Electrical properties of Copper（Ⅱ） phthalocyanine derivative thin films

This paper reports an investigation on the electrical properties of thin film devices made by Copper（Ⅱ） phthalocyanine derivative and polycarbonate （PC） composite. The conducting and injection mechanism are further discussed. Materials of a variety composition were prepared into the thin film via spin-coating. ITO and aluminum were used as the bottom and top electrode respectively. J-V characteristic was measured and the result demonstrates that at a small bias region an Ohmic contact was achieved. As the forward bias increased, the current became space charge limited. The result of AC impedance measurement indicates the device could be equivalent to a parallel RC system. The introduction of PC into the CuPc possibly reduces the charge overlapping between the aromatic rings and led to a reduction in the molecular interaction. Hence, the ac conductivity decreases sharply as PC composition increases. But no change in the transport mechanism is found.