New Category of "Invisible" Dyes Can Be Used for Labeling Textiles

Munich, DE, January 11, 2016—Scientists are developing a category of dyes that absorb light near the infrared spectrum and are therefore invisible to the human eye, reports Phys.org. 

“A research team led by LMU [Ludwig Maximilian University of Munich] chemist Professor Heinz Langhals now reports the synthesis of the first peri-arylene consisting of six basic subunits, whose absorption spectrum is almost entirely confined to the near-infrared (NIR) region. In other words, the substance appears colorless to the human eye, and this makes it suitable for use as an inconspicuous labeling agent.”

Such a dye could be utilized to, for instance, label carpet to facilitate sorting at recycling facilities.