Stress to distress: Triboluminescence and pressure luminescence of lanthanide diketonates

Abstract

Triboluminescence and high-pressure luminescence are stress-induced phenomena with potential in stress sensing. However, the understanding of the former process and the correlation between the two processes are lacking. In this contribution, we study the influence of the crystal packing and high pressure compression on triboluminescence by using a new family of halogen-containing EuIII diketonate complexes. The size and position of halogens determine the crystal symmetry and packing due to the change in intermolecular interactions. The role of pressure is examined by a diamond anvil cell (DAC), in which the material compression induces phase transition, peak shifting and broadening in the luminescence spectrum of the complex. The experimental results show the triboluminescence of our EuIII complexes occurs at low pressure and is a fracture-induced (mechano stress) process. This work contributes to the understanding of triboluminescence and for the first time explores the possibility of applying lanthanide complexes as stress sensors.