Polyimide photodevices without a substrate by electron-beam irradiation

• Published in: Applied surface science 2021-12, Vol.570, p.151185, Article 151185
• Main Authors: Yoon, Hongji, Kim, Bong Ho, Kwon, Soon Hyeong, Kim, Dong Wook, Yoon, Young Joon
• Format: Article
• Language: English
• Subjects: Electron beam; Flexible photodetector; Hybridized bond; Photoconductivity; Polyimide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.151185

[Display omitted] •A free-standing optoelectronic device of polyimide (PI) was fabricated.•Electron-beam irradiation (EBI) treatment was applied to improve PI properties.•EBI was optimized to improve optical and electrical characteristics of PI.•The PI photodetector achieved detectivity of 6.38 × 1010 Jones at 1 V with 450 nm laser.•Cyclic bending tests showed less than 25% reduction after 1,000 cycles of bending. 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.