Hexagonal Hybrid Bismuthene by Molecular Interface Engineering

[EN] High-quality devices based on layered heterostructuresare typicallybuilt from materials obtained by complex solid-state physical approachesor laborious mechanical exfoliation and transfer. Meanwhile, wet-chemicallysynthesized materials commonly suffer from surface residuals and intrinsicdefects. Here, we synthesize using an unprecedented colloidal photocatalyzed,one-pot redox reaction a few-layers bismuth hybrid of "electronicgrade" structural quality. Intriguingly, the material presentsa sulfur-alkyl-functionalized reconstructed surface that preventsit from oxidation and leads to a tuned electronic structure that resultsfrom the altered arrangement of the surface. The metallic behaviorof the hybrid is supported by ab initio predictionsand room temperature transport measurements of individual nanoflakes.Our findings indicate how surface reconstructions in two-dimensional(2D) systems can promote unexpected properties that can pave the wayto new functionalities and devices. Moreover, this scalable syntheticprocess opens new avenues for applications in plasmonics or electronic(and spintronic) device fabrication. Beyond electronics, this 2D hybridmaterial may be of interest in organic catalysis, biomedicine, orenergy storage and conversion. This work has been supported by the European Union (ERC-2018-StG 804110-2D-PnictoChem & and ERC Proof of Concept Grant 101101079-2D4H2 to G.A.; ERC-2021-StG 101042680 2D-SMARTiES awarded to J.J.B.), the Spanish MICINN (PID2019-111742GA-I00, PID2020-115100GB-I00, MRR/PDC2022-133997-I00, TED2021-131347B-I00, and Excellence Unit Maria de Maeztu CEX2019-000919-M), and the Generalitat Valenciana (CIDEGENT/2018/001, CIDEGENT/2018/005, and CDEIGENT/2019/022). Financial support by Severo Ochoa centre of excellence program (CEX2021-001230-S) is gratefully acknowledged. M.K. and H.B.W. acknowledge support by the Deutsche Forschungsgemeinschaft (DFG), under Projektnummer 182849149 (SFB 953, projects B08 and B13). Electron microscopy work carried out at UCM (M.V., G.S.S.) sponsored by MICINN PID2021-122980OB-C51 and Comunidad de Madrid MAD2D-CM-UCM3. G.S.S. acknowledges financial support from Spanish MCI Grant Nos. RTI2018-099054-J-I00 (MCI/AEI/FEDER, UE) and IJC2018-038164-I. C.D. and Y.M.E. thank the cluster of excellence 3DMM2O funded by DFG under Germany's Excellence Strategy - 2082/1 - 390761711 for financial support. The authors thank Lukas Grunwald and Erich Muller for helpful discussions. A.M.R. thanks the Spanish MIU (Gra