The growing demand for organic electronic devices warrants further development of the scalability and green solvent processibility of π-conjugated materials. Perylene diimide (PDI)-based materials have shown impressive performance as interlayers for electronic devices due to a low ELUMO energy and high charge mobility in films. The next step in the development of these materials is the transition toward scalable production and the fabrication of devices under ambient conditions. Here, we develop a green synthetic methodology to prepare a series of PDI-based electronically active materials (X2-5), which can be slot-die-coated into uniform thin films from green solvents in air. Compounds X2-5 comprised a monomeric PDI core with a functional cyclic secondary amine appended to the bay region. Bromine or cyano moieties are incorporated into the molecular scaffold to systematically tune optoelectronic properties. The utility of these materials is demonstrated by slot-die coating them from ethanol to serve as cathode interlayers in prototype air-processed conventional organic photovoltaics. Using a PM6:Y6 active layer, device power conversion efficiencies reached 10%, among the best reported under these conditions.
Keywords: electron transport layer; organic solar cell; organic synthesis; perylene diimide; slot-die coating.