NUV-excitation Dy(III) complexes: Synthesis, structural study and impact of secondary ligands on optoelectronic properties

Abstract

The ternary dysprosium complexes involving 1,1,1-trifluoro 5,5-dimethyl 2,4-hexanedione (TFDH) along with 2,2ʹ-bipyridyl and its derivatives have been synthesized. Elemental, infrared and proton NMR analyses were used to evaluate the bonding patterns between dysprosium ion and organic moieties. UV–Visible and photoluminescence spectroscopy were used to examine the optical characteristics. To confirm the anhydrous nature of synthesized complexes, IR and thermogravimetric data were utilized. The band gap value lies in semi-conducting region was explained by Tauc's plot and CV curve, respectively. The photophysical characteristics of dysprosium complexes have been studied in powdered form. The appearance of yellow luminescence on irradiation under NUV-light indicates a highly efficient transfer of energy mechanism from organic ligand to the Dy(III) ion. The CCT values were found to be suitable for cold light sources. The ∆J = 2 transition dominates the overall emission spectra with branching ratio ∼70% is ideal for laser reinforcement. The synthesized Dy(III) complexes possess band gap in semi-conducting range, good thermal stability and high luminous properties, which makes them suitable for applications in displays and lighting technologies.