Reversibly Photoswitchable Supramolecular Assembly and Its Application as a Photoerasable Fluorescent Ink

Now you see it, now you don’t

26 July 2017

An ink made from two compounds, both of which undergo distinct changes when exposed to light, could form the basis for new anti-counterfeit materials.

Yu Liu from the Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, and colleagues in China fabricated a light-sensitive ink that employs the properties of a luminescent compound and a ‘photochromic’ compound, which changes the arrangement of its atoms when exposed to different wavelengths of light.

The ink is invisible unless illuminated by visible light more than 420 nanometres in wavelength, when it fluoresces red. Exposing it to ultraviolet light for five minutes then ‘closes’ the atoms of the photochromic compound, quenching the other compound’s fluorescence. The process is reversible and can be repeated several times.

This repeatable and reversible molecular switch could find applications in the fields of computer information storage, light-controlled molecular devices, anti-counterfeit technology and reversible erase/rewrite systems.

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References

1. Advanced Materials 29, 1605271 (2017). doi: 10.1002/adma.201605271