Boosting temperature sensing capacity within isoreticular zinc(II) metal-organic frameworks luminescent thermometers

Abstract

Developing a convenient and accurate temperature detection method is of great importance in industrial production, biochemical processes and scientific research. As a noncontact optical temperature sensing technique, luminescence thermometry has been attracted increasing interest. Here we present two Zn(II) metal-organic frameworks (MOFs) with the formulas of {(H3O)[Zn2(btca)2(taz-NH2)x(taz-CH3)1-x]·H2O}n (x ​= ​1 (1); x ​= ​0 (2)) (H2btca ​= ​benzotriazole-5-carboxylic acid, Htaz-NH2 ​= ​5-amino-1H-tetrazole and Htaz-CH3 ​= ​5-methyl-1H-tetrazole) by virtue of the mixed-ligand approach for photoluminescence sensors as luminescence thermometries over tunable temperature range. Two MOFs exhibit 1D hexagonal nano-channels along the [100] direction, occupied by lattice water molecules. The temperature dependent photoluminescent characteristic of 1 and 2 reveal that the luminescence signals can be decreased as temperature rises from 120 to 400 ​K, thereby achieving the non-destructive temperature detection. Furthermore, linear correlations are presented between the luminescence intensities and the low temperatures for 1 and 2. Satisfying relative sensitivities of 0.49% K−1 for 1 and 0.61% K−1 for 2, and small temperature uncertainties of 0.062 ​K for 1 and 0.049 ​K for 2 ​at 400 ​K could be acheieved. Notably, the intensity-based luminescent thermometer measurements reveal that 2 shows extremely more linear with temperature and wider temperature range than those of 1, indicating that 2 is a more considerable luminescence thermometry over tunable temperature range.