafa Tavasli, Peter J. Skabara, Nuray Altinolcek, and Ahmet Battal
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Thermogravimetric analysis ,Solid-state chemistry ,Carbazole ,Organic Chemistry ,solvatochromism ,Analytical chemistry ,Nuclear magnetic resonance spectroscopy ,Full Research Paper ,lcsh:QD241-441 ,Chemistry ,chemistry.chemical_compound ,Differential scanning calorimetry ,chemistry ,electrochemistry ,lcsh:Organic chemistry ,carbazole ,formyl group ,lcsh:Q ,Emission spectrum ,fluorescence ,Cyclic voltammetry ,Absorption (electromagnetic radiation) ,lcsh:Science - Abstract
Tavasli, Mustafa/0000-0002-9466-1111; BATTAL, Ahmet/0000-0003-0208-1564 Two novel carbazole-based compounds 7a and 7b were synthesised as potential candidates for application in organic electronics. The materials were fully characterised by NMR spectroscopy, mass spectrometry, FTIR, thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, and absorption and emission spectroscopy. Compounds 7a and 7b, both of which were amorphous solids, were stable up to 291 degrees C and 307 degrees C, respectively. Compounds 7a and 7b show three distinctive absorption bands: high and mid energy bands due to locally excited (LE) transitions and low energy bands due to intramolecular charge transfer (ICT) transitions. In dichloromethane solutions compounds 7a and 7b gave emission maxima at 561 nm and 482 nm with quantum efficiencies of 5.4% and 97.4% +/- 10%, respectively. At positive potential, compounds 7a and 7b gave two different oxidation peaks, respectively: quasi-reversible at 0.55 V and 0.71 V, and reversible at 0.84 V and 0.99 V. At negative potentials, compounds 7a and 7b only exhibited an irreversible reduction peak at -1.86 V and -1.93 V, respectively. Scientific Research Programme Unit (BAP) of Uludag University [KUAP (F)-2018/14]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2211-C]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); University of Glasgow; EPSRC ERC Capital Award SchemeUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) [EP/S017984/1] This work was supported by the Scientific Research Programme Unit (BAP) of Uludag University [KUAP (F)-2018/14]. Nuray Altinolcek thanks the Scientific and Technological Research Council of Turkey (TUBITAK) for a Ph.D. scholarship for domestic priority areas (2211-C). Dr. Ahmet Battal thanks the Scientific and Technological Research Council of Turkey (TUBITAK) for 2219-International Postdoctoral Research Fellowship Programme for Turkish Citizens. Dr William Peveler acknowledges the University of Glasgow for an LKAS Scholarship, and the EPSRC ERC Capital Award Scheme (EP/S017984/1) for the Duetta instrument.
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- 2020
17. Synergistic electrodeposition of bilayer films and analysis by Raman spectroscopy
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Joseph Cameron, Luca Guerrini, Alexander L. Kanibolotsky, Peter J. Skabara, Saadeldin E. T. Elmasly, Neil J. Findlay, and Karen Faulds
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bilayer ,Letter ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,lcsh:QD241-441 ,symbols.namesake ,lcsh:Organic chemistry ,PEDOT:PSS ,QD ,lcsh:Science ,Raman ,PEDOT ,chemistry.chemical_classification ,Bilayer ,Organic Chemistry ,Doping ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Organic semiconductor ,Chemistry ,PEDTT ,Chemical engineering ,chemistry ,symbols ,lcsh:Q ,0210 nano-technology ,Raman spectroscopy ,Layer (electronics) ,electropolymerisation - Abstract
A novel methodology towards fabrication of multilayer organic devices, employing electrochemical polymer growth to form PEDOT and PEDTT layers, is successfully demonstrated. Moreover, careful control of the electrochemical conditions allows the degree of doping to be effectively altered for one of the polymer layers. Raman spectroscopy confirmed the formation and doped states of the PEDOT/PEDTT bilayer. The electrochemical deposition of a bilayer containing a de-doped PEDTT layer on top of doped PEDOT is analogous to a solution-processed organic semiconductor layer deposited on top of a PEDOT:PSS layer without the acidic PSS polymer. However, the poor solubility of electrochemically deposited PEDTT (or other electropolymerised potential candidates) raises the possibility of depositing a subsequent layer via solution-processing.
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- 2018
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18. Oligofluorene Truxene Laser Sensor: Towards Bacteria Growth Detection
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Peter J. Skabara, Anne-Marie Haughey, Alexander L. Kanibolotsky, Mark Scullion, Nicolas Laurand, and Eilidh Johnston
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Imagination ,Distributed feedback laser ,Chemical substance ,Materials science ,Organic laser ,business.industry ,media_common.quotation_subject ,Detector ,Bacterial growth ,Laser sensor ,Optoelectronics ,Science, technology and society ,business ,QC ,media_common - Abstract
Work toward the utilisation of an organic laser as a bacterial growth detector is presented here. The sensor used is an optically excited 2nd order DFB (distributed feedback laser) made of oligofluorene truxene. In the drive towards a practical bacterial growth detector, temperature stability and the optimum growth conditions of bacteria are challenges to be overcome. The resultant DFB laser exhibits a sensitivity of 9 nm/RIU.
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- 2019
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19. Nanoparticles of Cu2ZnSnS4as performance enhancing additives for organic field-effect transistors
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Joseph Cameron, Rupert G. D. Taylor, Paul O'Brien, Neil J. Findlay, Mohammad Azad Malik, Peter J. Skabara, Punarja Kevin, and Anto Regis Inigo
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chemistry.chemical_classification ,Organic field-effect transistor ,Materials science ,Transistor ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,Oleylamine ,law ,Materials Chemistry ,QD ,Field-effect transistor ,CZTS ,0210 nano-technology - Abstract
The addition of oleylamine coated Cu2ZnSnS4 (CZTS) nanoparticles to solutions of an organic semiconductor used to fabricate organic field-effect transistors (OFETs) has been investigated. The oligothiophene-based small molecule 5T-TTF and the polymer poly(3-hexylthiophene) (P3HT) were each applied in the transistors with various concentrations of CZTS (5–20%). Atomic force microscopy (AFM) was applied to characterise the surface morphology of the OFETs. The use of 5 and 10 wt% of the CZTS nanoparticles in 5T-TTF and P3HT solutions, respectively, appears to be a simple and effective way of improving OFET performance.
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- 2016
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20. A single emitting layer white OLED based on exciplex interface emission
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Dmytro Volyniuk, Khrystyna Ivaniuk, Juozas V. Grazulevicius, Sigitas Tamulevičius, Nataliya Kostiv, Pavlo Stakhira, Algirdas Lazauskas, Vladyslav Cherpak, Peter J. Skabara, Marian Chapran, Neil J. Findlay, Enrico Angioni, and Tell Tuttle
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Organic electronics ,Materials science ,business.industry ,Exciton ,02 engineering and technology ,General Chemistry ,Color temperature ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Excimer ,01 natural sciences ,0104 chemical sciences ,3. Good health ,Core (optical fiber) ,Materials Chemistry ,OLED ,Molecule ,Optoelectronics ,QD ,0210 nano-technology ,business ,Layer (electronics) - Abstract
A new triaryl molecule based on a benzene–benzothiadiazole–benzene core has been applied in a WOLED device. This very simple molecule emits from a combination of emissive states (exciton/electromer/exciplex/electroplex) to give white light with CIE coordinates of (0.38, 0.45) and a colour temperature of 4500 K.
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- 2016
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21. High brightness solution-processed OLEDs employing linear, small molecule emitters
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Alexander L. Kanibolotsky, Clarissa Forbes, Neil J. Findlay, Anto Regis Inigo, Benjamin Breig, and Peter J. Skabara
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Brightness ,Materials science ,business.industry ,Electron donor ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Triphenylamine ,01 natural sciences ,Oligomer ,Small molecule ,Luminance ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,OLED ,Optoelectronics ,QD ,0210 nano-technology ,business ,Diode - Abstract
Two novel linear oligomers that can be solution-processed to form green organic light-emitting diodes (OLEDs) are reported. Each oligomer has a donor–acceptor structure, incorporating a benzothiadiazole core with bifluorene arms attached at the 4- and 7-positions. Further electron donor behaviour is inferred from a terminal triphenylamine unit in Green 2. The resulting solution-processed OLEDs exhibited excellent performance, with a maximum luminance of 20 388 cd m−2 recorded for Green 2.
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- 2016
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22. Multifunctional asymmetric D-A-D’ compounds: Mechanochromic luminescence, thermally activated delayed fluorescence and aggregation enhanced emission
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Galyna Sych, Ramin Pashazadeh, Karolis Leitonas, Peter J. Skabara, Algirdas Lazauskas, Dmytro Volyniuk, Sohrab Nasiri, and Juozas V. Grazulevicius
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Mechanochromic luminescence ,Materials science ,Carbazole ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,Acceptor ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Excited state ,Environmental Chemistry ,Moiety ,Hypsochromic shift ,0210 nano-technology ,Luminescence - Abstract
Herein, we report synthesis and properties of new multifunctional materials, containing quinoxaline as an acceptor core and differently substituted carbazole moieties as the donors within unsymmetrical D-A-D’ type structures. The compounds exhibit thermally activated delayed fluorescence, luminescence variation in response to external stresses (from green to orange) and emission enhancement in the aggregated state. The effect of substitutions on the different properties is discussed. The investigation suggests that the strength of the donor determines the optical properties of unsymmetrical bipolar emitters. Density functional theory calculations revealed that in the ground and the excited state, electrons of the highest occupied molecular orbitals (HOMOs) are mainly localized on the stronger donor. Mechanochromism studies demonstrated that the bulky tert-butyl groups attached to the carbazole moiety give rise to a hypsochromic effect. It is also associated with the strong reversible colour contrast, in the range of 524–583 nm, in response to external stresses. Using the synthesized compound as an emitter in organic light emitting diode, maximum external quantum efficiency of 10.5% and luminance of 48800 cd.cm−2 were observed.
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- 2020
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23. Observation of dual room temperature fluorescence-phosphorescence in air, in the crystal form of a thianthrene derivative
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Fernando B. Dias, Algirdas Lazauskas, Anastasia Klimash, David Djurado, Stéphanie Pouget, Ramin Pashazadeh, Agnieszka Swist, Radoslaw Motyka, Juozas V. Grazulevicius, Peter J. Skabara, Piotr Pander, Przemyslaw Data, Jadwiga Sołoducho, Roman Turczyn, Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Service Général des Rayons X (SGX ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Spectrométrie Physique (LSP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Kaunas University of Technology (KTU), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
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Physics::General Physics ,Materials science ,Diffusion ,Phosphor ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,chemistry.chemical_compound ,[CHIM]Chemical Sciences ,Physical and Theoretical Chemistry ,Thianthrene ,ComputingMilieux_MISCELLANEOUS ,021001 nanoscience & nanotechnology ,Fluorescence ,0104 chemical sciences ,3. Good health ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,General Energy ,chemistry ,0210 nano-technology ,Luminescence ,Phosphorescence ,Derivative (chemistry) - Abstract
Thianthrenes have been nearly forgotten as phosphors in recent years, but are now coming back, showing their strong potential in luminescent applications. Here, we present a comprehensive photophysical study of a carbazolyl derivative of thianthrene in different matrices and environments. The diffusion of oxygen is slowed down in the rigid environment of thianthrene organic crystals, suppressing their phosphorescence quenching.Triplet–triplet annihilation is also not significantly active in these systems. Both conditions facilitate the observation of simultaneous fluorescence and phosphorescence emissions at room temperature, in air, giving origin to strong white luminescence. Moreover, the color coordinates of the dual fluorescence–phosphorescence white emission, which is observed only in rigid amorphous media and in crystals, can be tuned.
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- 2018
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24. An iminodibenzyl–quinoxaline–iminodibenzyl scaffold as a mechanochromic and dual emitter: donor and bridge effects on optical properties
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Ramin Pashazadeh, Peter J. Skabara, Piotr Pander, Juozas V. Grazulevicius, Audrius Bucinskas, and Fernando B. Dias
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Materials science ,Band gap ,Metals and Alloys ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,Catalysis ,0104 chemical sciences ,3. Good health ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Quinoxaline ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Moiety ,0210 nano-technology ,Phosphorescence ,Excited singlet ,Common emitter - Abstract
The influence of phenyl linkage and donor strength on the photophysical properties of new derivatives of quinoxaline-containing iminodibenzyl and iminostilbene moieties is studied. The donor-acceptor derivatives showed dual thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) despite a large energy gap between the excited singlet and triplet states (ca. 0.5 eV). This extremely rare observation is explained by the twisted and rigidified structure of the iminodibenzyl moiety.
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- 2018
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25. Impedance spectroscopy of OLEDs as a tool for estimating mobility and the concentration of charge carriers in transport layers
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Peter J. Skabara, Mieczyslaw Lapkowski, Pavel Chulkin, Przemyslaw Data, and Oleh Vybornyi
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010302 applied physics ,Materials science ,business.industry ,Charge density ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Dielectric spectroscopy ,Electric field ,0103 physical sciences ,Materials Chemistry ,OLED ,Optoelectronics ,Charge carrier ,0210 nano-technology ,business ,Voltage ,Common emitter - Abstract
The article presents a novel impedance spectroscopy based technique designed to characterise organic light emitting diodes (OLED) during operation. A number of devices based on NPB (N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine) and TPBi (2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) conducting layers, CBP (4,4′-bis(N-carbazolyl)-1,1′-biphenyl) as a host and BPTZ-DBTO2 (3,6-bis(10H-phenothiazine-10-yl)-9H-fluorene-[dibenzothiophene-S,S-dioxide]) as an emitter were taken as an example to validate the method. Using equivalent electrical circuits, values of capacitance and conductivity of both hole- (HTL) and electron-transport (ETL) layers were determined and analysed separately. Those parameters, as well as current–voltage characteristics, were used to calculate (i) mobility (μ, cm2 V−1 s−1) of both types of charge carriers, (ii) charge density (n, cm−3) of the charge carriers, and (iii) electric field intensity (E, V m−1) in both transport layers as functions of the applied voltage.
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- 2018
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26. The role of structural and electronic factors in shaping the ambipolar properties of donor–acceptor polymers of thiophene and benzothiadiazole
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Enrico Angioni, Peter J. Skabara, Wojciech Domagala, Neil J. Findlay, Przemyslaw Ledwon, and Neil Thomson
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Steric effects ,education.field_of_study ,General Chemical Engineering ,Population ,Intermolecular force ,General Chemistry ,Conjugated system ,Photochemistry ,chemistry.chemical_compound ,chemistry ,Intramolecular force ,Thiophene ,Side chain ,QD ,Charge carrier ,education - Abstract
The influence of different thiophene donor units on electrochemical and spectroscopic properties of benzothiadiazole based donor–acceptor π-conjugated organic materials is studied. Two different structure modification vectors of the donor units are being considered – one addressing the intermolecular interactions through off-conjugation side chain architecture, and the other focusing on intramolecular interactions tuned by in-conjugation substituents. Electrochemical and simultaneous in situ EPR-UV-Vis-NIR spectroelectrochemical studies of the oxidative (p-) and reductive (n-) doping processes, which are responsible for the optoelectronic properties of these materials, revealed their disparate course and dissimilar effects of redox reactions of the conjugated π-bond. While p-doping prevalent species were found to comprise intensively interacting spin bearing and spinless charge carriers, the n-doping state was found to involve only one type of negatively charged carrier, with spin carrying species being selectively generated at due cathodic potentials. No spin pairing of these negative polarons was observed with their increasing population behaving like a collection of localised charge carriers. Qualitative and quantitative comparisons between the p- and n-doping carrier populations provided independent support for the spin pairing phenomena of positive charge carriers. Steric effects of varying alkyl side chain substitution have demonstrated predominant impact on the electrochemical properties of investigated polymers, and, thereto related, stability of n-doped state, while mesomeric effects of different 3,4-ethylenechalcogenide thiophene functionalities have been found to shape the energy level related spectral properties of these polymers, with particular reference to p-doping induced charged states. These findings provide new insights into the factors requiring attention during structure tailoring of donor–acceptor assemblies for organic optoelectronic applications.
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- 2015
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27. p-Type Molecular Materials for Organic Solar Cells
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Peter J. Skabara, Rupert G. D. Taylor, and Adam C. Yeats
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Global energy ,Engineering ,Research groups ,Organic solar cell ,business.industry ,Fossil fuel ,Nanotechnology ,business ,Process engineering ,Molecular materials ,Inkjet printing ,Solar power ,Renewable energy - Abstract
The search for a clean, renewable source of energy as a replacement for fossil fuels has been at the forefront of scientific, economic and political research for the past few decades. Of the commonly investigated techniques, one strong contender that fits this role extremely well is solar power. The ability to harvest energy from sunlight incident on the Earth’s surface in an efficient and cost-effective manner would alleviate the global energy crisis with relative ease – more energy reaches the Earth from the Sun in one hour than all the energy consumed on the planet in an entire year. Progress has been both fast and expansive, with a large number of research groups across the globe finely tuning and improving solar-harvesting technology. Organic solar cells show huge promise for future energy-harvesting because they allow very low-cost production through the use of low-temperature fabrication techniques, such as roll-to-roll processing or inkjet printing. Organic solar cell materials can also be made to be flexible and semi-transparent and are extremely lightweight compared with the current market-leading silicon-based alternatives. This chapter aims to give a concise overview of some of the progress made to date, with attention focused on prepared and tested state-of-the-art, high-performance materials.
- Published
- 2017
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28. Nanostructured Materials for Type III Photovoltaics
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Mohammad Azad Malik and Peter J. Skabara
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Materials science ,Photovoltaics ,business.industry ,Nanostructured materials ,Nanotechnology ,business - Abstract
Materials for type III solar cells have branched into a series of generic groups. These include organic ‘small molecule’ and polymer conjugated structures, fullerenes, quantum dots, copper indium gallium selenide nanocrystal films, dyes/TiO2 for Grätzel cells, hybrid organic/inorganic composites and perovskites. Whilst the power conversion efficiencies of organic solar cells are modest compared to other type III photovoltaic materials, plastic semiconductors provide a cheap route to manufacture through solution processing and offer flexible devices. However, other types of materials are proving to be compatible with this type of processing whilst providing higher device efficiencies. As a result, the field is experiencing healthy competition between technologies that is pushing progress at a fast rate. In particular, perovskite solar cells have emerged very recently as a highly disruptive technology with power conversion efficiencies now over 20%. Perovskite cells, however, still have to address stability and environmental issues. With such a diverse range of materials, it is timely to capture the different technologies into a single volume of work. This book will give a collective insight into the different roles that nanostructured materials play in type III solar cells. This will be an essential text for those working with any of the devices highlighted above, providing a fundamental understanding and appreciation of the potential and challenges associated with each of these technologies.
- Published
- 2017
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29. An Ambipolar BODIPY Derivative for a White Exciplex OLED and Cholesteric Liquid Crystal Laser toward Multifunctional Devices
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Peter J. Skabara, Juozas V. Grazulevicius, Marian Chapran, Enrico Angioni, Tell Tuttle, Benjamin Breig, Vladyslav Cherpak, Yuriy A. Nastishin, Dmytro Volyniuk, Neil J. Findlay, Oleg D. Lavrentovich, and Pavlo Stakhira
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Electron mobility ,Materials science ,Cholesteric liquid crystal ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,BODIPY dye ,exciplex ,law.invention ,chemistry.chemical_compound ,law ,OLED ,QD ,General Materials Science ,QC ,Dye laser ,Ambipolar diffusion ,business.industry ,cholesteric liquid crystal laser ,organic light-emitting diodes (OLEDs) ,021001 nanoscience & nanotechnology ,Laser ,0104 chemical sciences ,chemistry ,Optoelectronics ,BODIPY ,0210 nano-technology ,business ,Lasing threshold ,white light - Abstract
A new interface engineering method is demonstrated for the preparation of an efficient white organic light-emitting diode (WOLED) by embedding an ultrathin layer of the novel ambipolar red emissive compound 4,4-difluoro-2,6-di(4-hexylthiopen-2-yl)-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (bThBODIPY) in the exciplex formation region. The compound shows a hole and electron mobility of 3.3 × 10-4 and 2 × 10-4 cm2 V-1 s-1, respectively, at electric fields higher than 5.3 × 105 V cm-1. The resulting WOLED exhibited a maximum luminance of 6579 cd m-2 with CIE 1931 color coordinates (0.39; 0.35). The bThBODIPY dye is also demonstrated to be an effective laser dye for a cholesteric liquid crystal (ChLC) laser. New construction of the ChLC laser, by which a flat capillary with an optically isotropic dye solution is sandwiched between two dye-free ChLC cells, provides photonic lasing at a wavelength well matched with that of a dye-doped planar ChLC cell.
- Published
- 2017
30. A saturated red color converter for visible light communication using a blend of star-shaped organic semiconductors
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Muhammad T. Sajjad, Pavlos P. Manousiadis, Dominic O'Brien, Ifor D. W. Samuel, Grahame Faulkner, Sujan Rajbhandari, Dimali A. Vithanage, Alexander L. Kanibolotsky, Neil J. Findlay, Hyunchae Chun, Peter J. Skabara, Graham A. Turnbull, C. Orofino, EPSRC, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. Condensed Matter Physics
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TP ,Physics and Astronomy (miscellaneous) ,chemistry.chemical_element ,Visible light communication ,Phosphor ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,TP Chemical technology ,Red Color ,law.invention ,chemistry.chemical_compound ,Optics ,law ,QB Astronomy ,Boron ,QC ,QB ,chemistry.chemical_classification ,business.industry ,Chemistry ,DAS ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,WHITE-LIGHT ,Organic semiconductor ,QC Physics ,Optoelectronics ,BODIPY ,0210 nano-technology ,business ,Light-emitting diode - Abstract
Authors would like to acknowledge the EPSRC for financial support for the UP-VLC (EP/K00042X/1). PJS and IDWS also acknowledge Royal Society Wolfson Research Merit Awards. We report a study of blends of semiconducting polymers as saturated red color converters to replace commercial phosphors in hybrid LEDs for visible light communication (VLC). By blending two star-shaped organic semiconductor molecules, we found a near complete energy transfer (> 90% efficiency) from the green-emitting truxene-cored compound T4BT-B to the red-emitting boron dipyrromethene (BODIPY) cored materials. Furthermore, we have demonstrated the capability of these materials as fast color converters for VLC by measuring their intrinsic optical modulation bandwidth and data rate. The measured 3 dB modulation bandwidth of blends (~55 MHz) is more than 10 times higher than commercially available LED phosphors and also higher than the red-emitting BODIPY color converter alone in solution. The data rate achieved with this blend is 20 times higher than measured with a commercially available phosphor based color converter. Postprint
- Published
- 2017
31. Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core
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Oleh Vybornyi, Neil J. Findlay, and Peter J. Skabara
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TADF ,Materials science ,General Chemical Engineering ,Thiophenes ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Chemical synthesis ,General Biochemistry, Genetics and Molecular Biology ,Synthesis ,chemistry.chemical_compound ,OLED ,QD ,TP155 ,Amination ,Molecular Structure ,General Immunology and Microbiology ,General Neuroscience ,Buchwald–Hartwig amination ,021001 nanoscience & nanotechnology ,Fluorescence ,Combinatorial chemistry ,0104 chemical sciences ,Characterization (materials science) ,Chemistry ,Pd cross-coupling ,chemistry ,Dibenzothiophene ,SCALE-UP ,Issue 128 ,Buchwald-Hartwig amination ,fluorescence ,0210 nano-technology - Abstract
We report a procedure to linearly scale-up the synthesis of 2,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)dibenzothiophene-S,S-dioxide (compound\ud 4) and 2,8-bis(10H-phenothiazin-10-yl)dibenzothiophene-S,S-dioxide (compound 5) using Buchwald-Hartwig cross-coupling reaction conditions.\ud In addition, we demonstrate a scaled-up synthesis of all non-commercially available starting materials that are required for the amination crosscoupling\ud reaction. In the present article, we provide the detailed synthetic procedures for all of the described compounds, alongside their spectral\ud characterization. This work shows the possibility to produce organic molecules for optoelectronic applications on a large scale, which facilitates\ud their implementation into real world devices.
- Published
- 2017
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32. Conducting Nanofibers and Organogels Derived from the Self-Assembly of Tetrathiafulvalene-Appended Dipeptides
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Alexander L. Kanibolotsky, Helena Gleskova, Mischa Zelzer, Nadezhda Shivarova, Swati Gupta, Peter J. Skabara, Rein V. Ulijn, Siva Krishna Mohan Nalluri, and Pim W. J. M. Frederix
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TP ,Materials science ,TK ,Nanofibers ,Ethyl acetate ,chemistry.chemical_compound ,Heterocyclic Compounds ,Polymer chemistry ,Electrochemistry ,Moiety ,Organic chemistry ,General Materials Science ,Fourier transform infrared spectroscopy ,Diphenylalanine ,Spectroscopy ,chemistry.chemical_classification ,Molecular Structure ,technology, industry, and agriculture ,Dipeptides ,Surfaces and Interfaces ,Electron acceptor ,Condensed Matter Physics ,QD450 ,chemistry ,Nanofiber ,Cyclic voltammetry ,Gels ,Tetrathiafulvalene - Abstract
In this article, we demonstrate the non-aqueous self-assembly of a low-molecular-mass organic gelator based on an electroactive p-type tetrathiafulvalene (TTF)-dipeptide bioconjugate. We show that a TTF moiety appended with diphenylalanine amide derivative (TTF-FF-NH2) self-assembles into one-dimensional nanofibers that further lead to the formation of self-supporting organogels in chloroform and ethyl acetate. Upon doping of the gels with electron acceptors (TCNQ/iodine vapor), stable two-component charge transfer gels are produced in chloroform and ethyl acetate. These gels are characterized by various spectroscopy (UV-vis-NIR, FTIR and CD), microscopy (AFM and TEM), rheology and cyclic voltammetry techniques. Furthermore, conductivity measurements performed on TTF-FF-NH2 xerogel nanofiber networks formed between gold electrodes on a glass surface indicate that these nanofibers show a remarkable enhancement in the conductivity after doping with TCNQ.
- Published
- 2014
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33. Field-Effect Mobility, Morphology and Electroluminescence of a Semiconductor Based on a DPPQuaterfluorene Quadrupolar Linear Conjugated System
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Neil J. Findlay, Peter J. Skabara, Anto Regis Inigo, Alexander L. Kanibolotsky, Sasikumar Arumugam, Clara Orofino-Pena, and Roisin E. Brown
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Organic semiconductor ,Electron mobility ,Semiconductor ,Chemistry ,business.industry ,OLED ,Field effect ,Optoelectronics ,Field-effect transistor ,General Chemistry ,Conjugated system ,Electroluminescence ,business - Abstract
An organic semiconductor, expressed as a quadrupolar linear conjugated system (DPP Linear-c), consisting of a 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) central unit and two quaterfluorenylphenyl arms at the 3- and 6- positions of the DPP fragment, is studied in organic field effect transistors (OFETs). The strong propensity of DPP Linear-c to aggregate in the solid state favours the hole mobility of the semiconductor due to the alignment of HOMOs in the aggregates. The fabrication of OFETs from this novel p-type semiconductor is reported, using different dielectrics to evaluate their effect on the overall device performance. Despite its aggregation, DPP Linear-c remains luminescent in the solid state. Electroluminescence of a non-optimised OLED fabricated from this material is demonstrated.
- Published
- 2014
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34. Electrochemical synthesis of ammonia from N2 and H2O based on (Li,Na,K)2CO3–Ce0.8Gd0.18Ca0.02O2−δ composite electrolyte and CoFe2O4 cathode
- Author
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Rong Lan, Christophe Tg Petit, Shanwen Tao, Ibrahim A. Amar, Gregory Bruce Mann, and Peter J. Skabara
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Renewable Energy, Sustainability and the Environment ,Chemistry ,Electrolytic cell ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Electrolyte ,Condensed Matter Physics ,Electrochemistry ,Nitrogen ,Cathode ,law.invention ,Anode ,Ammonia production ,Ammonia ,chemistry.chemical_compound ,Fuel Technology ,law ,QD - Abstract
Electrochemical synthesis of ammonia from water vapour and nitrogen was investigated using an electrolytic cell based on CoFe2O 4-Ce0.8Gd0.18Ca0.02O 2-δ (CFO-CGDC), CGDC-ternary carbonate composite and Sm 0.5Sr0.5CoO3-δ-Ce0.8Gd 0.18Ca0.02O2-δ (SSCo-CGDC) as cathode, electrolyte and anode respectively. CoFe2O4, CGDC and SCCo were prepared via a combined EDTA-citrate complexing sol-gel and characterised by X-ray diffraction (XRD). The AC ionic conductivities of the CGDC-carbonate composite were investigated under three different atmospheres (air, dry O 2 and wet 5% H2-Ar). A tri-layer electrolytic cell was fabricated by a cost-effective one-step dry-pressing and co-firing process. Ammonia was successfully synthesised from water vapour and nitrogen under atmospheric pressure and the maximum rate of ammonia production was found to be 6.5 × 10-11 mol s-1 cm-2 at 400 C and 1.6 V which is two orders of magnitude higher than that of previous report when ammonia was synthesised from N2 and H2O at 650 C.
- Published
- 2014
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35. Hybrid organic semiconductor lasers for bio-molecular sensing
- Author
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Martin D. Dawson, Alexander L. Kanibolotsky, Nicolas Laurand, Peter J. Skabara, Glenn A. Burley, Anne-Marie Haughey, Benoit Guilhabert, and C. Foucher
- Subjects
Luminescent Agents ,Molecular Structure ,business.industry ,Sensing applications ,Lasers ,Nanotechnology ,Biosensing Techniques ,Laser ,law.invention ,Biophotonics ,Organic semiconductor ,Nucleic Acid Probes ,Semiconductor ,Semiconductors ,Quantum dot ,law ,Quantum Dots ,Optoelectronics ,Colloids ,Organic Chemicals ,Physical and Theoretical Chemistry ,business ,Biosensor - Abstract
Bio-functionalised luminescent organic semiconductors are attractive for biophotonics because they can act as efficient laser materials while simultaneously interacting with molecules. In this paper, we present and discuss a laser biosensor platform that utilises a gain layer made of such an organic semiconductor material. The simple structure of the sensor and its operation principle are described. Nanolayer detection is shown experimentally and analysed theoretically in order to assess the potential and the limits of the biosensor. The advantage conferred by the organic semiconductor is explained, and comparisons to laser sensors using alternative dye-doped materials are made. Specific biomolecular sensing is demonstrated, and routes to functionalisation with nucleic acid probes, and future developments opened up by this achievement, are highlighted. Finally, attractive formats for sensing applications are mentioned, as well as colloidal quantum dots, which in the future could be used in conjunction with organic semiconductors.
- Published
- 2014
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36. Functional Organic Materials for Optoelectronic Applications
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Ivana Radosavljevic Evans, Graeme Cooke, and Peter J. Skabara
- Subjects
Materials science ,Field (physics) ,business.industry ,Materials Chemistry ,Optoelectronics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,0210 nano-technology ,business ,01 natural sciences ,0104 chemical sciences - Abstract
Guest Editors Graeme Cooke, Ivana Evans and Peter Skabara introduce this themed collection on functional organic materials for optoelectronic applications, in celebration of Professor Martin Bryce’s contributions to this field.
- Published
- 2019
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37. Journal of Materials Chemistry A, B & C: onwards and upwards
- Author
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Dongyuan Zhao, Christine E. Schmidt, Hiroshi Imahori, Peter J. Skabara, Fiona McKenzie, and Sam Kelti
- Subjects
Solid-state chemistry ,Materials science ,Polymer science ,Renewable Energy, Sustainability and the Environment ,Materials Chemistry ,Library science ,General Materials Science ,General Chemistry ,Engineering physics - Abstract
Welcome to Volume 3 of Journal of Materials Chemistry A, B & C! This Editorial, published in Issue 1 of all three journals, marks our third year of publication as three separate titles under the Journal of Materials Chemistry brand.
- Published
- 2015
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38. LED pumped polymer laser sensor for explosives
- Author
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Graham A. Turnbull, Paulina O. Morawska, Alexander L. Kanibolotsky, Yue Wang, Ifor D. W. Samuel, and Peter J. Skabara
- Subjects
Physics ,Distributed feedback laser ,Explosive material ,business.industry ,Far-infrared laser ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Optics ,law ,Laser power scaling ,0210 nano-technology ,business ,Excitation ,Beam (structure) ,Diode - Abstract
A very compact explosive vapor sensor is demonstrated based on a distributed feedback polymer laser pumped by a commercial InGaN light-emitting diode. The laser shows a two-stage turn on of the laser emission, for pulsed drive currents above 15.7 A. The ‘double-threshold’ phenomenon is attributed to the slow rise of the ∼30 ns duration LED pump pulses. The laser emits a 533 nm pulsed output beam of ∼10 ns duration perpendicular to the polymer film. When exposed to nitroaromatic model explosive vapors at ∼8 ppb concentration, the laser shows a 46% change in the surface-emitted output under optimized LED excitation.
- Published
- 2013
- Full Text
- View/download PDF
39. An organic semiconductor laser based on star-shaped truxene-core oligomers for refractive index sensing
- Author
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Benoit Guilhabert, Anne-Marie Haughey, Martin D. Dawson, Peter J. Skabara, Alexander L. Kanibolotsky, Nicolas Laurand, and Glenn A. Burley
- Subjects
Distributed feedback laser ,Fabrication ,business.industry ,Metals and Alloys ,Condensed Matter Physics ,Laser ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Organic semiconductor ,Semiconductor ,Optics ,Polyelectrolyte adsorption ,law ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,Thin film ,business ,Instrumentation ,Refractive index - Abstract
The sensing capabilities of an all-organic semiconductor distributed feedback laser based on star-shaped truxene-core molecules are described. Two assays are presented as a proof-of-principle demonstration. In the first, concentration changes in the range of 5–60% (v/v) glycerol solution in water were measured with a bulk detection sensitivity of 21 nm per refractive index unit. Secondly, layer-by-layer adsorption of polyelectrolytes to the laser surface, up to a thickness of ≈45 nm, was measured. The experimental results from both assays are compared to, and shown to agree with, a theoretical model. Organic semiconductor lasers of this type have a number of attractions including ease of large-scale fabrication, incorporation into existing assay equipment and no rigid optical alignment constraints for excitation and collection of emission, which makes them well-suited to sensing applications. Therefore, it is expected that this technology will be useful in biosensing applications where label-free samples are investigated.
- Published
- 2013
- Full Text
- View/download PDF
40. Electrochemistry and In Situ EPR Spectroelectrochemistry of Poly(3,4-ethylenedithiothiophene)
- Author
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Peter J. Skabara, Mieczyslaw Lapkowski, Pawel Zassowski, and Wojciech Domagala
- Subjects
Conductive polymer ,chemistry.chemical_classification ,Materials science ,Mechanical Engineering ,Polymer ,Electrochemistry ,Photochemistry ,law.invention ,chemistry.chemical_compound ,Monomer ,PEDOT:PSS ,chemistry ,Polymerization ,Mechanics of Materials ,law ,Polymer chemistry ,Polythiophene ,General Materials Science ,Electron paramagnetic resonance - Abstract
Polymer films of poly(3,4-ethylenedithiothiophene) obtained by electrochemical oxidative polymerisation of the corresponding monomer have been investigated. p-Doping process of the polymer was characterized by in situ EPR spectroelectrochemisty. Compared to its close relative – PEDOT, the polymer features two distinct voltammetric peaks. The results of our studies indicate that both represent faradaic processes and that each manifests generation of charge carriers in the polymer.
- Published
- 2013
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41. Location, Location, Location ‐ Strategic Positioning of 2,1,3‐Benzothiadiazole Units within Trigonal Quaterfluorene‐Truxene Star‐Shaped Structures
- Author
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Paul N. Stavrinou, Peter J. Skabara, Alexander L. Kanibolotsky, C. Belton, Donal D. C. Bradley, C. Orofino, James Kirkpatrick, and Saadeldin E. T. Elmasly
- Subjects
Amplified spontaneous emission ,Materials science ,Photoluminescence ,business.industry ,Molecular electronics ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Organic semiconductor ,symbols.namesake ,Molecular vibration ,Electrochemistry ,symbols ,Optoelectronics ,Molecule ,Light emission ,business ,Raman scattering - Abstract
The fused, bicyclic molecule, 2,1,3-Benzothiadiazole (BT), has become a key ingredient in the design of new organic semiconductors for light emission and energy harvesting applications. Here, the synthesis is reported of a series of trigonal, star-shaped compounds comprising a truxene core and three quater-dialkylfluorene arms into each of which a BT unit is inserted sequentially at each possible position (T4BT-A to T4BT-E). Analysis of the resulting electronic properties shows that as a consequence of conjugative coupling to the core and the resulting symmetry there are three distinct locations for the BT unit and the influence that these locations have on light emission and other spectroscopic characteristics is discussed. The systematic variation in photophysical properties for the different structural isomers helps to clarify the influence of BT unit addition to 9,9-dialkylfluorene chains. It also helps to establish a design template for the construction of donor-acceptor conjugated materials with targeted properties. For T4BT-E with a BT unit at the terminal position of each arm, the photoluminescence quantum efficiency is significantly reduced and no amplified spontaneous emission is observed under typical pumping conditions. Theoretical calculations assist in understanding the variation in behaviors among the T4BT-X family of compounds, especially in relation to their photoluminescence decay times and the Raman scattering intensities of their dominant BT-unit-centred molecular vibrations.
- Published
- 2013
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- View/download PDF
42. The development of sensors for volatile nitro-containing compounds as models for explosives detection
- Author
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Deepak Uttamchandani, Zuzana Vobecka, Peter J. Skabara, and Robert Blue
- Subjects
chemistry.chemical_classification ,Analyte ,Materials science ,Explosive material ,Inorganic chemistry ,Metals and Alloys ,Polymer ,Condensed Matter Physics ,Electrochemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Nitrobenzene ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Nitro ,Degradation (geology) ,Organic chemistry ,Electrical and Electronic Engineering ,Selectivity ,Instrumentation - Abstract
Sensors capable of detecting explosives or their degradation products are important devices needed to safeguard citizens and infrastructure. We report on the sensor application of novel customized polymer films that we have produced to have high affinity for chemical vapors containing the nitro (NO2) group, which is found in explosives such as TNT and DNT. We have used localized electrochemical growth of these polymers to realize miniature, high-selectivity capacitive sensors based on interdigitated electrodes (IDEs). These sensors have been tested for response to vapors of nitrobenzene and 2-nitrotoluene as model analytes for nitro vapors generated from explosive compounds. The sensors were demonstrated to be reversible and to have a very high selectivity to nitro-bearing compounds. In the ppm concentration region, our sensors exhibited a linear response up to three orders of magnitude higher to nitro groups than to other common volatile chemicals found in the atmosphere, which we believe is the highest selectivity to nitro compounds reported from a polymer-based chemicapacitor sensor.
- Published
- 2013
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43. ChemInform Abstract: Polythiophene and Oligothiophene Systems Modified by TTF Electroactive Units for Organic Electronics
- Author
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Alexander L. Kanibolotsky, Neil J. Findlay, and Peter J. Skabara
- Subjects
Organic electronics ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,Thiophene ,Polythiophene ,Nanotechnology ,General Medicine ,Conjugated system ,Hybrid material ,Ring (chemistry) ,Tetrathiafulvalene - Abstract
The aim of this review is to give an update on current progress in the synthesis, properties and applications of thiophene-based conjugated systems bearing tetrathiafulvalene (TTF) units. We focus mostly on the synthesis of poly- and oligothiophenes with TTF moieties fused to the thiophene units of the conjugated backbone either directly or via a dithiin ring. The electrochemical behaviour of these materials and structure–property relationships are discussed. The study is directed towards the development of a new type of organic semiconductors based on these hybrid materials for application in organic field effect transistors and solar cells.
- Published
- 2016
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44. Modification of emission wavelength in organic random lasers based on photonic glass
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Nicolas Laurand, Erdan Gu, Alexander L. Kanibolotsky, Johannes Herrnsdorf, Benoit Guilhabert, Martin D. Dawson, Yanfeng Zhang, Yujie Chen, and Peter J. Skabara
- Subjects
Random laser ,Materials science ,business.industry ,Mean free path ,Mie scattering ,Physics::Optics ,General Chemistry ,Coherent backscattering ,Condensed Matter Physics ,Laser ,Fluence ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,Wavelength ,Optics ,law ,Materials Chemistry ,Electrical and Electronic Engineering ,Photonics ,business - Abstract
Control of the emission wavelength of a random laser (RL) system over a 7-nm waveband is demonstrated using a green-emitting π-conjugated polymer infiltrated into a photonic glass formed by nano/micro-size monodisperse silica spheres. The use of a solution-based conjugated polymer enables the complete filling of the voids within the photonic glass without suffering from quenching and the gain can therefore be maximized. The emission wavelength of these structures is set by a combination of the material system spectral gain and of the transport mean free path, the latter being controlled by the mean diameter of the spheres in the nano-scale range. Transport mean free paths of photons in the RL’s active region are calculated using Mie scattering theory and corroborated with coherent backscattering measurements. Further wavelength modification is also possible by changing the pump spot size and the pump fluence.
- Published
- 2012
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45. Close Encounters of the 3D Kind - Exploiting High Dimensionality in Molecular Semiconductors
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Yves Geerts, Peter J. Skabara, and Jean-Baptiste Arlin
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Materials science ,Organic solar cell ,business.industry ,Mechanical Engineering ,Intermolecular force ,Nanotechnology ,Organic semiconductor ,Semiconductor ,Mechanics of Materials ,Molecule ,General Materials Science ,Self-assembly ,High dimensionality ,business ,Curse of dimensionality - Abstract
In this Research News article we discuss the significance of dimensionality on the charge-transport properties of organic semiconductors. Dimensionality is defined in two ways: as a function of (i) the -conjugated framework within the molecular structure, and (ii) the degree and direction of intermolecular close-contacts between molecules in the bulk. In terms of dimensionality, silicon is a good role model for organic semiconductors, since it demonstrates 3D architecture in the bulk through covalent bonding. Achieving this for organics is challenging and requires not only a 3D molecular structure, but also a network of intermolecular short contacts in three dimensions. This review identifies the limitations of low dimensional materials and summarizes the challenges faced in progressing towards fully 3D organic semiconductors.
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- 2012
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46. Structural and DFT Studies of Dibromine and Diiodine Adducts of a Sulfur‐Rich Thiocarbonyl Donor
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M. Carla Aragoni, Luca Pala, Francesco A. Devillanova, Neil Bricklebank, Mark E. Light, Michael B. Hursthouse, Peter J. Skabara, Massimiliano Arca, and Annalisa Mancini
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Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,Halogen bond ,chemistry ,Dimer ,Intramolecular force ,Intermolecular force ,Atom ,Hypervalent molecule ,Molecule ,Moiety ,Photochemistry - Abstract
4,5-Bis(benzoylthio)-1,3-dithiole-2-thione (1) forms molecular adducts with dibromine (2) and diiodine (3), which display a range of complementary primary X-X and S-X and secondary S center dot X and X center dot X bonding interactions. Compounds 2 and 3 were characterised by X-ray diffraction analysis and FT-Raman spectroscopy. Compound 2, which is derived from the additive dibromine oxidation of 1, features a near linear BrSBr moiety that is coplanar with the dithiole-2-thione heterocycle. The SBr bonds in 2 are asymmetric; the asymmetry arises mainly through a combination of intramolecular S center dot Br bonds between the Br atoms and the thioether S atoms of the donor, and an intermolecular S center dot Br contact between one of the bromine atoms and the hypervalent S atom of an adjacent molecule. DFT calculations carried out on 2 with different functionals agree and show that the geometry featuring the SBr2 moiety coplanar with the heterocycle is more stable by about 9 kcal mol1 than that with the SBr2 unit perpendicular to the plane of the heterocycle. DFT calculations indicate that the formation of 2 can be explained based on the charge distribution on the hypothetical cationic intermediate [1-Br]+. Diiodine complex 3 is a molecular charge-transfer species, with an almost linear S-I-I moiety. The unit cell contains two molecules of donor 1, related by a centre of inversion, which form a dimer pair held together by two intermolecular S center dot S and two S center dot O contacts. The packing of the dimers generates various cavities that are able to accommodate I2 molecules as guests, in one case the guest diiodine molecule bonds with the sulfur atoms of the benzoylthio-groups and acts as a bridge between adjacent dimers, in another the diiodine is disordered along the channel-like cavity. The terminal iodine atom of each SII fragment interacts with two additional I2 molecules leading to infinite chains in the [011] direction.
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- 2012
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47. Donor–Acceptor Conjugated Polymers Based on p- and o-Benzodifuranone and Thiophene Derivatives: Electrochemical Preparation and Optical and Electronic Properties
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John C. Forgie, Bernd Tieke, Peter J. Skabara, Filipe Vilela, and Kai A. I. Zhang
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Absorption spectroscopy ,Organic Chemistry ,Polymer ,Conjugated system ,Photochemistry ,Stille reaction ,Inorganic Chemistry ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Polythiophene ,Cyclic voltammetry - Abstract
A series of π-conjugated polymers consisting of bis-EDOT or bis-EDTT units and p- or o-diphenylbenzodifuranones have been prepared electrochemically. The monomers and polymers were investigated using UV/vis absorption spectroscopy and cyclic voltammetry. The monomers were synthesized from 3,4-ethylenedioxythien-2-yl or 3,4-ethylenedithiathien-2-yl trimethylstannane and 3,7-bis(4-bromophenyl)benzo[1,2-b:4,5-b′]difuran-2,6-dione or 3,6-bis(4-bromophenyl)benzo[1,2-b:6,5-b′]difuran-2,7-dione using Stille coupling. The polymers exhibit broad absorption bands, and strong donor–acceptor characteristics with very small band gaps (in a range from 0.40 to 1.20 eV). Electrochemically grown polymer thin films exhibit reversible behavior under oxidative and reductive conditions. Under reduction, the polymer films show color changes from dark to almost transparent.
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- 2011
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48. Electrochemical synthesis of ammonia based on doped-ceria-carbonate composite electrolyte and perovskite cathode
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Peter J. Skabara, Shanwen Tao, Lei Zhang, Ibrahim A. Amar, Christophe Tg Petit, and Rong Lan
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Materials science ,Hydrogen ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Electrolyte ,Condensed Matter Physics ,Electrochemistry ,Cathode ,law.invention ,Anode ,Dielectric spectroscopy ,Ammonia production ,Ammonia ,chemistry.chemical_compound ,chemistry ,law ,General Materials Science - Abstract
Electrochemical synthesis of ammonia was investigated using a cobalt-free La0.6Sr0.4Fe0.8Cu0.2O3-δ-Ce0.8Sm0.2O2-δ (LSFCu-SDC) composite cathode and SDC-ternary carbonate composite electrolyte. La0.6Sr0.4Fe0.8Cu0.2O3-δ and Ce0.8Sm0.2O2-δ were prepared via combined EDTA-citrate complexing sol–gel and glycine nitrate processes, respectively, and characterised by X-ray diffraction (XRD). Ammonia was successfully synthesised from wet hydrogen and dry nitrogen under atmospheric pressure using Ni-SDC, SDC-carbonate and LSFCu-SDC composites as anode, electrolyte and cathode respectively. Ammonia formation was observed at 400, 425, 450 and 475 °C and the maximum rate of ammonia production was found to be 5.39 × 10−9 mol s−1 cm−2 at 450 °C and 0.8 V. The AC impedance measurements were recorded before and after the ammonia synthesis in the range of temperature 400–475 °C. The formation of ammonia at the N2 side together with stable current at 450 °C under constant voltage demonstrates that SDC-(Li/Na/K)2CO3 composite electrolyte exhibits significant proton conduction at a temperature around 450 °C.
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- 2011
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49. Conjugated Microporous Networks on the Basis of 2,3,5,6‐Tetraarylated Diketopyrrolo[3,4‐ c ]pyrrole
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Bernd Tieke, Filipe Vilela, Peter J. Skabara, and Kai A. I. Zhang
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Luminescence ,Magnetic Resonance Spectroscopy ,Materials science ,Polymers and Plastics ,Nitrogen ,Polymers ,Surface Properties ,Color ,Sonogashira coupling ,Conjugated system ,Catalysis ,Polymer solar cell ,Polymerization ,chemistry.chemical_compound ,Adsorption ,Nickel ,Polymer chemistry ,Materials Chemistry ,Pyrroles ,Microwaves ,Pyrrole ,chemistry.chemical_classification ,Molecular Structure ,Organic Chemistry ,Polymer ,Microporous material ,Communications ,Solubility ,chemistry ,Porosity ,Palladium - Abstract
π-Conjugated microporous networks have been prepared from the tetraarylated diketopyrrolo[3,4-c]pyrrole unit as a tetrafunctional building block. The reactions are carried out using microwave-assisted Yamamoto or Sonogashira cross-coupling. Red insoluble powders are obtained, showing intense fluorescence. The polymer networks exhibit a high gas storage capability, with BET surface areas up to about 500 m(2)·g(-1).
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- 2011
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50. Optical Excitations in Star-Shaped Fluorene Molecules
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Arvydas Ruseckas, Graham A. Turnbull, Peter J. Skabara, Alexander L. Kanibolotsky, Martin J. Paterson, Jean-Christophe Denis, Ian Galbraith, Ifor D. W. Samuel, Stefan Schumacher, and Neil A. Montgomery
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Models, Molecular ,Fluorenes ,Luminescence ,Photoluminescence ,Molecular Structure ,Chemistry ,Relaxation (NMR) ,Fluorene ,Photochemistry ,Molecular physics ,Dipole ,chemistry.chemical_compound ,Excited state ,Quantum Theory ,Molecule ,Density functional theory ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) - Abstract
A detailed study of the low-energy optical transitions in two families of star-shaped molecules is presented. Both families have 3-fold rotational symmetry with oligofluorene arms attached to a central core. In one family, the core of the molecule is a rigid meta-linked truxene, while the other is a meta-linked benzene moiety. The low-energy transitions were studied both experimentally and using time-dependent density functional theory (TD-DFT). The optical transitions of these new star-shaped molecules were compared with corresponding linear oligofluorenes. Both families of star-shaped molecules showed higher absorption and fluorescence dipoles and photoluminescence quantum yields than straight chain oligofluorenes. TD-DFT calculations show that absorption takes place across the entire molecule, and after excited state relaxation, the emission results from a single arm. In both theory and experiment the transition dipole moments show an approximate n(0.5) dependence on the number of fluorene units in each arm.
- Published
- 2011
- Full Text
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