Fig. 3: ML brightness depending on the triboelectricity of polymer matrix.

a Home-made set-up for analysis AC-EL brightness of ZnS:Cu single layer attributed to independent triboelectricity of pure polymer matrices. b The output voltage and surface charge density of the polymer matrices. c AC-EL spectra of a ZnS:Cu single layer attributed to the output voltage of polymer matrices. The inset shows the AC-EL image of ZnS:Cu single layer attributed to output voltage of DS. d ML spectra according to the polymer matrices under the stretching, releasing, bending, scratching, and tearing, respectively. Inset images indicate the ML phenomenon under each mechanical motion.