Post‐Graphene 2D Chemistry: The Emerging Field of Molybdenum Disulfide and Black Phosphorus Functionalization

Abstract

The current state of the chemical functionalization of three types of single sheet 2D materials, namely, graphene, molybdenum disulfide (MoS2), and black phosphorus (BP) is summarized. Such 2D sheet polymers are currently an emerging field at the interface of synthetic chemistry, physics, and materials science. Both covalent and non‐covalent functionalization of sheet architectures allows a systematic modification of their properties, that is, an improvement of solubility and processability, the prevention of re‐aggregation, or band‐gap tuning. Next to successful functionalization concepts, fundamental challenges are also addressed. These include the insolubility and polydispersity of most 2D sheet polymers, the development of suitable characterization tools, the identification of effective binding strategies, the chemical activation of the usually rather unreactive basal planes for covalent addend binding, and the regioselectivity of plane addition reactions. Although a number of these questions remain elusive in this Review, the first promising concepts to overcome such hurdles are presented.

Production of monolayer-rich gold-decorated 2H–WS2 nanosheets by defect engineering

“…[17][18][19] Secondly, chemical functionalisation to further tailor the materials' properties on demand is currently in its infancy. [20][21][22] With few exceptions, 23,24 the covalent chemistry is currently limited to CE-1T-TMDs, which are of less interest in optoelectronic applications due to its lack of visible optical absorption or emission. In addition to the functionalisation routes involving the addition of organic molecules, 20,21 it has been shown that CE-1T-TMDs react with AuCl 3 even in the absence of additional reducing agents.…”

Synthesis Protocols of the Most Common Layered Carbide and Nitride MAX Phases

“…There also is the apparition of Ti 2 AlC. The following reactions are suggested + → Al Ti 5 Ti 3Ti Al 3 2 (2) + → TiAl 2 Ti 3TiAl 3 (3) + → TiAl TiC Ti AlC 2 (4) At 1200 °C, the phase of Ti 2 Al disappears while TiC and TiAl phases diminish to form Ti 2 AlC. At 1300 °C, the peaks remaining can all be linked to the Ti 2 AlC compound.…”

“…[24,86] The first method uses high-energy milling before the actual HP. [24] This method uses the elemental powders of Ti, Al, and activated C. This mixture is done by following the reaction below, aiming for 100 wt% of Ti 2 AlC, which appears to form Ti 3…”

“…Nowadays, there are dozens of newly reported 2D materials, from the monoelemental graphene or layered pnictogens, to 2D slabs comprising multielements, such as transition metal dichalcogenides or metal phosphorous trichalcogenides . These materials have in common that within the same layer, the atoms are covalently bound and, in turn, the individual sheets are weakly stacked by van der Waals forces.…”

Gitteröffnung durch reduktive kovalente Volumen‐Funktionalisierung von schwarzem Phosphor

“…

Eine chemisch-reduktive Volumen-Funktionalisierung von dünnlagigem schwarzem Phosphor (BP) wurde unter Verwendung von BP-Interkalationsverbindungen entwickelt. [10][11][12] Mittlerweile wurde eine erste Reihe von Vorschriften zur nicht-kovalenten Funktionalisierung verçffentlicht, die hauptsächlich darauf abzielen, die Instabilitätv on BP gegen Wasser und Sauerstoff zu verbessern. Die kovalente Funktionalisierung wurde umfassend mit mehreren spektroskopischen Methoden sowie DFT-Rechnungen nachgewiesen;e sl iegt ein hçherer Funktionalisierungsgrad als bei neutralen Funktionalisierungsreaktionen vor.

Seit2014hatderzweidimensionale(2D)schwarzePhosphor

(BP) wegen seiner hohen p-Typ-Ladungsträgermobilitätu nd seiner modifizierbaren, direkten Bandlücke große Aufmerksamkeit auf sich gezogen.

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