Excimer emission and magnetoluminescence of radical-based zinc(II) complexes doped in host crystals

A Zn^II complex based on a luminescent organic radical was doped into host molecular crystals. The 5, 10, and 20 wt%-doped crystals showed excimer emissions and their luminescent behaviours were significantly modulated by an external magnetic field. These are the first examples showing excimer emissions and magnetic-field–sensitive luminescent properties for complexes based on luminescent radicals. The excimer species contributing to magnetoluminescence was determined by analyzing the emission spectra and their magnetic-field dependencies. These results suggest the general nature of magnetic field effects on the luminescence of radicals as well as the importance of the type of interaction between radicals.