Thermal annealing effects of C22-Quinolium(TCNQ) Langmuir-Blodgett films

Thermal annealing effects of C22-Quinolium(TCNQ) LB films were investigated through a study of frequency-dependent dielectric properties. Thermal annealing was performed in the range of 20∼240 °C. Thickness measurement by ellipsometry shows that there is a thickness drop near 100 °C, which is supposed to be due to a softening of the alkyl chains. The film thickness above 120 °C becomes ∼ 20 % of the room-temperature value. Frequency-dependent dielectric properties show that there are two characteristics dispersions; one is a dispersion occuring ∼ 1 MHz coming from the electric polarization of the molecules. The other one is an interfacial polarization effect below ∼ 1 kHz when the annealing temperature is above 80 °C.