Influence of electric field on photoluminescence of lanthanide-doped nematic liquid crystal

Highly resolved luminescence and luminescence excitation spectra of recently synthesized LnL3bpy complexes, where Ln=Eu3+, Tb3+, bpy=2,2′- bipyridyne and L=phosphoroazo derivative of β-diketone: CCl3C(O)NP(O)(OCH3)2, in solid state and dissolved in nematic liquid crystal 6CHBT [4-(isothiocyanatophenyl)-1-(trans-4-hexyl)cyclohexane] were measured. The photoluminescence intensity of the complexes dissolved in 6CHBT was found to exhibit a strong dependence on the electric field. The mechanism of the effect and reason of its asymmetry with respect to the sign of electric field are discussed in the paper. Luminescence decay time in various environments and experimental quantum yields of the luminescence of these compounds in CDCl3 and CHCl3 solutions were measured.