Effect of solvent–vapour annealing on morphology, structure of copper(II) phthalocyanine thin films and device performance

Abstract

We investigate the molecular orientation transition and resulting morphology of copper phthalocyanine (CuPc) thin films induced by solvent–vapour annealing (SVA) in detail. Seven solvents are utilized to tune the morphology of CuPc thin films. The morphology, crystalline structure and optical properties of the CuPc active layer were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and ultraviolet–visible (UV–Vis) absorption spectrum, respectively. The result demonstrates that morphology and structure are depended on the type of solvents. The high crystallinity of the CuPc films with a larger grain size and less grain boundaries can be observed. As a result, the resistance of the conducting channel is decreased, leading to an improved performance of the organic field-effect transistor (OFET).