Investigation of the optical properties of Dy doped ZnO/PVA thin film: White light emission for LED application

Different concentration of Dysprosium (Dy)(0, 0.25, 0.5, 1, 2, 3 and 4 %) was doped in zinc oxide by solid-state sintering method and investigated the effect of different concentrations of Dysprosium on crystallite size, morphology and optical studies on ZnO. Spherical morphology with 90 nm was revealed by Scanning electron microscopy with a low bandgap (3.033 eV) and was noticed for the higher concentration of Dysprosium in ZnO lattice. Room temperature photoluminescence was investigated in detail. The different weight percentage of 4 % Dy doped ZnO was added in polyvinyl alcohol and a thin film was fabricated and the optical properties were investigated in detail. 2Dy-ZnOF exhibited higher transmittance (42 %) and a lower bandgap(3.18 eV) was noticed. The peaks at 482 nm and 492 nm correspond to the transition of 4F 9/2 to 6H 15/2 and 4F 9/2 to 6H 13/2 respectively. This transition is due to the magnetic dipole transition and electric dipole transition. Further, a weak emission at 651 nm is due to 4F 9/2 to 6H 11/2 transition. CIE color chromaticity revealed for flexible Dy doped ZnO/PVA thin film in the white light region. Hence it could be a potential candidate for White Light LEDs.