Structural and optical characterization of pvp/zno nanocomposites prepared by sol-gel dip-coating method

The effects of Polyvinlypyrrolidone (PVP) on ZnO thin films prepared by sol-gel dip-coating method were investigated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometer (FTIR) studies. The optical absorption and transmittance spectra of ZnO thin films have been recorded using UV Spectrophotometer. In addition, the Photoluminescence (PL) has also been obtained to investigate the optical properties of ZnO and PVP/ZnO thin films. The XRD patterns exhibited that, the films were formed in the preferred orientation along c-axis as a function of polyvinylpyrrolidone (PVP) concentration and which also confirms the formation of Wurtzite structure. The crystallite size was calculated using the Scherrer’s formula. The SEM images of ZnO, PVP/ZnO (0.05M) and PVP/ZnO (0.07M) prepared films have depicted a fairly uniform distribution of particle size, such as, 1.2μm, 0.7μm and 1.1μm respectively. The FTIR spectra confirm the presences of ZnO and PVP/ZnO peaks. A remarkable increase in the band gap of PVP/ZnO was observed by UV Spectrophotometric analysis, further it was noticed that, the band gap values were larger than the optical band gap of bulk ZnO material. Whereas,the PL excitation spectra have depicted a strong UV emission and blue emission.