Ahmed Iraqi
The University of Sheffield, Chemistry, Faculty Member
A carbazole of formula I: wherein R 1 and R 2 are each independently halo, B(OH) 2 , B(OR 7 ) 2 , Sn(R 8 ) 3 , C 1-20 hydrocarbyl, or C 1-20 hydrocarbyl comprising one or more hetero atoms, R 3 is H, halo, C 1-20 hydrocarbyl, C 1-20... more
A carbazole of formula I: wherein R 1 and R 2 are each independently halo, B(OH) 2 , B(OR 7 ) 2 , Sn(R 8 ) 3 , C 1-20 hydrocarbyl, or C 1-20 hydrocarbyl comprising one or more hetero atoms, R 3 is H, halo, C 1-20 hydrocarbyl, C 1-20 hydrocarbyl comprising one or more heteroatoms, or cyano, R 4 and R 5 are each independently H, halo, C 1-20 hydrocarbyl, C 1-20 hydrocarbyl comprising one or more heteroatoms, or cyano, and R 7 and R 8 are each independently C 1-20 hydrocarbyl, provided that R 4 and R 5 are not both H when R 3 is n-octyl, and conjugated 2,7 oligomers, polymers and co-polymers thereof. Embodiments of the oligomers, polymers and co-polymers can, for example, be formed into films which can be incorporated into electronic devices.
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Metal–organic framework nanosheets (MONs) are incorporated into the active layer of bulk heterojunction polymer–fullerene solar cells for the first time, resulting in an almost doubling of power conversion efficiency.
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The water soluble conjugated polyelectrolyte was synthesised by Suzuki cross coupling and increased the power conversion efficiency by improving hole charge transfer from active layer into the hole transporting layer.
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Fluorination of PCDTBT derivatives at different positions and to different extents causes major changes in their properties.
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Triisopropylsilylacetylene-functionalised anthracene-based donor–acceptor polymers are presented along with their optical, electrochemical and photovoltaic properties in bulk heterojunction solar cells.
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Experimental Details: Measurements: NMR spectra were recorded on Bruker 250 MHz, AMX400 400 MHz or DRX500 500MHz NMR spectrometers at 22 °C in chloroform-d 1 or acetone-d 6 solutions with TMS as the internal standard. IR absorption... more
Experimental Details: Measurements: NMR spectra were recorded on Bruker 250 MHz, AMX400 400 MHz or DRX500 500MHz NMR spectrometers at 22 °C in chloroform-d 1 or acetone-d 6 solutions with TMS as the internal standard. IR absorption spectra were recorded on the Nicolet Model 205 FT-IR Spectrometer. Liquid samples were analysed neat, using NaCl–plate method and solid samples were analysed using the Diamond ATR attachment for solid samples. Melting points were obtained using Gallenkamp Melting Point Apparatus. GC-MS spectra were recorded on Perkin Elmer Turbomass Mass Spectrometer equipped with Perkin Elmer PE-5MS Capillary Column. Mass spectra were obtained by the electron impact method (EI) or the chemical ionisation method (CI). GPC curves were recorded on the equipment consisting of Waters Model 515 HPLC Pump, GILSON Model 234 Autoinjector,
A series of alternating copolymers containing cyclopentadithiophene (CPDT) flanked by thienyl moieties as electron-donor units and benzothiadiazole dicarboxylic imide (BTDI) as electron-acceptor units were designed and synthesized for... more
A series of alternating copolymers containing cyclopentadithiophene (CPDT) flanked by thienyl moieties as electron-donor units and benzothiadiazole dicarboxylic imide (BTDI) as electron-acceptor units were designed and synthesized for solar cell applications. Different solubilizing side chains, including 2-ethylhexyl chains and n-octyl chains were attached to CPDT units, whereas 3,7-dimethyloctyl chains and n-octyl chains were anchored to the BTDI moieties. The impact of these substituents on the solubilities, molecular weights, optical and electrochemical properties, and thermal and structural properties of the resulting polymers was investigated. PCPDTDTBTDI-EH, DMO was synthesized via Suzuki polymerization, whereas PCPDTDTBTDI-8, DMO, and PCPDTDTBTDI-EH, 8 were prepared through direct arylation polymerization. PCPDTDTBTDI-8, DMO has the highest number average molecular weight (Mn = 17,400 g mol−1) among all polymers prepared. The PCPDTDTBTDI-8, DMO and PCPDTDTBTDI-8, 8 which have...
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In this review paper, we present a comprehensive summary of the different organic solar cell (OSC) families. Pure and doped conjugated polymers are described. The band structure, electronic properties, and charge separation process in... more
In this review paper, we present a comprehensive summary of the different organic solar cell (OSC) families. Pure and doped conjugated polymers are described. The band structure, electronic properties, and charge separation process in conjugated polymers are briefly described. Various techniques for the preparation of conjugated polymers are presented in detail. The applications of conductive polymers for organic light emitting diodes (OLEDs), organic field effect transistors (OFETs), and organic photovoltaics (OPVs) are explained thoroughly. The architecture of organic polymer solar cells including single layer, bilayer planar heterojunction, and bulk heterojunction (BHJ) are described. Moreover, designing conjugated polymers for photovoltaic applications and optimizations of highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy levels are discussed. Principles of bulk heterojunction polymer solar cells are addressed. Finally, strategies for ba...
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In this work four novel donor-acceptor copolymers, PCDTBTDI-DMO, PCDTBTDI-8, P2F-CDTBTDI-DMO and P2F-CDTBTDI-8, were designed and synthesised via Suzuki polymerisation. The first two copolymers consist of 2,7-carbazole flanked by thienyl... more
In this work four novel donor-acceptor copolymers, PCDTBTDI-DMO, PCDTBTDI-8, P2F-CDTBTDI-DMO and P2F-CDTBTDI-8, were designed and synthesised via Suzuki polymerisation. The first two copolymers consist of 2,7-carbazole flanked by thienyl moieties as the electron donor unit and benzothiadiazole dicarboxylic imide (BTDI) as electron acceptor units. In the structures of P2F-CDTBTDI-DMO and P2F-CDTBTDI-8 copolymers, two fluorine atoms were incorporated at 3,6-positions of 2,7-carbazole to investigate the impact of fluorine upon the optoelectronic, structural and thermal properties of the resulting polymers. P2F-CDTBTDI-8 possesses the highest number average molecular weight (Mn = 24,200 g mol−1) among all the polymers synthesised. PCDTBTDI-DMO and PCDTBTDI-8 show identical optical band gaps of 1.76 eV. However, the optical band gaps of fluorinated copolymers are slightly higher than non-fluorinated counterparts. All polymers have deep-lying highest occupied molecular orbital (HOMO) leve...
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In this work, four donor–acceptor copolymers, PFDTBTDI-DMO, PFDTBTDI-8, PDBSDTBTDI-DMO, and PDBSDTBTDI-8, based on alternating 2,7-fluorene or 2,7-dibenzosilole flanked by thienyl units, as electron-donor moieties and benzothiadiazole... more
In this work, four donor–acceptor copolymers, PFDTBTDI-DMO, PFDTBTDI-8, PDBSDTBTDI-DMO, and PDBSDTBTDI-8, based on alternating 2,7-fluorene or 2,7-dibenzosilole flanked by thienyl units, as electron-donor moieties and benzothiadiazole dicarboxylic imide (BTDI) as electron-accepting units, have been designed and synthesized for photovoltaic applications. All polymers were synthesized in good yields via Suzuki polymerization. The impact of attaching two different alkyl chains (3,7-dimethyloctyl vs. n-octyl) to the BTDI units upon the solubilities, molecular weights, optical and electrochemical properties, and thermal and structural properties of the resulting polymers was investigated. PFDTBTDI-8 has the highest number average molecular weight (Mn = 24,900 g·mol−1) among all polymers prepared. Dibenzosilole-based polymers have slightly lower optical band gaps relative to their fluorene-based analogues. All polymers displayed deep-lying HOMO levels. Their HOMO energy levels are unaffec...
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Two alternating copolymers of dithienosilole (DTS) were designed and synthesized with small optical band gaps, flanked by thienyl units as electron-donor moieties and benzothiadiazole dicarboxylic imide (BTDI) as electron-acceptor... more
Two alternating copolymers of dithienosilole (DTS) were designed and synthesized with small optical band gaps, flanked by thienyl units as electron-donor moieties and benzothiadiazole dicarboxylic imide (BTDI) as electron-acceptor moieties. The BTDI moieties were anchored to two different solubilizing side chains, namely 3,7-dimethyloctyl and n-octyl chains. An analysis of the effect of the electrochemical, optical, thermal, and structural characteristics of the resulting polymers along with their solubility and molecular weight is the subject of this paper. The Stille polymerization was used to synthesize PDTSDTBTDI-DMO and PDTSDTBTDI-8. The average molecular weight of PDTSDTBTDI-DMO and PDTSDTBTDI-8 is 14,600 and 5700 g mol−1, respectively. Both polymers have shown equivalent optical band gaps around 1.4 eV. The highest occupied molecular orbital (HOMO) levels of the polymers were comparable, around −5.2 eV. The lowest unoccupied molecular orbital (LUMO) values were −3.56 and −3.4...
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In this study, two novel conjugated polymers, poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy]pyrene-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)-6,7-difluoroquinoxaline) (PPyQxff) and... more
In this study, two novel conjugated polymers, poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy]pyrene-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)-6,7-difluoroquinoxaline) (PPyQxff) and poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy)pyren-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)quinoxaline) (PPyQx), consisting of quinoxaline units with and without fluorine substituents, as electron-accepting moieties and pyrene flanked with dithienyl units as electron-donating moieties were prepared via Stille polymerization reactions for use as electron donor materials in bulk heterojunction (BHJ) solar cells. PPyQxff and PPyQx were characterized by X-ray powder diffraction (XRD), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV−VIS absorption, and nuclear magnetic resonance (NMR) spectroscopy. PPyQxff and PPyQx revealed excellent solution processability in common organic solvents. PPyQxff and PPyQx presented decomposition temperatures above 300 °C....
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2, 2, 6, 6-Tetramethyl-4-[4-(3-thienyl) butoxycarbonyl] piperidin-1-yloxyl and the corresponding N-hydroxytosylate salt have been prepared and polymerized in good yields by chemical and electrochemical methods. The chemically prepared... more
2, 2, 6, 6-Tetramethyl-4-[4-(3-thienyl) butoxycarbonyl] piperidin-1-yloxyl and the corresponding N-hydroxytosylate salt have been prepared and polymerized in good yields by chemical and electrochemical methods. The chemically prepared tetramethylpiperidin-...
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Two novel low band gap donor–acceptor (D–A) copolymers, poly[9,10-bis(4-(dodecyloxy)phenyl)-2,6-anthracene-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole-N-5,6-(3,7-dimethyloctyl)dicarboxylic imide)] (PPADTBTDI-DMO) and... more
Two novel low band gap donor–acceptor (D–A) copolymers, poly[9,10-bis(4-(dodecyloxy)phenyl)-2,6-anthracene-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole-N-5,6-(3,7-dimethyloctyl)dicarboxylic imide)] (PPADTBTDI-DMO) and poly[9,10-bis(4-(dodecyloxy)phenyl)-2,6-anthracene-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole-5,6-N-octyl-dicarboxylic imide)] (PPADTBTDI-8) were synthesized in the present work by copolymerising the bis-boronate ester of 9,10-phenylsubstituted anthracene flanked by thienyl groups as electron–donor units with benzothiadiazole dicarboxylic imide (BTDI) as electron–acceptor units. Both polymers were synthesized in good yields via Suzuki polymerisation. Two different solubilizing alkyl chains were anchored to the BTDI units in order to investigate the impact upon their solubilities, molecular weights, optical and electrochemical properties, structural properties and thermal stability of the resulting polymers. Both polymers have comparable molecula...
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In this work three novel phthalate-based thermocleavable copolymers, PBTP-11, PBTDTP-11 and PFDTP-11 have been designed and synthesized. PBTP-11 and PBTDTP-11 were prepared by copolymerizing distannylated bithiophene without or with... more
In this work three novel phthalate-based thermocleavable copolymers, PBTP-11, PBTDTP-11 and PFDTP-11 have been designed and synthesized. PBTP-11 and PBTDTP-11 were prepared by copolymerizing distannylated bithiophene without or with flanked thienyl groups as the electron-donor units with dibrominated secondary phthalate ester as the electron-acceptor units. PFDTP-11 was prepared by copolymerizing distannylated fluorene flanked by thienyl groups as the electron-donor moieties with dibrominated secondary phthalate ester as the electron-acceptor moieties. All polymers were prepared via the Stille polymerization. The impact of two different electron-donor units on the solubility, molecular weights, optical properties, thermal and structural properties of the resulting polymers were investigated. PFDTP-11 had the highest average molecular weight (Mn = 16,400 g mol−1). The polymers had Eg in the range of 2.11–2.58 eV. After thermal treatment, the Eg of the polymers were reduced by around ...
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We report comparative indoor and outdoor stability testing of organic solar cells based on a blend between a donor-acceptor polyfluorene copolymer and a fullerene derivative. The outdoor testing was conducted for a period over... more
We report comparative indoor and outdoor stability testing of organic solar cells based on a blend between a donor-acceptor polyfluorene copolymer and a fullerene derivative. The outdoor testing was conducted for a period over 12,000 hours in Sheffield, England, with a Ts80 lifetime determined in excess of 10,000 hours (420 days). Indoor lifetime testing was performed on solar cells using a solar simulator under a constant irradiance of 1000 W/m(2) for more than 650 hours. We show that under the conditions explored here, device degradation under the two sets of conditions is approximately dependent on the absorbed optical energy dose.
Polyfluorenes and poly(p-phenylene)s have attracted a lot of interest in this area, and great advances have been achieved with these materials. We have recently been investigating alternative polymers that could be used in this area and... more
Polyfluorenes and poly(p-phenylene)s have attracted a lot of interest in this area, and great advances have been achieved with these materials. We have recently been investigating alternative polymers that could be used in this area and have found that poly(9-alkyl-9H-carbazole-2,7-diyl)s6 ...
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A Semibridging Hydrido Zirconium-Rhodium Complex: A ... Possible Way to Catalytic Hydrogen Transfer on do-de Systems ... Robert Choukroun,'' Ahmed Iraqi,la Danible Gervais, * la Jean-Claude Daran,lb and Yves Jeannin' ...... more
A Semibridging Hydrido Zirconium-Rhodium Complex: A ... Possible Way to Catalytic Hydrogen Transfer on do-de Systems ... Robert Choukroun,'' Ahmed Iraqi,la Danible Gervais, * la Jean-Claude Daran,lb and Yves Jeannin' ... Laboratoire de Chimie de Coordination du ...
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... View all references 22. (a) O'Brien , DF , Giebeler , C. , Fletcher , RB , Cadby , AJ , Palilis , LC , Lidzey , DG , Lane , PA , Bradley , DDC , & Blau , W. ( 2001 ). Synth. ... Electron., 11, 111; (b) Yan, H., Lee,... more
... View all references 22. (a) O'Brien , DF , Giebeler , C. , Fletcher , RB , Cadby , AJ , Palilis , LC , Lidzey , DG , Lane , PA , Bradley , DDC , & Blau , W. ( 2001 ). Synth. ... Electron., 11, 111; (b) Yan, H., Lee, P., Armstrong, NR, Graham, A., Evmenenko, GA, Dutta, P., & Marks, TJ (2005) . ...
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The preparation and characterization of poly(3,6-dimethyl-9-alkyl-9H-carbazole-2,7-diyl)s P1 and poly(3,6-dimethyl-9-alkyl-9H-carbazole-alt-9-alkyl-9H-carbazole-2,7 -diyl)s alternating copolymers P2 are presented. The polymers were... more
The preparation and characterization of poly(3,6-dimethyl-9-alkyl-9H-carbazole-2,7-diyl)s P1 and poly(3,6-dimethyl-9-alkyl-9H-carbazole-alt-9-alkyl-9H-carbazole-2,7 -diyl)s alternating copolymers P2 are presented. The polymers were prepared via Suzuki cross-coupling reactions, and ...
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Abstract New alternating copolymers comprising 2,7-linked-3,6-dimethyl-9-(2-hexyldecy)-9H -carbazole and 1, 4-phenylene units (P1), 2,5-difluoro-1,4-phenylene units (P2), and 2,3,5,6-tetrafluoro -1,4-phenylene units (P3) have been... more
Abstract New alternating copolymers comprising 2,7-linked-3,6-dimethyl-9-(2-hexyldecy)-9H -carbazole and 1, 4-phenylene units (P1), 2,5-difluoro-1,4-phenylene units (P2), and 2,3,5,6-tetrafluoro -1,4-phenylene units (P3) have been prepared using Suzuki cross-coupling conditions. ...
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Organic photovoltaic devices (OPVs) based on conjugated poly-mers and fullerene blends offer an attractive method to pro-duce renewable energy. It has been demonstrated that they can be manufactured on flexible substrates and at low cost... more
Organic photovoltaic devices (OPVs) based on conjugated poly-mers and fullerene blends offer an attractive method to pro-duce renewable energy. It has been demonstrated that they can be manufactured on flexible substrates and at low cost over large areas using the high ...
An alternating copolymer comprising 3,6-linked-9-(2-ethylhexyl)-9H-carbazole and 2,7-linked-3,6-dimethyl-9-(2-hexyldecy)-9H-carbazole has been prepared using Suzuki cross-coupling conditions. The polymer was characterised by nuclear... more
An alternating copolymer comprising 3,6-linked-9-(2-ethylhexyl)-9H-carbazole and 2,7-linked-3,6-dimethyl-9-(2-hexyldecy)-9H-carbazole has been prepared using Suzuki cross-coupling conditions. The polymer was characterised by nuclear magnetic ...
Research Interests: Engineering, Fluorescence Spectroscopy, Nuclear Magnetic Resonance, Organic Semiconductors, Ir, and 15 moreAbsorption spectroscopy, Physical sciences, Blue Light, Band Gap, Gel Permeation Chromatography, Iridium, Optoelectronic Devices, Molecular weight, Energy Transfer, Electroluminescence, Absorption Spectra, Copolymers, Nuclear Magnetic Resonance Spectroscopy, Light Emitting Diode, and Suzuki coupling
ABSTRACT
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Apart from a few cases where the ferrocene functionalised polythiophenes are prepared directly by chemical means on starting from ferrocene functionalised thiophene monomers,2 or post-modification of electrochemically deposited films of... more
Apart from a few cases where the ferrocene functionalised polythiophenes are prepared directly by chemical means on starting from ferrocene functionalised thiophene monomers,2 or post-modification of electrochemically deposited films of polythiophenes with activated ...
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A Semibridging Hydrido Zirconium-Rhodium Complex: A ... Possible Way to Catalytic Hydrogen Transfer on do-de Systems ... Robert Choukroun,'' Ahmed Iraqi,la Danible Gervais, * la Jean-Claude Daran,lb and Yves Jeannin' ...... more
A Semibridging Hydrido Zirconium-Rhodium Complex: A ... Possible Way to Catalytic Hydrogen Transfer on do-de Systems ... Robert Choukroun,'' Ahmed Iraqi,la Danible Gervais, * la Jean-Claude Daran,lb and Yves Jeannin' ... Laboratoire de Chimie de Coordination du ...
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Polyfluorenes and poly(p-phenylene)s have attracted a lot of interest in this area, and great advances have been achieved with these materials. We have recently been investigating alternative polymers that could be used in this area and... more
Polyfluorenes and poly(p-phenylene)s have attracted a lot of interest in this area, and great advances have been achieved with these materials. We have recently been investigating alternative polymers that could be used in this area and have found that poly(9-alkyl-9H-carbazole-2,7-diyl)s6 ...