Optical, electrical, and biological properties of PVP-PVA/Ca-doped CoO nanocomposites for opto-electronic and biological applications

Herein, we report the synthesis of calcium-doped cobalt oxide (Ca-CoO) nanocomposites using the simple and effective solution combustion method, and casting of polyvinyl pyrrolidone and polyvinyl alcohol (PVP-PVA) was done by solution intercalation method. Here, 0.5. 1.0, 2.0, and 4.0 wt% of nanofillers were introduced to polymer host. Polymer nanocomposites (PNCs) were subjected to various characterizations, where Fourier transform infrared spectroscopy (FTIR) reveals the positive interaction between the added nanofillers and polymer blends; meanwhile, scanning electron spectroscopy (SEM) analysis reveals the morphological behavior and particle size of 100–140 nm which was confirmed using DLS study. The PNCs reveal the steep UV absorption behavior using the optical absorbance study, while optical and electrical parameters were evaluated as they support the scope of engineering, the band gap, and dopant-dependent optical properties. The band gap energies were decreased from 5.0 to 3.60 eV as the weight % of nanofiller was increased. Dielectric properties along with AC conductivity were increased as the weight percentage of nanofiller increases. Additionally, PNCs were tested for the production of citric acid using Aspergillus niger, which shows that an increase in the wt% of PNCs increases citric acid production and 4% PNCs yields 17.0 g/L.