Binary molecular design for oriented crystalline film and so-lution-processed interdigitated hole injection layer in quan-tum dot LED devices

Printable electronics typically employ amorphous materials for layer uniformity, yet incorporating crystalline substances can significantly enhance device performance due to their superior carrier mobility. The implementation of interdigitated structures facilitates increased carrier injection and extraction while reducing transport paths, thus ele-vating device efficiency. This research addresses the challenges associated with the molecular design, assembly, and orientation control of crystalline structures on indium tin oxide substrates, focusing on augmenting hole injection and transport effi-ciency. We introduce a binary molecular design involving benzodipyrrole diesters (BDPCOs), where two polar-orienting ester groups are incorpo-rated into an aromatic BDP core. Our findings re-veal that the ester moiety's structure substantially influences film formation, with certain BDPCOs yielding highly crystalline films, whereas others result in oriented, non-crystalline films. Perovskite quantum dot (PVQD) LEDs incorporating a crystal-line BDPCO-based hole injection layer (HIL) ex-hibit superior luminescence compared to devices utilizing amorphous BDPCO or PEDOT:PSS HILs. This binary molecular design approach thus broad-ens the range of solution-processible crystalline films for advanced electronic device applications.