I have an HRTEM image of CuInSe2/ZnS core/shell nanocrystals where small individual dots can be seen. The size of the dot is roughly 0.2 nm. I summed up the ionic radius of Cu(+) +In(3+) 2* Se(2-) from the literature which is 0.616 nm. This means these small sized dots are the individual elements/ions as their size is lower than sum of ionic radius. So i assume that its possible to identify the individual elements (like Cu, In Se) based on the size of dots. However, i found it difficult to measure the exact size of the dots in picometer resolution using image J. So how do i do this? Is it possible?
Also is it possible to draw the crystal structure based on the position of these elements?
Note:
Ionic radius of Cu+ =140 pm, In3+ = 80 pm, Se2- = 198 pm
I have excluded the capping agents from this calculation
Thanks in advance
I would suggest to measure the latice distance to know at what surface you are looking at. But measuring a "dot" and define the element is not possible with this image and I have never seen an analysis doing this with HRTEM.
What you can even read in the Wikipedia article the "dots" are not the actual atoms or ions. If you want to learn more about it I recommend the book from Williams and Carter. I do not want to give an unprecise Explanation because it is a quite complex topic.
Thank you Matthias M. L. Arras . I am not familiar with simulation and i am learning. However, i have taken the words from the wikipedia page that you have shared and given below:
" High-resolution transmission electron microscopy (HRTEM) (or HREM) is an imaging mode of specialized transmission electron microscopes (TEMs) that allows for direct imaging of the atomic structure of the sample."
" At these small scales, individual atoms of a crystal and its defects can be resolved"
So what do they mean if the dots are not atoms?
Oh sorry. the Name is quite unsurprising: Transmission electron microscopy. It has several subchapters also one exspecially for HRTEM.
https://www.springer.com/de/book/9780387765006
We had it in our library and it was very useful for me.
I think in one chapter was a case where it was not clear if the "dot" you saw in the image was a doting ion, an error in the lattice or a vacancy.
Julian Opel Thanks for sharing. I will look at it.
Also see this video from Nature publisher where these dots are reported as individual atoms. Matthias M. L. Arras
https://www.youtube.com/watch?v=yqLlgIaz1L0
In a nanoparticle based on single element like Ag, Au, Pt, all these dots contain same element. However, in a nanoparticle based on binary or multinary elements, how do we identify?
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