A new and reliable way of making fluorescent solids has led to the creation of the brightest-ever class of fluorescent materials. The 3D-printable materials could one day help solar panels harvest more energy from the sun.
Some 100,000 different dyes are able to fluoresce, helped because individual molecules in solution are physically distant from each other, says Amar Flood at Indiana University. “But in solids, the particles are closer together and so interfere with each other, which stops them behaving as individuals.”
Flood says this means materials made using fluorescent dyes, such as fibres used in textiles, aren’t as fluorescent as the starting solution, a problem that chemists have recognised for 150 years.
His team has found a way around the obstacle by mixing doughnut-shaped molecules called cyanostars with the dyes. While brighter individual fluorescent materials exist, the team’s methods promise to make it dramatically easier to make fluorescent solids from a far-larger range of dyes.
The cyanostars are able to hold the positively charged dye molecules far apart from each other so they maintain their fluorescent properties, even though they are in a solid state. Some brightness is still lost in this conversion from liquid to solid, but it improves on previous methods by at least a magnitude of 10. The technique can be used with any positively charged dye and in conjunction with 3D printing to make solids that glow.
These materials might find a use in solar harvesting, says Bo Laursen at the University of Copenhagen, Denmark, another co-author of the paper. He says this technology could be made more effective by converting infrared rays or low visible rays from the sun into a form that can be captured by solar cells. “A lot of this relies on fluorescent materials being as fluorescent as possible,” says Laursen.
“This is elegant chemistry, showing that you can take dyes that wouldn’t normally fluoresce in a solid state, and make them do that,” says Andrew Beeby at Durham University, UK. “But it is still early days in figuring out what use these materials will have in the real world.”
Journal reference: Chem, DOI: 10.1016/j.chempr.2020.06.029
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