2 research outputs found
Electro-optical interfacial effects on a graphene/?-conjugated organic semiconductor hybrid system.
The influence of graphene and retinoic acid (RA) ? a ?-conjugated organic semiconductor ? interface on their hybrid system is investigated.
The physical properties of the interface are assessed via scanning probe microscopy, optical spectroscopy (photoluminescence
and Raman) and ab initio calculations. The graphene/RA interaction induces the formation of a well-organized ?-conjugated
self-assembled monolayer (SAM) at the interface. Such structural organization leads to the high optical emission efficiency of
the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin
probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the
optical excitation of the RA monolayer generates surface potential changes on the hybrid system. In summary, interface-induced
organized structures atop 2D materials may have an important impact on both design and operation of ?-conjugated nanomaterialbased
hybrid systems
Raman evidence for pressure-induced formation of diamondene.
Despite the advanced stage of diamond thin-film technology, with applications ranging
from superconductivity to biosensing, the realization of a stable and atomically thick
two-dimensional diamond material, named here as diamondene, is still forthcoming. Adding
to the outstanding properties of its bulk and thin-film counterparts, diamondene is predicted
to be a ferromagnetic semiconductor with spin polarized bands. Here, we provide spectroscopic
evidence for the formation of diamondene by performing Raman spectroscopy of
double-layer graphene under high pressure. The results are explained in terms of a breakdown
in the Kohn anomaly associated with the finite size of the remaining graphene sites
surrounded by the diamondene matrix. Ab initio calculations and molecular dynamics
simulations are employed to clarify the mechanism of diamondene formation, which requires
two or more layers of graphene subjected to high pressures in the presence of specific
chemical groups such as hydroxyl groups or hydrogens