Multifunctional Flexible Device Based on Phosphor on Piezoelectric Polymer: Lighting, Speaking, and Pressure-Light Converting

摘要

In this paper, the tri-functional flexible device by using ZnS powder as phosphorrnlayer and flexible piezoelectric polymer as dielectric layer is demonstrated. Thernfabricated device generates the electroluminescent (EL) light from the phosphorrnand the sound from the piezoelectric sheet under a supply of external electricrnpower, and additionally harvests the mechanical energy harvesting to bernconverted into EL light. Under sinusoidal applied voltage, the EL luminancesrnare exponentially increased, to our best knowledge, with the best-recordrnluminous efficiency of 10 lmW~(-1) at 100 V and 400Hz, and the sound pressurernlevels (SPLs) are linearly increased. The EL luminances are linearly dependentrnon the applied frequency while the SPLs show the parabolic increase behaviorrnbelow 2000Hz and then flat response. The temperature dependence on the ELrnluminances and the SPLs is demonstrated; the former is drastically increasedrnand the latter is slightly decreased with the increase of temperature. Finally, asrnan energy harvesting application, the piezoelectric electroluminescence effect isrndemonstrated by applying the external pressure on the device without electricrnpower. This trifunctional device is expected to be applicable to emergencyrnwarning system, advertising panel, and remote stress sensor in both power-onrnand -off circumstances.