Investigation on organic magnetoconductance based on polaron-bipolaron transition

TL;DR

This paper investigates the magnetoconductance effect in organic semiconductors by modeling bipolaron formation and transitions influenced by magnetic and hyperfine interactions, aligning theory with experimental data.

Contribution

It introduces a dynamic equation model for bipolaron transitions in organic semiconductors, highlighting the role of hyperfine interaction and predicting maximum magnetoconductance conditions.

Findings

Theoretical results match experimental data.

Hyperfine interaction significantly influences magnetoconductance.

Maximum MC occurs at a specific bipolaron branching ratio.

Abstract

We explore the magnetoresistance (MC) effect in an organic semiconductor device based on the magnetic field related bipolaron formation. By establishing a group of dynamic equations, we present the transition among spin-parallel, spin-antiparallel polaron pairs and bipolarons. The transition rates are adjusted by the external magnetic field as well as the hyperfine interaction of the hydrogen nuclei. The hyperfine interaction is addressed and treated in the frame work of quantum mechanics. By supposing the different mobility of polarons from that of bipolarons, we obtain the MC in an organic semiconductor device. The theoretical calculation is well consistent to the experimental data. It is predicated that a maximum MC appears at a suitable branching ratio of bipolarons. Our investigation reveals the important role of hyperfine interaction in organic magnetic effect.