Slit-coating of nematic liquid crystal and organic fluorophore mixtures to fabricate a lumina-forming film for polarization and wavelength conversion

Abstract In this study, intending to develop light-functionalized films for agricultural use, we proposed a thin film that combines molecular orientation control and optical functionality of organic fluorescent dyes using the guest–host effect, and evaluated thin films formed on hydrophilic-treated polyester films using a slit coating method. Polarized optical microscopy observation and absorption spectrum measurement confirmed that liquid crystal molecules and red fluorescent dye (Solvent Red 197) were uniformly and parallelly aligned with respect to the substrate surface, yielding an external quantum efficiency of 12.28%. Furthermore, in a three-layer structure sandwiched between a polarizer and a quarter-wave plate, we demonstrated that left-handed elliptical polarization can be generated in the 600–700 nm wavelength range while wavelength converting green light in the 500–600 nm range to red fluorescence. These results are expected to contribute significantly to applications in solar conversion films for agricultural use.