Interface Engineering in Organic Solar Cells

Solution-processed organic solar cells (OSCs) have attracted much attention due to their low cost, flexibility and high transparency. Recently, the power conversion efficiency (PCE) of OSCs is approaching 20%. However, the unsatisfied interface issues limit further improvement in PCEs and stability of OSCs, through affecting the physical processes such as exciton separation and/or charge transport/extraction/recombination in the device. Our recent study on interface engineering in OSCs has shown that the introduction of new electron transporting materials could enhance the PCE and suppress the photodegradation at the cathode interface, achieving over 10000 hours of storage and thermal stability in OSCs. An original strategy for selecting an optimal interfacial layer based on the surface energy has been proposed, to optimize the morphology of the active layers by regulating the surface energy and its microscopic distribution of the interface layer. At the end, we have constructed semi-transparent devices by utilizing optical microcavities, achieving high uniformity of device transmission and controllable adjustment of reflection color, which offers a viable design strategy for semi-transparent OSCs toward applications in next-generation smart photovoltaic windows.