Development of highly fluorescent distyryl dyes for liquid crystal lasers

Abstract We developed new reddish fluorescent distyryl dyes, showing strong fluorescence around 600 nm, for optoelectronic devices. They have high fluorescent quantum efficiencies over 0.8, with large Stokes’ shifts exceed 60 nm in 1,4-dioxane. These features of new dyes are desirable for optoelectronic applications such as electroluminescent and dye-laser devices. We fabricated distributed feedback cholesteric liquid crystal lasers using the dyes and observed laser oscillation at a low excitation power of ∼22 nJ/pulse. Laser emission characteristics of the dyes are partly different from expectation from steady-state dichroic measurements. The origin of the discrepancy is discussed considering the relaxation process of the dyes.