Triphenylamine- and triazine-containing hydrogen bonded complexes: liquid crystalline supramolecular semiconductors

This article is part of the themed collection: Recent Open Access Articles.Despite the fact that triphenylamine derivatives have been widely explored as hole-transporting materials, studies on charge transport properties in the liquid crystal phase have been overlooked. Here, it is reported that triphenylamine liquid crystals can attain very high hole mobility values in a hexagonal columnar mesophase, up to μ ≈ 5 cm2 V−1 s−1. The columnar liquid crystalline phase was obtained by a proper design of a supramolecular mesogen, and this is unprecedented for triphenylamine liquid crystals. In fact, the supramolecules were formed by hydrogen-bonded 1 : 3 complexes of a star-shaped triazine core and three triphenylamine peripheral units. The resulting hexagonal columnar mesophase acts as a successful scaffold that confines TPA units at the periphery of columns. Challenging DFT theoretical investigations into a model based on such supramolecular systems involving a large number of atoms were undertaken to explore the stability and geometry of the complexes and their electronic properties.This work was financially supported by the MICIU-FEDER funds (project PGC2018-093761-B-C31), the Gobierno de Aragón-FSE (E47_20R and B. F. grant B084/13), the Consejería de Economía y Conocimiento, Junta de Andalucía (FQM-337), and the Universidad de Jaén (Acción 1). A. G. thanks support from the ELIOTROPO project (PON03PE_00092_2). R. T. was supported by the MERAVIGLIE project (CUP J28C17000080006). The authors would like to thank the Centro de Servicios de Informática y Redes de Comunicaciones (CSIRC), Universidad de Granada, for providing the computing time and the Servicios Generales de Apoyo a la Investigación-SAI and CEQMA, Universidad de Zaragoza-CSIC.We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe