Tag: MDABCO

News

BCA Spring meeting

Hamish, Pat and Harry attended the British Crystallographic Association (BCA) Spring Meeting in Leeds, 25-28 March 2024, where a lot of exciting things happened!

Harry gave a talk about his PhD work, entitled “Driving Forces in the Phase Behaviour of MDABCO-based Ferroelectric Perovskites“, and Pat gave a talk about the group’s work on “Investigations of ZIF Crystallisation Mechanisms“.

After organising part of the meeting programme as one of the representatives of the Chemical Crystallography Group (CCG), Hamish was elected to be the Chair of the CCG Committee of the BCA, a post he will hold for the next three years.

Most excitingly, it was announced at the meeting that Pat has won the 2024 CCG-CCDC Prize for Younger Scientists, which is awarded each year “to a younger scientist who has performed original research in the field of chemical crystallography or the application of crystallographic information to structural chemistry”.

Well done on the talks, Harry and Pat, and congratulations Pat on the CCG-CCDC Prize!

Papers

Origins of Ferroelectricity

Congratulations to former Masters student Dom Allen, whose work on ferroelectricity in MDABCO-based perovskites has just been published in the Journal of Materials Chemistry C!

MDABCO perovskites (MDABCO = N-methyl-1,4-diazoniabicyclo[2.2.2]octane) are one of a new class of ferroelectric materials, which have properties that rival best-in-class materials such as barium titanate or lead zirconate titanate. Ferroelectrics have a wide range of hugely important applications as capacitors and memory storage (e.g., in smartphones and computers), sensors, actuators and non-linear optics.

Dom’s modelling showed that the key ingredients that drive spontaneous polarisation in [MDABCO][NH4][I3] and related structures are (i) alignment of the A-site cation along <111> directions, (ii) ever-present dipolar coupling, and (iii) strain coupling between neighbouring sites. Contrary to prevailing wisdom, he found that hydrogen bonding, whilst it may still be important in determining the magnitude of polarisation or transition temperature, is actually not essential to drive this phenomenon.

The paper, which was invited for cover art, is Open Access and can be read here.

Dom’s work was supplemented by first-principles calculations from Nick Bristowe and his co-supervisor at Oxford was Andrew Goodwin. Well done all!