Solvothermal synthesis and device fabrication of a Eu3+-based metal–organic framework as a turn-on and blue-shift fluorescence sensor toward Cr3+, Al3+ and Ga3+†
Abstract
A novel three-dimensional Eu3+-based metal–organic framework with the formula {[(CH3)2NH2][Eu(BTDI)]·H2O·DMF}n (JXUST-25) was prepared by solvothermal method based on Eu3+ and 5,5′-(benzothiadiazole-4,7-diyl)diisophthalic acid (H4BTDI) with benzothiadiazole (BTD) luminescent groups. Due to the presence of Eu3+ and organic fluorescence ligand, JXUST-25 displays turn-on and blue-shift fluorescence toward Cr3+, Al3+ and Ga3+ with limits of detection (LOD) of 0.073, 0.006 and 0.030 ppm, respectively. Interestingly, the alkaline environment can change the fluorescence of JXUST-25 toward Cr3+/Al3+/Ga3+ and the addition of HCl solution realizes the reversible change of the fluorescence of JXUST-25 toward Cr3+/Al3+/Ga3+. It is noteworthy that the fluorescent test paper and light-emitting diode lamp based on JXUST-25 can effectively detect Cr3+, Al3+ and Ga3+ by the visual changes. In addition, the turn-on and blue-shift fluorescence between JXUST-25 and M3+ ions may be caused by the host–guest interaction and the absorbance caused enhancement mechanism.