A diamond containing nitrogen-vacancy (NV) defects centres is illuminated by a 532-nm green laser. The red light appears because the NV centres fluoresce.
Functional materials are generally characterised as those materials which possess particular native properties and functions of their own. For example, ferroelectricity, piezoelectricity, magnetism or energy storage functions.
Functional materials are found in all classes of materials: ceramics, metals, polymers and organic molecules. Functional materials are often used in electromagnetic applications from KHz to THz and at optical frequencies where the plasmonic properties of metals assume particular importance. Functional materials are also of critical importance in materials for energy such as electro- and magnetocaloric materials, for energy storage and for solar harvesting functions.
The thin film activity in the Department of Materials takes place in two groups:
Physical Electronics and Thin Film Materials
This group is headed by Professor Neil Alford MBE FREng and the main emphasis is on functional oxides. These are materials such as piezoelectrics where the application of a voltage causes a change in dimensions, or ferroelectrics where the application of a voltage causes a change in the relative permittivity. Ferromagnetic materials are used in magnetic storage devices. Recent research into functional materials has been towards combining two or more of these into what is now known as multiferroic materials so for example, a piezolectric “buzzer” is caused by the application of an AC voltage to a piezoelectric material causing it to vibrate. The electric field controls the polarisation, the magnetic field controls the magnetisation and the stress controls the strain. We have compiled a list of microwave dielectric resonator materials and their properties.
Molecular Thin Films
Professor Sandrine Heutz’s group is developing capability in the growth and characterisation of molecular thin films. Molecular materials offer attractive alternatives to inorganics for optoelectronic applications, due to their low cost, low weight and the possibility to modify their properties easily through the insertion of functional groups by chemical synthesis. Their semiconducting character is due to the presence of delocalised π-orbitals, more often C-C double bonds, which leads to a lowering of the bandgap.
The research focuses on commercially available polyaromatic molecules, such as phthalocyanines and perylene derivatives. Those small molecules can be sublimed in the vapour phase, either in vacuum or in a flow of inert gas, leading to the formation of high purity films and self-assembled nanostructures. It is possible to modify the growth conditions (substrate and chamber temperature, flow rate, etc.) to control the film morphological, structural and spectroscopic properties – the typical characteristics of a CuPc film deposited on a glass substrate held at room temperature are shown in figure 2. One of the strengths of the molecular thin films is that they can be deposited onto any substrate including polymers and that flexible complex heterostructures can be formed without the constraints of epitaxy, opening up avenues for plastic electronic and spintronics.
Network and centres
|Centre for Plastic Electronics
The Centre for Plastic Electronics' mission is to actively stimulate new, cutting-edge, high-impact research and to meet Imperial’s strategic intent to harness the strengths and breadth of our research to address the global challenges of climate change, energy and global health and security.
|Centre for Terahertz Science and Engineering (CTSE)
Imperial College London hosts a number of THz research activities within the Departments of Materials, Electrical and Electronic Engineering, and Physics. CTSE collaborates closely with Imperial's Institute of Security Science and Technology. The Department of Materials at Imperial College London provides a dedicated laboratory for the Centre.
Functional Materials Staff
Professor Neil Alford MBE FREng
Professor Neil Alford MBE FREng is Associate Provost (Academic Planning) and Professor of Physical Electronics and Thin Film Materials at Imperial College London.
His current research is targeted towards Energy Materials and he currently leads an EPSRC Programme Grant in Energy Materials. This is closely linked to the nanotechnology activites at Imperial.
In 2011, he and colleagues Mark Oxborrow and Jon Breeze discovered that a Bragg resonator with sapphire plates of aperiodic thickness could achieve an extraordinarily high Q factor for the resonator. This led them to the discovery that it was possible to construct a MASER operating at room temperature and in the earth's magnetic field
>> Read more about Neil
Dr Andrew Cairns
Dr Andrew Cairns is a Lecturer in the Department of Materials at Imperial College London.
His research focuses on understanding and exploiting unusual properties of flexible framework materials. Central to this work is the ability to reveal the atomic structure—how atoms are arranged in 3D space—using crystallography. Knowing the atomic structure allows us to design better materials,and push materials with unique properties towards application.
>> Read more about Andrew
Dr Michele Conroy
Dr Michele Conroy is a Royal Society University Research Fellow, specialising in in-situ transmission electron microscopy (TEM) and electron spectroscopy (EELS). She worked at Pacific Northwest National Laboratory as a permanent staff scientist before joining the University of Limerick as a Science Foundation Ireland Analog Devices Research Fellow (PI). Dr Conroy holds a PhD in GaN thin film growth and in-situ TEM from Tyndall National Institute.
Dr Conroy’s URF grant ‘Improper Ferroelectric Domain Wall Engineering for Dynamic Electronics’ is focused on thin film growth of the ferroelectric/ferroelastic boracites and in-situ 4DSTEM strain analysis. The project is in collaboration with the National Center for Electron Microscopy at Lawrence Berkeley National Laboratory and SuperSTEM the EPSRC National Research Facility for Advanced Electron Microscopy.
Professor Sandrine Heutz
Professor Sandrine Heutz is a Professor of Functional Molecular Materials, Director of Facilities at the Department of Materials and co-Director of the London Centre for Nanotechnology.
Current research directions are focused on magnetic properties of molecular thin films, spintronic applications, novel fabrication methods for oxides, detailed structural characterisation of films and interfaces, and nanowire devices. We also work in partnership with industry, for example to explore surfaces with BP-ICAM.
>> Read more about Sandrine
Professor Norbert Klein
Professor Norbert Klein is Chair in Professor of Electromagnetic Materials and Sensors in the Department of Materials at Imperial College London.
His main scientific activities are in the area of electromagnetic material characterization and sensor applications, but also on microwave and terahertz devices for communciation and sensing. One current focus is on graphene and related 2D materials, where Norbert is currently establishing a cluster system for 4" graphene growth by chemical vapour deposition. The other focus is on microwave-to-terahertz biosensing, in particular blood analysis by microfluidic-resonator assemblies and single cell detecion in biological liquids.
Professor Klein has developed practical sensors for security applications - based on earlier work on microwave filters and oscillators for mobile communication, and he holds more than 15 patents. In 2007, he spun out a company (EMISENS), which successfully commercializes a microwave based bottle scanner for airport checkpoints.
>> Read more about Norbert
Dr Robert Hoye
Dr. Robert Hoye is a Lecturer and Royal Academy of Engineering Research Fellow in the Department of Materials at Imperial College London.
His current research is focused on the development of electronic materials for clean energy conversion, with applications including photovoltaics and light-emitting diodes. There are three main areas of research: 1) the development of materials that can tolerate defects, 2) scalable manufacturing of semiconductors, and 3) engineering of advanced devices, including in-depth characterisation to understand the loss mechanisms. His work has led to new non-toxic solar cell materials that can be efficient when made by low-cost methods, as well as new emitters with ultrasharp electroluminescence.
Dr Cecilia Mattevi
Dr Cecilia Mattevi is Senior Lecturer and a Royal Society University Research Fellow in the Department of Materials.
Cecilia’s current funding supports: science and engineering of 2D semiconducting materials (EPSRC 1st grant, EPSRC-Royal Society fellowship engagement, The Royal Society University Research Fellowship), the development of methods for large scale synthesis of graphene for applications in different technology areas from energy storage to polymer/ceramic composite materials (EPSRC-Graphene Engineering), engineering large scale implementation of graphene-composite (Petronas), and energy applications of graphene derivatives (EU-Graphene Flagship).
>> Read more about Cecilia
Professor Mark Oxborrow
Dr Mark Oxborrow is a Reader in Functional Microwave Materials and Devices in the Department of Materials at Imperial College London.
His research interests are in the development of extremely low-noise microwave amplifiers based on organic paramagnetic materials for applications in space communication and medical diagnostics.
>> Read more about Mark
Dr Peter Petrov
Dr Petrov is Principal Scienctist in the Department of Materials. He heads the Thin Film Technology Laboratory located in the Deptment of Materials. The Laboratory is part of the London Centre for Nanotechnology and provides the lead UK Universities and industrial partners with facilities for nano-scale thin film deposition, device patterning and electrical characterisation.
Dr Fang Xie
Dr Fang Xie is a Reader in Functional Materials in the Department of Materials.
Her research concerns novel nanomaterials synthesis and fabrication and their applications in energy and life sciences. Metal and semiconducting nanoparticles are prepared by both bottom-up and top-down methods such as colloidal lithography, nanoimprint lithography, and wet chemical synthesis/self-assembly.
Dr Jessica Wade
Dr Jessica Wade is an Imperial College Research Fellow investigating spin selective charge transport through chiral systems in the Department of Materials.
Broadly speaking, her research considers new materials for optoelectronic devices, with a focus on chiral organic semiconductors. She currently works in SPIN-Lab at Imperial, which is led by Professor Sandrine Heutz.