The importance of intra-molecular electron spin relaxation in small molecular semiconductors
Abstract
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 spin probe. We find that two functionalized acenes (polycrystalline tri(isopropyl)silyl-pentacene and amorphous 5,6,11,12-tetraphenyltetracene) exhibit eSRs with an Arrhenius-like temperature dependence, each with two characteristic energy scales similar to those expected from vibrations. Polycrystalline tris(8-hydroxyquinolate)gallium shows a similar behavior. The observed eSR for these molecules is no greater than 0.85 MHz at 300 K. The variety of crystal structures and transport regimes that these molecules possess, as well as the local nature of the probe, strongly suggest an intra-molecular phenomenon general to many organic semiconductors, contrasting the commonly assumed spin relaxation models based on inter-molecular charge carrier transport.
Keywords
Cite
@article{arxiv.1006.2651,
title = {The importance of intra-molecular electron spin relaxation in small molecular semiconductors},
author = {L. Schulz and M. Willis and L. Nuccio and P. Shusharov and S. Fratini and F. L. Pratt and W. P. Gillin and T. Kreouzis and M. Heeney and N. Stingelin and C. A. Stafford and D. J. Beesley and C. Bernhard and J. E. Anthony and I. Mckenzie and J. S. Lord and A. J. Drew},
journal= {arXiv preprint arXiv:1006.2651},
year = {2015}
}