Controlled deintercalation of graphene/organic superlattices with dense atomic-scale steric Schottky heterojunctions for extreme microwave absorption.

Integrating 2D (semi)metals and semiconductors into atomic-scale Schottky heterojunctions offers a promising pathway for achieving robust charge separation, crucial for microwave absorbers, electromagnetic interference shielding materials, electrocatalysts, photocatalysts, etc. However, conventional bottom-up assembly approaches often encounter challenges of severe agglomeration of 2D components and non-basal contacts due to lattice mismatch, resulting in a suboptimal interfacial density and insufficient charge separation. This study introduces a top-down approach involving the thermal deintercalation of graphene/alkylamine superlattices, leading to the in-situ formation of Schottky heterojunctions between the thermally reduced p-type rGO-alkylamine superlattice phase and entirely deintercalated semimetallic rGO phase (rGO denotes reduced graphene oxide), which can be flexibly tuned by the length of the alkylamines. A spatial network of 2D/2D vertical/lateral Schottky heterojunctions is thus formed with high interfacial density, greatly facilitating charge separation, and thereby strengthening polarization loss while reducing conduction loss. This ensures steady permittivity in the Ku band, maintaining strong absorption under small oblique incidence. Accordingly, a record-high simulated far-field bistatic radar cross-section reduction of 72.68 dB at 1° is attained along with diversified adaptive multifunctionality. This paper provides a groundbreaking avenue realizing spatially distributed atomic-scale 2D/2D Schottky heterojunctions in 2D materials, promoting various related functional materials.