Oligomeric approach to 2D materials modeling

Oligomeric approach has been originally developed to study electronic properties of conjugated polymers. This approach allows to access electronic properties of 1D systems otherwise difficult to calculate. We successfully extended this method to study electronic properties of 2D materials. In this review we summarize our recent work in this area. It has been established that large graphene nanoflake possess multiconfigurational singlet or even high spin ground state. Doping of 2D systems has also been explored and it has been demonstrated that doping allows to tune their electronic properties, including ionization potentials, electron affinities, reorganization energies and the very nature of the ground state. The electronic properties of novel 2D allotropies of carbon, phosphorus, germanium and silicon have been studied as well as their complexes with Li. Heterostructures, of different 2D allotropies are readily formed. This is an alternative method for tuning of their electronic properties.

B(OH)2-functionalized graphene nanoflake as a promising nanocarrier for letrozole delivery: A DFT study

We studied the capability of pristine, Al-doped and B(OH)2-functionalized graphene nanoflakes for delivery of Letrozole (LT) anticancer agent using density functional theory calculations. It was shown that LT/pristine graphene complex includes very weak physical interaction with Ead = -2.447 kcal.mol-1 which is so weak to be applied in drug delivery purposes. So, graphene nanoflake was doped by Al atom and the calculations demonstrated the LT adsorption energy was increased significantly (Ead = -33.571 kcal.mol-1). However, the LT release study showed that the adsorption energy did not change efficiently upon protonation in acidic environment (Ead = -31.857 kcal.mol-1). Finally, the LT adsorption was investigated on B(OH)2-functionalized graphene. The calculations represented that the adsorption energy was -9.607 kcal.mol-1 which can be attributed to the possible hydrogen bonding between LT molecule and B(OH)2 functional group. The adsorption energy was changed to -1.015 kcal.mol-1 during protonation process. It can be concluded that the protonation of LT/B(OH)2-functionalized graphene complex in carcinogenic cells area, separates the LT from the nanocarrier. Thus, B(OH)2-functionalized graphene nanoflakes can be considered as a promising nanocarrier candidate for LT delivery.

Molecular Dynamics Study on Graphene-Nanoflake Sensor Sandwiched Between Crossed Graphene-Nanoribbon Junctions

We present a design of a nanoscale inertial measurement unit or a data archive using a graphene-nanoflake (GNF) sandwiched between crossed graphene-nanoribbon (GNR) junctions. When an external force applied is below the retracting force, the inertial force exerted on the movable GNF can telescope it. Then, the self-restoring force increases as the attractive van der Waals force between the GNF and the GNRs, which enables the GNF to automatically and fully retract back into the sandwich position immediately after the externally applied force is released. When the external force exceeds the retracting force, the GNF escapes from the crossed GNR junctions, which enables the device to be used as non-volatile memory. The heterostructure of GNR/h-BN/GNR can be considered as an advanced structure in the proposed scheme.

A New One-Step Deposition Approach for a Low Friction Graphene Nanoflakes Coating

Recent studies have shown that graphene can improve the tribological performance of materials by lowering the coefficient of friction and increasing wear resistance. In this present work, the authors evaluate an inductively coupled plasma process that synthesizes graphene nanoflakes in-flight and uniformly deposits them on metallic substrates. The quality of the graphene flakes was characterized and coating surface friction was measured using a ball-on-three-plates tribometer. Test results showed that graphene nanoflake coatings reduced the coefficient of friction of steel from 0.6 to less than 0.2.