Black phosphorus (BP) was functionalized with organic moieties on the basis of liquid exfoliation. The treatment of BP with electron-withdrawing 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) led to electron transfer from BP to the organic dopant. On the other hand, the noncovalent interaction of BP with a perylene diimide was mainly due to van der Waals interactions but also led to considerable stabilization of the BP flakes against oxygen degradation.

A free-base porphyrin carrying two hexabenzocoronene (HBC) substituents in a trans arrangement and its zinc complex have been prepared. The compounds were characterized extensively and found to form tricationic dimers in the gas phase. X-ray crystallography confirms for the zinc complex a profound π-stacking of the HBC moieties. In contrast, the free-base porphyrin incarcerates n-heptane which essentially prevents π-stacking. Upon excitation of the HBC substituents, efficient energy transfer to the central porphyrin is observed.

Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under http://dx.

This commmunication presents a study of atomic layer deposition of Al 2 O 3 on transition metal dichalcogenide (TMD) two-dimensional films which is crucial for use of these promising materials for electronic applications. Deposition of Al 2 O 3 on pristine chemical vapour deposited MoS 2 and WS 2 crystals is demonstrated. This deposition is dependent on the number of TMD layers as there is no deposition on pristine monolayers. In addition, we show that it is possible to reliably seed the deposition, even on the monolayer, using non-covalent functionalisation with perylene derivatives as anchor unit.The integration of transition metal dichalcogenides (TMDs) into existing semiconductor technology is of major interest. 1,2 The synthesis of these materials has been vastly improved over the last few years and many possible devices have been proposed and realised. [3][4][5][6] But to finally achieve their large-scale integration and production, it is necessary to make TMDs fully CMOS processable. One prerequisite for this is the deposition of subsequent layers on top of the TMD for gating and passivation as the performance and stability of TMD based devices hugely depends on their dielectric environment. This task is nontrivial as any impact on the surface of the TMD will result in the destruction of its electronic properties. It has been shown that encapsulation of the 2D material by mechanical deposition of hexagonal boron nitride results in the best preservation of its electronic properties but this approach is not scalable. 7 Other frequently used deposition methods for oxides such as sputtering or plasma-enhanced chemical vapour deposition (PECVD) are not suitable as their application will cause damage to the monolayer.Atomic layer deposition (ALD) is a mild and highly precise technique for thin film deposition, mainly used for depositing gate oxides in integrated circuits. 8 The most common ALD process is the deposition of Al 2 O 3 from alternating exposures of trimethylaluminium (TMA, Al(CH 3 ) 3 ) and water according to the reaction: 9 2Al(CH 3 ) 3 + 3H 2 O -Al 2 O 3 + 6CH 4 DH = À376 kcal This reaction is thermodynamically highly favourable and works over a large range of temperatures with temperatures between 33 1C and 500 1C demonstrated, making it very reliable and common in the silicon and III-V semiconductor industries. 10,11 However, in the initial step the TMA needs a surface hydroxyl group with which it reacts and the lack of such groups on the TMD's basal plane makes starting the deposition non-trivial; a challenge also encountered with graphene. [12][13][14][15] Using ozone instead of water may prove harmful to the oxidation-sensitive TMD layers, though there have been some recent successes. 16 An initial, purely adsorptionbased deposition can be achieved but tends to be dependent on temperature and other factors like underlying electronic structure and is therefore often not entirely reproducible; it has been shown several times that studies may not reproduce results under apparently similar condit...

The surfactant assisted exfoliation and non-covalent functionalization of twodimensional layered materials, like graphene, transition metal dichalcogenides, etc., has extraordinarily been propelled forward within the last 5 years. Numerous molecules have been designed and attached to the exfoliated layers, and based on their outstanding properties, perylene based dyes have become one of the most frequently used π-detergents. Therefore, the prospect of this micro review is to summarize the most prominent achievements in this rapidly progressing field of research. IntroductionGraphene, [1] the prototype of novel 2D materials, has become a highly promising icandidate for future carbon-based devices. [2] Nowadays, the most important chemical routes towards its production are the liquid-phase exfoliation of graphite, [3][4] the reduction of graphene oxide, [5][6] and its bottom-up synthesis, starting from small precursor molecules. [7] Besides its production, also its functionalization has attracted a lot of interest in the scientific community due to its unprecedented physical properties and the wide range of possible applications where this carbon nano-material and its derivatives can be implemented. With this objective, the covalent functionalization of graphene has been investigated in detail [8] and also the non-covalent modification of graphene and other 2D materials has extraordinarily been propelled forward within the last 5 years.