A joint group of researchers from Skoltech, the University of Tromsø (Norwegian Arctic University), the Institute of Solid State Chemistry and Mechanochemistry SB RAS (ICHCT SB RAS) performed a theoretical analysis of the properties of ultrathin diamond films. The group determined which of them are suitable for displays with field emission, this was told to the information service and the press service of Skoltech. The study is published in the first quartile journal ACS Applied Materials & Interfaces.
These flat screens were originally developed along with LCD displays that are now common. And the technology of ultra-thin diamond films has potential advantages: it is low power consumption, a wide viewing angle and inertia: - pixels change color quickly.
Diaman is an ultra-thin diamond film obtained by putting two or more layers of graphene on top of each other and attaching atoms of fluorine, hydrogen or some other elements to the outer surfaces of this structure. As a result, graphene is bent, and its layers are combined into a flat diamond. Such a material can be suitable for displays of computers, telephones, televisions and other devices with field emission due to its electronic properties. However, the properties of diamans are difficult to calculate and depend on many parameters.
Skoltech Senior Lecturer from the Energy Transition Project Center
“We examined various diamonds from the point of view of the influence of a number of factors on their electronic properties, and hence on their applicability in field emission displays. In total, 60 ultra-thin diamond films were considered - this number is obtained by multiplying three variables. First, the number of carbon layers could be from one to six. Secondly, the type of atoms that cover the surface of the films: fluorine or hydrogen. Thirdly, graphene layers can be moved relative to each other; in this case, five variants of their mutual orientation were studied.”
In their study, the scientists calculated a key characteristic for each of the 60 diamond configurations, namely how much energy it takes to knock an electron off the surface of the diamond film. This parameter is important for field emission displays, as they use electron radiation to light the pixels on the screen. So the less energy used, the better. This value depends on the so-called band gap of the material: which energy states are available to electrons in it, and which are not. The authors of the study also calculated this zone, and the most optimal diamond configuration for displays is six layers, hydrogenation (that is, hydrogen, not fluorine) and the orientation of the carbon film with the surface.
In addition, surface dipole moments affect the electronic properties of diamans, including electron emission. Therefore, the information obtained is valuable for the development of field emission displays and the selection of alternative materials for these devices.
Senior Research Fellow of ICTTM SB RAS, Arctic University of Norway, first author of the study
“In addition to electronic properties, we have determined surface dipole moments by creating a semi-quantitative approach based on the electronegativity scale developed by me and Professor Oganov at Skoltech. This approach makes it possible to avoid complex and lengthy first-principles calculations and to predict the reactivity of the surface of new two-dimensional materials.”
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