Covalently functionalized graphene derivatives were synthesized via benchmark reductive routes using graphite intercalation compounds (GICs), in particular KC. We have compared the graphene arylation and alkylation of the GIC using 4-tert-butylphenyldiazonium and bis(4-(tert-butyl)phenyl)iodonium salts, as well as phenyl iodide, n-hexyl iodide, and n-dodecyl iodide, as electrophiles in model reactions. We have put a particular focus on the evaluation of the degree of addition and the bulk functionalization homogeneity (H). For this purpose, we have employed statistical Raman spectroscopy (SRS), and a forefront characterization tool using thermogravimetric analysis coupled with FT-IR, gas chromatography, and mass spectrometry (TGA/FT-IR/GC/MS). The present study unambiguously shows that the graphene functionalization using alkyl iodides leads to the best results, in terms of both the degree of addition and the H. Moreover, we have identified the reversible character of the covalent addition chemistry, even at temperatures below 200 °C. The thermally induced addend cleavage proceeds homolytically, which allows for the detection of dimeric cleavage products by TGA/FT-IR/GC/MS. This dimerization points to a certain degree of regioselectivity, leading to a low sheet homogeneity (H). Finally, we developed this concept by performing the reductive alkylation reaction in monolayer CVD graphene films. This work provides important insights into the understanding of basic principles of reductive graphene functionalization and will serve as a guide in the design of new graphene functionalization concepts.

The chemical bulk reductive covalent functionalization of thin-layerb lack phosphorus (BP) using BP intercalation compounds has been developed. Through effective reductive activation, covalent functionalization of the charged BP by reaction with organic alkylh alides is achieved. Functionalization was extensively demonstrated by means of several spectroscopic techniques and DFT calculations;t he products showed higher functionalization degrees than those obtained by neutral routes.Since 2014, two-dimensional (2D) black phosphorus (BP) has attracted tremendous attention throughout the scientific community due to its high p-type charge carrier mobility and its tunable direct band gap. [1][2][3][4][5][6][7][8][9] In contrast to graphene,B P exhibits amarked puckering of the sp 3 structure,constituting atwo-dimensional s-only system, involving one lone electron pair at each Pa tom. Whereas its outstanding physical and materials properties have been intensively investigated, its chemistry remains almost unexplored. [10][11][12] Indeed, af irst series of noncovalent functionalization protocols has been reported, mainly focused on improving the intrinsic instability of BP against water and oxygen. [13][14][15][16][17] Beyond these approaches,t he covalent functionalization of the interface is one of the most promising routes for fine-tuning the chemical and physical properties of 2D nanomaterials. [18,19] In this sense,only afew recent reports on single-flake chemistry with diazonium salts, [20] and wet-chemistry on previously exfoliated flakes with nucleophiles [21][22][23] or carbon-free radicals [24] have been reported so far.This is probably due to the intrinsic low degree of reactivity of neutral BP towards these reactions and the difficulties associated with overcoming the huge van der Waals energy stored within aBPcrystal, thus blocking the direct functionalization of BP.A long this front, ab ulk wetchemical derivatization sequence remains to be found. Moreover, an unambiguous determination of the covalent binding and its influence in the chemical structure of the P-layers is required to systematically explore the characteristics of BP reactivity.To address these challenges we took advantage of the well-known reductive graphene chemistry using graphite intercalation compounds (GICs). [18,[25][26][27] As af irst success in this direction, we have recently reported the preparation of BP intercalation compounds (BPICs) with alkali metals (K and Na). [28] This paves the way for the exploration of the reductive route using activated negatively charged BP-ite nanosheets and electrophiles (E) as covalent reaction partners.Herein, we provide the first real proof for covalent binding in BP with alkyl halides using abattery of characterization techniques.F urthermore,d ensity functional theory (DFT) calculations were carried out to rationalize our results, providing adeep understanding of the covalent derivatization of BP.This thorough study reveals for the first time the lattice opening in BP,absent in graphene,which is a...

Antimonene, a novel group 15 two-dimensional material, is attracting great attention due to its outstanding physical and chemical properties.

Antimonene, a monolayer of β-antimony, is increasingly attracting considerable attention, more than that of other monoelemental two-dimensional materials, due to its intriguing physical and chemical properties. Under ambient conditions, antimonene exhibits a high thermodynamic stability and good structural integrity. Some theoretical calculations predicted that antimonene would have a high oxidation tendency. However, it remains poorly investigated from the experimental point of view. In this work, we study the oxidation behavior of antimonene nanosheets (ANS) prepared by ultrasonication-assisted liquid-phase exfoliation. Using a set of forefront analytical techniques, a clear effect of sonication time on the surface chemistry of prepared ANS is found. A dynamic oxidation behavior has been observed, which upon annealing at moderate temperature (210 °C) resulted in a semiconducting behavior with a bandgap of approximately 1 eV measured by ultraviolet photoelectron spectroscopy. This study yields valuable information for future applications of antimonene and paves the way towards novel modification approaches in order to tailor its properties and complement its limitations.

Two-dimensional (2D) sheets of antimonene have attracted increasing attention due to their unique physical and chemical properties prompting potential for diverse applications. We present a facile method to prepare high-quality antimonene nanosheets (ANSs) by micromechanical exfoliation on SiO2/Si substrate. The temperature-and laser power-dependent Raman studies of exfoliated ANSs are reported and analyzed. It was found that both the out-of-plane A1g and the in-plane Eg modes red-shift linearly with increase in temperature, pointing towards anharmonic vibrations of the lattice. The thermal response of the ANSs on a SiO2/Si surface is also described using numerical simulation of the heat transfer to study their laser-induced oxidation mechanisms. These results offer a deeper understanding of the phonon properties and oxidation susceptibility of 2D antimonene paving the way for the development of antimonene-based technologies, such as electronic devices or photothermal cancer therapy.

2D materials show outstanding properties that can bring many applications in different technological fields. However, their uses are still limited by production methods. In this context, antimonene is recently suggested as a new 2D material to fabricate different (opto)electronic devices, among other potential applications. This work focuses on optimizing the synthetic parameters to produce high‐quality antimonene hexagons and their implementation in a large‐scale manufacturing procedure. By means of a continuous‐flow synthesis, few‐layer antimonene hexagons with ultra‐large lateral dimensions (up to several microns) and a few nanometers thick are isolated. The suitable chemical post‐treatment of these nanolayers with chloroform gives rise to antimonene surfaces showing low oxidation that can be easily contacted with microelectrodes. Therefore, the reported procedure offers a way to solve two critical problems for using antimonene in many applications: large‐scale preparation of high‐quality antimonene and the ability to set electrical contacts useful for device fabrication.

Eine chemisch-reduktive Volumen-Funktionalisierung von dünnlagigem schwarzem Phosphor (BP) wurde unter Verwendung von BP-Interkalationsverbindungen entwickelt. Durche ffektive reduktive Aktivierung wurde die kovalente Funktionalisierung des geladenen BP mit Alkylhalogeniden erreicht. 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. [1][2][3][4][5][6][7][8][9] Im Unterschied zu Graphen besteht BP aus gewellten Schichten, die ausschließlich aus einem 2D-s-System gebildet werden und in denen jedes P-Atom ein freies Elektronenpaar aufweist. Während seine bemerkenswerten physikalischen und Materialeigenschaften bereits intensiv untersucht wurden, bleibt seine Chemie nahezu unerforscht. [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. [13][14][15][16][17] Abgesehen von diesen Ansätzen gilt die kovalente Funktionalisierung der Oberfläche als eines der vielversprechendsten Konzepte zur Modifizierung der chemischen und physikalischen Eigenschaften von 2D-Nanomaterialien. [18,19] In diesem Sinne wurden bisher nur wenige Arbeiten, wie die Funktionalisierung einzelner Flocken mit Diazoniumsalzen [20] oder die nasschemische Funktionalisierung von zuvor hergestellten Flocken mit Nukleophilen [21][22][23] sowie mit freien Kohlenstoffradikalen, [24] publiziert. Der Grund hierfürl iegt wahrscheinlich in der niedrigen Reaktivitätv on neutralem BP bei diesen Reaktionen. In diesem Zusammenhang wird die direkte kovalente Funktionalisierung oftmals verhindert, da die BP-Schichten durch eine hohe Va n-der-Waals-Energie zusammengehalten werden. Ausd iesem Grund muss eine effektive nasschemische Funktionalisierungssequenz erst noch gefunden werden. Eine eindeutige Bestimmung der kovalenten Bindung und ihres Einflusses auf die chemische Struktur der BP-Schichten ist zudem zur systematischen Untersuchung der Reaktivitätvon BP erforderlich.Wirh aben uns die bekannte reduktive Graphenchemie, die auf der Verwendung von Graphit-Interkalationsverbindungen (GICs) beruht, zunutze gemacht. [18,[25][26][27] Als ersten Erfolg in dieser Richtung haben wir 2017 die Herstellung von BP-Interkalationsverbindungen (BPICs) mit Alkalimetallen (K und Na) beschrieben. [28] Dies ebnet den Wegz ur Erforschung der reduktiven Route basierend auf der Nutzung von

Two‐dimensional (2D) black phosphorus (BP) represents one of the most appealing 2D materials due to its electronic, optical, and chemical properties. Many strategies have been pursued to face its environmental instability, covalent functionalization being one of the most promising. However, the extremely low functionalization degrees and the limitations in proving the nature of the covalent functionalization still represent challenges in many of these sheet architectures reported to date. Here we shine light on the structural evolution of 2D‐BP upon the addition of electrophilic diazonium salts. We demonstrated the absence of covalent functionalization in both the neutral and the reductive routes, observing in the latter case an unexpected interface conversion of BP to red phosphorus (RP), as characterized by Raman, 31P‐MAS NMR, and X‐ray photoelectron spectroscopies (XPS). Furthermore, thermogravimetric analysis coupled to gas chromatography and mass spectrometry (TG‐GC‐MS), as well as electron paramagnetic resonance (EPR) gave insights into the potential underlying radical mechanism, suggesting a Sandmeyer‐like reaction.