First demonstration of the π-f orbital interaction depending on the coordination geometry in Eu(III) luminophores

Herein, the pi-f orbital interaction depending on the coordination geometry in the Eu(III) complex is demonstrated. Thermal analysis and computational calculations showed the phase transition of the Eu(III) complex based on the change in the coordination geometry. A red-shifted LMCT band and radiative rate changes associated with the phase transition were found in the Eu(III) complex.