Browsing by Author "Nigussa, Zelalem"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Junction Studies between Aluminum and Polymer, Poly[2-Methoxy-5-(30,70- Dimethyloctyloxy)-1, 4-Phenylene Vinylene], Mdmo-Ppv and Mdmo-Ppv Blended With C60
    (Addis Ababa University, 2005-06) Nigussa, Zelalem; Tessema, Genene (PhD)
    This thesis is based on the experimental investigation of the junction between reactive low work function metal, Aluminum and Conjugated polymer, MDMO-PPV. The polymer is blended with C60 and the composition were also made with pure polymer. The techniques employed are absorption spectroscopy, current-voltage characteristics measurement and complex impedance spectroscopy. The absorption measurement shows that MDMO-PPV is a semiconductor with energy band gap of about 2.0032eV. The current density-voltage curve is found to be asymmetric and non-ohmic and shows Schottky barrier type recti¯cation. The recti¯cation ratio of fullerene blended MDMO-PPV is found to be 100 whereas that of pure MDMO-PPV is between 10 and 20, and more diode characteristics are observed in the case of fullerene blended polymer. The complex impedance spectra are single semi-circle displaced from the origin that show the existence of mobile charge depleted regions with some contact resistance. The radius of the semi-circle is found to depend on the bias of the junction