Dear sir/Madam, I have synthesized the Cu doped TiO2. i got the XPS results. from that the Cu confirmed as Cu (II) state. My question is weather it is in crystal lattices of TiO2 or on the surface of TiO2.
Thank you for your valuable suggestions to all the three scientists. I synthesized a nanomaterial. which has the particle size nearly 15 nm width and thickness below 15 nm. how can i measure by XPS. Please let me know sir.
Here with i am attaching the TEM image.
Hi Udayabhanu,
Just consider that XPS probe depth is in the range of the photoelectron escape depth, i.e. around few Angstroms. Hence, with XPS you are probing some nm below the very top surface of your sample at most. If you are working with nanoparticles or very thin films, the information you acquire can be interpreted as a "whole volume" informatio (even if it is formally uncorrect to speak of a bulk).
Instead, if you are working with micron-sized samples, or bulk ones, you will be sure that the XPS data concern only the near-surface (selvedge) region, and nothing could be said about the bulk distribution of materials. Concerning the crystalline structure, it is usually difficult to get this kind of information from XPS, and you should use other techniques, as some angle-resolved spectroscopy
Thank you for your valuable suggestions to all the three scientists. I synthesized a nanomaterial. which has the particle size nearly 15 nm width and thickness below 15 nm. how can i measure by XPS. Please let me know sir.
Here with i am attaching the TEM image.
SAMPLE PREPARATION for XPS is as important as the same XPS measurement.
I understand that preparing the sample for XPS is a somewhat difficult task. Pressing may not be possible if you have small or very small quantities of your particles. If you have produced a nanopowder, you could try dispersing your particles in pure water and cast it on your metallic sample holder by just dropping it. However, you should be careful to match a couple of requirements;
1 - the nanoparticle traces after casting and drying may be limited and disconnected due to hydrophilicity of the holder surface, that would require a number of sequential dropping/drying steps to get enaugh material compacted over an area larger than few square millimeters (typical spot size for standard XPS photon beam)
2 - a perfect drying must be accomplished before measurements without modifying the chemistry of your deposited sample, which would require a capped storage of the sample under low vacuum atmosphere and at relatively low temperature (e.g., 70-80 degrees centigrade.
Perhaps tedious, but surely possible.
On the other side I would avoid dispersing your particles in carbon-based solvents, because surface traces of carbonaceous residues may humper the XPS analysis (you would measure such carbon residues coating your nanoparticle sample.
I think that your collegues or technicians operating the XPS analyses are quite aware of that and can help you with the most proper sample preparation.
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