Ultra-sensitive mechanoluminescent ceramic sensor based on air-plasma-sprayed SrAl2O4:Eu2+, Dy3+ coating

Mechanoluminescence is a newly developed technology for the optical sensing of stress or surface pressure. One unfortunate limiting factor in its application is the sensors’ low sensitivity to stress (usually in the MPa range). In this study, an ultra-sensitive mechanoluminescent sensor is created based on the phosphor SrAl 2 O 4 :Eu 2+ , Dy 3+ , that showed greatly enhanced sensitivity (by a hundred times) than that of conventional mechanoluminescent sensors. This sensor took the form of a ceramic coating that was prepared via air plasma spray and vacuum tempering retreatment. Pure SrAl 2 O 4 :Eu 2+ , Dy 3+ powder was used with no supporting matrix to eliminate the negative effects of the elastic mismatch on the sensitivity. The sensor could resolve stress variations on the order of kPa based on the calibration results. We also demonstrated interesting applications based on this sensor, such as tactile sensing and air-pressure sensing, which show great promise for wireless mechanical perception.