Development of luminescent liquid crystals based on excited-state intramolecular proton transfer fluorophores

Abstract

2-(2-Hydroxyphenyl)benzazole (HBX) derivatives are colorless and efficiently luminescent in visible region even in the aggregated state. We have developed luminescent nematic liquid crystals (LCs) by introducing particular substituents into the HBX cores. The selection guideline of these substituents for increasing the fluorescent quantum yield was established. The LC HBX derivatives showed polarized luminescence. The guest-host type LCs prepared from the newly synthesized HBX derivatives and room-temperature (chiral) nematic LCs also showed polarized luminescence, together with amplified spontaneous emission and cholesteric LC laser emission.