Synthesis and characterization of CuPc-PEPC composite thin films and photovoltaic devices by drop casting method

Abstract

Using a drop casting method, stronger absorbent and photosensitive composite thin films based on a copper-phthalocyanine (CuPc) oligomer and a poly (N-epoxypropylcarbazole) (PEPC) copolymer were developed. Morphology, structural behavior and optical properties of CuPc:PEPC composite thin films have been studied using scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-VIS spectroscopy. The SEM images of pure CuPc organic thin films show the formation of some elongated shapes, while the morphology of CuPc:PEPC composite thin films is mainly controlled by the content of CuPc. XRD analysis of the CuPc:PEPC composite thin films reveal good crystallinity and the beta-copper phthalocyanine phase. Study of optical properties of CuPc:PEPC composite thin films after annealing in hydrogen atmosphere show decrease of the average optical transmittance. In addition, the broadening of the absorption bands increases the light harvesting capacity of the composite material for photovoltaic applications.