Temperature-dependent luminescence properties of lanthanide(iii) β-diketonate complex-doped LAPONITE®

Abstract

In this work, by doping the lanthanide(III)–hexafluoroacetylacetone complex into LAPONITE®, we obtained a lanthanide-based organic–inorganic hybrid material. The resulting hybrid materials were fully characterized with elementary analysis, scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) techniques. The Ln³⁺ and HFA loadings were experimentally determined to be roughly 0.3 per u.c. and 0.72 per u.c. by analyzing the supernatant (titration against EDTA) and elemental analysis, respectively. XRD patterns suggest that at least partial complexes are intercalated within the interlayers of the LAPONITE®. The in situ formation of luminescent Ln³⁺ complexes is confirmed by the luminescence data. Furthermore, the emission intensity ratio of the ⁵D₄ → ⁷F₅ transition (Tb³⁺) to the ⁵D₀ → ⁷F₂ transition (Eu³⁺) of the hybrid material containing both Eu³⁺ and Tb³⁺ can be linearly related to temperature in the range from 197 K to 287 K (temperature sensitivity: 1.107% per K), which will be an appealing alternative for in situ and real time detection of temperature in many special areas. This strategy presents new opportunities for the development of highly sensitive and stable thermo sensors.