Ultrafast Laser-Controlled Carbonization of Polyimide Film for Flexible Film Capacitors

With the development of electronic technology, the demand for flexible electronic devices has rapidly increased. Polyimide (PI) is an ideal substrate for flexible electronic devices due to its excellent dielectric properties and high flexibility. Laser carbonization technology can directly convert PI into conductive carbon material, which can be used to manufacture flexible and reliable electronic devices. This technology is environmentally friendly and cost-effective. In this work, a useful method of controllable carbonization of PI film through ultrafast laser is proposed. The dependence of the conductivity of carbon arrays on laser processing parameters was investigated by preparing flexible resistors by changing different laser processing parameters. By preparing the minimum resistance, the optimal carbonization laser processing parameters can be obtained. In addition, based on the optimal laser processing parameters, flexible film capacitors using carbonized PI film is successfully prepared. Under the condition of a scanning rate of 25 mV/s, the area capacitance can reach 1.32 mF/cm² and these capacitors can exhibit almost 100% electrochemical stability after 3000 charge/discharge cycles. This technique provides a new strategy for high-precision fabrication of miniature flexible electronic devices and has a wide range of applications in future.