Chiral Nanohoops as an Efficient Spin Polarization System

A central challenge in molecular spintronics is to achieve a high spin polarization at low operating voltages and ambient conditions while maintaining good electrical conductivity. Chiral conjugated nanohoops, characterized by their curved and strained π-systems, as well as their ability to be functionalized with anchoring groups, represent promising scaffolds for organic spintronics. Here, the synthesis and spin-selective properties of axially chiral nanohoops incorporating an antiaromatic dibenzo[a,e]pentalene (DBP) unit are reported. DBP enables good charge transport and can be functionalized with a thiomethyl anchoring group. Using magnetic-conductive atomic force microscopy (mc-AFM) and magnetoresistance (MR) measurements, asymmetry in spin transport is shown, with temperature-dependent MR indicating vibrational contributions to spin selectivity. Despite the formation of a supramolecular structure and non-selective adsorption on the surface, the nanohoops exhibit high spin polarization at ambient temperature and low voltage operation, along with a high conductivity, a rare combination in organic spintronics.