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].
|Tidskrift||Journal of Applied Physics|
|Status||Publicerad - 1998|