Investigating the structural and linear/nonlinear optical parameters of PVA/CMC blend loaded by ZnS quantum dots

Abstract

Polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) blend loaded with different ratios (0, 5, 10, 15, 20%) from zinc sulfide quantum dots (ZnS QDs) was formed with thermolysis and casting methods. X-ray diffraction analysis applying Rietveld method, SEM and TEM techniques were employed to examine the nano nature of the powder filler. Utilizing the UV–vis diffuse reflectance spectroscopy, the effect of ZnS QDs loaded ratio on the optical features of the PVA/CMC blend was examined in detail. The optical energy bandgap was found to decrease (5.52 → 3.5 eV for direct, and 5.1 → 3.08 eV for indirect) upon increasing the nanofiller giving the possibility of a wide range for tailoring the band gap. The optical conductivity significantly increased in the range 250–400 nm. Also, the refractive index significantly increased (1.57 → 2.54) around the range 350–600 nm. The nonlinear optical parameters for PVA/CMC blend were improved when loaded with 20% wt. ZnS in the whole wavelength range. Fluorescence spectroscopy indicated all blends exhibited UV, violet, two blues, green and orange colors but the emitted intensity depended on the nanofiller loading ratio. The wide range of tuning the optical bandgap, refractive index, optical conductivity, nominate the present materials to be employed in wide range of applications in optoelectronics, coatings, and lenses.[Figure not available: see fulltext.]