Oxo‐Functionalized Graphene: A Versatile Precursor for Alkylated Graphene Sheets by Reductive Functionalization

Abstract

Controlled covalent functionalization of graphene remains a challenging task owing to the heterogeneous nature of materials. Functionalization approaches for graphene either lack in quantifying the degree of functionalization or they do not discriminate between covalent and non-covalent functionalization. Here, graphite is oxidized and exfoliated in a three-step procedure and subsequently reduced and functionalized by hexylation. Although Raman spectroscopy is powerful to determine the degree of in-plane lattice defects (θ ) and functionalization (θ ), the method fails at detecting introduced hexyl groups at a concentration of about 0.03 %, next to the pre-existing in-plane lattice defects of 0.7 %. However, sensitive thermogravimetric analysis coupled with gas chromatography and mass spectrometry (TGA-GC/MS) can prove the hexylation reaction. The efficiency of functionalization is comparable to reductive functionalization of pristine chemical vapor deposition (CVD)-graphene and bulk graphite.

Selective Functionalization of Graphene at Defect‐Activated Sites by Arylazocarboxylic tert‐Butyl Esters

“…S G fulfills these requirements and was obtained from aqueous oxo‐ S G using sodium borohydride as a reducing agent in the presence of sodium cholate as a surfactant ( S G/SCH). This material bears slightly more lattice defects than S G on surfaces owing to the different method of reduction . As the preparation of large amounts of functionalized graphene is highly desired for any application, we investigated the reactivity of S G/SCH towards four different 4‐RC 6 H 4 N 2 Boc derivatives (R=Br, CN, NO 2 , and OC 7 H 15 ) and analyzed the obtained and purified products by TGA‐MS.…”

Ultrathin Nanosheets of Oxo‐functionalized Graphene Inhibit the Ion Migration in Perovskite Solar Cells

“…The chemical structure was thoroughly investigated in an earlier study. [23][24][25]28] The microstructure of the ultrathin nanosheets of oxo-G/DA-wrapped perovskite formed during the crystallization of perovskite can effectively reduce the defects of oxo-G/DA agglomeration formation. In several reports, we have verified the size and layer distribution of oxo-G/DA nanosheets by particle size analyzer and atomic force microscopy (AFM).…”

“…In this regard, ion migration inhibition can be achieved by passivating the grain boundary, regulating the crystal growth process or using additives to inhibit the movement of ions themselves. [23][24][25] The use of DA-modified oxo-G not only increases the dispersibility of oxo-G/DA in an organic solvent, which even forms a large number of single-layer nanosheets under its action. [23][24][25][26][27] Herein, we report on ultrathin 2D nanosheets of oxo-functionalized graphene/ dodecylamine (oxo-G/DA) incorporated into triple cation PSCs by solution processing, leading to high efficiency and durability.…”

Selektive Funktionalisierung von Graphen an defektaktivierten Bereichen durch Arylazocarbonsäure‐tert‐butylester

“…S G erfüllt die Anforderungen und wird aus wässrigem oxo‐ S G unter Verwendung von Natriumborhydrid als Reduktionsmittel in Gegenwart von Natriumcholat als Tensid ( S G/SCH) erhalten. Dieses Material ist etwas defektreicher als S G, was wohl auf die unterschiedliche Reduktionsmethode zurückzuführen ist . Da die Herstellung großer Mengen von funktionalisiertem Graphen in jedem Anwendungsbereich sehr erwünscht ist, haben wir die Reaktivität von S G/SCH gegenüber vier verschiedenen 4‐R‐ArN 2 Boc‐Derivaten (R=‐Br, ‐CN, ‐NO 2 und ‐OC 7 H 15 ) untersucht und die gereinigten Produkte mit TGA‐MS analysiert.…”