ProfessorMartyn McLachlan

My research interests have evolved considerably since I began my career as a PhD student studying the self-assembly of optically active structures. At the time, photonics was an emerging and particularly exciting field, offering the prospect of all-optical computing, faster telecommunications and new ways of controlling light.

The structures I prepared were ultimately too defective for their intended photonic application. Although initially frustrating, this result redirected my research in an important and productive way. I became fascinated by their structural complexity and began exploring how they could instead be used as templates for the fabrication of periodic nanostructures. This work formed the basis of my Royal Academy of Engineering Postdoctoral Research Fellowship and established a research direction that has continued to develop throughout my career.

Today, my group studies functional thin-film materials for energy and optoelectronic applications. Our work brings together materials synthesis, advanced characterisation and device fabrication to understand how composition, processing and structure determine material performance.

We develop solution- and vapour-based approaches to the preparation of metal-halide perovskite thin films and nanomaterials. Our research explores their use in photovoltaics, light-emitting devices and photodetectors, with a growing emphasis on sustainable processing, materials recovery and recycling.

We investigate functional oxide semiconductors prepared using a broad range of physical and chemical deposition methods. A central aim is to understand how precursor chemistry, deposition conditions and post-processing treatments influence film composition, morphology, defect chemistry and electronic properties.

Advanced characterisation is central to our research. We use complementary techniques—including X-ray and electron diffraction, electron microscopy and atomic force microscopy—to connect structure and microstructure with the optical and electronic behaviour of thin films and nanomaterials.

We study charge transport in oxide and hybrid semiconductors using techniques including field-effect transistor measurements, Hall-effect analysis and four-point-probe conductivity measurements. These methods are combined with work-function, spectroscopic and defect-sensitive measurements to build a more complete understanding of material electronic structure.

We investigate how light interacts with functional thin films and how photoexcited charge carriers are generated, transported and lost. Photoluminescence, optical absorption and time-resolved measurements are used to identify recombination pathways, electronic defects and the processes that limit material and device performance.

Our work frequently involves the design of bespoke deposition and processing methods for oxide, organic and hybrid semiconductors. Developing this capability allows us to control materials growth more precisely and to explore processing conditions that are not readily accessible using conventional equipment.

We fabricate photovoltaics, light-emitting diodes, photodetectors and thin-film transistors as platforms for evaluating new materials and processing strategies. Device measurements provide an essential test of whether changes in composition, structure or processing lead to meaningful improvements in functional performance.

The unifying theme across this work is the relationship between composition, processing, structure and properties. I am particularly interested in the influence of electronic and structural defects on the behaviour of thin films and devices.

These factors cannot be understood in isolation. Materials with apparently identical compositions can exhibit very different properties depending on how they are prepared, the interfaces they form and the environments in which they operate. Our aim is therefore not simply to produce materials or devices with improved performance, but to understand why they behave as they do. This understanding provides the basis for designing materials that are more efficient, reproducible, stable and sustainable..