"This IEF project aims to address both hurdles apparent in the fabrication of Bulk Heterojunction Organic Photovoltaics (OPVs), i.e. the tailoring of the domain size to be close to the excitonic diffusion length and the stability of the blend morphology, through a wise incorporation of block copolymers in the blend that forms the active layer of OPVs. My target is to fabricate highly efficient solar cells with enhanced morphological stability and prolonged lifetimes, applying process techniques that can be easily adopted by industry. The self-assembly properties of block copolymers as well as their ability to form well controlled nanostructures and to act as compatibilizers in the blends of the respective homopolymers will be exploited to form stable nanomorphologies with optimum domain size, according to the specifications required for OPV applications. An integrated study will be conducted, starting from fundamental research on the polymer physics of the ternary system: rod-like homopolymer A – homopolymer B – rod-coil copolymer A-B. Next, the blends which exhibit the desirable co-continuous morphological characteristics will be incorporated into OPVs and the device performance and stability will be studied and optimized. Finally, I am going to apply the concepts of graphoepitaxy, a novel technique applied for the fabrication of well-ordered arrays of block copolymers, in the construction of OPVs, in an effort to realize the ideal interpenetrating structure proposed and achieve even higher efficiencies through a precise control of the nanostructure. The scope of the proposed research lies on the cutting-edge field of organic electronics (OE), which is of strategic importance for the competitiveness and the advancement of the socio-economic conditions of the European Union. The skills acquired during my studies will be complemented by the extensive experience of the host institute on OE to assure a successful accomplishment of this fully interdisciplinary project."