Surface modifications and optical studies of irradiated flexible PDMS materials

This work aimed to modify the surface properties of polydimethylsiloxane (PDMS) for use in optoelectronic devices by utilizing a handmade ion source. PDMS films were exposed to hydrogen fluences of 6 × 10¹⁷, 9 × 10¹⁷ and 12 × 10¹⁷ ions/cm². X-ray diffraction and Fourier transform infrared spectroscopy were used to reveal the changes in PDMS after irradiation. Similarly, scanning electron microscopy was employed to examine the morphological alterations of irradiated surfaces. The bandgaps and band tails of pristine and treated films were estimated using Tauc’s methodology. When the hydrogen fluence was increased from 6 × 10¹⁷ to 12 × 10¹⁷ ions/cm², the bandgap lowered from 5.06 to 4.86 eV. Furthermore, the band tail energy improved from 0.53 eV for PDMS to 0.55 eV for 6 × 10¹⁷ ions/cm² and to 0.63 eV for 9 × 10¹⁷ ions/cm². In addition, the dispersion characteristics of PDMS were estimated using the Wemple–DiDomenico method. Moreover, the extinction coefficients and refractive indices were calculated. The recorded relaxation time reduced from 2.06 × 10⁻⁷ to 1.65 × 10⁻⁷ s when the ion fluence was enhanced from 6 × 10¹⁷ to 12 × 10¹⁷ ions/cm². According to the results found, ion beam irradiation induces modifications in irradiated films for use in optical devices.