Mechanoluminescence ratiometric thermometry via MgF₂:Tb³

Mechanoluminescent materials have attracted considerable attention over the past two decades, owing to the ability to convert external mechanical stimuli into useful photons. Here we present a new, to the best of our knowledge, type of mechanoluminescent material, i.e., MgF₂:Tb³⁺. In addition to the demonstration of traditional applications, such as stress sensing, we show the possibility of ratiometric thermometry using this mechanoluminescent material. Under stimulation of an external force, rather than the conventional photoexcitation, the luminescence ratio of ⁵D₃→⁷F₆ to ⁵D₄→⁷F₅ emission lines of Tb³⁺ is confirmed to be a good indicator of temperature. Our work not only expands the family of mechanoluminescent materials, but also provides a new and energy-saving route for temperature sensing.