Effect of thermal, mechanical and photophysical properties of high emissive photoluminescence organic pigments

Abstract

This research aims to synthesize highly visible, bright emission fluorescent dye molecules in daylight to produce PU films and PU resource safety materials. Here we have developed four different types of highly visible PU films in which a cyano-substituted methoxyphenylene core with an additional electron-withdrawing and-donating unit is used to produce a bright orange color with twisted rigid conformational dyes. Modifications in the mechanical behavior and thermal stability properties of PU films were tested by tensile tests, TGA and DSC. The samples of PU film exhibit exceptional elasticity, with a high elongation breaking point and good young's modulus value. Furthermore, these synthesized dyes were measured for photophysical properties and other parameters such as solvent effect, quantum yield and lifetime. The quantum yields of highly visible dyes were measured in both solution and solid phase and found to be in the range of 0.25–0.48 and 0.15 to 0.55, respectively. The HOMO-LUMO energy gap of the dyes in the solid state is significantly lower than that in the solution state. This related to the dyes which exhibiting a lifetime in THF solution of about 1.96–2.41 ns, whereas in the solid state, the lifetime is much better about 6.43–19.61 ns. This indicating that the dyes in the solid state are energetically easier and hence the solid state of dyes shows higher lifetime.