Developing color-tunable fluorescent materials with simple chemical compositions that are easy to synthesize is highly desirable, but practically challenging. Now scientists at ETH Zurich have succeeded in using a new approach to produce a wide variety of fluorescent dyes, including red, which was previously difficult to make.

The dyes are affordable and fairly easy to make. The dyes are modular structured polymers. Depending on their color, they have a variable number of subunits. The subunits used are easily synthesized by chemists or are readily available in the market as simple compounds.

Together with scientists at RMIT University in Melbourne, the team developed artificial intelligence algorithms that help determine which molecular subunits are needed in what numbers for a given color.

The fluorescent inks can be used as UV-activated security for banknotes, certificates, passports or to encrypt data. The process can also create inks with color-changing properties under prolonged UV exposure. The scientists used two fluorescent inks, initially red, to illustrate this in their most recent work. One fluorescent ink turned blue after a few minutes of UV radiation, while the other remained red. In addition, security elements can be added to this property.

Other applications for the new fluorescent molecules are in solar power plants, or they could one day be combined with semiconducting molecules to produce low-cost organic light-emitting diodes (OLEDs) for displays.

Magazine reference:

  1. Ye S, Meftahi N, Lyskov I, Tian T, Kumar S, Christofferson AJ, Winkler DA, Shih CJ, Russo S, Leroux JC, Bao Y: Machine Learning-Assisted Exploration of a Versatile Polymer Platform with Charge Transfer Dependent Full Color Emission, Chem, 2 January 2023. DOI: 10.1016/j.chempr.2022.12.003