1. Stability of the interface between indium-tin-oxide and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) in polymer light-emitting diodes
- Author
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M.J.A. de Voigt, L.J. van IJzendoorn, M. P. de Jong, and Applied Physics and Science Education
- Subjects
chemistry.chemical_classification ,Conductive polymer ,Materials science ,Physics and Astronomy (miscellaneous) ,chemistry.chemical_element ,Polymer ,Indium tin oxide ,Organic semiconductor ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,PEDOT:PSS ,Polymer chemistry ,Polymer blend ,Indium ,Poly(3,4-ethylenedioxythiophene) - Abstract
A cause for degradation of polymer light-emitting diodes is the oxidation of the polymer by oxygen diffusing out of the indium-tin-oxide (ITO) anode. This problem can be solved by the introduction of an organic hole-injecting film, poly-(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS), between the ITO and the emissive polymer. Indeed, a dramatic improvement of the lifetime and also the luminous efficiency has been observed. However, our Rutherford backscattering (RBS) studies show that the ITO/PEDOT:PSS interface is not stable. In as prepared glass/ITO/PEDOT:PSS samples 0.02 at. % indium was found in the PEDOT:PSS film. Annealing in a nitrogen atmosphere at 100 °C during 2500 h increased the indium concentration to 0.2 at. %. Upon exposure to air much faster degradation of the ITO/PEDOT:PSS interface was observed; after several days in air the amount of indium reached a saturation concentration of 1.2 at. %. The degradation of the interface can be explained by etching of the ITO due to the strong acidic nature of PEDOT:PSS. ©2000 American Institute of Physics.
- Published
- 2000
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