Charge transport in accumulation layers of organic heterojunctions

We studied the charge transport in organic heterojunction films consisting of copper phthalocyanine (CuPc) and copper hexadecafluorophthalocyanine (F16CuPc). The heterojunction effect between CuPc and F16CuPc induced high-density carriers at both sides of heterojunction. The Hall effect was observed at room temperature, which demonstrated the existence of free carriers and their delocalized transport under heterojunction effect. The Hall mobility of 1.2cm2∕Vs for holes and 2.4cm2∕Vs for electrons indicated that the transport capability of the heterojunction films is comparable to single crystals. The transport process was further explained by the multiple trap-and-release model according to the temperature dependence of conduction.