Multifunctional luminescence properties of co-doped lanthanide metal organic frameworks

Abstract

Two novel lanthanide metal organic frameworks [Eu₄(bpt)₄(DMF)₂(H₂O)₆]·(DMF)₅·(H₂O)₄ (1) and [Tb₄(bpt)₄(DMF)₂(H₂O)₈]·(DMF)₅·(H₂O)₃ (2) were synthesized under hydrothermal conditions, forming a three-dimensional structure (H₃bpt = biphenyl-3,4′,5-tricarboxylate). Single crystal X-ray diffraction reveals that compounds 1 and 2 are heteromorphic and have different topologies due to the change of metal ions with different radii and coordination steric hindrance. The unique luminescence properties of Eu³⁺ and Tb³⁺ ions motivated us to dope different amounts of Tb³⁺ into a single host to obtain light tunable materials. The tunable multicolor emissions, including red, red-orange, orange, yellow and green, can be readily achieved from the doped Ln-MOFs 3–6 by increasing the concentration of Tb³⁺. In addition, compounds 5 and 6 also exhibit different temperature-dependent luminescence behaviors when the concentration of Eu³⁺ is low, generating new Ln-MOF thermometers.