Innovative First Step toward Mechanoluminescent Ubiquitous Light Source for Trillion Sensors

Recently, there have been innovative mechanoluminescent (ML) particles made available, each of which repeatedly emits light in response to small applied stresses even in an elastic region.When dispersedly coated onto a structure, each particle acts as a sensitive mechanical sensor, while the two-dimensional emission pattern of the whole assembly reflects the dynamical stress distribution inside the structure and the mechanical information around cracks and defects.On the other hand, ML ubiquitous light sources, the other final goal of mechanoluminescence, have been discussed and investigated toward innovative nano-light sources, which can be utilized anytime and anywhere, even in deep tissue and cells for an energy harvesting system for trillion sensors.In this review, we would like to focus on the activity toward the ML ubiquitous light sources, and introduce them from the next four viewpoints; the potential of the ML light source, the performance of a single ML ubiquitous light source, nondestructive and noninvasive mechanical stimulation, and application.