Cyano-substituted oligo(p-phenylene-vinylene)s having linear and branched octyloxy groups: control of aggregation and emission properties via C8 alkyl chain difference

Abstract

We report the control of solid-state emission properties of cyano-substituted oligo(p-phenylene-vinylene)s, COPVs, via C8 alkyl chain. COPVs having C₈H₁₇O–, n-octyloxy and 2-ethylhexyloxy, groups were synthesized by Knoevenagel condensation. The alkyl (alkoxy) chains attached to COPV did not influence the optical properties in solution but affected the solid-state properties. In the solid-state, COPV with branched alkyl chains showed lower energy emission than COPV with linear alkyl chains at both sides. Alkyl chain structures induced the tuning of H- and J-aggregation, resulting in different solid-state optical properties. The macrostructure of the COPVs showed different aggregation behaviors depending on the alkyl chains present.