It is the main goal of this project to bring to the host institution and the European Research Area the knowledge and technology to prepare current record flexible dye sensitized photovoltaic devices, previously developed by the candidate in South Korea and then the USA, in order to be able to further improve them, while endowing them with semi-transparency, using stretchable and bendable optical materials. The candidate has demonstrated that several key materials and processes provide better performance of bendable dye solar cells, i.e., enhanced efficiency and flexibility, by allowing the preparation of electrodes in which the electron diffusion length is longer and charge collection efficiency is consequently enhanced. However, highly efficient dye solar cells are opaque as a consequence of the particular diffuse scattering design employed to improve light absorption, which limits their application in building or automotive integrated photovoltaics. This proposal seeks to solve such drawback by introducing photonic nanostructures in different configurations, yielding both light harvesting enhancement and preserving transparency, hence placing Europe at the forefront of research in this specific area within the field of renewable energy.This final goal will be attempted through different approaches, each one challenging from the materials science perspective. Preparation of such highly efficient and transparent devices will combine the flexible solar cell processing tools previously developed by the candidate with the versatile optical material preparation techniques pioneered by the host institution. More specifically, integration of novel porous flexible photonic structures into the light harvesting layer, use of flexible mirrors attached to the back of the counter-electrode, and designed distribution of scatterers will be employed to reach the target.