Laboratory for Molecular Surfaces and Nanotechnology


Stefano Ippolito


LIQUID PHASE EXFOLIATION (LPE) OF TWO-DIMENSIONAL MATERIALS: PRODUCTION, FUNCTIONALIZATION AND MULTISCALE CHARACTERIZATION

Following the discovery of the outstanding physical and chemical properties of graphene obtained via scotch tape exfoliation, scientists have focused their attention on developing new and upscalable methods to produce 2D materials, such as hexagonal boron nitride (BN), silicates, borophene and transition metal dichalcogenides (TMDCs). Electrochemical exfoliation of bulk materials represents one of the most common solution-processing technique to obtain single-layer, overcoming the well-known limitation of mechanical (schotch tape) exfoliation, in terms of quantity of materials that can be produced. In general, liquid-phase exfoliation processes maximize the results in terms of scalability and yield, making them a perfect alternative to mechanical exfoliaiton, chemical vapour deposition (CVD) or epitaxial growth on SiC.
In my research activities, incollaboration with the NANOCHEMISTRY LABORATORY, at the Institut de Science et d’Ingénierie Supramoléculaires, of the Université de Strasbourg (UNISTRA) & CNRS, I focused my attention on the liquid-phase exfoliation processes of bulk molybdenum disulfide (MoS2) and graphite to produce high quality dispersions of MoS2 and graphene nanoflakes. Microscopic and spectroscopic investigations provided insight into the structural and electronic properties of exfoliated flakes. Moreover, electrical measurements were carried out on films composed of binary hybrid material comprising MoS2 and graphene, revealing unique properties which are of interest for applications in optoelectronic.