Impact of loading PVA/CMC/PVP blend with CdS<inf>0.9</inf>M<inf>0.1</inf> non-stoichiometrically doped by transition metals (M)

Abstract

PVA/CMC/PVP (50:25:25%) blends, pure and loaded with non-stoichiometric CdS0.9M0.1 (M = Cu, Co, Mn, or Zn) were produced. X-ray Rietveld analysis was performed for determining phases formed in CdS0.9M0.1 samples, their percentage, structural and microstructural parameters. X-ray diffraction, FT-IR, SEM and EDS techniques were utilized to characterize the obtained PVA/CMC/PVP/CdS0.9M0.1 composites. The impact of loading CdS0.9M0.1 on the optical parameters and emitted fluorescence features of PVA/CMC/PVP blend was studied. Absorbance was increased and the optical band gaps decreased with the different extents depending on the dopant metal in CdS0.9M0.1. The obtained values of direct and indirect optical band gaps for PVA/CMC/PVP pristine and filled with CdS0.9M0.1 are (5.2, 4.88, 4.37, 4.75, 4.47) and (4.95, 3.98, 3.36, 3.73, 3.57) eV for pure, Cu, Co, Mn, Zn, respectively. Upon nanofiller loading, the refractive index (n) highly increased in the visible range, acquiring the highest values for the blend filled with CdS0.9Co0.1. n for pristine blend decreased with the wavelength monotonically, but for loaded blends, it varied nonlinearly with λ; decreased for λ < 460 nm, increased for 460 < λ < 560 nm then decreased beyond this range. The Fluorescence (FL) intensity of PVA/CMC/PVP polymer blend was almost quenched upon loading CdS0.9M0.1 attaining its lowest value for CdS0.9Co0.1. The enhanced nonlinearity and the FL quenching nominate the present polymer/nanomaterial composite for many applications.