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Updated: Jan 11, 2026

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
Hybrid Planar-Twisted Chair-Shaped Indoline Donor Enabling Bright Molecular and Aggregated State Near-Infrared
Qiqi Xu1, Ying Wang1,2, Yiyan Guan3
1Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Shanghai Key Laboratory of Functional Materials Chemistry, Feringa Nobel Prize Scientist Joint Research Center, Institute of Fine Chemicals, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Abstract:
Organic near-infrared (NIR) fluorophores with donor-acceptor (D-A) architectures have emerged as a preeminent paradigm in optoelectronic engineering and biomedical applications. However, conventional D-A NIR emitters often suffer from aggregation-induced quenching or weak absorption owing to the use of planar (e.g., carbazole) or highly twisted (e.g., triphenylamine) donor units, which impairs their versatile utility in molecular and aggregated states. Herein, we proposed a unique chair-shaped indoline donor (cID) with a hybrid planar-twisted conformation, which affords bright various states (solution, solid, microspheres, nanoparticles, and films) NIR emission spanning 650-1200 nm, with tails extending to 1600 nm. The cID donor promotes electron localization, imparting higher oscillator strength and a smaller HOMO-LUMO energy gap to the designed NIR fluorophores, which together enhance light-harvesting capacity and induce red-shifted emission. Meanwhile, the sterically hindered nonconjugated group in cID effectively restricts low frequency vibration-induced non-radiative decay, as evidenced by the reduced reorganization energy and Huang-Rhys factor in both isolated and crystalline phase. Through structurally π-conjugation extension, these NIR fluorophores exhibit robust various-state NIR-I (photoluminescence quantum yields up to 67.8% and brightness up to 15668 M-1 cm-1) and NIR-II emission, which allows diverse advanced applications in porous ceramic damage detection, stimulated emission depletion (STED) microscopy, and NIR-II vascular imaging, thereby positioning cID as a versatile toolkit to create a novel NIR dye library for biomedical and optoelectronic field.
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