Red luminous Eu(III) complexes: Preparation, spectral, optical and theoretical evaluation

Abstract

A series of luminous europium complexes were synthesized with general formula Eu(DAM)3L; DAM symbolizes diacetylmethane and L refers to the substituted 1,10-phenathroline derivatives. Results of spectral analyses affirm the binding of Eu3+ ion with DAM and heteroaromatic auxiliary units via oxygen and nitrogen atoms respectively. From Tauc’s plot, optical band gap was determined which shows the conducting behavior of synthesized complexes. Energy transfer mechanism reveals the effective sensitization of Eu3+ ion via antenna effect. Photoluminescence emission spectra have displayed most intense peak at ∼612 nm corresponding to 5D0→7F2 electric dipole transition. Synthesized ternary europium complexes exhibit red emission which is further confirmed by the position of chromaticity coordinates in CIE triangle. Structure and energy of various frontier molecular orbitals were determined computationally. These thermally stable red emissive complexes could be utilized in solid state lighting and displays.