In addition, PE is a promising technology for enabling flexible and wearable smart devices to be compatible with various plastic materials and papers, achieving the fabrication of electronic devices with some advantages of slight-weight, flexible, and foldable which are highly demanded in the next-generation smart electronics. Since, to date, fine-line fabrication, variation of materials, and improvement of processes have been demonstrated in the development of PE, PE enables the fabrication of a variety of devices and is becoming important as critical techniques for some applications in diverse areas.