The dimensionality dependence of resonance energy transfer is of great interest due to its importance in understanding energy transfer on cell membranes and in low-dimension nanostructures. Light harvesting two-dimensional metal–organic layers (2D-MOLs) and three-dimensional metal–organic frameworks (3D-MOFs) provide comparative models to study such dimensionality dependence with molecular accuracy. The scientists at the Xiamen University, China and the University of Chicago, USA report the construction of 2D-MOLs and 3D-MOFs from a donor ligand and a doped acceptor ligand. These 2D-MOLs and 3D-MOFs are connected by similar hafnium clusters, with key differences in the topology and dimensionality of the metal–ligand connection. Energy transfer from donors to acceptors through the 2D-MOL or 3D-MOF skeletons is revealed by measuring and modeling the fluorescence quenching of the donors. We found that energy transfer in 3D-MOFs is more efficient than that in 2D-MOLs, but excitons on 2D-MOLs are more accessible to external quenchers as compared with those in 3D-MOFs. These results not only provide support to theoretical analysis of energy transfer in low dimensions, but also present opportunities to use efficient exciton migration in 2D materials for light-harvesting and fluorescence sensing.
† Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
‡ Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, United States
J. Am. Chem. Soc., 2017, 139 (20), pp 7020–7029
Figure 1. (a) Structure of the M12 SBU in 2D-MOL. (b) Top view and (c) side view of 2D-MOL. The elements are represented as C, black and orange ball; Hf, cyan and green polyhedra; O, red ball. (d) Structure of Hf6 SBU in MOFs. (e) Crystal structure of 3D-MOF and (f) a slice of the 3D-MOF as highlighted in green in (e). The elements are represented as C, black ball; Hf, purple polyhedra; O, red ball.