Enhanced Spin Transport of Conjugated Polymer in the Semiconductor/Insulating Polymer Blend.

Conjugated polymers are of high potential in the development of spintronic devices. In this paper, we report systematic studies on spin transport properties of a semiconducting polymer PBDTTT-C-T in the permalloy/polymer/Pt trilayer using the spin pumping method. Pure spin current with long spin relaxation time is observed via the inverse spin Hall effect (ISHE) measurements. Furthermore, spin current is also found to propagate through the blend film consisting of a small amount of PBDTTT-C-T in an insulating matrix. The polymer blend exhibits a remarkably enhanced spin relaxation length (56 nm) and carrier mobility compared to pristine PBDTTT-C-T. From film microstructural characterizations, we propose that the enhanced spin/carrier transport properties are attributed to the formation of interlinked nanonetwork comprising of the PBDTTT-C-T chain bundles in the inert matrix to afford efficient intrachain charge conduction pathway. Temperature- dependent ISHE measurements support the spin-orbit coupling dominated spin relaxation mechanism.