Influence of the morphology of the copper(II) phthalocyanine thin film on the performance of organic field-effect transistors

•CuPc through petroleum ether SVA improving film morphology and crystalline.•The field-effect mobility values increase 10 times after petroleum ether SVA.•The absolute value of the threshold voltage decreased slightly from 17 to 10.5 V.•The on/off ratio increased from 10 to 102-103 after petroleum ether SVA.

Organic thin-film transistors (OTFTs) with high crystallization copper phthalocyanine (CuPc) active layers were fabricated. The performance of CuPc OTFTs was studied without and with treatment by Solvent Vapor Annealing on CuPc film. The values of the threshold voltage without and with solvent-vapor annealing are −17 V and −10.5 V respectively. The field-effect mobility values in saturation region of CuPc thin-film transistors without and with Solvent Vapor Annealing are 0.00027 cm2/V s and 0.0025 cm2/V s respectively. Meanwhile, the high crystallization of the CuPc film with a larger grain size and less grain boundaries can be observed by investigating the morphology of the CuPc active layer through scanning electron microscopy and X-ray diffraction. The experimental results showed the decreased of the resistance of the conducting channel, that led to a performance improvement of the OTFTs.