Method for manufacturing energy harvester comprising piezoelectric polymer microstructure array

A method for manufacturing an energy harvester comprising a piezoelectric polymer microstructure array, the method comprising:

• 1) fabricating an array of circular holes on a surface of a silicon chip by photolithography and etching processes whereby obtaining an imprint mold, and performing surface treatment on the imprint mold;
• 2) using a first fluorine-doped tin oxide (FTO) or tin-doped indium oxide (ITO) conductive glass as a substrate;
• spin coating a layer of a piezoelectric polymer solution having a thickness of um scale on a surface of the substrate by a spin coater;
• and evaporating a solvent residue on a hot plate at 100° C.;
• 3) pressing the imprint mold after treatment on a polymer film with a pressure of 8 megapascal in an oven;
• raising a temperature in the oven to be higher than a glass transition temperature of the piezoelectric polymer;
• after between 10 and 30 min, cooling the imprint mold and the polymer film to room temperature;
• demolding the polymer film from the imprint mold, whereby forming a column array of the piezoelectric polymer on the substrate;
• 4) using a second FTO or ITO conductive glass as an upper electrode, and allowing the upper electrode and the substrate to form a pair of plate electrodes comprising an air gap therebetween;
• controlling the air gap between the upper electrode and the substrate to be between 2 and 4 times of a height of the column array by disposing a polyimide film therebetween;
• placing the pair of the plate electrodes into the oven;
• applying an external DC power supply by connecting a positive electrode thereof to the upper electrode and connecting a negative electrode thereof to the substrate;
• raising the temperature of the oven to be higher than the glass transition temperature of the piezoelectric polymer;
• regulating a voltage whereby enabling an electric force applied on the column array of the piezoelectric polymer o counteract a surface tension and a viscous resistance rheology;
• and maintaining the voltage for between 20 and 50 min until the column array of the piezoelectric polymer reaches the upper electrode to form a mushroom-shaped structure array;
• and
• 5) maintaining the voltage constantly, cooling the oven to room temperature and removing the voltage whereby obtaining a group of microstructure array of the piezoelectric polymer connected to the substrate and the upper electrode;
• removing the polyimide film from between the substrate and the upper electrode, whereby obtaining a piezoelectric energy harvester formed by the microstructure array of the piezoelectric polymer, the substrate, and the upper electrode.