Structural and optical studies of ZnO doped PMMA thin film and its photocatalytic and antibacterial activities

Abstract

The structural properties of ZnO/PMMA thin film are studied using FESEM, XRD and FTIR, where uniform deposition of ZnO nanoparticles was observed in PMMA matrix. The FTIR spectroscopy is employed to elucidate the presence of the attached functional groups and the type of bonding involved. For optical properties of ZnO/PMMA thin film, UV–Vis spectroscopy is used and the maximum absorption is observed around 320 nm and 378 nm for PMMA and ZnO/PMMA thin films, respectively. It is noted that the optical band gap for ZnO/PMMA thin film decreases from 2.83 eV to 2.6 eV. The decrease in the band gap is due to the ZnO nanoparticles. The photoluminescence spectra peak for ZnO/PMMA thin film is observed at 436 nm or 2.83 eV. The excitation dependent fluorescence is observed in ZnO/PMMA thin film for range 380 nm–430 nm and the PL peak shows red shift from 434 nm to 500 nm and the corresponding CIE coordinates are represented. ZnO/PMMA thin film shows 96% degradation of industrial dye Methylene Blue without use of any reducing agent with reaction rate constant k = 0.0331 min−1. The thin film was reused for repeated dye degradation and up to 90% degradation was observed for 5 cycles. It also shows the zone of inhibition against E-Coli bacteria. By comparing our results with similar works reported by other researchers, the ZnO doped PMMA thin film shows better Photocatylatic and Antibacterial Activities and is useful in fabricating highly efficient optoelectronic devices, waste water treatment and removal of hazardous industrial dye.