Spin-dependent recombination probed through the dielectric polarizability

Bayliss, S. L. , Greenham, N. C., Friend, R. H., Bouchiat, H. and Chepelianskii, A. D. (2015) Spin-dependent recombination probed through the dielectric polarizability. Nature Communications, 6, 8534. (doi: 10.1038/ncomms9534) (PMID:26439933) (PMCID:PMC4600752)

Abstract

Despite residing in an energetically and structurally disordered landscape, the spin degree of freedom remains a robust quantity in organic semiconductor materials due to the weak coupling of spin and orbital states. This enforces spin-selectivity in recombination processes which plays a crucial role in optoelectronic devices, for example, in the spin-dependent recombination of weakly bound electron-hole pairs, or charge-transfer states, which form in a photovoltaic blend. Here, we implement a detection scheme to probe the spin-selective recombination of these states through changes in their dielectric polarizability under magnetic resonance. Using this technique, we access a regime in which the usual mixing of spin-singlet and spin-triplet states due to hyperfine fields is suppressed by microwave driving. We present a quantitative model for this behaviour which allows us to estimate the spin-dependent recombination rate, and draw parallels with the Majorana–Brossel resonances observed in atomic physics experiments.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bayliss, Dr Sam
• Authors: Bayliss, S. L., Greenham, N. C., Friend, R. H., Bouchiat, H., and Chepelianskii, A. D.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Nature Communications
• Publisher: Nature Publishing Group
• ISSN: 2041-1723
• ISSN (Online): 2041-1723
• Copyright Holders: Copyright © 2015 The Authors
• First Published: First published in Nature Communications 6: 8534
• Publisher Policy: Reproduced under a Creative Commons License