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

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)[Zn-2(btca)(2)(taz-NH2)(x)(taz-CH3)(1-x)].H2O}n (x = 1 (1); x = 0 (2)) (H(2)btca = 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 ther-mometries 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.