Insights into radiation damage from atomic resolution scanning transmission electron microscopy imaging of mono-layer CuPcCl16 films on graphene

Abstract

Atomically resolved images of monolayer organic crystals have only been obtained with scanning probe methods so far. On the one hand, they are usually prepared on surfaces of bulk materials, which are not accessible by (scanning) transmission electron microscopy. On the other hand, the critical electron dose of a monolayer organic crystal is orders of magnitudes lower than the one for bulk crystals, making (scanning) transmission electron microscopy characterization very challenging. In this work we present an atomically resolved study on the dynamics of a monolayer CuPcCl16 crystal under the electron beam as well as an image of the undamaged molecules obtained by low-dose electron microscopy. The results show the dynamics and the radiation damage mechanisms in the 2D layer of this material, complementing what has been found for bulk crystals in earlier studies. Furthermore, being able to image the undamaged molecular crystal allows the characterization of new composites consisting of 2D materials and organic molecules.

Atomic-scale Imaging of Atomically-thin Organic Crystals via Low-dose STEM

“…As shown in Figure 1c, the class averages of 2000 frames of nominally identical regions of bilayer CoTMPP, each acquired at a dose of 51 e -/Å 2 , allow us to visualize the metal center and the orientation of methoxyphenyl groups. For monolayer CuPcCl (Figure 2a-c), we resolve 16 individual chlorine atoms that decorate the edge of the molecule, consistent with previous reports [5]. Uniquely, our averages obtain contrast from the carbon atoms, visible as fluctuations in the image intensity in the region between the metal atom at the center and the chlorine atoms at the edge.…”

Distinctive stability of a free-standing monolayer clay mineral nanosheet via transmission electron microscopy

“…[8][9][10][11][12][13] Furthermore, for materials with simple structures such as graphene and transition metal dichalcogenide nanosheets, single-atom and single-molecule observations within hybrid materials have been achieved. [14][15][16][17][18][19][20][21] However, (S)TEM imaging of free-standing monolayer clay minerals, which have a more complicated structure than their preceding few-atom thick materials, such as graphene, at the atomic-scale has not been achieved, except in our recent study. 22 Once non-destructive direct imaging of clay mineral nanosheet or useful clay mineral-based organicinorganic hybrid materials at the atomic scale is established, it will strongly promote their applicability such as selective adsorption for heterogeneous catalyst or sensing, 23 or photoenergy conversion.…”

Fluorination vs. Chlorination: Effect on the Sensor Response of Tetrasubstituted Zinc Phthalocyanine Films to Ammonia

“…Chlorosubstituted metal phthalocyanines ones are also widely investigated. Similarly to MPcFx, films of chlorosubstituted MPcCl x can also be deposited by thermal evaporation [27][28][29][30][31]. Parameters of crystal cell of CuPcCl x (x = 4, 8, 16) have been determined by Fryer and co-authors [32] using the method of electron diffraction, while later the single crystal structure of CuPcF 4 -np have been refined [33].…”