Optical properties of molecular photoswitches and metal-organic frameworks: a GW/BSE perspective

Thursday 12 January 2023, 14:00

Roberta Poloni

Recently, molecular photoswitches have been employed as an efficient solution for gas capture and release technologies as light, possibly in the visible range, rather than temperature, can be used to change the gas adsorption properties of the material. Recent experimental efforts have demonstrated that this can be achieved by functionalizing metal-organic frameworks (MOFs) using azobenzenes.
In my talk I will discuss our recent efforts towards the understanding of the optical properties of these materials and their similarity with the molecular case. The use of an orbital-tuning Bethe-Salpeter approach to select the exchange and correlation functional for the initial DFT calculations [1] will be discussed and the role of the starting point electronic density [3] assessed. Finally, I will show and compare BSE and GW calculations within a QM/MM scheme with periodic results to clarify the character of the low energy excitations in these materials [2] and to settle the longstanding debate on the semiconducting character of one of the most iconic MOFs: MOF-5 [3].

[1] https:doi.org/ 10.1021/acs.jctc.9b01257 ;
[2] https://doi.org/10.1021/ acs.jpcc.1c00367 ;
[3] https://pubs.acs.org/doi/full/10.1021/acs.jpclett.1c00543.

Video of the webinar is available here.