Continuous-flow rapid synthesis of wavelength-tunable luminescent lanthanide metal-organic framework nanorods by a microfluidic reactor

Abstract Lanthanide metal-organic frameworks (Ln-MOFs) have been widely used in fluorescence sensing, bioimaging and light emitting diode due to their excellent optical properties. However, the preparation of Ln-MOFs is energy and time-consuming due to the constraints of the conventional wet chemical methods. In this paper, a synthetic strategy for the rapid preparation of Ln-MOFs nanorods with adjustable emission wavelength in a microchannel reactor is proposed. Compared with the wet chemical methods, the efficient mass and heat transfer capability of the microchannel shortens the reaction time from 12 h to 50 min. More importantly, Ln-MOFs nanorods with different emission wavelengths can be easily prepared by adjusting the flow rate of different components of the microchannel, which can be adjusted in real-time according to the preparation needs. The result shows that the Ln-MOFs prepared by microfluidic method is in the shape of nanorods with widely emission wavelength from 470 nm (blue light) to 615 nm (red light). In addition, the fluorescence emission intensity of Ln-MOFs is confirmed to have a wide reversible temperature (30–220 ℃) and is expected to be used for high-precision temperature sensing in the future.