Owing to weak spin-orbit coupling, molecular semiconductors are among the few materials supporting room-temperature spin functionality, yet their low spin-transport efficiency (ηs, ∼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 ηs 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 ηs 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.

Advanced Materials, 2026; e73826 https://advanced.onlinelibrary.wiley.com/doi/epdf/10.1002/adma.73826