Hierarchical Accordion-like Lanthanide-Based Metal–Organic Frameworks: Solvent-Free Syntheses and Ratiometric Luminescence Temperature-Sensing Properties

Rational design of lanthanide (Ln)-based metal–organic frameworks (MOFs) enables great potential in luminescence applications; however, it keeps a challenge in the development of controlled synthesis strategy toward luminescent Ln-MOFs with intriguing morphology. Herein, we report a facile solvent-free solid-state grinding procedure followed by a subsequent thermal heating to prepare novel accordion-like lanthanide-based MOFs (Ln-MOFs, Ln = Er, Dy, Eu, Y, and Tm). These self-assembled Ln-MOFs with a MIL-78 topological structure exhibit characteristic lanthanide photoluminescence properties. Among them, Eu3+, Dy3+ codoped Y-MOF was successfully fabricated exhibiting temperature-dependent Dy3+/Eu3+ dual blue/red characteristic emissions, which can be used as ratiometric thermometer, serving for temperature-sensing applications. The high-temperature relative sensitivity for Eu, Dy-doped Y-MOF (0.640% K–1 at 170 K), as well as their excellent temperature resolution in the wide measured temperature range (80–200 K), render them great potential applications. The present solvent-free synthesis strategy used in this work opens a general way to scale up the synthesis of lanthanide-MOF materials and explore their luminescence applications.