White-light emitting materials with tunable luminescence based on steady Eu(iii) doping of Tb(iii) metal–organic frameworks

Abstract

A sequence of isostructural lanthanide metal–organic frameworks, namely [Ln(Hbtca)(phen)] (Ln = Tb (1) and Eu (2), H₄btca = biphenyl-2,3,3′,5′-tetracarboxylic acid and phen = 1,10-phenanthroline), has been successfully synthesized under a hydrothermal reaction. The single X-ray diffraction studies reveal that the structure of the Ln-MOFs is a double-paned 2D network. Thermogravimetric analysis has been used to characterise the Ln-MOFs, which display good thermal stability. By adjusting the ratio of Eu³⁺ to Tb³⁺, a series of co-doped lanthanide coordination polymers [Eu_xTb_1−x(Hbtca) (phen)] (0 ≤ x ≤ 1) has been successfully acquired, with emission colors changes from an initial red, to yellow and lastly green. Excitingly, a white emission material has been successfully obtained with the ratio Eu_0.0167Tb_0.9833-MOF and the CIE coordinates (0.3199, 0.3381), these values are very close to the standardized values (0.3333, 0.3333).