Tuning of linear and non-linear optical properties of MoS2/PVA nanocomposites via ultrasonication

Abstract

MoS2/PVA polymer nanocomposites have been synthesized using In-Situ technique with varying concentrations of MoS2 in polyvinyl alcohol (PVA). The samples of varying concentrations have been sonicated at different times. The effect of sonication time on the structural, linear and non-linear (NL) optical properties have been studied. Structural properties are investigated with the help of X-ray diffraction (XRD). The morphology of the prepared samples has been studied using Field Effect Scanning Electron Microscopy (FESEM). UV–visible (UV–vis) spectroscopy is used to study linear absorption properties. The smoothly varying absorption spectra acknowledge the presence of saturable absorption (SA) in MoS2/PVA nanocomposites. Photo-luminescence (PL) spectroscopy is used to investigate the emission spectra of the prepared nanocomposites with sonication. Fourier Transform Infrared (FTIR) spectroscopy depicts the presence of various physiochemical bondings within the prepared nanocomposites. NL optical properties are studied with the help of the Z-scan technique. The result confirms the occurrence of SA in the MoS2/PVA nanocomposites. Further, it can be seen that with rise in the concentration of MoS2 nanoparticles within the polymer matrix, self-focusing transforms into self-defocusing. The maximum order of NL refractive index and NL absorption coefficient obtained is 10−5 cm2/W and 10−6 cm/W, respectively. In this article, we have found that the NL optical properties of MoS2/PVA nanocomposites can be tuned by varying concentration of MoS2 nano-particles within the polymer matrix as well as by sonicating the particular concentration for different times.