Preparation and characterization of MEH-PPV:ZnO nanocomposite thin films / Nurul Zayana Yahya

This thesis presents the study of nanocomposite thin films consisting of MEH-PPV as organic matrix and zinc oxide as nanofillers. The aim is to achieve an improvement of optical and structural properties of the nanocomposites.The MEH-PPV:ZnO nanocomposite thin films were prepared using spin coating technique to produce uniform thin films. Tetrahydrofuran is the best organic solvents to dissolve MEHPPV.The purchased and synthesized of ZnO were used to obtain nanocomposite thin films. The purchased ZnO nanoparticles were annealed , grinded and surface treated with oleic acid before added into MEH-PPV solutions while the synthesized ZnO was prepared by precipitation method in presence of sodium dodecyl sulphate (SDS) and different concentrations of potassium hydroxide (KOH) solutions. The structural properties of ZnO was analyzed using XRD, FESEM, FTIR and PL while for optical and structural properties of MEH-PPV:ZnO nanocomposite thin films were analyzed using UV-Vis, PL and FESEM. The absorbance peak and emission peak of MEHPPV:ZnO nanocomposite thin films increased as the amounts of ZnO added increased compared to the pure MEH-PPV. The peak increments indicate a considerable interaction between MEH-PPV and ZnO nanoparticles. For nanocomposite thin films morphologies, surface treated of ZnO with OA is well disperse and the agglomeration is reduced compared to the as purchased, grinded and annealed ZnO nanoparticles.For synthesized ZnO, in presence of SDS the radial shaped rods were obtained and its
UV emission is high which is indicates that the ZnO is high crystal quality and good optical property. For synthesized ZnO at different concentration of KOH shows different morphology of ZnO. The nanoflower composed flakes was obtained at 0.45 M of KOH concentrations while at 0.90 M, 1.35 M and 1.80 M the rods was obtained. The ZnO rods grow bigger and longer with increasing of KOH concentrations. The absorbance peak and emission peak of MEH-PPV nanocomposite thin films filled with synthesized ZnO increased compared to pure MEH-PPV. From this study, the ZnO and MEH-PPV:ZnO nanocomposite thin films have been successfully prepared. The optical properties of MEH-PPV added with ZnO are increased compared to pure MEH-PPV. The homogeneity and dispersion of ZnO into MEH-PPV improved as the ZnO treated with GA.