Luminescent metal-organic frameworks for chemical sensing and solid-state lighting

Luminescent metal-organic frameworks (LMOFs) are crystalline solids constructed via self-assembly of metal cations and organic ligands. The organic ligands often contain aromatic moieties that are subject to excitation, giving rise to optical emission upon irradiation. Utilizing this ligand-based emission, the applications of LMOFs to chemical sensing and solid-state lighting are explored. LMOFs’ tunable porosity (non-porous LMOFs are not the focus of this study) and easy-to-functionalize surface enable them to selectively capture targeted analytes. By monitoring the changes in their optical emission profiles caused by strong guest-host interactions, the accurate identification of analytes is achieved. The electron and energy transfer mechanisms which govern the fluorescence signal transduction are also studied by a combination of experimental and computational (density functional theory or DFT) approaches. LMOFs are also strong candidates as rare-earth-free phosphors for solid-state lighting. The immobilization of molecular chromophores into rigid LMOF backbones inhibits the non-radiative decay caused by ligand rotation, vibration, and torsion, therefore enhances the quantum efficiency of the resulting compounds. The prescreening of the electronic properties of molecular chromophores through a computational (DFT) method facilitates the design of LMOF phosphors with desired emissions. Overall, LMOFs’ applications to chemical sensing and solid-state lighting are studied; the sensing mechanisms and principles of designing LMOF phosphors are also addressed.Ph.D.Includes bibliographical referencesby Zhichao H