Exciton and Spin Dynamics of Luminescent Molecular Materials

The spin of ground and excited levels in molecular materials dictates the exciton mechanisms for any photonic, optoelectronic and quantum technology applications. This talk explores the photo- and spin physics of excitons as revealed by optical and magnetic resonance studies. Where organic semiconductors operate via singlet (spin, <i>S</i> = 0) and triplet (<i>S</i> = 1) excitons, achieving higher luminescence efficiency from these states will generally lead to higher performance, for example in OLEDs. Studies of spin conversion and the orbital-nature of the triplet excitons that dictates luminescence are presented for novel series of fluorescent and phosphorescent emitters. Recent interest in organic radicals containing unpaired electrons has emerged from the design of new materials that undergo efficient light absorption and emission from transitions between doublet spin (S = 1/2) ground and excited levels. As well as being potential candidates for functional emitters in light-emitting devices, opportunities emerge to couple their optical, spin and magnetic properties in molecular excitons that could enable future technology platforms.