Multicolor Mechanoluminescence From Lu3Al2Ga3O12: Tb, Eu for Stress and Temperature Visual Sensing

Mechanoluminescence (ML) refers to the luminescence phenomenon that occurs when a material is under external mechanical stimuli. However, relying solely on stress information to obtain ML signals is prone to test errors in complex test conditions. In this work, a Tb3+/Eu3+-doped Lu3Al2Ga3O12 multicolor ML material is reported, in which the ML color can be adjusted from white to red (CIE color coordinates: from (x = 0.313, y = 0.3293) to (x = 0.6183, y = 0.379)) by changing the Eu3+ concentration. In addition, LAGO: 0.25% Tb3+ and LAGO: 1.5% Eu3+ are physically mixed at different mass ratios, and the varied stimuli-responsed emission characteristics of Tb3+ and Eu3+ ions are used to develop a stress and temperature dual sensing device. Stress and temperature information can be further reflected simultaneously through the blue/red emission ratio I-R (I-Tb/I-Eu). As the temperature increases, the color changes from white to red (CIE color coordinates: from (x = 0.3259, y = 0.306) to (x = 0.4707, y = 0.3625)), and the relative temperature sensitivity (Sr) is as high as 1.209% K-1 at 298 K. This sensing device provides a new idea for potential structural safety monitoring, multi-modal anti-counterfeiting technology, etc.