Rare-earth UiO-66 for temperature sensing near room temperature

Abstract

In the last decade, rare-earth metal–organic frameworks (RE-MOFs) have received notable interest in luminescence thermometry, which involves correlating the absolute temperature of an object to an optical emission. Numerous investigations that are already reported deal mainly with mixed Eu/Tb coordination polymers and MOFs, and they are based on the Eu³⁺-to-Tb³⁺ emission ratio between the transitions ⁵D₄→⁷F₅ and ⁵D₀→⁷F₂ of the Tb³⁺ and Eu³⁺ ions, respectively. In this study, we focus our attention on the well-known UiO-66, which can be also built with lanthanoid cations to give RE-UiO-66 analogues. Thus, we investigated the thermometric properties of RE-UiO-66 by synthesizing three different bimetallic Eu/Tb materials, with the aim to develop new sensitive luminescent thermometers.