Tailoring Photochromism Beyond Human Eye Visibility: On/Off Switchable NIR Absorption in an Aluminosilicate

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optics

Background:

• Photochromic materials reversibly change color upon UV radiation exposure, reversed by light or heat.
• Inorganic photochromes offer high durability but were limited to fixed wavelengths, unlike tunable organic counterparts.
• Recent advances showed hackmanites offer tunable visible photochromism, expanding inorganic material possibilities.

Purpose of the Study:

• To introduce the first photochromic material with absorption solely in the near-infrared (NIR) spectrum.
• To demonstrate invisible photochromism that operates beyond human visual perception.
• To explore the potential of this novel material for secure tagging applications.

Main Methods:

• Synthesis and characterization of a davyne-type aluminosilicate structure.
• Investigation of photochromic properties under UV and white light/heating.
• Development of a camera-based system for detecting invisible NIR photochromic changes.

Main Results:

• A davyne-type material was identified as the first photochromic substance with exclusive NIR absorption.
• The material exhibits reversible photochromic behavior without any visible color alteration.
• Invisible NIR photochromic changes were successfully detected using a standard camera setup.

Conclusions:

• This study presents the first inorganic material enabling invisible, reversible near-infrared photochromism.
• The davyne-type structure opens new avenues for materials that function beyond the visible spectrum.
• The material's unique properties hold significant promise for innovative tagging and security applications.