Morphology, defects and polymer concentration related nonlinear absorption and optical limiting properties of electrospun polyamide 6 nanofibers
Yasemin Pepe, Şerife Akkoyun, Ahmet Karatay, Elif Akhüseyin Yıldız, Hüseyin Ünver, Aytunç Ateş, Ayhan Elmalı
Abstract
Abstract The effects of morphology, defects and polymer concentration on nonlinear absorption characteristics of electrospun polyamide 6 (PA 6) nanofibers were studied systematically. Scanning electron microscopy measurements showed that a deviation from uniform nanofibers to irregular cob‐web nanofibers morphology occurred with increasing PA 6 concentration and fiber diameter. Open aperture Z‐scan results indicated that the thinner uniform PA 6 nanofibers present higher nonlinear absorption. This observation is mainly attributed to a greatest light scattering for thicker uniform nanofibers, considering the linear optical analysis of the PA 6 nanofibers. As a secondary factor, this could be associated with defect state distribution within the band gap, which facilitates the contribution of two photon absorption (TPA) and free carrier absorption (FCA) to nonlinear absorption. Moreover, the thinner uniform nanofibers exhibit higher optical limiting behavior. Polyamide 6 nanofibers attract more attention for biomedical applications due to their good biocompatibility. However, to our knowledge, no study exists on PA 6 nanofibers nonlinear optical properties and their dependency on nanofiber morphology. Therefore, in line with the reported results, this report reveals that PA 6 nanofibers are a promising material for optoelectronic applications as well as biomedical applications.