Researchers from Indiana University, Copenhagen University, and the University of Southern Mississippi have created the brightest fluorescent material which is the first of its kind on the planet.
A major problem in fluorescent materials is the tendency of fluorescent dyes to fade and change colors when converted to a solid-state from a liquid
By formulating positively charged fluorescent dyes into a new class of materials called small-molecule ionic isolation lattices (SMILES), a compound’s brilliant glow was seamlessly transferred to a solid, crystalline state, researchers reported on August 6 in the journal Chem.
“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,” said chemist Amar Flood of Indiana University.
The way fluorescence works is that the molecules absorb light, and then re-emit it at longer, lower-energy wavelengths, and there are 100,000 such dyes on the planet but almost all are problematic while converting them to solids. The problems when these dyes are converted to solids are dimming, color change, and quantum efficiency degradation.
This dimming is a result of the phenomena called exciton coupling. Due to conversion to solid, the dyes gets packed together and this coupling happens.
So, the researchers developed a solution to the above problem based on keeping the fluorescent molecules apart. They took a colorless solution of macrocycle molecules called cyanostars, and mixed them with the fluorescent dye.
This use of macrocycles (a large class of ring-shaped molecules) isn’t a new idea, and others have tried it before. But the big difference is that these earlier attempts used colored macrocycles.
As their new solution dried, it formed what the team called small-molecule ionic isolation lattices (SMILES) that effectively kept the dye molecules compartmentalized apart from each other, preventing them from interacting and preserving their optical properties with high fidelity.
Journal Reference:
Chem, Benson et al.: “Plug-and-Play Optical Materials from Fluorescent Dyes and Macrocycles” www.cell.com/chem/fulltext/S2451-9294(20)30310-7 , DOI: 10.1016/j.chempr.2020.06.029
