Materials Hipster #2: Aron Walsh
tags: [materials_hipster hybrid_halides photovoltaics Aron is chair in materials theory at Imperial College London, where I met up with him for this interview. He is also my former post-doctoral boss and one of the original materials hipsters. Aron hails from Swords, on the wrong side of Dublin. After a PhD in Trinity College Dublin he worked at NREL (Colorado), UCL (London) and Bath before taking his position at ICL, he is also visiting professor at Yonsei University, Seoul. You can find his tastefully modernist, minimal group webpage here.
What’s your all time favourite material?
It has to be methylammonium lead iodide (MAPI) - I’ve spent the last six years of my life working on this material. There’s so much complexity from just three components and we are still a long way from understanding its full range of properties.
What material is super hot right now?
At the recent APS, superconductivity in bilayer graphene seems had the crowds very exited.1 This is where two 2D lattices are placed exactly on top of each other and slightly twisted to produce a superconducting state. It’s a little too hot for me!!
Do you have any top tips for the next big thing?
I’d say there’s a future for solar batteries. Integrating light harvesting with energy storage, so that the sun directly charges the battery. For example, you can harness solar-driven ion-diffusion, which would then build up a charge gradient, or it could be a solar super-capacitor. One example with halide perovskites was published this year (Photo-Rechargeable Organo-Halide Perovskite Batteries).
If you could only read one journal, which one would it be?
At the moment, it would be ACS Energy Letters. It has timely reports across the field of energy materials covering solar energy, batteries, thermoelectrics, with quite a lot of materials chemistry. While other publishers have “energy” journals, ACS Energy Letters is quite unique in that the editor has a real drive to deliver a fast turn-around; that’s part of the reason it was quickly adopted by the perovskite solar-cell community.
Tell me about a criminally underrated journal?
Proceedings of the Royal Society! You find a lot of pioneering research was published there in the past. Mott, Faraday, I think even Maxwell published there [he did: here]. There’s a lot of history, but somehow it just went out of vogue. It still has original and interesting papers, but they are not necessarily highly cited. It has such an important history, I feel that the Royal Society could do a better job of making people aware of it.
PRL or JACS?
These days, JACS. Maybe five years ago I would have said PRL, but they have cut a lot of their materials content. They used to publish quite a lot of semiconductor physics, but those papers have drifted to other materials specific journals. I think that JACS has a nice balance, and it covers areas of physical and materials chemistry reasonably well.
Best crafted paper you’ve read recently?
The most recent paper I have read, but also very well crafted, is a review on anion redox materials for batteries by Assat and Tarascon in Nature Energy. Usually transition metal redox gives rise to the energy storage capacity of batteries, but there is an emerging class of materials where the anion can provide additional redox power. This review gives a nice historical perspective and shows there are many opportunities in the field.
Who’s papers always make you read deeper?
Marshall Stoneham. Beyond his 1000 page monograph on Theory of Defects in Solids , I have learned a lot from reading his papers. They are often hard to read initially but with persistence, and following up a number of references, you get increased value as you reread them. A little like listening to My Bloody Valentine, it’s worth the effort when it finally clicks. Good example: Quantum Theory of Diffusion with Application to Light Interstitials in Metals
Favourite conference?
The fall meeting of the Materials Research Society, despite the fact I left my laptop in a taxi the evening before my first ever presentation there. If you have a symposium that you are interested in, you can spend a day with 50 to 100 of the top people working in that area, all while being part of an international conference with 1000s of delegates.
Best conference catering?
Probably my first conference as a PhD student, which was CIMTEC. It was in Sicily at a resort hotel and it had five days of buffet. As a poor and hungry PhD student, buffet lunches every day at a top hotel is hard to beat - I have never had an experience to better it yet!
Worst conference catering?
Ah, I had an incident at the EMRS in Lille. They had very few vegetarian options for the buffet dinner, which was being held in a dimly lit room. Given the lack of main courses, I thought I’d go straight for dessert; you can’t go wrong with a nice dessert. I went for the mousse, which after I started to eat it turned out to be foie gras … as soon I put it in my mouth and knew that something was wrong and had to expel it very quickly!!
Outside of materials, what do you like to do?
I spend most of my spare time at the cinema. Movies take me away from chemistry in short bursts.
Any top tip on movies to see?
Not a movie I’d naturally recommend, but if you look carefully at the battle scene in Braveheart, before Mel Gibson charges over the hill, you can see me running away as a 12 year old peasant. Although it is set in Scotland, much of Braveheart was filmed in Ireland and I earned a healthy sum as an extra that summer.
Whisky or gin?
My drink of choice at the moment is Korean Makgeolli. Makgeolli is unfiltered rice wine, which is white in colour and can taste a little like a light yogurt. Traditionally Makgeolli is a cheap drink, but now craft Makgeolli batch brewing is all the rage in Seoul.