Dr Alan Dunbar
Department of Chemical and Biological Engineering
Senior Lecturer in Energy
Assistant Faculty Director of Learning and Teaching (Student Experience)
+44 114 222 7551
Full contact details
Department of Chemical and Biological Engineering
Sir Robert Hadfield Building
I attained my MPhys in Physics with Electronics at UMIST (Manchester) in 1997, and my PhD entitled `Preparation and characterisation of Silicon – Germanium quantum dots´ in 2001 under the supervision of Dr M. Halsall. After my PhD, I moved to the University of Canterbury, Christchurch, New Zealand to work for two years with Associate Professor Simon Brown investigating the electrical properties of metallic nano-particles. I applied percolation theory to explain the onset of conduction in thin films of deposited nano-particles in conjunction with morphological data obtained by atomic force microscopy and electron microscopy.
I then returned to the UK to begin working in the University of Sheffield's Department of Physics and Astronomy where I developed gas sensors for volatile organic compounds with Dr T. Richardson. The porphyrin based gas sensors undergo strong colour changes upon exposure to specific toxic gases which co-ordinate to the porphyrin as axial ligands.
I then took up a research post working with Prof. R. Jones FRS and Prof D Lidzey focused on the optimization of polymer based solar cells through understanding how the nano-scale morphology of the thin polymer films wthin the devices influences the device efficiency. This involved in situ spectroscopic ellipsometry and x-ray reflectivity to investigate the development of phase separation during the deposition of the thin films of solar cell materials.
In 2009 I was appointed as lecturer in energy in the Department of Chemical Engineering and Biological at the University of Sheffield, and in 2010 I took on the role of first year tutor. In Jan 2014 I took on the role of Post Graduate Research Tutor, and then in Sept 2014 became Director of Student Support. In 2015 I was promoted to Senior Lecturer in Energy. I now lead an active and diverse research group studying various research interests.
- Research interests
- Polymer Based Solar Cells
- Experimental techniques to characterise nano-scale phase separation in polymers
- Thin film toxic gas sensors
- Electrical properties of nano-structured systems
- Perovskite crystallization dynamics during spin-casting : an In situ wide-angle x-ray scattering study. ACS Applied Energy Materials, 3(7), 6155-6164.
- Low cost, high sensitivity detection of waterborne Al3+ cations and F− anions via the fluorescence response of a morin derivative dye. Analytica Chimica Acta, 1105, 1-10. View this article in WRRO
- Profile retrieval of a buried periodic structure using spin echo grazing incidence neutron scattering. Applied Physics Letters, 116(10). View this article in WRRO
- In−situ monitoring Poly(3-hexylthiophene) nanowire formation and shape evolution in solution via small angle neutron scattering. Solar Energy Materials and Solar Cells, 202. View this article in WRRO
- Interfacial width and phase equilibrium in polymer-fullerene thin-films. Communications Physics, 2(1). View this article in WRRO
- Adaptive and sensitive fibre-optic fluorimetric transducer for air- and water-borne analytes. Talanta, 199, 40-45. View this article in WRRO
- Enhancement of Dunaliella salina growth by using wavelength shifting dyes. Journal of Applied Phycology. View this article in WRRO
- Determination of the Thin Film Structure of Zwitterion Doped Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate). A Neutron Reflectivity Study.. ACS Applied Materials & Interfaces. View this article in WRRO
- Stoichiometry-dependent local instability in MAPbI3 perovskite materials and devices. Journal of Materials Chemistry A. View this article in WRRO
- Does 1,8-diiodooctane affect the aggregation state of PC71BM in solution?. Royal Society Open Science. View this article in WRRO
- Understanding the gas adsorption kinetics of Langmuir-Schaefer porphyrin films using two comparative sensing systems. Sensors and Actuators B: Chemical, 254, 669-680. View this article in WRRO
- Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction. The Journal of Physical Chemistry B. View this article in WRRO
- An X-ray scattering and electron microscopy study of methylammonium bismuth perovskites for solar cell applications. Journal of Materials Research. 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
- Monitoring the Formation of a CH₃NH₃PbI₃–⨯Cl⨯ Perovskite during Thermal Annealing Using X-Ray Scattering. Advanced Functional Materials, 26(27), 4934-4942. View this article in WRRO
- Controlling surface adsorption to enhance the selectivity of porphyrin based gas sensors. Applied Surface Science, 362, 191-201.
- Physical mechanisms responsible for the water-induced degradation of PC61BM P3HT photovoltaic thin films. Journal of Polymer Science Part B: Polymer Physics, 54(2), 141-146. View this article in WRRO
- Minimising microbubble size through oscillation frequency control. Chemical Engineering Research and Design, 104, 357-366. View this article in WRRO
- 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
- Improving the selectivity of a free base tetraphenylporphyrin based gas sensor for NO2 and carboxylic acid vapors. Sensors and Actuators B: Chemical, 206, 74-83.
- A proto-type sensor for volatile organic compounds based on magnesium porphyrin molecular films. Sensors and Actuators, B: Chemical, 202, 854-860.
- Real time laser interference microscopy for bar-spread polystyrene/poly(methyl methacrylate) blends. Journal of Polymer Science Part B: Polymer Physics, n/a-n/a.
- Morphology Development in Amorphous Polymer: Fullerene Photovoltaic Blend Films During Solution Casting. Advanced Functional Materials. View this article in WRRO
- Direct observation of morphological development during the spin-coating of polystyrene-poly(methyl methacrylate) polymer blends. Journal of Polymer Science, Part B: Polymer Physics, 51(11), 875-881.
- 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.
- Fabricating high performance, donor-acceptor copolymer solar cells by spray-coating in air. Advanced Energy Materials, 3(4), 505-512.
- A neutron spin echo resolved grazing incidence scattering study of crystallites in organic photovoltaic thin films. Applied Physics Letters, 102(7).
- Competition between substrate-mediated π-π stacking and surface-mediated Tg depression in ultrathin conjugated polymer films. The European Physical Journal E, 35(12). View this article in WRRO
- 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.
- Correlating structure with function in thermally annealed PCDTBT:PC
70BM photovoltaic blends. Advanced Functional Materials, 22(7), 1399-1408.
- Macroscopic expansion of tetraphenylporphyrin Langmuir layers stimulated by protonation. SOFT MATTER, 8(10), 2807-2811.
- In situ imaging and height reconstruction of phase separation processes in polymer blends during spin coating.. ACS Nano, 5(6), 5124-5131.
- Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend.. Adv. Energy Mater., 1(4), 499-504.
- A Phase Diagram of the P3HT:PCBM Organic Photovoltaic System: Implications for Device Processing and Performance. MACROMOLECULES, 44(8), 2908-2917.
- Nanoscale Phase Separation of P3HT PCBM Thick Films As Measured by Small-Angle X-ray Scattering. MACROMOLECULES, 44(16), 6503-6508.
- Tuning free base tetraphenylporphyrins as optical sensing elements for volatile organic analytes. J MATER CHEM, 21(13), 4882-4887.
- Detection of volatile organic compounds using porphyrin derivatives.. J Phys Chem B, 114(36), 11697-11702.
- Macroscopic manifestation of a vapour-induced molecular switching phenomenon. SOFT MATTER, 6(14), 3157-3159.
- The development of nanoscale morphology in polymer: fullerene photovoltaic blends during solvent casting. SOFT MATTER, 6(17), 4128-4134.
- Depletion of PCBM at the cathode interface in P3HT/PCBM thin films as quantified via neutron reflectivity measurements.. Adv Mater, 22(22), 2444-2447.
- A solution concentration dependent transition from self-stratification to lateral phase separation in spin-cast PS:d-PMMA thin films.. Eur Phys J E Soft Matter, 31(4), 369-375. View this article in WRRO
- Alkylamine sensing using langmuir-blodgett films of n-alkyl-N-phenylamide-substituted zinc porphyrins.. J Phys Chem B, 112(36), 11278-11283.
- Langmuir-Schaefer films of five different free base tetraphenylporphyrins for optical-based gas sensing of NO2. SENSOR ACTUAT B-CHEM, 128(2), 468-481.
- Modeling the kinetics of gas adsorption in multilayer porphyrin films.. Langmuir, 23(4), 1759-1767.
- Experimental and simulational study of the operation conditions for a high transmission mass filter. Review of Scientific Instruments, 78(5).
- Investigation of free base, Mg, Sn, and Zn substituted porphyrin LB films as gas sensors for organic analytes.. J Phys Chem B, 110(33), 16646-16651.
- Morphological differences between Bi, Ag and Sb nano-particles and how they affect the percolation of current through nano-particle networks. European Physical Journal D, 39(3), 415-422.
- Construction and application of a UHV compatible cluster deposition system. Journal of Nanoparticle Research, 8(3-4), 405-416.
- Optical changes induced in Zn porphyrin solutions and LB films by exposure to amines. J PORPHYR PHTHALOCYA, 10(7), 978-985.
- Formation of Electrically Conducting Mesoscale Wires Through Self-Assembly of Atomic Clusters. IEEE Transactions on Nanotechnology, 3(1 SPEC. ISS.), 61-66.
- Templated-assembly of conducting antimony cluster wires. Nanotechnology, 15(9), 1382-1387.
- Templated cluster assembly for production of metallic nanowires in passivated silicon V-grooves. Microelectronic Engineering, 73-74, 583-587.
- Hole confinement and dynamics in δ-doped Ge quantum dots. Journal of Luminescence, 108(1-4), 329-332.
- Electrical measurements of nanoscale bismuth cluster films. European Physical Journal D, 24(1-3), 291-294.
- Strain seeding of Ge quantum dots grown on Si (001). Physica Status Solidi (B) Basic Research, 224(1), 257-260.
- Three-dimensional compositional analysis of quantum dots. Journal of Physics D: Applied Physics, 34(4), 636-644.
- The effect of strain field seeding on the epitaxial growth of Ge islands on Si(001). Applied Physics Letters, 78(12), 1658-1660.
- Structural, compositional and optical properties of self-organised Ge quantum dots. Physica Status Solidi (B) Basic Research, 224(1), 265-269.
- Electron diffraction and Raman studies of the effect of substrate misorientation on ordering in the AlGaInP system. Journal of Applied Physics, 85(1), 199-202.
- Erbium photoluminescence in sol-gel derived titanium dioxide films. Proceedings of SPIE - The International Society for Optical Engineering, 3725, 239-242.
- Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials. Journal of Visualized Experiments(83).
- View this article in WRRO The electricity demand of an EV providing power via Vehicle-to-Home and its potential impact on the grid with different electricity price tariffs. Energy Reports.
- Efficient planar heterojunction mixed-halide perovskite solar cells deposited via spray-deposition. Energy and Environmental Science, 7(9), 2944-2950.
- Improved Performance and Stability of Organic Solar Cells by the Incorporation of a Block Copolymer Interfacial Layer. Advanced Materials Interfaces, 2000918-2000918.
Conference proceedings papers
- Fabrication and characterization of hybrid photovoltaic devices based on N-type GaAs and polymer composites. Proceedings of the 2nd International Conference of Energy Harvesting, Storage, and Transfer (EHST'18) (pp 116-1-116-10). Niagara Falls, Canada, 7 June 2018 - 9 June 2018. View this article in WRRO
- Understanding the interactions of porphryin LB films with NO2. COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol. 284 (pp 339-344)
- Characterisation of the reaction of free-base porphyrin to nitrogen dioxide. COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol. 284 (pp 345-349)
- Assembly of bismuth clusters into nanowires using etched V-grooves as templates. Conference on Optoelectronic and Microelectronic Materials and Devices, Proceedings, COMMAD (pp 327-330)
- Measurement of the Conductivity Exponent in Random Percolating Networks of Nanoscale Bismuth Clusters.. ICMENS (pp 350-356)
- Formation of electrically conducting mesoscale wires through self-assembly of atomic clusters. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 5118 (pp 411-420)
- Formation of Nanowires at the Percolation Threshold in Rectangular 2D Systems. Proceedings of SPIE - The International Society for Optical Engineering, Vol. 5055 (pp 189-203)
- Studies of compositional variations in germanium quantum dots grown on silicon. Materials Research Society Symposium - Proceedings, Vol. 638 (pp F1451-F1456)
- Investigations of ordering in AlGaInP. MICROSCOPY OF SEMICONDUCTING MATERIALS 1997(157) (pp 257-260)
- Teaching activities
- CPE430/ CPE6000 Low Carbon Energy, Science and Technology
- CPE1002 Chemical Engineering Design (Chemical Process Principles 1)