Solar Thermionic Energy Converters

About the project or challenge area

Solar thermal technology is promising for both small and utility scale renewable energy systems and solar thermionics is an emerging technology where solar energy heats a metal such that electrons are emitted and collected by a cooled anode to create an electric current. This project is a collaboration between Physics, Chemistry and Electrical & Electronic Engineering whereby nanostructured surfaces will be optimised for solar absorption, thermal emissivity and electron emission with the use of nanocrystalline diamond. This work is an extension to an EPSRC grant where a number of proof of principle results were obtained that show solar thermionic energy converters are a practical possibility. This work will build on these results and will aim to make a practical solar thermionic device, this will include electromagnetic modelling, nano and micro-surface processing and characterisation and optical and electrical characterisation.

Why choose this opportunity?

The student will have the opportunity to learn about solar thermal energy conversion and selective surfaces [1,2] and learn about nanostructured surfaces in terms of both optical and materials properties as outlined in our published papers [3-11]

[1] Granqvist C 1985 “Spectrally selective coatings for energy efficiency and solar applications” Phys. Scr. 32 401–7

[2] Naito H, Kohsaka Y, Cooke D and Arashi H 1996” Development of a solar receiver for a high-efficiency thermionic/ thermoelectric conversion system” Sol. Energy 58 191–5

[3] Martin T L, O’Donnell K M, Shiozawa H, Giusca C E, Fox N A, Silva S R P and Cherns D 2011 “Lithium monolayers on single crystal C(100) oxygen-terminated diamond” MRS Online Proc. Libr. 1282

[4] Dominguez-Andrade, H, Croot, A, Wan, G, Smith, JA & Fox, NA, 2019, ‘Characterisation of thermionic emission current with a laser-heated system’. Review of Scientific Instruments, vol 90., pp. 045110

[5] EP/K030302/1 Energy and the Physical Sciences:Beta-enhanced thermionic energy converters and nuclear batteries employing nanostructured diamond electrodes

[6] S. Nunez-Sanchez, H. D. Andrade, J. Harwood, I. Bickerton, N. A Fox, M. J.Cryan, “Molybdenum Gratings as a High Temperature Refractory Platform for Plasmonic Heat Generators in the Infrared”, IET Micro and Nano Letters, Micro & Nano Letters, 2018, Vol. 13, Iss. 9, pp. 1325–1328 doi: 10.1049/mnl.2018.0156

[7] N.Ahmad, S.Núñez-Sánchez, J.R.Pugh and M.J.Cryan, “Deep-Groove Nickel Gratings For Solar Thermal Absorbers”, Journal of Optics, 18, 105901, Sept 2016 (doi:10.1088/2040-8978/18/10/105901) selected for 2016 Highlights :

[8] Chenglong Wan, Yinglung Ho, S.Nunez-Sanchez, Lifeng Chen, M.Lopez-Garcia, J.Pugh, Bofeng Zhu, P. Selvaraj, T.Mallick, S.Senthilarasu and M.J.Cryan, “A Selective Metasurface Absorber with An Amorphous Carbon Interlayer for Solar Thermal Applications”, Nano Energy, June 2016 (10.1016/j.nanoen.2016.05.013)

[9] C.Wan, L.Chen, M.J.Cryan, “Broadband Metasurface Absorber for Solar Thermal Applications”, Journal of Optics, 17, 125103, Nov 2015 (doi:10.1088/2040-8978/17/12/125103)

[10] N.Ahmad, J.Stokes and M.J.Cryan, “Solar Absorbers Using 1D and 2D Periodic Nanostructured Nickel Films”, Journal of Optics, 16 125003, Dec 2014 (doi:10.1088/2040-8978/16/12/125003)

[11] N.Ahmad, J.Stokes, N.A.Fox, M.Teng and M.J.Cryan, “Ultra-Thin Metal Films for Enhanced Solar Absorption”, Nano Energy (Elsevier) August 2012(

About you

Ideally the student should have a first degree in Electrical Engineering, Physics or related disciplines.

Bench fees

A bench fee of £1,500 is required.

How to apply

All students can apply using the button below, following the Master's by Research Admissions Statement. Please note that this is an advertised project, which means you only have to complete Section A of the Research Statement Template (Office document, 69kB).


Your supervisor for this project will be Martin Cryan, Professor of Applied Electromagnetics and Photonics in the Faculty of Engineering. You can contact him at +44 (0) 117 954 5176 or email


Your co-supervisor for this project will be Dr Neil Fox, Reader in Wide Band Gap Nanomaterials in the School of Chemistry. You can contact him at +44 (0) 117 928 8729 or email

Find out more about your prospective research community

The Low Carbon Energy theme is a vibrant community of researchers who integrate expertise across multiple disciplines to develop sustainable energy policy and technologies which are crucial to providing a safe, reliable and low-cost energy supply for a growing global population. We innovate in every part of the energy system, from generation and storage, to regulation and end-user demand Find out more about the Low Carbon Energy theme.

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