Dr Ahmed Iraqi
Department of Chemistry
Reader in Polymer Chemistry
+44 114 222 9566
Full contact details
Department of Chemistry
13 Brook Hill
Dr. Iraqi obtained his BSc from the University of Fes (Morocco) in 1984. This was followed by an MSc in Chemistry from University Paul Sabatier in Toulouse in 1985 and a PhD from the same institution in 1988. Until 1996 he was a Postdoctoral Research Associate at the University of St Andrews, when he became a Lecturer at Lancaster University. In 2000 he was appointed Lecturer at the University of Sheffield, where he was promoted to Senior Lecturer in 2009 and Reader in 2013.
- Research interests
Research in the area of organic conjugated polymers has developed rapidly over the last few years in view of their potential applications in electronic devices. Our research objectives are toward the design, synthesis and exploitation of the unique physical properties of these materials, in the fields of light emitting diodes, sloar cells and field effect transistors. Themes of the research programme include:
Design and development of conjugated polymers for application in displays: Considerable research efforts are devoted to develop new highly fluorescent blue light emitting polymers. Such materials are required for efficient emission in the blue part of the electromagnetic spectrum and also as energy-transfer donors and hosts for lower band gap fluorophores and phosphorescent dyes in an effort to enable the use of both singlet and triplet excitons in the radiative decay process.
Polyfluorenes have attracted a lot of interest in this area and great advances have been achieved with these materials, however, polyfluorenes suffer from luck of stability of blue light emission in devices which compromises their use. We are interested in developing alternative materials for application in this area.
Carbazole-based polymers such as poly(vinylcarbazole) (PVK) are widely used as hole-transporting materials, as well as wide band gap hosts to various fluorophores. However, PVK is a saturated main-chain polymer and alternative main-chain conjugated polymers are required. In our group we are developing a range of 2,7-linked and 3,6-linked carbazole main-chain conjugated polymers for application in this area.
Special attention is given to 2,7-linked carbazole polymers and copolymers whose physical properties can be tailored by judicious choice of either the co-monomers used in these carbazole based materials or the nature of substituents at the 3,6-positions as well as the 9-positions of carbazole repeat units.
Design and development of conjugated polymers for application in solar cells: There is at the moment a great deal of research interest in the development of new sources of renewable energy. Photovoltaic (PV) cells offer an attractive alternative in this area; however, the cost of the current technology based on single or polycrystalline silicon PV cells is the primary limiting factor for this technology. Polymer solar cells based on blends of conjugated polymer donors and molecular acceptors (often referred to as bulk heterojunction solar cells) are attracting a great deal of interest.
These systems have potential technological value due to their ease of fabrication and their relatively low production costs. Efficient harvesting of solar energy requires the development of polymers with high absorption coefficients and extended absorption spectra in order to enable photocurrent generation from lower-energy photons. This in turn will require low band gap polymers that absorb at wavelengths extending in the near-IR region of the electromagnetic spectrum.
Our work in this area involves the development of new low band gap conjugated polymers that are able to absorb a wider portion of solar light than established polymers used in this area like poly(3-hexylthiophene)s. We are at present developing a range of low band gap donor/acceptor carbazole based conjugated copolymers for application in this area.
Other areas of investigation involve the synthesis and characterisation of a wide range of tractable functionalised regioregular polythiophenes by post-modification of preformed precursor polymers. Structurally homogeneous precursor polymers poly(3-(omega-bromoalkyl)thiophene)s are made with full regioregular control and further functionalised by covalent binding with desired functional groups.
This synthetic approach allows obtainment of tractable redox active functionalised polythiophenes that are easily characterised by conventional analytical techniques as opposed to similar materials obtained using different polymerisation methods. The physical properties of these materials (photovoltaic and electrocatalytic activity) are being investigated.
- Metal–organic framework nanosheets for enhanced performance of organic photovoltaic cells. Journal of Materials Chemistry A. View this article in WRRO
- High-Performance Multilayer Encapsulation for Perovskite Photovoltaics. Advanced Energy Materials, 8(24). View this article in WRRO
- Molecular engineering of conjugated polymers for efficient hole transport and defect passivation in perovskite solar cells. Nano Energy, 45, 28-36. View this article in WRRO
- Achieving over 11% power conversion efficiency in PffBT4T-2OD-based ternary polymer solar cells with enhanced open-circuit-voltage and suppressed charge recombination. Nano Energy, 44, 155-163. View this article in WRRO
- Synthesis of the conjugated polymer with Fluoronated carbazole donor and benzothiadiazole acceptor linked through thienothiophene. ASM Science Journal, 11(Special Issue 2), 253-262.
- Preparation and properties of fluorene-based thienothiophene substituted benzothiadiazole copolymer for the application of polymeric solar cells. Malaysian Journal of Chemistry, 20(1), 24-32.
- Comparative indoor and outdoor stability measurements of polymer based solar cells. Scientific Reports, 7. View this article in WRRO
- Improved efficiency in organic solar cells via conjugated polyelectrolyte additive in the hole transporting layer. Journal of Materials Chemistry C, 4(45), 10722-10730. View this article in WRRO
- Preparation and photovoltaic properties of pyrene-thieno[3,4-c]pyrrole-4,6-dione-based donor-acceptor polymers. European Polymer Journal, 85, 225-235. View this article in WRRO
- Pyrene–benzothiadiazole-based copolymers for application in photovoltaic devices. Polymers for Advanced Technologies. View this article in WRRO
- Synthesis and Characterization of novel Thiophene and Carbazole-based Polymers – Optical and Electrochemical Characterization. International Journal of Electrochemical Science, 5111-5127. View this article in WRRO
- Anthracene-thieno[3,4-c]pyrrole-4,6-dione based donor-acceptor conjugated copolymers for applications in optoelectronic devices. Polymers for Advanced Technologies, 27(4), 525-531. View this article in WRRO
- Thermally Stable Solution Processed Vanadium Oxide as a Hole Extraction Layer in Organic Solar Cells. Materials, 9(4), 235-235. View this article in WRRO
- PCDTBT based solar cells: one year of operation under real-world conditions. Scientific Reports, 6(1). View this article in WRRO
- Effect of fluorination pattern and extent on the properties of PCDTBT derivatives. New Journal of Chemistry, 40(2), 1655-1662. View this article in WRRO
- Dependence on material choice of degradation of organic solar cells following exposure to humid air. Journal of Polymer Science Part B: Polymer Physics, 54(2), 216-224. View this article in WRRO
- View this article in WRRO Synthesis of carbazole based co-polymers containing thienothiophene and benzothiadiazole units in a direct arylation scheme. Polymers and Polymer Composites, 24(9), 703-710.
- Thienothiophene units properties on the carbazole-based polymers for organic solar cell devices. Malaysian Journal of Analytical Sciences, 19(6), 1205-1217.
- Polymer-based solar cells having an active area of 1.6 cm2 fabricated via spray coating. APL Materials, 3(12). View this article in WRRO
- The effect of residual palladium catalyst on the performance and stability of PCDTBT:PC70BM organic solar cells. Organic Electronics, 27, 266-273. View this article in WRRO
- Grain size dependence of degradation of aluminium/calcium cathodes in organic solar cells following exposure to humid air. Solar Energy Materials and Solar Cells, 140, 25-32.
- Organic photovoltaic devices with enhanced efficiency processed from non-halogenated binary solvent blends. Organic Electronics, 21, 216-222. View this article in WRRO
- Vertical stratification and its impact on device performance in a polycarbazole based copolymer solar cells. Journal of Materials Chemistry C, 3(16), 4007-4015. View this article in WRRO
- The role of the hole-extraction layer in determining the operational stability of a polycarbazole:fullerene bulk-heterojunction photovoltaic device. Applied Physics Letters, 106(7), 073301-073301. View this article in WRRO
- Impact of fluorine substitution upon the photovoltaic properties of benzothiadiazole-fluorene alternate copolymers. RSC Adv., 5(57), 46386-46394. View this article in WRRO
- Molecular weight dependent vertical composition profiles of PCDTBT:PC₇₁BM blends for organic photovoltaics.. Sci Rep, 4, 5286. View this article in WRRO
- The fabrication of polyfluorene and polycarbazole-based photovoltaic devices using an air-stable process route. Applied Physics Letters, 105(22), 223302-223302.
- Synthesis and properties of alternating vinylene-benzothiadiazole-based copolymers with carbazole and fluorene derivatives for photovoltaic applications. International Journal of Electrochemical Science, 9(4), 1920-1941.
- Morphology Development in Amorphous Polymer: Fullerene Photovoltaic Blend Films During Solution Casting. Advanced Functional Materials. View this article in WRRO
- Fluorene-based co-polymer with high hole mobility and device performance in bulk heterojunction organic solar cells.. Macromol Rapid Commun, 34(14), 1157-1162.
- Air processed organic photovoltaic devices incorporating a MoOx anode buffer layer. Applied Physics Letters, 102(18).
- The Infl uence of MoOx Anode Stoicheometry on the Performance of Bulk Heterojunction Polymer Solar Cells. Advanced Energy Materials.
- Polymer Solar Cells: Fabricating High Performance, Donor-Acceptor Copolymer Solar Cells by Spray-Coating in Air (Adv. Energy Mater. 4/2013). Advanced Energy Materials, 3(4), 410-410.
- Synthesis and physical properties of a "double-cable" polymer for photovoltaic applications. International Journal of Electrochemical Science, 8(4), 5575-5593.
- Fabricating high performance, donor-acceptor copolymer solar cells by spray-coating in air. Advanced Energy Materials, 3(4), 505-512.
- Selenophene vs. thiophene in benzothiadiazole-based low energy gap donor–acceptor polymers for photovoltaic applications. Journal of Materials Chemistry A, 1, 5165-5171.
- Anthracene-based donor-acceptor low band gap polymers for application in solar cells.. Chem Commun (Camb), 49(22), 2252-2254.
- Competition between substrate-mediated π-π stacking and surface-mediated T(g) depression in ultrathin conjugated polymer films.. Eur Phys J E Soft Matter, 35(12), 9807. View this article in WRRO
- Theoretical investigations on the electronic and optical properties of bridged oligothiophenes.. J Phys Chem A, 116(39), 9730-9738.
- Solar Cells: Correlating Structure with Function in Thermally Annealed PCDTBT:PC70BM Photovoltaic Blends (Adv. Funct. Mater. 7/2012). Advanced Functional Materials, 22(7), 1321-1321.
- Optimising the efficiency of carbazole co-polymer solar-cells by control over the metal cathode electrode. Organic Electronics, 13(8), 1401-1408.
- Correlating structure with function in thermally annealed PCDTBT:PC
70BM photovoltaic blends. Advanced Functional Materials, 22(7), 1399-1408.
- Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend.. Adv. Energy Mater., 1(4), 499-504.
- A simple route to rod-coil block copolymers of oligo- and polythiophenes with PMMA and polystyrene. Macromolecular Chemistry and Physics, 212(11), 1129-1136.
- A novel 2,7-linked carbazole based "double cable" polymer with pendant perylene diimide functional groups: preparation, spectroscopy and photovoltaic properties. J MATER CHEM, 21(3), 851-862.
- A regioregular head to tail thiophene based "double-cable" polymer with pendant anthraquinone functional groups: Preparation, spectroscopy and photovoltaic properties. Solar Energy Materials and Solar Cells.
- Aryl amine substituted low energy gap carbazole polymers: preparation and photovoltaic properties. J MATER CHEM, 20(33), 6990-6997.
- Preparation and properties of alternating 2,7-linked carbazole copolymers with phenylene units with varying number of fluorine substituents. J MATER SCI, 44(12), 3172-3178.
- Alternating 2,7-and 3,6-linked carbazole copolymers as wide band gap energy transfer donors. THIN SOLID FILMS, 517(9), 2840-2844.
- Single molecule spectroscopy of red- and green-emitting fluorene-based copolymers.. J Chem Phys, 130(4), 044903.
- Narrow Energy Gap Polymers with Absorptions up to 1200 nm and their Photovoltaic Properties. MACROMOL RAPID COMM, 29(22), 1804-1809.
- Fluoro-protected carbazole main-chain polymers as a new class of stable blue emitting polymers. POLYM ADVAN TECHNOL, 19(4), 299-307.
- Observation of the beta-phase in two short-chain oligofluorenes. ADV FUNCT MATER, 18(4), 600-606.
- N-Aryl 2,7-Linked Carbazole Polymers and Copolymers with Fluorine Protecting Groups: A New Class of Blue Emitting Polymers for LED Applications. MOL CRYST LIQ CRYST, 497, 461-473.
- Triarylamine N-functionalized 3,6-linked carbazole main chain polymers and copolymers: Preparation and physical properties. J POLYM SCI POL CHEM, 45(24), 5957-5967.
- A new class of blue-emitting materials for LED applications: Triarylamine N-functionalised 2,7-linked carbazole polymers. MACROMOL RAPID COMM, 28(10), 1155-1160.
- Preparation and properties of 4-dialkylamino-phenyl N-functionalized 2,7-linked carbazole polymers. CHEM MATER, 18(24), 5789-5797.
- Preparation and characterisation of tractable regioregular head-to-tail poly(3-alkylthiophene)s with ferrocene substituents. POLYM INT, 55(7), 780-783.
- Postmodification of poly(9-alkyl-9H-carbazole-2,7-diyl)s as a route to new main-chain-functionalized carbazole polymers. J POLYM SCI POL CHEM, 44(10), 3336-3342.
- Effects of methyl substitution of poly(9-alkyl-9H-carbazole-2,7-diyl)s at the 3,6-positions on their physical properties. CHEM MATER, 18(4), 1007-1015.
- Synthesis and characterisation of functionalised thiophene copolymers with electron donor and acceptor substituents. REACT FUNCT POLYM, 66(1), 195-200.
- 3,6-linked 9-alkyl-9H-carbazole main-chain polymers: Preparation and properties. J POLYM SCI POL CHEM, 42(23), 6041-6051.
- Preparation and properties of 2,7-linked N-alkyl-9H-carbazole main-chain polymers. CHEM MATER, 16(3), 442-448.
- Synthesis and characterisation of telechelic regioregular head-to-tail poly(3-alkylthiophenes). J MATER CHEM, 8(1), 25-29.
- Covalent binding of redox active centres to preformed regioregular polythiophenes. J MATER CHEM, 8(1), 31-36.
- SYNTHESIS, SPECTROELECTROCHEMISTRY AND THERMOCHROMISM OF REGIOREGULAR HEAD-TO-TAIL OLIGO-[3-ARYLOXYHEXYLTHIOPHENES] AND POLY-[3-ARYLOXYHEXYLTHIOPHENES]. J MATER CHEM, 5(11), 1831-1836.
- AMINOXYL FUNCTIONALIZED POLYTHIOPHENE - SYNTHESIS AND ELECTROCHEMICAL APPLICATIONS. J MATER CHEM, 5(9), 1291-1295.
- POLYRADICALS - SYNTHESIS, SPECTROSCOPY, AND CATALYSIS. CHEM SOC REV, 23(3), 147-153.
- PREPARATION AND CHARACTERIZATION OF THIENONAPHTHOQUINONES AND THEIR RADICAL IONS. J CHEM SOC PERK T 2(9), 1589-1595.
- Polyradicals: Synthetic Strategies and Characterization. Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 236(1), 231-235.
- ANALYSIS OF THE COMPOSITION OF POLYCARBOXYLIC ACIDS OBTAINED BY CATALYTIC HYDROCARBOXYLATION OF POLYBUTADIENES. J MATER CHEM, 2(11), 1149-1154.
- CATALYTIC HYDROSILATION OF POLYBUTADIENES AS A ROUTE TO FUNCTIONAL POLYMERS. J MATER CHEM, 2(10), 1057-1064.
- PREPARATION AND REACTIVITY OF POLYEPOXIDES AND POLYKETONES - CATALYTIC-OXIDATION OF POLYBUTADIENES. J MATER CHEM, 2(2), 183-190.
- POLYMER-BOUND LIGANDS AND METAL-COMPLEXES VIA CATALYZED-REACTIONS OF POLYBUTADIENES. J CHEM SOC CHEM COMM(24), 1767-1769.
- HYDROGENATION OF ACRYLIC ACIDS CATALYZED BY COMPLEXES OF RHODIUM(I) CONTAINING MIXED ANHYDRIDES OF ACRYLIC AND DIPHENYLPHOSPHINOUS ACIDS. J CHEM SOC DALTON(8), 1929-1935.
- POLYKETONES VIA OXIDATION OF POLYBUTADIENES CATALYZED BY COMPLEXES OF PLATINUM(II). POLYHEDRON, 10(9), 993-995.
- ChemInform Abstract: Linkage Isomerism in Rhodium(I) Complexes of Mixed Anhydrides of Diphenylphosphinous and Acrylic Acids: Crystal and Molecular Structure of (RhCl(PPh3)(Ph2PO2CCH=CHMe)).. ChemInform, 21(14).
- LINKAGE ISOMERISM IN RHODIUM(I) COMPLEXES OF MIXED ANHYDRIDES OF DIPHENYLPHOSPHINOUS AND ACRYLIC ACIDS - CRYSTAL AND MOLECULAR-STRUCTURE OF [RHCL(PPH3)(PH2PO2CCH=CHME)]. J CHEM SOC DALTON(1), 29-34.
- A HIGH-ACTIVITY MOLYBDENUM CONTAINING EPOXIDATION CATALYST AND ITS USE IN REGIOSELECTIVE EPOXIDATION OF POLYBUTADIENE. J CHEM SOC CHEM COMM(21), 1688-1690.
- CHARACTERIZATION AND CATALYTIC ACTIVITY OF BIMETALLIC CATIONIC RHODIUM-TITANIUM AND RHODIUM-ZIRCONIUM COMPLEXES. J ORGANOMET CHEM, 353(1), 45-52.
- A SEMIBRIDGING HYDRIDO ZIRCONIUM RHODIUM COMPLEX - A POSSIBLE WAY TO CATALYTIC HYDROGEN TRANSFER ON D0-D8 SYSTEMS. ORGANOMETALLICS, 6(6), 1197-1201.
- ChemInform Abstract: A Zirconium-Rhodium Hydrido Complex, Cp2Zr(CH2PPh2)2RhH(PPh3), as Catalyst for the Hydroformylation of 1-Hexene.. ChemInform, 18(3).
- A ZIRCONIUM-RHODIUM HYDRIDO COMPLEX, CP2ZR(CH2PPH2)2RHH(PPH3), AS CATALYST FOR THE HYDROFORMYLATION OF 1-HEXENE. J ORGANOMET CHEM, 311(3), C60-C62.
- Donor- Acceptor Carbazole and Uinoxaline Based Polymers for Application in Solar Cells. Physical Science International Journal, 10(2), 1-8.
- Triisopropylsilylacetylene-functionalised anthracene-alt-benzothiadiazole copolymers for application in bulk heterojunction solar cells. RSC Advances, 5(123), 101607-101615. View this article in WRRO
- Impact of dithienyl or thienothiophene units on the optoelectronic and photovoltaic properties of benzo[1,2,5]thiadiazole based donor–acceptor copolymers for organic solar cell devices. RSC Adv., 4(81), 43142-43149.
- ChemInform Abstract: Polyradicals: Synthesis, Spectroscopy, and Catalysis. ChemInform, 25(47), no-no.
- ChemInform Abstract: Preparation and Characterization of Thienonaphthoquinones and Their Radical Ions.. ChemInform, 24(51), no-no.
- ChemInform Abstract: Hydrogenation of Acrylic Acids Catalysed by Complexes of Rhodium(I) Containing Mixed Anhydrides of Acrylic and Diphenylphosphinous Acids.. ChemInform, 22(45), no-no.
- Pyrene- benzo[1,2,5]thiadiazole based conjugated polymers for application in BHJ solar cells. Journal of Saudi Chemical Society. View this article in WRRO
- Carbazole and Thienyl Benzo[1,2,5]Thiadiazole Based Polymers with Improved Open Circuit Voltages and Processability for Application in Solar Cells. Journal of Materials Chemistry.
Conference proceedings papers
- Preparation of poly(9-alkylcarbazole-3,6-diyl)s via palladium catalysed cross-coupling reactions. SYNTHETIC METALS, Vol. 119(1-3) (pp 159-160)
- Synthesis, characterisation and study of photoluminescent properties of head to tail poly(3-pentoxythiophene), poly(3-cyclohexylthiophene) and mixed alkoxy cyclohexyl 3-substituted polythiophenes. SYNTHETIC METALS, Vol. 102(1-3) (pp 1220-1221)
- New synthetic routes to polyacenes. SYNTHETIC METALS, Vol. 101(1-3) (pp 100-101)
- Synthesis of thiophene substituted ruthenium and rhenium bipyridyl complexes.. SYNTHETIC METALS, Vol. 84(1-3) (pp 441-442)
- Functionalization of poly(p-phenylenevinylene) polymers with pendant nitroxide groups. SYNTHETIC METALS, Vol. 84(1-3) (pp 333-334)
- Synthesis of methacrylate and silicone polymers with pendant thiophene groups. SYNTHETIC METALS, Vol. 84(1-3) (pp 377-378)
- POLYRADICALS - SYNTHETIC STRATEGIES AND CHARACTERIZATION. SYNTHETIC METALS, Vol. 55(2-3) (pp 867-872)
- POLYRADICALS - SYNTHETIC STRATEGIES AND CHARACTERIZATION. MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, Vol. 234 (pp 771-775)
- Teaching interests
Polymer Chemistry; Organometallic Chemistry.
- Teaching activities
Undergraduate and postgraduate taught modules
- Chemistry and the World Around Us (Level 1): The Chemistry Behind Things that Glow
Introducing some simple chemical principles of familiar aspects of the world around us which we often take for granted and to highlight the significance of chemistry to everyday life, society, and the future of our planet.
- Group Theory in Chemistry (Level 2)
This course introduces group theory in chemistry, and applies it to the analysis of molecular orbital diagrams and to determining the stretching vibrations in simple molecules.
- Main Group Chemistry 2 (Level 2)
This lecture course expands upon and introduces more of the wonderful and varied chemistry of the main group elements.
- New Materials (Level 4)
This course gives an overview of the design, preparation and uses of organic conjugated polymers and oligomers in the electronics industry and focuses on the factors governing their physical properties and their structure-property relationship in electronic device applications.
- Smart Polymers and Polymeric Materials (Postgraduate level)
- This module focuses on the syntheses, structures, behaviours of polymers and polymeric materials that are responsive to external stimuli such as heat, light, electric potential, pH and ionic strength.
- Tutorials: Level 2 Organic Chemistry.
- Skills for Success: Databases Project.
- Level 3 Literature Review
- MSc Laboratories
- Level 4 Research Project
- Chemistry and the World Around Us (Level 1): The Chemistry Behind Things that Glow