Preparing highly ordered copper phthalocyanine thin-film by controlling the thickness of the modified layer and its application in organic transistors

•Highly ordered copper phthalocyanine (CuPc) thin films were prepared.•Dependence of p-6P thickness on the performance of CuPc transistors was studied.•High field-effect mobility of 0.18 cm2/V s was obtained by CuPc transistors.

Para-sexiphenyl (p-6P) ultrathin film was utilized as the modified layer to grow copper phthalocyanine (CuPc) thin film. The order of the CuPc thin-film morphology exhibits an obvious dependence on p-6P thickness. A conversion of p-6P growth mode from layer-by-layer to island growth was observed. The highest mobility of CuPc transistor based on p-6P modified layer has been obtained by 0.18 cm2/V s with the p-6P thickness of 2.4 molecule layer. Therefore, the thickness of modified layer plays a crucial role in thin film growth of organic semiconductor that results in a remarkable influence on the electric characteristics of devices.