Microwave-assisted synthesis of nanoscale Eu(BTC)(H2O)·DMF with tunable luminescence

Abstract

Nanoscale europium(III) metal-organic frameworks, Eu(BTC)(H2O)·DMF, were synthesized by rapid microwave-assisted method. The components of the as-prepared products were confirmed by the elemental analysis, X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA) and Fourier-transform infrared spectra (FTIR) analyses. Eu(BTC)(H2O)·DMF with various morphologies, including particle-like, rod-like, straw-sheaf-like nanostructures, could be simply prepared by controlling the concentrations of the starting reactants. The optical measurements on the obtained Eu(BTC)(H2O)·DMF indicated that all the nanomaterials show the characteristic emissions of the Eu3+ ions at 578, 590, 612, 650, and 699 nm, which were attributed to 5D0→7F J (J=0–4) transitions of the Eu3+ ion, respectively. It was also noticed that the luminescent properties of the as-prepared products were heavily dependent on the morphologies and sizes of the nanomaterials. The assembled straw-sheaf-like architectures displayed the strongest emissions and the longest luminescence lifetime, which was mainly due to the fewest surface defects.