Efficient Narrow Band Pure Red Emitting Molecular Europium Complexes for White Light-Emitting Diodes and Anticounterfeiting Applications

Abstract

The luminescent ternary Eu(III) complexes, Eu(DBM)3Phen-pCH3-mCF3, Eu(DBM)3Phen-pCH3-pCH3 of phenanthro-imidazole derivatives and dibenzoylmethane (DBM) were synthesized and explored for versatile applications. The phenanthro-imidazole derivatives and their respective Eu(III) complexes are characterized well and studied their electrochemical and photophysical properties successfully. PL emission spectra of ligands show blue emission whereas Eu(III) complex are showing red emission in solid while in solution phase Eu(DBM)3Phen-pCH3-mCF3 are showing multiple emission (near white emission). The energy transfer mechanism was better comprehended by theoretical (DFT/TD-DFT) calculation. Fabrication of light-emitting diodes (LED) has been done by conjugating the Eu-complex with near UV LED. The obtained results are very close to the National Television System Committee (NTSC) standard for pure red emission. LED fabrication of Eu(DBM)3Phen-pCH3-pCH3with 1:50 ratio show near white emission with CIE color coordinate (x = 0.32, y = 0.38), CRI (80) and CCT (5912K), respectively. In addition, the presently studied Eu(III) complex shows excellent sensing behavior in the thermo-sensor (in the range 303 K- 453 K) and vapoluminescent sensing application.