In
this work, we fabricate two types of hierarchical microspheres,
i.e., one coassembled from two fluorene-based oligomers (1 and 2) and one self-assembled from a fluorene-based
oligomer (1), for ultrasensitive and selective detection
of trace sulfur mustard (SM) vapor. On the basis of distinct fluorescence
responses of 1–2 coassembled and
individual 1 hierarchical microspheres that originate
from differential noncovalent interactions between analytes and these
sensors, SM vapor can be ultrasensitively detected (30 ppb) and easily
discriminated from various sulfides and other potential interferents.
Our work that utilizes differential noncovalent interactions to give
sensitive and selective fluorescence response patterns represents
a new detection approach for SM and other hazardous chemicals.
A novel,
highly sensitive fluorescence sensor for phthalates is
developed by introducing nitrophenyl groups to a trifluorene molecule
that can form porous crystalline ribbons. On the basis of single-crystalline
analysis and theoretical calculations, we demonstrate that phthalate
molecules can diffuse into the caves of crystalline ribbons and effectively
suppress the rotation of nitrophenyl groups via noncovalent interactions
to enhance the emission. Because of this novel response mechanism,
fluorescence detection of phthalates with high sensitivity (the limit
of detection of widely used di(2-ethylhexyl) phthalate (DEHP) is 0.03
ppb) and rapid reversible turn-on responses is achieved. Sensitive
detection of phthalates released from commercial polyvinyl chloride
(PVC) products further illustrate the utility of such a sensor in
in situ and real-world applications.
Here, we report the fabrication of metastable and stable assembles from tricarbazole-based oligomers via a pathway complex that is achieved by subtly changing the alkyl end chain length. Importantly, compared to stable nanoribbons, the resulting metastable nanoribbons have about a 3-fold enhanced exciton diffusion length that leads to 2-to 4-fold sensitivity enhancement for a broad range of explosives. These results will motivate preparation of kinetically trapped structures with improved properties via pathway complexity, particularly by subtly changing the substituents of molecules.
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