LAUSR

One key challenge in the development of viable organic photovoltaic devices is to design component molecules that do not degrade during combined exposure to oxygen and light. They should thus remain comparatively unreactive towards singlet molecular oxygen and not act as photosensitizers for the generation of this undesirable species. Here we present novel redox-active chromophores that combine these two properties. By functionalizing indenofluorene-extended tetrathiafulvalenes (IF-TTFs) with cyano groups at the indenofluorene core using Pd-catalyzed cyanation reactions, we find that the reactivity of the exocyclic fulvene carbon-carbon double bonds towards singlet oxygen is considerably reduced. The new cyano-functionalized IF-TTFs were tested in non-fullerene acceptor based organic photovoltaic "proof-of-principle" devices, revealing enhanced device stability.