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2D multiferroics with magnetoelectric coupling combine the magnetic order and electric polarization in a single phase, providing a cornerstone for constructing high-density information storages and low-energy-consumption spintronic devices. The strong interactions between various order parameters are crucial for realizing such multifunctional applications, nevertheless, this criterion is rarely met in classical 2D materials at room-temperature. Here an ingenious space-confined chemical vapor deposition strategy is designed to synthesize atomically thin non-layered ε-Fe

Epitaxial growth and controllable doping of wafer-scale atomically thin semiconductor single crystals are two central tasks to tackle the scaling challenge of transistors. Despite considerable efforts have been devoted, addressing such crucial issues simultaneously under two-dimensional (2D) confinement is yet to be realized. Here we design an ingenious epitaxial strategy to synthesize record-breaking 4-inch Fe-doped transition-metal dichalcogenides (TMDCs) single crystals on industry-compatible c-plane sapphire without miscut angle. Atomically thin transistors with the highest recorded electron mobility (~231 cm2 V−1 s−1) and remarkable on/off current ratio (~109) are fabricated based on 4-inch Fe-MoS2 single crystals, due to the ultralow contact resistance (~489 Ω µm) and subthreshold swing (~95 mV dec−1). In-depth characterizations and theoretical calculations reveal that the introduction of Fe significantly decreases the formation energy of parallel steps on sapphire surfaces and contributes to the edge-nucleation of unidirectional alignment TMDCs domains (>99%), as well as the modulation of band structures. This work represents a substantial leap in terms of bridging synthesis and doping of wafer-scale 2D semiconductor single crystals without the need for substrate miscut, which should promote the further device downscaling and extension of Moore’s law.

Tin selenide (SnSe

Self-assembly of identical organometallic supramolecules into ordered superstructures is of great interest in both chemical science and nanotechnology due to its potential to generate neoteric properties through collective effects. In this work, we demonstrate that large-scale self-organization of atomically precise organometallic supramolecules can be achieved through cascaded on-surface chemical reactions, by the combination of intra- and inter-supramolecular interactions. Supramolecules with defined size and shape are first built through intramolecular reaction and intermolecular metal coordination, followed by the formation of well-ordered two-dimensional arrays with the assistance of Br atoms by -C-H···Br interactions. The mechanism of this process has been investigated from the perspectives of thermodynamics and kinetics.

Two-dimensional (2D) tessellation of organic species acquired increased interests recently because of their potential applications in physics, biology, and chemistry. 2D tessellations have been successfully constructed on surfaces via various intermolecular interactions. However, the transformation between 2D tessellation lattices has been rarely reported. Herein, we successfully fabricated two types of Kagome lattices on Cu(111). The former phase exhibits (3,6,3,6) Kagome lattices, which are stabilized via the intermolecular hydrogen bond interactions. The latter phase is formed through direct chemical transferring from the former one maintaining almost the same Kagome lattices, except for that the unit cell rotates for 4°. Detailed scanning tunneling microscopy and density functional calculation studies reveal that the chemical transformation is achieved by the formation of the N-Cu-N metal-organic bonds via dehydrogenation reactions of the amines.

Metal–organic frameworks prepared on surfaces (SMOFs) have been considered to have potential applications in various research fields. Traditionally, the SMOFs are prepared by coadsorbing organic li...

The electrocatalytic reduction of nitrogen (N2) has recently emerged as an attractive technology for producing ammonia (NH3) under mild conditions. Nevertheless, achieving a high selectivity of N2 reduction with respect to hydrogen evolution at relatively low overpotential, and thus increasing the energy efficiency of ammonia production, has remained a key challenge. Herein, with systematic density functional theory (DFT) calculations, we report that the dipole of the NN triple bond in the adsorbed N2 molecule is a more efficient and accurate theoretical indicator compared with the previous ones for predicting the catalytic performance of active sites in the nitrogen reduction reaction (NRR). By screening single transition metal atoms anchored on two-dimensional phthalocyanine (2D Pc) organic frameworks, we show that 2D Mo-Pc is a promising single-atom-catalyst in the NRR with an extremely low onset potential of −0.25 V. The origin of such high catalytic activity can be interpreted by the large dipole moment introduced into the NN bond via strong Mo–N interactions. As a result, the injection of electrons into the anti-bonding orbitals of nitrogen molecules is promoted. In addition, the competing hydrogen evolution reaction (HER) can be effectively inhibited due to the unfavourable bonding interactions between the H and the single Mo atom.

2D semiconductors are emerging as plausible candidates for next-generation "More-than-Moore" nanoelectronics to tackle the scaling challenge of transistors. Wafer-scale 2D semiconductors, such as MoS

As an emerging discipline in the intersection of chemistry and physics, on-surface chemistry has been at the forefront of surface science since its inception. On-surface chemistry has obvious differences from classical solution chemistry although they are closely related. Many reactions in solution become applicable in on-surface reactions under ultra-high vacuum conditions without the involvement of solvents. Furthermore, with the aid of surface confinement effects, a series of highly accurate, highly selective chemical reactions that are difficult to achieve in traditional solution reactions can be accomplished, which shows attractive potential for functional macromolecule design, synthetic chemistry, and new material fabrication. In this review, we present some representative on-surface reactions. By comparing the differences in reaction paths and products with traditional solution reactions, the characteristics of on-surface chemistry are epitomized. In addtion, we make a brief outlook for the opportunities and challenges of this novel synthetic tool facing in the future.

In on-surface chemistry, the efficient preparation of metal-organic hybrids is regarded as a primary path to mediate controlled synthesis of well-ordered low-dimensional organic nanostructures. The fundamental mechanisms in forming these hybrid structures, however, are so far insufficiently explored. Here, with scanning tunneling microscopy, we studied the bonding behavior of the adsorbed phenol derivatives with different molecular lengths. We reveal that shorter molecules favor bonding with extracted metal adatoms and result in metal-organic hybrids, whereas longer molecules prefer to bond with lattice metal atoms. The conclusions are further confirmed by density functional theory calculations.