Oblique argon ion irradiation induced optical and structural modifications of polycarbonate polymer

Abstract

Oblique ion beam induced modifications in polymeric materials can be treated as an indispensable tool for fabrication of advanced functional materials having wide range of technological applications. In this context, we have examined the influence of 100 keV argon ion irradiation on optical and structural properties of Polycarbonate (PC) polymer at various oblique incidences of 30°, 40° and 50°. UV-visible analysis reveals that optical absorption edge shifted towards the visible region of the spectrum with decrease in angle of incidence which indicate towards the decrease in optical energy gap. A significant increase in Urbach energy (disorder content) from 0.09 eV to 0.795 eV has been observed. Interestingly, with decrease in angle of incidence optical energy gap decreases from 3.06 eV (virgin) to 2.45 eV at lowest angle of 30°. Moreover, FTIR transmission spectra shows drastic alterations in transmittance which are associated with structural modifications as a result of oblique ion irradiation. Further, the size of carbon clusters is found to be enhanced with decrease in angle of incidence. The observed optical changes have been further correlated with the structural modifications in the polymeric matrix as a result of oblique ion irradiation.