In an all-RUG collaboration, the Optical Condensed Matter Physics and Theory of Condensed Matter Physics (both at the Zernike Institute for Advanced Materials) groups have joined forces with the Molecular Dynamics group (Groningen Biomolecular Sciences and Biotechnology Institute) to obtain a complete picture of the static and dynamic fluctuations of individual molecular nanotubes – an artificial analogue of natural light-harvesting antennae. The researchers used a powerful combination of single-molecule photoluminescence, ultrafast correlation spectroscopies, and theoretical multiscale modeling to obtain quantitative description of the molecular scale fluctuations in large supramolecular assemblies. The scientists demonstrated that although there exists considerable disorder at molecular scale, different nanotubes are remarkably similar to each other in their optical properties, because the disorder at the optical level is strongly suppressed by intermolecular interactions. This marks an important step towards a complete understanding of how delocalized excited states in large self-assembled systems are spatially and temporally constrained and mobilized by static and dynamic disorder.
The results of this work are published in The Journal of the American Chemical Society (B. Kriete, A. S. Bondarenko, R. Alessandri, I. Patmanidis, V. V. Krasnikov, T. L. C. Jansen, S. J. Marrink, J. Knoester, and M. S. Pshenichnikov, “Molecular versus excitonic disorder in individual artificial light-harvesting systems”, Journal of the American Chemical Society., 2020; JACS first online 28 September 2020).
“Why disordered light-harvesting systems produce ordered outcomes” -- popular story by Rene Fransen (in English)
Maxim Pchenitchnikov together with Thomas Jansen (Theory of Condensed Matter group were awarded a Dutch Research Council (NWO) grant for the proposal entitled “Self-assembly pathways of an artificial light harvesting complex”. The aim of the project is to study how thousands and thousands of molecules organize themselves into highly-ordered functional structures without external guidance. The key to elucidating self-assembly intermediate stages and their kinetics is to confront the spectroscopic data with those predicted theoretical calculations.
Despite the fact that push-pull molecules based on Triphenylamine (TPA)/Tetracyanobutadiene (TCBD) strongly absorb in the visible spectrum, they do not show detectable photoluminescence in solution which is in agreement with the short excited state depopulation time of ~ 10 ps. The latter significantly increases in the solid state making TPA / TCBD derivatives potential candidates for photovoltaic applications.
This was published by Benedito Raul et al. as part of the SEPOMO network, a Horizon 2020 Marie Sklodowska-Curie ITN Programme.
Triphenylamine/Tetracyanobutadiene-based π-Conjugated Push-Pull Molecules End-capped with Arene Platforms: Synthesis, Photophysics, and Photovoltaic Response
Published in : Chem. Eur. J. 10.1002/chem.202002810
May 8, 2020
On May 8, 2020, Björn Kriete succesfully defended his PhD thesis, entitled "Exciton Dynamics in Self-Assembled Molecular Nanotubes".
The degree was awarded with the distinction : Cum Laude.
We employed a lab-on-a-chip approach as a means to obtain in situ control of the structural complexity of an artificial light-harvesting complex: molecular double-walled nanotubes.
Rapid and stable dissolution of the outer wall was realized via microfluidic mixing thereby rendering the thermodynamically unstable inner tubes accessible to spectroscopy. By measurement of the linear dichroism and time-resolved photoluminescence of both double-walled nanotubes and isolated inner tubes we show that the optical (excitonic) properties of the inner tube are remarkably robust to such drastic perturbation of the system’s supramolecular structure as removal of the outer wall.
This work was published in the journal Physical Chemistry Chemical Physics
It can be downloaded here.