White Light Emission from Luminescent Lanthanide Molecular Complex/Terbium Doped Graphene Quantum Dots/PMMA Composites

Construction of multicolor emissive PMMA composite films are reported using luminescent lanthanide Schiff-Base complexes and Terbium doped Graphene Quantum dots (GQD@Tb) for white light generation. Terbium-doped green emissive Graphene Quantum Dots are synthesized hydrothermally using ortho-phenyldiammine (OPDA), Triethylamine and Tb(NO₃)₃.6H₂O and is thoroughly characterized by microscopic and spectroscopic techniques. Isostructural lanthanides (III) complexes [Dy^III ₂(L)₂(NO₃)₂(dmf)₂] (1), and [Sm^III ₂(L)₂(NO₃)₂(dmf)₂] (2) are isolated from an organic Schiff base ligand, H₂L, ligand is prepared by 1:1 condensation of salicylaldehyde and 2-(2-Aminoethoxy)ethanol, and are characterized. The photoluminescent data analysis reveals green emission of GQD@Tb, pure blue emissive Dy^IIIL and red emission of Sm^IIIL. Additionally, intensified ligand emission attests for the blue emitter-Dy^IIIL complex while the "antenna effect" is witnessed for red fluorophore Sm^IIIL. Co-doping of metal complexes and GQD@Tb into the Poly(methyl methylacrylate) [PMMA] polymer improves luminescence intensity due to inhibition of aggregation-induced quenching. By conscientious combination of red-Sm^IIIL with green-GQD@Tb in a specified concentration, distinct white light is accomplished for the first time with Commission Internationale de I'Éclairage (CIE) values of 0.29, 0.32, very close to the ideal white emitter. The newly developed nano and molecular complex composite of GQD@Tb and Sm^IIIL-PMMA films are transparent and highly desired materials in optoelectronics, microscopy, and sensing.