Thermally stable and strongly emitted CPL in Eu(d-facam)3 hybrid solids with an alkylammonium salt

Abstract

A novel europium-based hybrid material, Eu(D-facam)₃-TMAOAc (tetramethylammonium acetate), with ultra-high luminescence, excellent circular polarization and remarkable thermostability was prepared. Its photophysical performance was studied based on the luminescence properties and energy transfer process. Compared to Eu(D-facam)₃, Eu(D-facam)₃-TMAOAc exhibited much brighter luminescence and stronger circular polarization. Additionally, Eu(D-facam)₃-TMAOAc well retained its structure and luminescence properties even after heat treatment at 200 °C for 24 hours, whereas Eu(D-facam)₃ rapidly decomposed. Eu(D-facam)₃-TMAOAc was characterized by TG analysis, elemental analysis, ESI-mass spectrometry, PXRD, and FT-IR spectroscopy. It was found that TMAOAc acted as a bidentate bridge linker with Eu(D-facam)₃ at a 1 : 1 ratio. This coordination structure contributed to the excellent photophysical properties and thermal stability of Eu(D-facam)₃-TMAOAc. Furthermore, Eu(D-facam)₃-TMAOAc showed a high solubility in common organic solvents, and it could maintain its outstanding luminescence properties in solid as well as solution states.