Dr Martin Grell

Photo of Martin GrellSenior Lecturer in Physics

Head of Foundation Year in Physics

Contact details

Group website

Research Page



I have 20 years experience in the physics, chemical physics, electronics and photonics of functional organic, and solution- processed inorganic, materials. Past research includes liquid crystalline polyfluorenes for linearly polarized light sources and the combination of chiral nematics and organic dyes for circularly polarized light sources; both research areas included the demonstration of lasing devices. Since ~2003, I work on organic thin film transistors (OTFTs), including work on OTFT contacts, nanoparticle-filled gate insulators, organic memory, and high capacitance gate insulators. Over the years, me and my students, postdocs, and collaborators have developed innovative OTFT and other sensor devices, e.g. for NO2, volatile organics (VOCs) and odours indicating food spoilage. In recent years, I built the UK’s leading laboratory for electrolyte- gated TFTs with strong publication record in the area. In parallel, we develop evanescent wave fibre optic sensor devices for waterborne analytes.

I run a dedicated laboratory for TFT and fibre optic sensor development, facilities include standard TFT preparation and characterisation equipment as well as electronic prototyping for bespoke electrolyte- gated TFT sensor measurement and Lock- In fibre optic absorbance meter. To date, 8 PhDs have graduated from my group, 6 more are currently under my supervision or lined up to join me in the near future. I regularly present my work in topical conferences, and published ~ 90 research papers with an h- index of 34.


‘Diplom Physiker’, TU Darmstadt, Germany, 1990
‘Dr. rer. nat.’ in polymer physics, TU Darmstadt and ‘Deutsches Kunststoff- Institut’ (now Fraunhofer Institute LBF), Darmstadt, Germany, 1994

Academic career

1995 Marie Curie postrdoctoral fellow, Universtiy of Wales, Bangor
1996 – 2000 DFG (German Research Council) and EPSRC postodoctoral research associate, Dept. of Physics, Sheffield
2000 Lecturer (2010 Senior Lecturer) in Physics, Sheffield

Departmental / University administration

Head of Foundation Year in Physics
USIC link tutor for Physics
Member of Postgraduate Committee, representing international research students, and their supervisors


Research Interests

My current research focuses on sensors for waterborne analytes, which are of great interest to human health and wealth. I head the UK’s leading laboratory for electrolyte- gated thin film transistors, which may display selectivity and sensitivity e.g. for amines or cations, when suitably sensitized. Also we develop evanescent- wave fibre optic sensor systems for optical detection of waterborne analytes with water- insoluble sensitisers. Research is assisted by dedicated laboratories and the development of bespoke measurement- and characterization systems. Recent research highlights include the demonstration of membrane- free sensors for waterborne analytes, including both water- gated transistors and evanescent wave optrodes, and the discovery of a new processing route for Zinc oxide based on a water- soluble precursor, avoiding the need for organic solvents.

Research funding

I am the Department’s leading supervisor of international research students (IRSs), looking forward to my 10th IRS support grant by Oct 2017

Oct 2017  International Research Student (IRS) grant for Zarah Alqahtani, Royal
embassy of Saudi Arabia, £66k

Feb 2017  IRS grant for Nawal Alghamdi, Royal embassy of Saudi Arabia. £ 66k

Jan 2017  IRS grant for Alhulw Alshammari, Royal Embassy of Saudi Arabia, £ 66k

2015 – 2018 IRS grant for Abbad Albaroot, Royal Embassy of Saudi Arabia, £ 61k

2014 – 2017 IRS grant for Abraham Kirwa Tuwei. Commonwealth Scholarship Commission. £ 54k

2013 – 2014 CI ‘Co-planar organic/magnetic transistors’ (PI DA Allwood). USFD ‘Proof of Concept’ fund, project code 138720. £48k.

2013 – 2016 IRS grant for Talal Althagafi. Royal Embassy of Saudi Arabia, £58k

2012 - 2015 IRS grant for Krisna Adhitya. Privately funded, £58k

2012-2015 IRS grant for Saud Algarni. Royal Embassy of Saudi Arabia. £58k

2010 - 2013 IRS grant for A Alnaim. Royal Embassy of Saudi Arabia, £53k

2010 - 2013 Sheffield investigator, ‘FlexSmell’ ITN under EU FP7,
PITN-GA-2009-238, Sheffield grant volume £296k

2009 - 2012 IRS grant for Hadi AlQahtani. Royal Embassy of Saudi Arabia, £53k

2006 - 2009 co- investigator 'Low cost sensor arrays using organic semiconductors' Home Office Scientific Development Branch (HOSDB), File 04/05/54, Sheffield grant volume £172k

2005 - 2009 co-investigator 'Basic Technology: The Snomipede' EPSRC,
EP/C523857/1, total grant volume £606k

2004 – 2007 co- investigator, ‘Accelerated Discovery for new organic
semiconductors’, EPSRC GR/S96685/01, total grant volume £234k

2002 – 2005 co- investigator, ‘High mobility organic semiconductors’, EPSRC
GR/S02303/01(02), total grant volume £557k

2002 – 2005 principle investigator, ‘Alternative gate insulators for organic
transistors’, EPSRC GR/R88328/01(P), grant volume £87k

2001 - 2003 principle investigator, ‘Emission and manipulation of light with
polymers and liquid crystals: An integrated approach’,
EPSRC GR/R41200/01(P), grant volume £58k


Undergraduate taught modules (current)

PHY377/477 ‘Soft Condensed Matter’
PHY009/010 ‘Foundations of Physics’ (with Dr P Smith)
PHY346 Industrial Project

Undergraduate taught courses (past)

PHY6007 ‘Organic Semiconductors’
PHY221 ‘Classical Physics’
PHY343 3rd year project


Many of my recent publications are freely available from White Rose Research Online (WRRO)
Enter ‘Grell’ into the first search box on http://eprints.whiterose.ac.uk/cgi/search/simple

Recent publications

A new precursor route to semiconducting Zinc oxide
T M Althagafi, A Al Baroot, M Grell, IEEE Electron Devices 37, 1299 (2016)

A membrane- free cation selective water- gated transistor
T M Althagafi, A Al Baroot, S Algarni, M Grell, Analyst 141, 5571 (2016)

Innate cation sensitivity in a semiconducting polymer
T M Althagafi, S Algarni, M Grell, Talanta 158, 70 (2016)

Fibre optic absorbance meter with low limit of detection for waterborne cations
A Kirwa Tuwei, N Williams, M Grell, Sens. Act. B, doi 10.1016/j.snb.2016.05.065 (2016)

A water-gated organic thin film transistor as a sensor for water-borne amines
S Algarni, T M Althagafi, A Al Naim, M Grell, Talanta 153, 107 (2016)

Precursor-route ZnO films from a mixed casting solvent for high performance aqueous electrolyte-gated transistors
Talal M. Althagafi, Saud A. Algarni, Abdullah Al Naim, Javed Mazher, Martin Grell Phys. Chem. Chem. Phys. 17, 31247 (2015)

Intensity-Modulated Spectroscopy on Loaded Organic Photovoltaic cells
K Adhitya, A Alsulami, A Buckley, R C Tozer, M Grell, IEEE Journal of Photovoltaics 5, 1414 (2015)

An electrical characterization system for the real- time acquisition of multiple independent sensing parameters from organic thin film transistors
A Dragoneas, L Hague, M Grell, J. Sens. Sens. Syst. 4, 169 (2015)

An ionic liquid- gated polymer thin film transistor with exceptionally low ‘on’ resistance
S Algarni, T M ALthagafi, P J Smith, M Grell, Appl. Phys. Lett. 104, 182107 (2014)

Planar organic spin valves using nanostructured Ni80Fe20 magnetic contacts
AlQahtani, H; Bryan, MT; Hayward, TJ; Hodges, MP; Im, MY; Fischer, P; Grell, M; Allwood, DA; Organic Electronics 15, 276 (2014)

Water-gated organic nanowire transistors
Al Naim, Abdullah; Hobson, Adam; Grant, Richard T.; Grell, M; et al., Organic Electronics 14, 1057 (2013)

Morphology-Driven Sensitivity Enhancement in Organic Nanowire Chemiresistors
Dragoneas, A.; Grell, M.; Hampton, M.; Macdonald, J E; Sensor Letters 11, 552 (2013)

Study of polymer-magnetic electrode interfaces using XPS
Morley, N. A.; Al Qahtani, H. R. H.; Hodges, M. H.; Grell, M et al., Applied Surface Science 265, 570 (2013)

Organic solvents as gate media for thin-film transistors
Al Naim, A F; Grell, M, J Appl. Phys. 112, 114502 (2012)

Electron transporting water-gated thin film transistors
Al Naim, Abdullah; Grell, Martin, Appl. Phys. Lett. 101, 141603 (2012)

A swelling-based chemiresistor for a biogenic odour
AlQahtani, Hadi; Puzzovio, Delia; Dragoneas, Antonis; Grell, Martin; Talanta 99, 50 (2012)

Manifold sensitivity improvement of swelling-based sensors
AlQahtani, Hadi; Alduraibi, Mohammad; Richardson, Tim; Grell, Martin Phys. Chem. Chem. Phys. 14, 5558 (2012)