Tb3+‐Doped Ca3Ga4O9 Phosphors with Color‐Tunable Photoluminescence and Non‐Pre‐Irradiation Mechanoluminescence for Multimodal Applications.

Materials that can emit light under optical/mechanical stimulation are usually called photoluminescent/mechanoluminescent (PL/ML) materials. PL materials are used in diverse fields for half a century. While, ML materials have burst out in the last two decades, and now are showing great application potential in the fields of anti‐counterfeiting, information storage, and stress imaging. It is of great significance to explore new luminescent materials with PL and ML dual response. In this study, Tb3+‐doped Ca3Ga4O9 phosphors with color‐tunable PL and non‐pre‐irradiation ML properties are reported. Ca3Ga4O9 exhibits a broadband blue emission centering at 425 nm, which originates from the 4T2‐4A2 transition of electrons in d orbits of Ga3+. Due to the energy transfer from host to Tb3+, color‐tunable emission from blue to cyan, and ultimately to green can be realized by increasing the concentration of Tb3+. Particularly, ML is seen from Ca3Ga4O9:Tb3+ under grinding and from the Ca3Ga4O9:Tb3+/PDMS film under bending or stretching originated from the triboelectric mechanism. The non‐pre‐irradiation ML behavior is evidenced by the contrast thermoluminescence (TL) experiments. This study not only provides a new candidate toward multi‐purpose luminescent applications, but also demonstrates a good case in which the triboelectric effect can efficiently trigger the non‐pre‐irradiation ML behavior. [ABSTRACT FROM AUTHOR]