Photophysical and optical properties of 4-(4'-(diphenylamino) benzylidene)-2-phenyloxazol-5(4H)-ones induced by the peripheral substituent

Photophysical and optical properties of 4-(4'-(diphenylamino)benzylidene)-2-phenyloxazol-5(4H)-ones differing in the peripheral substituent have been investigated in chloroform, solvent mixture, polymer matrix and solid state. These properties are influenced by the nature of the substituent on the phenyl ring and the environment. The dye bearing phenyl group or without substituent in para position of the phenyl group in 2-phenyloxazol-5 (4H)-one moiety has the brightest emission in a solid state, whereas the dye with cyano functional group pos-sesses the strongest emission in chloroform. The spectral behavior of the tested dyes is dependent on the solvent mixture. The fluorescence of the oxazolone dye in CHCl3/MeOH was reduced due to hydrogen bond formation, whereas addition of water to the THF or DMSO indicate the enhancement in emission caused by aggregation induced emission (AIE). The absorption and fluorescence spectra of the oxazolone polymer thin film are shifted to blue compared to the dyes dissolved in chloroform.The surface topography of the oxazolone thin films was examined using atomic force microscopy (AFM). The optical properties of the dye layers and dyes immobilized in PMMA matrix were determined by spectroscopic ellipsometry (SE). The absorption coefficient, refractive index, extinction coefficient and the energy bandgap can be effectively manipulated by changing substituent in the dye structure.

Automated summary

The photophysical and optical properties of 4-(4'-(diphenylamino)benzylidene)-2-phenyloxazol-5(4H)-ones with different peripheral substituents were investigated in various environments. The nature of the substituent on the phenyl ring and the solvent mixture influenced these properties. The brightest emission was observed in solid state for the dye with a phenyl group or no substituent in the para position, while the dye with a cyano functional group showed the strongest emission in chloroform. The spectroscopic behavior of the dyes depended on the solvent mixture.