High‐Efficiency Asymmetric Spin Transport Enabled by Nanocolumn Molecular Semiconductors

Owing to weak spin‐orbit coupling, molecular semiconductors are among the few materials supporting room‐temperature spin functionality, yet their low spin‐transport efficiency ( η s , ∼5%) limits applications. Here, we report molecular spintronic devices featuring vertically asymmetric nanocolumn channels formed by phase separation. These channels confine spins and generate built‐in electric fields, boosting room‐temperature η s to 20%—the highest value reported to date, over five times that of unstructured films. Simultaneously, the nanocolumn channels induce pronounced bias‐dependent asymmetry, with η s of 20% at +0.2 V versus 1% at −0.2 V, yielding a record asymmetry factor, significantly outperforming other material systems (e.g., metal oxides, 2D materials, conventional molecular/inorganic semiconductors). This dual achievement of record‐high efficiency and strong asymmetry establishes a platform for new spintronic functionalities. As a proof of concept, we demonstrate its potential for information‐secure applications via spin‐signal encryption elements and two‐stage spin true random number generators, integrating structural design with spintronic operation.