Chirality-Induced Spin Selectivity in Conjugated Polymers

In nature, chirality extends from individual molecules to large-scale biological structures, playing a fundamental role in life by allowing for highly specific molecular recognition and functionality [1]. Chirality can also couple with the spin of electrons, leading to the chiral-induced spin selectivity (CISS) effect, where charge transport depends on spin orientation [2,3]. While CISS has been widely studied in biomolecules and inorganic chiral systems, its behavior in conjugated polymers is still not fully understood. Conjugated chiral polymers are particularly promising because their chiral structures and electronic properties can be tuned through molecular design and processing.

In this study, we aim to explore CISS in structurally chiral conjugated polymers using in-plane device architectures. We prepared printed polymer films of p(g₄2T-TT) with well-defined left- and right-handedness with heavy-metal electrodes [4]. When a charge current flows along the polymer’s chiral axis, spin-polarized currents are injected into the platinum strip, producing a transverse voltage via the inverse spin Hall effect. The voltage reverses sign with both polymer handedness and current direction, demonstrating direct evidence of lateral CISS in soft organic films. These findings expand the material basis for spin-selective charge transport and point toward the development of soft, flexible, and biocompatible spintronic technologies [3].