Layered Rare Earth-Organic Framework as Highly Efficient Luminescent Matrix: The Crystal Structure, Optical Spectroscopy, Electronic Transition, and Luminescent Sensing Properties

This work reported an unpresented rare-earthion bearing metal-organic framework (MOF)Y-10(C8H4O4)(6)(CO3)(3)(OH)(12) built of inorganic slabs as structural units. Eu3+ has been introduced into the lattice of Y-10(C8H4O4)(6)(CO3)(3)(OH)(12) to make it optically active. Systematical structural analysis combined with single crystal X-ray diffraction demonstrates Eu3+ was incorporated into the lattice of Y-10(C8H4O4)(6)(CO3)(3)(OH)(12) endowing the MOF with promising optical activity. Even though there was a trace amount of Eu3+ < 1%, this compound displayed excellent luminescent activity with quantum efficiency reaching up to 69%, benefiting from the inorganic circumstance of Y3+/Eu3+ in layered structure. The concentration-dependent electronic transition character of Eu3+ is systematically studied, according to Judd-Ofelt theory normally applicable in inorganic compounds. The phase analysis and optical spectroscopy study result reveal that the local crystallographic circumstance of the rare-earth metal ion basically remained inactive after the replacement of Y3+ by Eu3+. Benefiting from this rigid structure, such Eu3+-substituted Y-10(C8H4O4)(6)(CO3)(3)(OH)(12) powder exhibits good luminescence probing ability toward Fe3+ ion, displaying a limit detection concentration of Fe3+ down to 12.7 mu M in aqueous solution. The findings here confirm Eu3+ is not only an environmental probing ion but could also serve an ideal indicator for investigating the structure change and properties of luminescent MOFs for diverse applications.