Effect of Tetrapropylammonium Iodide Doping Amounts on the Structural, Electric and Optical Characteristics of the PVA/PVP

Abstract

Polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) blended polymer loaded with (x) wt. % tetrapropylammonium iodide (TPAI) were fabricated. X-ray diffraction was used to identify the TPAI and crystallinity changes in the blend. TPAI doping’s effects on the blends linear and nonlinear optical parameters were examined. The direct and indirect energy gap values of the PVA/PVP blend were reduced from (5, 4.81) eV to (4.77, 4.27) eV and from (4.72, 4.39) eV to (5.11, 4.85) eV as it doped with 25% TPAI in the case of PVA/PVP prepared with distilled water (DW) and dimethylsulfoxide (DMSO), respectively. The value of refractive index at 500 nm was enlarged from 1.32 to 2.3 for the blend doped with TPAI and increased further to 2.67 as it was prepared with DW. A small doping amount of TPAI did not produce a noteworthy alteration in the real part of the dielectric constant (εr) value. By increasing the amount of TPAI (>12.5%), εr increased considerably, with the rate of increase in the blends prepared with DW being higher than that prepared with DMSO. At 500 nm, εr of PVA/PVP increased from 1.8 to 7.11 and 5.34 as it was doped with 31.25%TPAI in the case of the blends prepared with DW and DMSO, respectively. The influences of the solvent, amount of TPAI doping, and excitation wavelength on the fluorescence intensity and emitted colors were also investigated. The maximum DC conductivity (1.89 x10−7 and 1.06 x 10−5 s m−1) was detected at 338 K as the blend was doped with 12.5 wt. % TPAI and prepared with DW and DMSO, respectively. The effects of the amount of TPAI doping and the temperature on the DC conductivity of the various blends were also explored.