Stress-induced color manipulation of mechanoluminescent elastomer for visualized mechanics sensing

The intrinsic relationship between mechanics and luminescent signals in mechanoluminescence materials presents unique advantages for visualized mechanics sensing. However, the quantitative or semi-quantitative sensing of mechanics in previous mechanoluminescence-based devices are always established based on brightness/intensity variations, which are hard to apply in practice. In this work, we designed an efficient mechanoluminescent system, Sr2P2O7:Eu,Y, in which two types of luminescent centers are introduced with blue and red emissions, respectively. The luminescent centers exhibited a strikingly distinct stress/strain responsiveness, and therefore a stress/strain-induced color manipulation is realized. Based on this intriguing performance, a visualized semi-quantitative sensing technique for mechanics was developed, by which the detailed stress/strain level could be acquired from the mechanoluminescent color. Because the luminescent color possessed a relatively high reliability with no need for complicated monitoring equipment, this visualized semi-quantitative sensing for mechanics presents high application values in various fields.