The frequency dependence of alternating-current polymeric light-emitti
ng diodes has been studied. Langmuir-Blodgett (LB) films of poly(3-hex
ylthiophene) have been used as the active emitting material sandwiched
between LB films of emeraldine base polyaniline to form the device. W
e have shown that by reducing the thickness of the emitting layer usin
g the LB deposition technique, one can increase the high-frequency ope
rating limit of the device. From the -3 dB frequency, we have calculat
ed the carrier mobility in the emitting polymer layer, and compared it
with the Poole-Frenkel model. The electroluminescence and photolumine
scence spectra have been studied. (C) 1997 American Institute of Physi
cs.