The monochromatic photoemission from diamondoid monolayers provides a new strategy to create electron sources with low energy dispersion and enables compact electron guns with high brightness and low beam emittance for aberration-free imaging, lithography, and accelerators. However, these potential applications are hindered by degradation of diamondoid monolayers under photon irradiation and electron bombardment. Here, we report a graphene-protected diamondoid monolayer photocathode with 4-fold enhancement of stability compared to the bare diamondoid counterpart. The single-layer graphene overcoating preserves the monochromaticity of the photoelectrons, showing 12.5 meV ful width at half-maximum distribution of kinetic energy. Importantly, the graphene coating effectively suppresses desorption of the diamondoid monolayer, enhancing its thermal stability by at least 100 K. Furthermore, by comparing the decay rate at different photon energies, we identify electron bombardment as the principle decay pathway for diamondoids under graphene protection. This provides a generic approach for stabilizing volatile species on photocathode surfaces, which could greatly improve performance of electron emitters.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.nanolett.7b04645 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Preparation and characterization of non-aromatic ether self-assemblies on a HOPG surface.
Nanotechnology
June 2022
Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10 000 Zagreb, Croatia.
On-surface self-assemblies of aromatic organic molecules have been widely investigated, but the characterization of analogous self-assemblies consisting of fully sp-hybridized molecules remains challenging. The possible on-surface orientations of alkyl molecules not exclusively comprised of long alkyl chains are difficult to distinguish because of their inherently low symmetry and non-planar nature. Here, we present a detailed study of diamondoid ethers, structurally rigid and fully saturated molecules, which form uniform 2D monolayers on a highly oriented pyrolytic graphite (HOPG) surface.
View Article and Find Full Text PDFOptical Properties of Single- and Double-Functionalized Small Diamondoids.
J Phys Chem A
April 2018
Institute for Computational Physics , Universität Stuttgart, Allmandring 3 , 70569 Stuttgart , Germany.
The rational control of the electronic and optical properties of small functionalized diamond-like molecules, the diamondoids, is the focus of this work. Specifically, we investigate the single- and double- functionalization of the lower diamondoids, adamantane, diamantane, and triamantane with -NH and -SH groups and extend the study to N-heterocyclic carbene (NHC) functionalization. On the basis of electronic structure calculations, we predict a significant change in the optical properties of these functionalized diamondoids.
View Article and Find Full Text PDFMonochromatic Photocathodes from Graphene-Stabilized Diamondoids.
Nano Lett
February 2018
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
The monochromatic photoemission from diamondoid monolayers provides a new strategy to create electron sources with low energy dispersion and enables compact electron guns with high brightness and low beam emittance for aberration-free imaging, lithography, and accelerators. However, these potential applications are hindered by degradation of diamondoid monolayers under photon irradiation and electron bombardment. Here, we report a graphene-protected diamondoid monolayer photocathode with 4-fold enhancement of stability compared to the bare diamondoid counterpart.
View Article and Find Full Text PDFSupramolecular organic frameworks: engineering periodicity in water through host-guest chemistry.
Chem Commun (Camb)
May 2016
Department of Chemistry, Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), Fudan University, 220 Handan Road, Shanghai 200433, China.
The development of homogeneous, water-soluble periodic self-assembled structures comprise repeating units that produce porosity in two-dimensional (2D) or three-dimensional (3D) spaces has become a topic of growing interest in the field of supramolecular chemistry. Such novel self-assembled entities, known as supramolecular organic frameworks (SOFs), are the result of programmed host-guest interactions, which allows for the thermodynamically controlled generation of monolayer sheets or a diamondoid architecture with regular internal cavities or pores under mild conditions. This feature article aims at propagating the conceptually novel SOFs as a new entry into conventional supramolecular polymers.
View Article and Find Full Text PDFCarbene-mediated self-assembly of diamondoids on metal surfaces.
Nanoscale
April 2016
Institute for Computational Physics, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany.
N-heterocyclic carbenes (NHC)s are emerging as an alternative class of molecules to thiol-based self-assembled monolayers (SAMs), making carbene-based SAMs much more stable under harsh environmental conditions. In this work, we have functionalized tiny diamondoids using NHCs in order to prepare highly stable carbene-mediated diamondoid SAMs on metal substrates. Using quantum-mechanical simulations and two different configurations for the carbene-functionalized diamondoids attached on gold, silver, and platinum surfaces we were able to study in detail these materials.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!