1,720,983 research outputs found
The effect of the PEDOT:PSS surface energy on the interface potential barrier
No full textCommercial PEDOT:PSS dispersions have been used to study the PEDOT:PSS interface properties; ITO/PEDOT:PSS/Al devices have been analyzed by the means of current-voltage and capacitance-voltage measurements where the effect of a barrier has been observed. Then by contact angle measurements employed on the PEDOT:PSS layer, the surface energy has been compared to the built-in potential obtaining an empirical law relating the polar component of the energy with the internal potential. The results have been interpreted in terms of interaction between the organic permanent dipoles and the metal that favours the tuning of the built-in potential. © 2011 Elsevier B.V. All rights reserved
Admittance electrical model of polyfluorene based organiclight emitting diodes
No full textIn order to obtain an AC electrical model of polyfluorene-PEDOT poly(3,4-ethylenedioxythiophene) based organic light emitting diodes, different devices have been realized using three PEDOT dispersions. Static current-voltage characteristics have revealed exponential like transport in all the samples and the bias has shown no dependence on admittance spectra. An electrical model is proposed and the estimated capacitance has been analyzed in terms of polyfluorene bulk intra-gap state distribution obtaining a state density of about 10(16) eV(-1) cm(-3). The hypothesis of a space charge involving completely the polyfluorene layer has been discussed. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3634121
Effects of the PEDOT interface trap distribution in polymeric OLEDs
No full textFour kinds of commercial PEDOT dispersions have been used to realize ITO/PEDOT/PF6/Al polymeric OLEDs. The effects of the different PEDOT layers have been analyzed by the means of static current-voltage characterizations and admittance spectra. The measurements have revealed a good agreement with the Nicollian-Brews model returning the density of the interface traps; moreover the role of the trapping rate has been focused in terms of density of carriers available for the conduction. © 2011 Elsevier B.V. All rights reserve
Admittance spectroscopy of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) based organic light emitting diodes
No full textAdmittance spectroscopy of Indium Tin Oxide (ITO)-poly(3,4- ethylenedioxythiophene) (PEDOT)-polyfluorene-Al organic light emitting diodes is analyzed by varying PEDOT dispersion. Loss-frequency diagrams show one or two peaks. The results have been interpreted by using the Nicollian and Brews admittance model. Single level and multi level interface state distributions are found for each kind of PEDOT. Surface state density is about 1011 eV-1cm-2 for all distributions while the interface time constant varies between 471 s and 220 ns. Good agreement is found between experimental data and analytical model. The combined effect of PEDOT conductivity and the inferred interface state density is analyzed and discussed. © 2011 American Institute of Physics
Influence of electrical, chemical and morphological properties of inorganic/organic interface on light emettingdevices performance
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