Room Temperature Liquid Formulation by Attaching Alkyl Chains on π-Conjugated Molecules

Abstract

Room temperature liquid formulation of intrinsically stiff, optically or optoelectronically active, π-conjugated molecules, such as anthracenes, oligo(p-phenylenevinylenes), and fullerenes, by attaching soft branched long-alkyl chains is demonstrated. Multiple modification with the branched long-alkyl chains on the periphery of an emissive π-conjugated moiety results in isolation of the π-unit core, thus generating a room temperature liquid state with almost no π-π interaction among the adjacent π-units and which shows considerably good luminescence. When only partially wrapping a π-unit core, e.g. C₆₀, attached by branched alkyl chains, those alkyl-π compounds are liquid/amorphous at room temperature, which however, can be directed into assembly by adding either of their own molecular segments, the π-unit or the alkyl-unit (alkane solvents). These ordered materials change from non-photoconductive monomer species to photoconductive assemblies.