3C08 Carrier transport characteristics in low temperature region in the smectic phase of terthiophene derivative

Abstract

Liquid crystalline semiconductors exhibiting smectic phases below room temperature, alkynylterthiophene derivatives are synthesized. Propylhexynylterthiophene exhibits SmB_<crystal> phase down to -100℃ in cooling process. Hole mobility at room temperature is 6X10^<-2> cm^2/Vs which is comparable to those of aromatic molecular crystals, and its carrier transport characteristics is found to be described by the Gaussian disorder model, giving σ and Σ to be 46 meV and 1.98 respectively, which are quite smaller than those of amorphous organic semiconductors. High μ_0, 3.5 indicates that closer intermolecular packing in highly ordered smectic phases should be important to increase carrier mobility.