Frequency response of molecularly thin alternating current light-emitting diodes

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Osterbacka R, Pal AJ, Kallman KM, Stubb H
Publication year: 1998
Journal: Journal of Applied Physics
Journal acronym: J APPL PHYS
Volume number: 83
Issue number: 3
Start page: 1748
End page: 1752
Number of pages: 5
ISSN: 0021-8979
eISSN: 1089-7550


The frequency response of molecularly thin alternating-current polymeric light-emitting diodes has been studied. Langmuir-Blodgett (LB) films of poly(3-hexylthiophene) (PHT) were used as the active emitting material and the device was formed by sandwiching PHT films between LB films of emeraldine base polyaniline. As a step towards molecular electronic devices, we have shown that even two molecular layers of PHT (approximate to 6 nm) are sufficient for light emission. The high frequency operation limit of the device has been discussed in terms of a charge accumulation process at the polymer-polymer interface. The electroluminescence (EL) spectra of different structures have been compared with corresponding photoluminescence spectra. A significant blueshift in EL has been observed in thinner structures and its origin has been discussed. (C) 1998 American Institute of Physics. [S0021-8979(98)02103-3].

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