Davyne changes color beyond human sight, opening path to invisible security tags

Researchers have discovered a new material called davyne, which exhibits a unique property of changing color in the near-infrared region, beyond human vision. The color change is invisible to the naked eye but can be detected using a spectrometer or an infrared-sensitive camera. This property of davyne, a cancrinite-structure material, arises due to electron transfer to chlorine vacancies, similar to the mechanism observed in hackmanite, another photochromic material.

Davyne was discovered as a byproduct during the synthesis of calcium hackmanite, a modified form of hackmanite. The researchers initially struggled to produce pure davyne due to the material's chemical equilibrium preferring to shift towards calcium hackmanite. However, with optimization and the aid of machine learning techniques, they successfully developed a method to produce the purest possible form of davyne.

The color-changing mechanism of davyne is analogous to that of hackmanite, involving the transfer of an electron from a specific ion to a chlorine vacancy in the structure. Despite having a different atomic structure than hackmanite, davyne showcases a reversible photochromic change in the near-infrared range. This property allows davyne to be utilized in various applications such as anti-counterfeit tags for banknotes, passports, and consumer products.

The near-infrared activity of davyne can be switched on and off, enabling it to be activated for inspection and then reverted to an invisible state.