Fabrication and evaluation of PVA/SrTiO 3 -Co 2 O 3 futuristic films for biomedical and energy storage applications

The casting method was used to produce new inexpensive optoelectronic nanocomposite films containing strontium titanate (SrTiO 3 ) and cobalt oxide (Co 2 O 3 ) nanoparticles in a polyvinyl alcohol (PVA) host polymer matrix. According to the images taken with the optical microscope, the nanoparticles were evenly dispersed throughout the polymer matrix. Looking at the FTIR spectra in comparison to PVA shows that certain peaks have changed intensity and others have moved locations. Results show that the optical constants are proportional to the concentration of (SrTiO 3 -Co 2 O 3 ) nanoparticles (NPs), indicating that optical constants increase with concentration and transmittance decreases with further concentration. With a rise in (SrTiO 3 -Co 2 O 3 ) nanoparticle concentration. The optical band gap significantly decreased from 4.1 eV to 3.4 eV, facilitating indirect transitions, as the concentration of SrTiO 3 –Co 2 O 3 increased. This indicates that localized states improved, resulting in enhanced optoelectronic performance. At a loading of 6 wt% of SrTiO-Co 2 O 3 , the dielectric constant, dielectric loss, and AC electrical conductivity increased to 1.187, 0.523, and 2.90 × 10 −11  S/cm, respectively. This indicates an improvement in charge transfer and interfacial polarization. The antibacterial assays indicated that Staphylococcus aureus had inhibition zones measuring up to 34 mm, while Escherichia coli displayed inhibition zones of up to 26 mm. This confirmed that the antibacterial activity intensified with increasing nanoparticle concentration. The pressure sensing performance was markedly enhanced, with the nanocomposite exhibiting a peak sensitivity of 72.66% at a 6 wt% nanoparticle concentration, highlighting its suitability for flexible pressure sensor applications. In general, the addition of SrTiO 3 –Co 2 O 3 nanoparticles altered the optical band gap, enhanced the dielectric and electrical properties, and rendered the material significantly more sensitive to pressure and more effective in the elimination of bacteria. The combined functions of PVA/SrTiO 3 –Co 2 O 3 nanocomposite films suggest that they may be beneficial for antimicrobial applications, flexible pressure sensors, and optoelectronic devices.