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Professor of Materials Chemistry

MChem University of Wales Swansea
PhD University of Wales Swansea

Functional Photoactive Materials

My research uses materials chemistry to design functional soft materials (e.g. polymers, surfactants, colloids/nanoparticles, organic-inorganic hybrids) which absorb, produce or respond to light. Such materials are the basis of many cutting-edge technologies, including light-emitting displays, solar cells, optical sensors and bioelectronic devices. I am particularly interested in developing methods to control the structural organisation of photoactive materials, from the nano- to the macroscale, since this controls many of their fundamental properties, for example, photoluminescence and charge transport. My research is highly interdisciplinary and we use a range of spectroscopy, scattering (light/neutrons/X-rays) and microscopy techniques to unravel structure-property relationships in a variety of systems.

Spectral converters for enhanced solar energy conversion

Single junction photovoltaic cells fail to achieve their theoretical efficiency due to an inability to harness all wavelengths of the solar spectrum. Spectral losses may be overcome through the addition of a spectral converter coating to the surface of a finished solar cell, which, through a photoluminescence process, converts solar photons into wavelengths suitable for use. While suitable spectral conversion lumophores are easily identifiable from studies in solution, translation of their potency to solid-state devices is often challenging. To tackle this, we are investigating the bottom-up design and fabrication of new photoactive organic-inorganic hybrid spectral converters, which exhibit tuneable spectral, optical, elastic and mechanical properties in the solid-state and can be tailored to improve the performance of different classes of solar cell.

Stimuli-responsive materials

Stimuli-responsive materials exhibit a change in their structure, conformation, chemical or physical properties in response to an external signal, e.g. light, pH, temperature. These materials find application in a variety of fields including drug delivery, sorting and purification of substrates, and sensing. Our research is focussed on the design of photoactive surfactants and particles and understanding their cooperative self-assembly into light-responsive micelles, emulsions and lyotropic liquid crystal phases. We are exploring the application of these systems in solar-thermal energy storage, as responsive templates for the synthesis of porous nanomaterials and membranes for use in catalysis and environmental remediation of pollutants, and as controlled delivery or reaction centres. 

Polymer membranes for solar steam generation

Polymer membranes are important energy materials, with a variety of uses including fuel cells, hydrogen production and solar vapour generation. The surface area, size and morphology of the internal porous structure of the membrane often determines its efficacy in its intended application. We are exploring new templating approaches to prepare polymer membranes with a hierarchical level of porosity and improved 3D connectivity to facilitate large area desalination and purification of water supplies.

Optical materials for visible light communications

Visible-light communication (VLC or "LiFi") based on white light-emitting diodes is predicted to provide high-bitrate data communication in indoor environments. Challenges in VLC include mitigation of signal attenuation and fading control. We are investigating the development of new optical amplifier materials based on organic-inorganic hybrid polymer to improve signal coverage in indoor spaces.

A large area luminescent solar concentrator delivers energy down-shifted solar simulated light to edge-bound silicon solar cells.

  • A. R. Bastos, G. Lyu, T. Silvério, P. S. André, R. C. Evans and R. A. S. Ferreira, "Flexible Blue-Light Fiber Amplifiers to Improve Signal Coverage in Advanced Lighting Communication Systems", Cell Reports Physical Science 1 (2020) 100041.
  • E. A. Kelly, N. Willis-Fox, J. E. Houston, C. Blayo, G. Divitini, N. Cowieson, R. Daly and R. C. Evans, "A Single-Component Photorheological Fluid with Light-Responsive Viscosity", Nanoscale 12 (2020) 6300-6306
  • G. Lyu, J. Kendall, I. Meazzini, E Preis, S. Bayseç, U. Scherf, S. Clement, and R. C. Evans, "Luminescent Solar Concentrators Based on Energy Transfer from an Aggregation-Induced Emitter Conjugated Polymer", ACS Applied Polymer Materials 1, 11 (2019) 3039-304.
  • L. J. Brennan, F. Purcell-Milton, B. McKenna, T. M. Watson, Y. K. Gun’ko, and R. C. Evans, "Large Area Quantum Dot Luminescent Solar Concentrators for Use with Dye-Sensitised Solar Cells", Journal of Materials Chemistry A 6 (2018) 2671-2680.