Importance of intramolecular electron spin relaxation in small molecule semiconductors

摘要: Electron spin relaxation rate (eSR) is investigated on several organic semiconductors of different morphologies and molecular structures, using avoided level crossing muon spectroscopy as a local probe. We find that two functionalized acenes (polycrystalline tri(isopropyl)silyl-pentacene amorphous 5,6,11,12-tetraphenyltetracene) exhibit eSRs with an Arrhenius-like temperature dependence, each characteristic energy scales similar to those expected from vibrations. Polycrystalline tris(8-hydroxyquinolate)gallium shows behavior. The observed eSR for these molecules no greater than 0.85 MHz at 300 K. variety crystal structures transport regimes possess, well the nature probe, strongly suggest intra-molecular phenomenon general many semiconductors, contrasting commonly assumed models based inter-molecular charge carrier transport.