Formation of TTF-TCNQ charge-transfer complex in co-evaporated films

We have investigated the formation process of charge-transfer (CT) complex and the electric conductivity of TTF-TCNQ co-evaporated films by varying the growth temperature (Tg). The molar ratio of TTF to TCNQ in the co-evaporated film is constant at a value of 1.0 in the Tg range between 31°C and 42°C. The formation of the single crystal of the CT complex is enhanced and the electric conductivity increases with Tg. The temperature dependence of the surface conductivity is explained by the combination of the single-crystalline conduction of the grains and the activation-type conduction of the amorphous phase between the grains.