If you’ve ever been to a neon rave, you’ll appreciate the novelty that comes with fluorescence, from body paint to lighting it sparks the moth within all of us that just wants to gaze at bright lights. If that sounds like you, I have good news, as chemists have just formulated the brightest ever fluorescence and the results are dazzling. The research, published in the journal Chem, uses a new class of materials to boost the properties of dye, creating the brightest known fluorescent materials in existence.
Existing fluorescent dyes have always been held back in their brightness due to the fact they don’t mix well together when being transformed into solid optical materials. Dyes undergo a process called "quenching" when they enter a solid state, which relates to how they behave when smushed together and tends to result in a decreased intensity of their fluorescence.
To overcome this “subdued glow” effect, the researchers mixed a colored dye with a clear solution called cyanostar, a star-shaped macrocycle molecule that prevents the “quenching” effect when dyes are transformed into a solid. The cyanostar stops the quenching effect as it forms a lattice-like structure, which keeps the dyes apart from each other.
"The problem of quenching and inter-dye coupling emerges when the dyes stand shoulder-to-shoulder inside solids," said Amar Flood, a chemist at Indiana University and co-senior author on the study, in a statement. "They cannot help but 'touch' each other. Like young children sitting at story time, they interfere with each other and stop behaving as individuals."
As the clear cyanostar and dye combination became a solid, a new class of materials called – and we’re not joking here – small-molecule ionic isolation lattices, or SMILES, formed in the mixture. Previous research had tried using these divider macrocycles to keep the dyes apart, but these macrocycles also had their own color that dulled the effect. Flood’s team realized that having colorless macrocycles was the key to revealing the dye’s true fluorescent potential.
"Some people think that colorless macrocycles are unattractive, but they allowed the isolation lattice to fully express the bright fluorescence of the dyes unencumbered by the colors of the macrocycles," said Flood. "These materials have potential applications in any technology that needs bright fluorescence or calls for designing optical properties, including solar energy harvesting, bioimaging, and lasers.
"These materials are totally new, so we do not know which of their innate properties are actually going to offer superior functionality. We also do not know the materials' limits. So, we will develop a fundamental understanding of how they work, providing a robust set of design rules for making new properties.”