Structural and Photometric Study of cool White Light Emitting Dy(III) Complexes Sensitized with β-diketone for Lighting Applications

The present paper reports synthesis of five Dy(III) complexes with bidentate ligand (3-benzylidene-2,4-pentanedione) and auxiliary ligands i.e. 2,2'-bipyridyl (bipy), 4,4'-dimethyl-2,2'-bipyridyl (dmbipy), neocuproine (neo) and 1,10-phenanthroline (phen). The structural and photometric parameters of the complexes were investigated through 1H NMR, energy dispersive X-ray analysis, Fourier transform infrared, photoluminescence and ultra-violet visible spectroscopy. The optical energy gap values validated their role in semiconducting devices. These complexes exhibit suitable thermal stability revealing their utility in fabrication of white OLEDs. The emission profile of Dy(III) complexes displayed peaks at 575 nm (yellow emission) and 484 nm (blue emission) accredited to 4F9/2 -> 4H13/2,15/2 transitions of dysprosium ion. The decay curve exhibit monoexponential behaviour suggesting the existence of one luminescent centre in dysprosium complexes. Moreover, their CCT and CIE coordinates value authenticate them as cool white light emitting complexes.