Mechanically induced photons from ultraviolet-C to near-infrared in Tm 3+ -doped MgF 2

Abstract

Mechanoluminescence (ML) plays a vital role in various fields, and has gained increasing popularity over the past two decades. The widely studied materials that are capable of generating ML can be classified into two groups, self-powered and trap-controlled. Here, we demonstrate that both self-powered ML and trap-controlled ML can be achieved simultaneously in MgF 2 :Tm 3+ . Upon stimulation of external force, the 1 I 6 → 3 H 6 and 3 H 4 → 3 H 6 transitions of Tm 3+ are observed, ranging from the ultraviolet-C to near-infrared. After exposure to X-rays, MgF 2 :Tm 3+ presents a stronger ML than the uncharged sample. After cleaning up at high temperatures, the ML returns to the initial level, which is a typical characteristic of trap-controlled ML. In the end, we demonstrate the potential applications of MgF 2 :Tm 3+ in dynamic anti-counterfeiting, and structure inspection.