Polyimide photodevices without a substrate by electron-beam irradiation

Abstract Despite the insulating properties of polyimide (PI), this study implemented an optoelectronic device comprising only PI. To realize suitable photocharacteristics of the PI photodetector, the PI-coated glass substrate was irradiated with an electron beam to transform the optical and electrical characteristics of PI from lower light absorption and insulation to relatively higher light absorption and conductive properties; the substrate was then removed. With the optimization of the electron-beam irradiation treatment conditions, detectivity of 6.38 × 1010 Jones was exhibited for the PI photodetector at 1 V under laser illumination at a wavelength of 450 nm. Furthermore, the mechanical characteristics of the free-standing PI photodetector under cyclic bending tests suggested a reduction of less than 25% after 1,000 cycles of bending. This demonstrates an innovative approach to the design of stable, flexible PI photodevices through elimination of a separate substrate.