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Dr Kevin Donovan

Reader in Molecular Physics

Department School of Physics and Astronomy
 G O Jones 117, Mile End
Telephone +44 (0)20 7882 3410
Email k.j.donovan@qmul.ac.uk
Homepage http://ph.qmul.ac.uk/directory/k.j.donovan

Research Keywords

Molecular Electronics, Electron Transport, Polydiacetylenes, Langmuir-Blodgett Films, Carbon nanotubes

Research Interests

1. Single Walled Carbon Nanotubes. The induced polarisability of single walled carbon nanotubes, SWCNTs, has provided a powerful tool for their study. While there is no permanent dipole moment  the induced dipole can be substantial at even moderate fields allowing the manipulation of the SWCNTs under the action of various forces. This leads to several related but seperate studies;

(i) Dielectrophoresis.The differential polarisability of different species of SWCNT, specifically metallic and semiconducting, make the dielectrophoretic force an interesting candidate for use in the separation of SWCNTs. In a non-uniform electric field the induced dipole experiences a dielectrophoretic translational force and the motion of nanotubes under the action of such forces is the subject of study. Of particular interest is the relationship between Brownian and viscous forces and their action on nanoscale objects compared with the more familiar mesoscale objects described by classical hydrodynamics

 (ii) The Kerr Effect. In a uniform electric field, SWCNTs in suspension will experience a rotational torque and can be made to rotate in viscous media. The consequent alignment renders a previously  isotropic suspension anisotropic and thus birefringent (refractive index depending on polarisation state of light). The study of rotational dynamics of nanoscale objects becomes possible by imposing transient electric fields.

(iii) Induced Dichroism. Similarly, in a uniform field the isotropic sample will become increasingly dichroic (absorption depending on polarisation state of light) as alignment proceeds. Dynamic studies are undertaken of induced linear dichroism in order to more closely relate the dynamics of nanoscale objects to their well studied mesoscale counterparts.

(iv) Rheology of SWCNT suspensions. The application of a controllable torque and the measurement of the dynamic response of SWCNTs allows study of the efffect of the SWCNTs on the viscosity of their local environment and how the nanotube concentration affects this.

2. Charge Transport.  A second research interest is the study of the effects of reduced dimensionality on charge transport. This is a situation commonly encountered when the condensed matter is held together by a mixture of van der Waals and covalent bonding and has consequences for the rates of charge carrier scattering (mobility), trapping and bimolecular recombibnation which have been studied in the context of polydiacetylene single crystals.

The technique of photoconductivity including time resolved photoconductivity with temporal resolution covering times from 100 picoseconds to DC is used to study the effects of reduced dimensionality on charge transport. The high end of this temporal resolution is among the fastest achieved anywhere, worldwide. The Auston switch technique has been developed to this end with a novel application for samples suspended in solvents and contained in an integrated co-axial geometry cell based around the Auston technique.

The charge transport in a range of organic materials has been studied and these include;

(i) Columnar, Discotic Liquid Crystals.

(ii) Carbon nanotubes.

(iii) Polydiacetylene conjugated polymers. 

(iv) Langmuir Blodgett multilayers.

Key Publications

Donovan KJ and Scott K (2013). Anomalous intrinsic viscosity of octadecylamine-functionalised carbon nanotubes in suspension. J Chem Phys  vol. 138, (24) 10.1063/1.4811279

Robb-Smith TJ, Donovan KJ, Scott K and Somerton M (2011). Induced electro-optic effects in single-walled carbon nanotubes. II. Hydrodynamics of nanotubes in viscous media. Phys Rev B  vol. 83, (15) 10.1103/PhysRevB.83.155415

Robb-Smith TJ, Donovan KJ, Scott K and Somerton M (2011). Induced electro-optic effects in single-walled carbon nanotubes. I. Polarizability of metallic nanotubes. Phys Rev B  vol. 83, (15) 10.1103/PhysRevB.83.155414

Scott K, Somerton M, Bunning JC and DONOVAN KJ (2005). Bimolecular recombination on carbon nanotubes. Phys. Rev. B  vol. 71, (8) 085412-1-085412-6. 10.1103/PhysRevB.71.085412

Kreouzis T, Donovan KJ, Boden N, Bushby RJ, Lozman OR and Liu Q (2001). Temperature-independent hole mobility in discotic liquid crystals. J Chem Phys  vol. 114, (4) 1797-1802. 10.1063/1.1334958

2018

Arenas-Guerrero P, Delgado ÁV, Donovan KJ, Scott K, Bellini T, Mantegazza F and Jiménez ML (2018). Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods. Sci Rep  vol. 8, (1) 10.1038/s41598-018-27840-0

2017

Arenas-Guerrero P, Jiménez ML, Scott K and Donovan KJ (2017). Electric birefringence of carbon nanotubes: Single- vs double-walled. Carbon  vol. 126, 77-84. 10.1016/j.carbon.2017.10.001

2016

Sun YW, Hernández I, González J, Scott K, Donovan KJ, Sapelkin A, Rodríguez F and Dunstan DJ (2016). Significance of bundling effects on carbon nanotubes' response to hydrostatic compression. Journal of Physical Chemistry C  vol. 120, (3) 1863-1870. 10.1021/acs.jpcc.5b09082

2014

Velarde MG, Chetverikov AP, Ebeling W, Wilson EG and Donovan KJ (2014). On the electron transport in polydiacetylene crystals and derivatives. Epl  vol. 106, (2) 10.1209/0295-5075/106/27004

2013

Donovan KJ and Scott K (2013). Anomalous intrinsic viscosity of octadecylamine-functionalised carbon nanotubes in suspension. J Chem Phys  vol. 138, (24) 10.1063/1.4811279

2012

Donovan KJ and Scott K (2012). Anomalous effective hydrodynamic radius of octadecylamine functionalised single walled carbon nanotubes. Carbon  vol. 50, (10) 3807-3815. 10.1016/j.carbon.2012.04.007

2011

Robb-Smith TJ, Donovan KJ, Scott K and Somerton M (2011). Induced electro-optic effects in single-walled carbon nanotubes. II. Hydrodynamics of nanotubes in viscous media. Phys Rev B  vol. 83, (15) 10.1103/PhysRevB.83.155415

Robb-Smith TJ, Donovan KJ, Scott K and Somerton M (2011). Induced electro-optic effects in single-walled carbon nanotubes. I. Polarizability of metallic nanotubes. Phys Rev B  vol. 83, (15) 10.1103/PhysRevB.83.155414

2010

Preece MMPINSPRASKKJDAJA (2010). Design and Synthesis of Novel Calamitic and Discotic Materials Based on the Photorefractive Carbazole Unit. Inforaworld  Mol. Crys. Liq. Crys  vol. 84, (518) 84-100. 10.1080/15421400903568054

2006

Donovan KJ, Scott K, Somerton M, Preece J and Manickam M (2006). Transient photocurrents in a charge transfer complex of trinitrofluorenone with a carbazole substituted discotic liquid crystal. Chem Phys  vol. 322, (3) 471-476. 10.1016/j.chemphys.2005.09.036

2005

Donovan KJ and Scott K (2005). Transient electric birefringence in suspensions of single-walled carbon nanotubes. Phys Rev B  vol. 72, (19) 10.1103/PhysRevB.72.195432

Lutz T and Donovan KJ (2005). Macroscopic scale separation of metallic and semiconducting nanotubes by dielectrophoresis. Carbon  vol. 43, (12) 2508-2513. 10.1016/j.carbon.2005.05.002

Bunning JC, Donovan KJ, Bushby RJ, Lozman OR and Lu Z (2005). Electron photogeneration in a triblock co-polymer discotic liquid crystal. Chem Phys  vol. 312, (1-3) 145-150. 10.1016/j.chemphys.2004.11.032

Scott K, Somerton M, Bunning JC and DONOVAN KJ (2005). Bimolecular recombination on carbon nanotubes. Phys. Rev. B  vol. 71, (8) 085412-1-085412-6. 10.1103/PhysRevB.71.085412

Bushby RJ, Donovan KJ, Kreouzis T and Lozman OR (2005). Molecular engineering of triphenylene-based discotic liquid crystal conductors. Opto-Electron Rev  vol. 13, (4) 269-279.

2004

Bunning JC, Donovan KJ and Scott K (2004). Observation of transient photocurrents on suspended nanotubes. J Appl Phys  vol. 96, (7) 3939-3944. 10.1063/1.1789268

2003

Bunning JC, Donovan KJ, Kreouzis T, Scott K, Bushby RJ, Boden N and Lozman OR (2003). Quantum efficiencies of photogeneration in discotic liquid crystals. Part 2: Electric field and temperature dependence. Molecular Crystals and Liquid Crystals  vol. 397, 563-571. 10.1080/15421406390214194

Scott K, Donovan KJ, Kreouzis T, Bunning JC, Bushby RJ, Boden N and Lozman OR (2003). Quantum efficiency of photogeneration in discotic liquid crystals: Part 1: Temperature and wavelength dependence. Molecular Crystals and Liquid Crystals  vol. 397, 553-561. 10.1080/15421400390214185

Donovan KJ, Kreouzis T, Scott K, Bunning JC, Bushby RJ, Boden N, Lozman OR and Movaghar B (2003). Molecular engineering the phototransport properties of discotic liquid crystals. Molecular Crystals and Liquid Crystals  vol. 396, 91-112. 10.1080/15421400390213221

2002

Pecchia A, Lozman OR, Movaghar B, Boden N, Bushby RJ, Donovan KJ and Kreouzis T (2002). Photoconductive transients and one-dimensional charge carrier dynamics in discotic liquid crystals. Phys Rev B  vol. 65, (10) 10.1103/PhysRevB.65.104204

2001

Boden N, Bushby RJ, Donovan K, Liu QY, Lu ZB, Kreouzis T and Wood A (2001). 2,3,7, 8,12,13-Hexakis[2-(2-methoxyethoxy)ethoxy]-tricycloquinazoline: a discogen which allows enhanced levels of n-doping. Liq Cryst  vol. 28, (12) 1739-1748. 10.1080/02678290110082383

Kreouzis T, Donovan KJ, Boden N, Bushby RJ, Lozman OR and Liu Q (2001). Temperature-independent hole mobility in discotic liquid crystals. J Chem Phys  vol. 114, (4) 1797-1802. 10.1063/1.1334958

2000

Kreouzis T, Scott K, Donovan KJ, Boden N, Bushby RJ, Lozman OR and Liu Q (2000). Enhanced electronic transport properties in complementary binary discotic liquid crystal systems. Chemical Physics  vol. 262, (2-3) 489-497. 10.1016/S0301-0104(00)00323-2

Donovan KJ, Elliott JE, Jeong IS, Scott K and Wilson EG (2000). Influence of electric field on interwell tunneling rate in quasi two dimensional organic quantum wells. Journal of Chemical Physics  vol. 113, (17) 7606-7612. 10.1063/1.1312869

Elliott JE, Jeong IS, Scott K, Donovan KJ and Wilson EG (2000). Bimolecular recombination quenching in Langmuir Blodgett multilayers. Journal of Chemical Physics  vol. 113, (17) 7598-7605. 10.1063/1.1312868

Jeong IS, Scott K, Donovan KJ and Wilson EG (2000). On the non-Arrhenius temperature dependence of the interwell electron tunneling rate in quasi two dimensional organic quantum wells. Journal of Chemical Physics  vol. 113, (17) 7613-7620. 10.1063/1.1312870

Donovan KJ and Kreouzis T (2000). Deconvolution of time of flight photocurrent transients and electronic response time in columnar liquid crystals. Journal of Applied Physics  vol. 88, (2) 918-923. 10.1063/1.373755

Donovan KJ, Elliott JE, Scott K and Wilson EG (2000). Measurement of intermolecular electron current in supramolecular assemblies created by the Langmuir-Blodgett technique. Journal of Applied Physics  vol. 87, (2) 914-924. 10.1063/1.371970

1999

Donovan KJ, Scott K, Spagnoli S and Berrehar J (1999). DC photoconduction action spectra in thin film polymer crystals of 3 and 4BCMU polydiacetylene. Chemical Physics  vol. 250, (1) 61-70. 10.1016/S0301-0104(99)00279-7

Spagnoli S, Donovan KJ, Scott K, Somerton M and Wilson EG (1999). Carrier range on finite, isolated molecular wires in a monomer crystalline matrix: Example: Polydiacetylene, 4BCMU. Chemical Physics  vol. 250, (1) 71-79. 10.1016/S0301-0104(99)00280-3

Donovan KJ and Spagnoli S (1999). Carrier range on conjugated polymers as molecular wires. Example: Polydiacetylene, 4BCMU. Chemical Physics  vol. 247, (2) 293-298. 10.1016/S0301-0104(99)00208-6

Donovan KJ, Scott K and Spagnoli S (1999). Carrier range and photocarrier generation efficiency on thin-film crystalline-conjugated polymers. Journal of Applied Physics  vol. 86, (3) 1472-1476. 10.1063/1.370915

1998

Donovan KJ, Kreouzis T, Boden N and Clements J (1998). One dimensional carrier trapping in the crystalline phase of a columnar liquid crystal. Journal of Chemical Physics  vol. 109, (23) 10400-10408. 10.1063/1.477695

Donovan KJ, Hargrave P, Scott K, Somerton M and Spagnoli S (1998). Time resolved electron motion on isolated polymer chains in solution. Physical Review Letters  vol. 81, (17) 3731-3734. 10.1103/PhysRevLett.81.3731

Boden N, Bushby RJ, Clements J, Donovan K, Movaghar B and Kreouzis T (1998). Charge dynamics and recombination kinetics in columnar discotic liquid crystals. Physical Review B  vol. 58, (6) 3063-3074. 10.1103/PhysRevB.58.3063

1996

Donovan KJ, Elliott JE, Scott K, Wilson EG, Batzel DA, Clark TR and Kenney ME (1996). Electron tunnelling rates as a function of intermolecular distance, measured in a Langmuir-Blodgett assembly. Thin Solid Films  vol. 273, (1-2) 229-231. 10.1016/0040-6090(95)06777-9

1995

Boden N, Bushby RJ, Clements J, Movaghar B, Donovan KJ and Kreouzis T (1995). Mechanism of charge transport in discotic liquid crystals. Phys Rev B Condens Matter  vol. 52, (18) 13274-13280. 10.1103/PhysRevB.52.13274

1994

Donovan KJ, Elliot J, Scott K, Sudiwala RV, Wilson EG, Clark TR, Batzel DA and Kenney ME (1994). Comparison of tunnelling rates in two Langmuir-Blodgett quantum well structures differing only in barrier width. Thin Solid Films  vol. 244, (1-2) 928-931. 10.1016/0040-6090(94)90602-5

Donovan KJ, Scott K, Sudiwala RV, Wilson EG, Bonnett R, Wilkins RF, Paradiso R, Clark TR, Batzel DA and Kenney ME (1994). Determination of the parallel and perpendicular intermolecular tunnelling rates in two Langmuir-Blodgett quantum well systems. Thin Solid Films  vol. 244, (1-2) 923-927. 10.1016/0040-6090(94)90601-7

Scott K, Sudiwala RV, Donovan KJ, Wilson EG, Clark TR, Batzel DA and Kenney ME (1994). Control of electron transfer in a nanostructure assembled from organic molecules. Thin Solid Films  vol. 242, (1-2) 187-190. 10.1016/0040-6090(94)90527-4

Donovan KJ, Scott K, Sudiwala RV, Wilson EG, Bonnett R, Wilkins RF, Paradiso R, Clark TR, Batzel DA and Kenney ME (1994). Determination of the parallel and perpendicular intermolecular tunnelling rates in two Langmuir-Blodgett quantum well systems. Thin Solid Films  vol. 244, (1 -2 pt 3) 923-927. 10.1016/0040-6090(94)90601-7

Donovan KJ, Elliott J, Scott K, Sudiwala RV, Wilson EG, Clark TR, Batzel DA and Kenney ME (1994). Comparison of tunneling rates in two Langmuir-Blodgett quantum well structures differing only in barrier width. Thin Solid Films  vol. 244, (1 -2 pt 3) 928-931. 10.1016/0040-6090(94)90602-5

1993

Donovan KJ, Scott K, Sudiwala RV, Wilson EG, Bonnett R, Wilkins RF, Paradiso R, Clark TR, Batzel DA and Kenney ME (1993). Determination of anisotropic electron transport properties of two Langmuir-Blodgett organic multiple quantum wells. Thin Solid Films  vol. 232, (1) 110-114. 10.1016/0040-6090(93)90771-G

Donovan KJ, Elkins JWP and Wilson EG (1993). Novel coulomb glass creation in electronic one dimensional systems. Synthetic Metals  vol. 57, (2-3) 5032-5039. 10.1016/0379-6779(93)90858-T

Donovan KJ, Elkins JWP and Wilson EG (1993). Novel Coulomb glass creation in electronic one dimensional systems. Synthetic Metals  vol. 57, (2 -3 pt 6) 5032-5039.

Donovan KJ, Elkins JWP and Wilson (1993). Electron-electron interactions and coulomb glass creation in electronic one dimensional systems. Molecular Crystals and Liquid Crystals Science and Technology. Section a. Molecular Crystals and Liquid Crystals  vol. 236, (1) 157-164. 10.1080/10587259308055223

1992

Donovan KJ, Sudiwala RV and Wilson EG (1992). Fast photoconduction in Langmuir-Blodgett multilayers of polydiacetylenes. Thin Solid Films  vol. 210-211, (PART 1) 271-273. 10.1016/0040-6090(92)90231-Y

Donovan KJ, Paradiso R, Scott K, Sudiwala RV, Wilson EG, Bonnett R, Wilkins RF, Batzel DA, Clark TR and Kenney ME (1992). Electron transport across organic quantum wells: new results on amphiphilic phthalocyanines. Thin Solid Films  vol. 210-211, (PART 1) 253-256. 10.1016/0040-6090(92)90226-2

1991

Donovan KJ, Elkins JWP and Wilson EG (1991). The effect of electric field on the bimolecular recombination rate in a one-dimensional polymer single crystal. Journal of Physics: Condensed Matter  vol. 3, (13) 2075-2081. 10.1088/0953-8984/3/13/010

Donovan KJ and Wilson EG (1991). Reply by K J Donovan and E G Wilson. Journal of Physics: Condensed Matter  vol. 3, (21) 3845-3847. 10.1088/0953-8984/3/21/016

Burrows PM, Donovan KJ, Scott K, Sudiwala RV and Wilson EG (1991). The inchworm memory - progress towards a new Langmuir Blodgett molecular electronic device. Synthetic Metals  vol. 42, (1-2) 10.1016/0379-6779(91)91890-M

Donovan KJ, Willock DJ and Wilson EG (1991). Carrier recombination in polydiacetylenes the scaling with sample size. Synthetic Metals  vol. 41, (1-2) 10.1016/0379-6779(91)91051-B

Donovan KJ, Elkins JPW and Wilson EG (1991). The effect of electric field on the bimolecular recombination rate in a one dimensional polymer single crystal. Synthetic Metals  vol. 41, (1-2)

Burrows PM, Donovan KJ, Scott K, Sudiwala RV and Wilson EG (1991). Inchworm memory. Progress towards a new Langmuir Blodgett molecular electronic device. Synthetic Metals  vol. 42, (1-2)

Donovan KJ and Wilson EG (1991). Temporal resolution of electron motion along a molecular wire in solution. Synthetic Metals  vol. 41, (1-2)

Donovan KJ, Willock DJ and Wilson EG (1991). Carrier recombination in polydiacetylenes: The scaling with sample size. Synthetic Metals  vol. 41, (1-2)

Donovan KJ, Elkins JPW and Wilson EG (1991). Effect of electric field on the bimolecular recombination rate in a one dimensional polymer single crystal. Synthetic Metals  vol. 41, (1-2)

1990

Donovan KJ and Wilson EG (1990). The field-independent early-time drift velocity of carriers in polydiacetylenes: Solitary-wave acoustic polaron or dispersive trap-limited transport in 1D? Journal of Physics: Condensed Matter  vol. 2, (6) 1659-1664. 10.1088/0953-8984/2/6/022

1989

Burrows PE, Donovan KJ and Wilson EG (1989). Electron motion perpendicular to Langmuir-Blodgett multilayers of conjugated macrocyclic compounds: The organic quantum well. Thin Solid Films  vol. 179, (1-2) 129-136. 10.1016/0040-6090(89)90174-0

Donovan KJ and Wilson EG (1989). The observation of electron motion along individual polydiacetylene chains in solution: The molecular wire. Synthetic Metals  vol. 28, (3) 10.1016/0379-6779(89)90746-7

Donovan KJ and Wilson EG (1989). The search for east transits using the Auston switch technique in single crystal polydiacetylenes. Synthetic Metals  vol. 28, (3) 10.1016/0379-6779(89)90745-5

Bleier H, Donovan K, Friend RH, Roth S, Rothberg L, Tubino R, Vardeny Z and Wilson G (1989). Non-solitonic nature of picosecond photoconductivity in trans-polyacetylene. Synthetic Metals  vol. 28, (3) 10.1016/0379-6779(89)90691-7

Donovan KJ, Fisher NE and Wilson EG (1989). Unipolar carrier transport in quasi one dimensional systems:- novel results in polydiacetylene. Synthetic Metals  vol. 28, (3) 10.1016/0379-6779(89)90744-3

Burrows PE, Donovan KJ and Wilson EG (1989). Electron motion perpendicular to Langmuir-Blodgett multilayers of conjugated macrocyclic compounds. The organic quantum well. Thin Solid Films  vol. 179, (1 -2 pt 2) 129-136. 10.1016/0040-6090(89)90174-0

1988

Ahmed FR, Burrows PE, Donovan KJ and Wilson EG (1988). Organic quantum wells:- Electron transport across Langmuir-Blodgett films of conjugated organic molecules. Synthetic Metals  vol. 27, (3-4) 593-600. 10.1016/0379-6779(88)90205-6

1986

Donovan KJ and Wilson EG (1986). Temperature dependence of pulsed photocurrents in the one-dimensional semiconductor pdats. Journal of Physics C: Solid State Physics  vol. 19, (17) L357-L361. 10.1088/0022-3719/19/17/002

1985

Donovan KJ, Freeman PD and Wilson EG (1985). Micro-engineering of a novel organic molecular electronic structure. Journal of Physics C: Solid State Physics  vol. 18, (11) L275-L282. 10.1088/0022-3719/18/11/001

Donovan KJ and Wilson EG (1985). Carrier trapping in one-dimensional systems: Example organic PDATS. Journal of Physics C: Solid State Physics  vol. 18, (2) L51-L54. 10.1088/0022-3719/18/2/003

1984

Movaghar B, Murray DW, Donovan KJ and Wilson EG (1984). Anomalous electric field dependence of carrier drift in one-dimensional systems. Example: Organic PDA-TS. Journal of Physics C: Solid State Physics  vol. 17, (7) 1247-1255. 10.1088/0022-3719/17/7/017

1981

Donovan KJ and Wilson EG (1981). Demonstration of an ultra-high mobility organic polymer. Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties  vol. 44, (1) 9-29. 10.1080/01418638108222364

Donovan KJ and Wilson EG (1981). Photocarrier creation in one dimension. Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties  vol. 44, (1) 31-45. 10.1080/01418638108222365

1979

Donovan KJ and Wilson EG (1979). Demonstration of high-mobility one-dimensional semiconducting polymers. Journal of Physics C: Solid State Physics  vol. 12, (22) 4857-4869. 10.1088/0022-3719/12/22/027

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