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Physical Chemistry

Chemistry In Pictures

Chemistry in Pictures: Catch a wave

by Alexandra A. Taylor
November 4, 2020


A composite image with photos of a vial from two different angles and the emission spectra for the amorphous and crystalline forms of the dye in the vials.
Credit: João Avó

These photos show two different forms—amorphous and crystalline—of a naphthalimide dye in a single vial from two angles. In the side view (top, left), amorphous nanosized aggregates of the dye appear as a greenish-yellow cloud, while the blue-green, bladelike crystals are most visible in the top-down view (top, right). The nanoaggregates have an emission maximum at about 540 nm (bottom, left), and the crystals have a maximum around 500 nm (bottom, right). João Avó, a postdoc at the Instituto Superior Técnico, designed the dye for a research project for which he is the principal investigator. His aim is to create systems that exhibit thermally activated delayed fluorescence in aqueous media for use in optical time-resolved imaging in live cell cultures. He’s encouraged by the ability of this particular dye and its analogs to display strong emission in the aggregate state.

Submitted by João Avó (@JoaoMAvo)

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