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Updated: Sep 15, 2025

Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
Rotaxane Formation Increases Squaraine Fluorescence Brightness beyond 900 nm by 25-fold
Joash Y Lau1, Kejia Shi1, Allen G Oliver1
1Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
Abstract:
A squaraine dye with two flanking benzo[cd]indoles absorbs strongly at 881 nm, but the fluorescence quantum yield is very low due to dye flexibility. Rigidification of the squaraine structure by encapsulation within a rotaxane produces a 25-fold increase in fluorescence brightness with an SWIR emission band that peaks at 915 nm and extends beyond 1100 nm. Excitation of the rotaxane's anthrylene sidewalls with 375 nm light produces a very large pseudo-Stokes shift of 540 nm.
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