Homeotropic alignment and delayed fluorescence of thin films of a columnar liquid crystal doped with multiwalled carbon nanotubes

Molecular ordering is one of the desired factors for the enhancement of device efficiency. Herein, we have homeotropically aligned a columnar liquid crystal (ColLC) doped with multi-walled carbon nanotubes (MWCNTs). The aligned films showed higher absorption and emission intensities, and photoluminescence quantum yield (PLQY) values than non-aligned films. In steady-state photoluminescence spectra, a quenching of the ColLC emission was observed upon the addition of the nanotubes. Furthermore, time-dependent photoluminescence measurements showed that MWCNTs impact delayed fluorescence associated with triplet–triplet annihilation (TTA) between the LC molecules.