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We have fabricated highly stable organic electroluminescent devices based on spin-coated soluble phenyl-substituted poly-p-phenylene-vinylene (Ph-PPVs) thin films. The electrical properties of aluminum cathode, prepared by ion-beam-assisted deposition, on Ph-PPV have been investigated and compared to those prepared by thermal evaporation. Although energetic particles of Al assisted by Ar+ ion may damage the organic material, I–V–L characteristics are improved by evaporating a thin Al buffer layer prior to ion-beam-assisted deposition. In addition, a dense Al cathode inhibits the permeation of H2O and O2 into Ph-PPV film by suppressing pinhole defects, and thus retards dark spot growth. This may be deduced from highly packed structure of Al cathode with smaller contact resistance between Al and Ph-PPV. The lifetime of an organic light-emitting device has been extended by dense Al film through an ion-beam-assisted deposition process. [ABSTRACT FROM AUTHOR]

Abstract: Diamond-like carbon (DLC) layer was deposited by the Cs+ ion sputtered negative ion deposition technique between hole transport layer and indium tin oxide (ITO) anode for polymeric electroluminescent device. An acidic poly(styrene sulfonate)-doped poly(3,4-ethylene dioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS) solution acting as a hole transporting material etches the ITO surface and the PEDOT:PSS/ITO interface is not stable. X-ray photoelectron spectroscopy and Rutherford backscattering spectrometry have been used to measure the indium contamination in the organic layers such as PEDOT:PSS and poly[2-methoxy-5-( 2′-ethyl-hexyloxy)-1,4-phenylene vinylene]. From the result, it was found that the DLC buffer layer protects ITO surface from acidic PEDOT:PSS solution and restrains the indium diffusion into organic layer. The device with the DLC layer also has electroluminescent efficiency by almost 2 times in the polymeric electroluminescent device compared with the device without diamond-like carbon layer. [Copyright &y& Elsevier]

Abstract: Highly stable organic electroluminescent devices based on spin-coated poly-p-phenylene-vynylene (PPV) thin films have been achieved. We investigated the electrical properties of ion beam assisted aluminum cathode contacting PPV compared that of thermal evaporation. Energetic particles of Al assisted by Ar+ ion increase the contact area between Al and PPV minimizing contact resistance. In addition, dense Al cathode inhibits the permeation of H2O and O2 through pinhole defects, which results in retarding dark spot growth. It is believed that the lifetime of organic light-emitting diode (OLED) device was enhanced effectively by ion beam assisted deposition process resulting from dense Al structure. [Copyright &y& Elsevier]

Abstract: A long-lived organic light emitting diode (OLED) was fabricated using a dense aluminum cathode prepared by the ion-beam-assisted deposition (IBAD) process. We investigated the passivation properties of ion-beam-assisted and thermal evaporation-induced aluminum cathodes mounted on Ph-PPV. The dense and highly packed Al cathode effectively prevents the permeation of H2O and O2 through pinhole defects, which results in retarding dark spot growth. Employing thin Al buffer layer diminished Ar+ ion-induced damages in Ph-PPV and limited permeation against H2O and O2. The interface between Al and Ph-PPV may be modified in IBAD case, even though buffered Al layer was deposited to 30nm by thermal evaporation prior to Ar+ ion beam irradiation. It is believed that the buffered Al film cannot screen the Ar+ ions or Al atoms wholly due to the existence of pinholes or non-deposited regions among the columnar structures. [Copyright &y& Elsevier]

Abstract: We have fabricated highly stable organic electroluminescent devices based on spin-coated poly-p-phenylene-vynylene (PPV) thin films. The electrical properties of aluminum cathode, prepared by ion beam assisted deposition, on PPV have been investigated and compared to those by thermal evaporation. Although energetic particles of Al assisted by Ar+ ion may damage the organic material, I–V–L characteristics are improved by applying thin Al buffer layer. In addition, a dense Al cathode inhibits the permeation of H2O and O2 into PPV film through pinhole defects, and thus retards dark spot growth. It may be deduced from highly packed structure of Al cathode with smaller junction resistance between Al and PPV. In conclusion, the lifetime of organic light-emitting device (OLED) has been extended effectively by dense Al film through ion beam assisted deposition process. [Copyright &y& Elsevier]