Scanning the time and space evolution of anisotropy in single molecular crystals based on 3-(furan-2-yl)-2-(4-{[(2-hydroxy-5-methylphenyl)methylidene]amino}phenyl)prop-2-enenitrile.

The 3-(furan-2-yl)-2-(4-{[(2-hydroxy-5-methylphenyl)methylidene]amino}phenyl)prop-2-enenitrile (LAXYUI)), acting as a model, is a type of outstanding organic fluorophore. Using a transient absorption approach, the excitation relaxation behavior of LAXYUI in the monomolecular system and ordered crystals was identified. The polarization optical properties of LAXYUI crystals, including anisotropy of absorption and photoluminescence, polarization PL decay at different temperatures, and the evolution of optical anisotropy as a function of propagation length, are thoroughly investigated using a series of home-built polarization optical techniques. Our results can help people better understand the time- and space-dependent optical anisotropy that occurs in organic crystals, which will be important in the future to improve or broaden the performance of polarization optical systems based on organic crystals. • The aggregation molecule has a longer excited state lifetime and a stronger fluorescence. • The fluorescence lifetime of the crystal changes periodically with the polarization direction of the excitation. • Under horizontal excitation, the fluorescence lifetime is shortened more obviously with the increase of temperature. • The space-dependent evolution of anisotropy should be assigned to the difference of refractive index along the axis. [ABSTRACT FROM AUTHOR]