Iraqi, Ahmed - University of Sheffield - Department of Chemistry

个人简介

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.

研究领域

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.

近期论文

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Kwak C, Perez G, Freestone B, Al-Isaee S, Iraqi A, Lidzey DG & Dunbar A (2016) Improved efficiency in organic solar cells via conjugated polyelectrolyte additive in the hole transporting layer. Journal of Materials Chemistry C. View this article in WRRO Alqurashy BA, Iraqi A, Zhang Y & Lidzey DG (2016) 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 Iraqi A, Cartwright L, Zhang Y, Lidzey DG & Alqurashy BA (2016) Pyrene–benzothiadiazole-based copolymers for application in photovoltaic devices. Polymers for Advanced Technologies. View this article in WRRO Ali B. Alghamdi A (2016) 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 Alsulami A, Griffin J, Alqurashi R, Yi H, Iraqi A, Lidzey D & Buckley A (2016) 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 Cartwright L, Neal TJ, Rutland NJ & Iraqi A (2016) 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 Cartwright L, Yi H & Iraqi A (2016) Effect of fluorination pattern and extent on the properties of PCDTBT derivatives. New J. Chem., 40(2), 1655-1662. View this article in WRRO Zhang Y, Bovill E, Kingsley J, Buckley AR, Yi H, Iraqi A, Wang T & Lidzey DG (2016) PCDTBT based solar cells: one year of operation under real-world conditions. Scientific Reports, 6, 21632-21632. View this article in WRRO