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Physics Seminar

"Hot" electrons in plasmonic nanostructures – a very different view

Speaker: Dr Yonatan Sivan (Ben-Gurion University of the Negev)
Date: Tuesday 21 May 2019
Time: 14:00
Venue: Queens Buildings N/3.28

We present a self-consistent theory of the steady-state electron distribution in metals under continuous-wave illumination which treats, for the first time, both thermal and non-thermal effects on the same footing [1,2]. We show the number of non-thermal electrons (i.e., the deviation from thermal equilibrium) is a very weak effect, so that the power that ends up generating these non-thermal electrons is many orders of magnitude smaller than the amount of power that leads to regular heating. Using this theory, we re-examine the exciting claims on the possibility to enhance chemical reactions with these non-thermal electrons. We identify a series of errors in the temperature measurements in some of the most famous papers on the topic which led their authors to under-estimate regular heating effects. As an alternative, we show that a very simple 19th century theory, based on just simple heating, can explain the published experimental data with excellent accuracy [3,4].

[1] Y. Dubi, Y. Sivan, "hot" electrons in metallic nanostructures – thermal vs. non-thermal effects, https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Farxiv.org%2Fabs%2F1810.00565&data=01%7C01%7COhS2%40cardiff.ac.uk%7C57e88ff50d8d42c69f2008d6d4a58b7e%7Cbdb74b3095684856bdbf06759778fcbc%7C1&sdata=5smBYpDjvQpD7DnFfO%2FRFeJRQjp9VSD3MBEhjmm%2BWzA%3D&reserved=0.
[2] Y. Sivan, I.W. Un, Y. Dubi, Assistance of plasmonic nanostructures to photocatalysis – just a regular heat source, Faraday Discussions, in Press (2019).
[3] Y. Sivan, J. Baraban, I.W. Un, Y. Dubi, Comment on "Quantifying hot carrier and thermal contributions in plasmonic photocatalysis", Science 364 (6439), eaaw9367.
[4] Y. Dubi, I.W. Un, Y. Sivan, Thermal effects - an alternative mechanism for plasmonic-assisted photo-catalysis, https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Farxiv.org%2Fabs%2F1902.03169&data=01%7C01%7COhS2%40cardiff.ac.uk%7C57e88ff50d8d42c69f2008d6d4a58b7e%7Cbdb74b3095684856bdbf06759778fcbc%7C1&sdata=%2F3GgLkKBeSR3VSmD1YSfEX79Jb31PtnUBENpnzhPEkI%3D&reserved=0.