Disordered and Conductive Chiral Spin-Selective Strategy to Enhance Small-Molecule-Based Spintronic Application

Chiral materials, which can manipulate the electron spin by the chiral-induced spin selectivity (CISS) effect without involving the complicated magnetic components, exhibits great potentials in low-cost spin optoelectronics. However, ideal CISS usually requires a relatively ordered and conductive (or insulated but ultrathin) chiral layer, which contradicts the disordered-packing and high-impedance characteristics of chiral molecules, preventing the direct application of most chiral molecules for CISS and increasing the difficulty to prepare chiral spin-selective layers. Here, a general disordered and conductive chiral molecular strategy is proposed to simply construct the small-molecule-based spin polarizer. Directly spin-coating chiral molecules onto the electrode forms the disordered chiral thin film, which exhibits obvious CISS effects demonstrated by an electrochemical oxygen evolution reaction (OER) and a magnetic conductive probe-atomic force microscopy (mcp-AFM). More importantly, by disorderly doping conductive graphite nanoparticles into this film, the high impedance of the chiral molecular layers can be effectively reduced, which results in a higher OER activity with lower H₂O₂ byproduct and a stronger spin-polarization degree. This can be attributed to a conductivity-enhanced disordered CISS effect, which may lay the foundation for designing universal and high-performance spintronic devices.