Details

Autor(en) / Beteiligte

• Vasilopoulou, M.
• Palilis, L.C.
• Georgiadou, D.G.
• Argitis, P.
• Kennou, S.
• Kostis, I.
• Papadimitropoulos, G.
• Stathopoulos, Ν.Α.
• Iliadis, A.A.
• Konofaos, N.
• Davazoglou, D.
• Sygellou, L.

Titel

Tungsten oxides as interfacial layers for improved performance in hybrid optoelectronic devices

Ist Teil von

• Thin solid films, 2011-06, Vol.519 (17), p.5748-5753

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Tungsten oxide (WO 3) films with thicknesses ranging from 30 to 100 nm were grown by Hot Filament Vapor Deposition (HFVD). Films were studied by X-Ray Photoemission Spectroscopy (XPS) and were found to be stoichiometric. The surface morphology of the films was characterized by Atomic Force Microscopy (AFM). Samples had a granular form with grains in the order of 100 nm. The surface roughness was found to increase with film thickness. HFVD WO 3 films were used as conducting interfacial layers in advanced hybrid organic–inorganic optoelectronic devices. Hybrid-Organic Light Emitting Diodes (Hy-OLEDs) and Organic Photovoltaics (Hy-OPVs) were fabricated with these films as anode and/or as cathode interfacial conducting layers. The Hy-OLEDs showed significantly higher current density and a lower turn-on voltage when a thin WO 3 layer was inserted at the anode/polymer interface, while when inserted at the cathode/polymer interface the device performance was found to deteriorate. The improvement was attributed to a more efficient hole injection and transport from the Fermi level of the anode to the Highest Occupied Molecular Orbital (HOMO) of a yellow emitting copolymer (YEP). On the other hand, the insertion of a thin WO 3 layer at the cathode/polymer interface of Hy-OPV devices based on a polythiophene–fullerene bulk-heterojunction blend photoactive layer resulted in an increase of the produced photogenerated current, more likely due to improved electron extraction at the Al cathode.