"This project aims to accomplish an understanding of the processes that currently limit the power conversion efficiency of solution-processed organic photovoltaic (OPV) devices, by identifying the factors that are responsible for the losses in device photocurrent generation. In particular, attention will be given to the origin of the photocurrent generation losses in OPV devices that take place due to the recombination of free charge carriers, prior to charge collection at the device electrodes. For the realization of the study a new set of non-fullerene based perfluorinated materials will be used as electron-acceptors and commercially available polymeric matrices such as poly(fluorene)-copolymers and poly(thiophene)s will be used as electron-donors. Free carrier recombination in the fabricated OPV layers and in their devices will be monitored by the detection of delayed luminescence in the μs – ms time scales, as a function of the photoactive layer morphology. The resulting luminescence dynamics will be then correlated to the photocurrent generation efficiency of the corresponding OPV devices and to the charge transport capabilities of the OPV layers. The project aims to deliver a new insight on the nature and the dynamics of charge transfer excited states that survive at delayed times after photoexcitation (delxplexes) in photoactive donor/acceptor composites. Throughout the project the photophysical and electrical characterization of next generation electron-acceptor materials will be realized and this will contribute in the progress of the OPV research field. The significance of the proposed project stems from the high potential of organic semiconductors to produce inexpensive and efficient photovoltaic systems. The project will mutually benefit the applicant and the Host Institution by supporting a smooth exchange of knowledge, by integrating their different expertise on the field of organic semiconductors and by accelerating the applicant's research career."