Fabrication of lead zirconium titanium and silica composite films on copper/polyimideflexible substrates

Abstract

This paper uses the sol–gel technique to deposit lead zirconium titanium (PZT)and silica composite film onto a copper (Cu)/polyimide (PI) flexible structure at150 °C. First,the PZT nanoparticles (NPs) were dispersed in a silica sol. Silica sols with different concentrationsof PZT particles were spin coated on Cu/PI substrates. Finally, the substrates were sintered at150 °C to form PZT–silica composite films. The thickness of the PZT–silica composite film was7 µm with three coatings. The PZT–silica composite films show a random orientation andpolycrystalline phase in XRD. The fabricated PZT–silica composite films were thenimplemented into flexible actuator and flexible sensor applications and were designed in theform of a cantilever beam. For the actuator application, the flexible actuators werelighter than silicon-based actuators and had lower resonance frequencies thansilicon-based actuators. The flexible actuators also had a larger tip displacement (400 µm) than silicon-basedactuators (14.04 µm) when both of the films were driven by 10 V at the first resonance frequency. For the sensorapplication, the flexible sensor was excited at the first resonance mode to generate themaximum vibration amplitude. The applied strain and induced charges were compared. Inour results, the sensor output was 428 mV, when the size of the electrodes was10 mm × 10 mm at 42 Hz.