Eu3+ photoluminescence in mononuclear coordination compounds with different ligands

Abstract

Novel Eu3+-based photoluminescent (PL) organic coordination compounds have been synthesized; their optical properties in the UV–Vis spectrum have been characterized. The paper presents results of studying mononuclear coordination compounds (MCCs) with the Eu3+ ion, namely, Eu(o-MBA)3Phen, Eu(TTA)3(Ph3PO)2, Eu(DBM)3Phen, and Eu(DBM)3(Ph3PO)1H2O. The energy of the absorption threshold (Eg) for all the studied ligands has been found to be greater than the energy required for excitation of the 7F0→5D0 transitions within the transitions 4f orbital of the Eu3+ ion. The PL emission spectra of the studied coordination compounds are associated with the internal transitions of the Eu3+: 5D0→7Fi (i = 0, 1, 2, 3, 4). Emission peak positions in the PL spectra are registered around 537, 580, 612, 650, and 702 nm. The FWHM of the dominant PL band at 612 nm is less than 10 nm; this finding indicates that MCCs exhibit atomic-like fluorescence emission and color purity.