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Self‐Assembled Conjugated Thiophene‐Based Rotaxane Architectures: Structural, Computational, and Spectroscopic Insights into Molecular Aggregation
Author(s) -
Zalewski Leszek,
Brovelli Sergio,
Bonini Massimo,
Mativetsky Jeffrey M.,
Wykes Michael,
Orgiu Emanuele,
Breiner Thomas,
Kastler Marcel,
Dötz Florian,
Meinardi Francesco,
Anderson Harry L.,
Beljonne David,
Cacialli Franco,
Samorì Paolo
Publication year - 2011
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201001135
Subject(s) - rotaxane , dumbbell , materials science , supramolecular chemistry , scanning tunneling microscope , photoluminescence , nanotechnology , conjugated system , molecule , polythiophene , micrometer , stacking , chemical physics , polymer , optoelectronics , chemistry , organic chemistry , medicine , physics , composite material , conductive polymer , optics , physical therapy
A comparative study of the self‐assembly at a variety of surfaces of a dithiophene rotaxane 1 ⊂ β ‐CD and its corresponding dumbbell, 1, by means of atomic force microscopy (AFM) imaging and scanning tunneling microscopy (STM) imaging on the micrometer and nanometer scale, respectively. The dumbbell is found to have a greater propensity to form ordered supramolecular assemblies, as a result of π–π interactions between dithiophenes belonging to adjacent molecules, which are hindered in the rotaxane. The fine molecular structure determined by STM was compared to that obtained by molecular modelling. The optical properties of both rotaxane and dumbbell in the solid state were investigated by steady‐state and time‐resolved photoluminescence (PL) experiments on spin‐cast films and diluted solutions. The comparison between the optical features of the threaded and unthreaded systems reveals an effective role of encapsulation in reducing aggregation and exciton migration for the rotaxanes with respect to the dumbbells, thus leading to higher PL quantum efficiency and preserved single‐molecule photophysics for longer times after excitation in the threaded oligomers.