Bonding in 2D Donor–Acceptor Heterostructures

Abstract

The ability to alter distances between atoms is among the most important tools in materials design. Despite this importance, controlling the interlayer distance in stacks of 2D materials remains a challenge. Here we show from firstprinciples that stacking electrenesa new class of electrondonating 2D materialswith other 2D materials provides this control. The resulting donor−acceptor heterostructures have interlayer distances 1 Å less than van der Waals layered materials but 1 Å more than covalent or ionic bonds. This yields a class of quasi-bonds that exhibit characteristics of both ordinary chemical bonds and van der Waals interactions. We show how quasi-bonds have tunable polarities and strengths and that these bonds can be understood by drawing on familiar concepts from molecular orbital theory. We also demonstrate several useful properties of 2D donor−acceptor heterostructures, including superlubricity, ultralow work functions, and greatly improved voltages for lithium-ion batteries

Au3-to-Ag3coordinate-covalent bonding and other supramolecular interactions with covalent bonding strength

“…[3][4][5][6] Between binary stacked complexes, donor-acceptor type ground-state charge transfer exists due to uneven electron density distribution and will be enhanced by noncovalent interactions. [7][8][9][10] Among stacked complexes, metal-metal (typically metallophilic) interactions cannot be neglected to describe the attraction between homo-and hetero-atomic closed-shell metal ions with shorter distances than the sum of their van der Waals radii in metal complexes. [11][12][13] When it comes to d 10 block metals, like Cu I , Ag I , Au I , and Hg II , their electronic congurations still allow attractive forces to occur between metals that typically arise from van der Waals forces.…”

“…18 Our group has studied cyclic trinuclear complexes of d 10 coinage metal ionscyclo-M 3 (m-L) 3 (M ¼ coinage metal, L ¼ anionic ligand)bearing 9-membered rings (Scheme 1 depicts two examples). [19][20][21][22][23][24][25][26] These d 10 complexes possess (near-)planar geometries and a variety of properties that can be both neand coarse-tuned via rational manipulation of metals (M), ligands (L) and ligand substituents (R), e.g., p vs. Brønsted vs. Lewis acid-base chemistry, host/guest chemistry, supramolecular assemblies, M-M-bonded excimers, ordered monolayers, metalloaromaticity and metallophilic interactions. [19][20][21][22][23][24][25][26][27] These cyclo-M 3 (m-L) 3 complexes exhibit photoluminescence, thermochromic, acid-base, and donor-acceptor properties.…”

Insights into the direct formation of [Ca24Al28O64]4+(4e−) and its electrical characterization

“…As seen in Figure A, DSC graphs of the oxide mixture precursors with Al addition amounts of 0%‐1.98% was investigated by simultaneous thermal analyzer under an atmosphere of He. All DSC results showed an endothermic peak near 430°C, which corresponded with the decomposition process of tiny amounts of Ca(OH) 2 due to water adsorption of CaO . Furthermore, it should be noted that the endothermic peaks on the DSC curves of the precursors with Al addition of 0.78%‐1.98% at 820°C were mainly caused by the melting process of Al.…”

“…All DSC results showed an endothermic peak near 430°C, which corresponded with the decomposition process of tiny amounts of Ca(OH) 2 due to water adsorption of CaO. 27 Furthermore, it should be noted that the endothermic peaks on the DSC curves of the precursors with Al addition of 0.78%-1.98% at 820°C were mainly caused by the melting process of Al. The intensities of the melting peak were enhanced with the increase of Al addition, which can be ascribed to the uniformity process of Al in the oxide matrix.…”

From Highly Purified Boron Nitride to Boron Nitride‐Based Heterostructures: An Inorganic Precursor‐Based Strategy

“…Alternatively, the remarkable properties of h-BN also make it an ideal candidate in the fabrication of van der Waals heterostructures by combining it with other materials such as graphene and transition metal dichalogenides, which can be tuned to specific desirable properties. [6,13,[22][23][24] However, their low melting point, easy decomposition, as well as the electroneutral nature of organic precursors make them difficult for use in the mass fabrication of h-BN-based heterostructures via a thermal treatment method. [6] Mesoporous carbon (MC) and carbon nanotube (CNT) have attracted much interest in the fields of materials science, [25] but h-BN/MC and h-BN/CNT heterostructures have been rarely reported due to the lack of an efficient synthetic process.…”