Fabrication of Lanthanide-Functionalized Hydrogen-Bonded Organic Framework Films for Ratiometric Temperature Sensing by Electrophoretic Deposition

Developing a noncontact ratiometric luminescent temperature sensor with high sensitivity, widely available emission range, and reliable performance is a challenge in materials science. Herein, we demonstrated that this goal can be achieved by fabricating a lanthanide-functionalized hydrogen-bonded organic framework film (named the Eu@HOF-TCBP film). The unbonded carboxylic groups that existed in the structure not only enable lanthanide ions to bind with the framework for bringing dual emission but also allow for preparing a hydrogen-bonded organic framework (HOF) film through the facile electrophoretic deposition. The obtained film exhibits ratiometric temperature sensing performance in the range of 297-377 K with a maximum relative sensitivity of 5.787% K^-1 and shows repeated use without sensitivity loss. Moreover, the material can be easily recycled and refabricated with consistent performance, demonstrating its unique merits of easy recyclability and regeneration as an HOF material. We believe that the reported strategies for preparing a dual-emitting HOF and fabricating a thin film will open a window for HOF applications.