Hi!
I want to obtain SEM images of gold nanoparticles of a diameter in the range of 20 nm, dispersed in solution. When I searched for literature, I couldn't find relavent information on a suitable magnification, resolution and accelarating voltage for this size of nanoparticles in solution though SEM images for 20 nm gold nanoparticles in tissues and cells were available. Information on TEM for 20 nm gold nanoparticles could be found in many articles too. I'm very new to this field and It would be a great help if someone can provide me with a solution or related literature in this regard.
Thank you in advance!
Dear Navoda,
The characteristics of magnification, voltage, etc. will depend on the microscope. Each microscope responds differently. An SEM is not the same as a Field Emission SEM. The results are very different; the quality and the possible magnification also. My recommendation is to carry out different tests until the desired quality and magnification are achieved, although this will depend on the microscope.
Dear Navoda,
The characteristics of magnification, voltage, etc. will depend on the microscope. Each microscope responds differently. An SEM is not the same as a Field Emission SEM. The results are very different; the quality and the possible magnification also. My recommendation is to carry out different tests until the desired quality and magnification are achieved, although this will depend on the microscope.
According to my experience, nanogold it’s highly conducive so, low voltage by FESEM 3kv and well stigmation with magnification 100nm can show sharp field and decrease work distance
the choice of the experimental conditions depend obviously on the microscope but also on the aim of the research. High or low magnification should be chosen depending on which characteristics of the sample you want to see. In general, for nanoparticles higher magnifications are necessary with respect to bulk materials
It depends upon the capabilities of SEM. Generally, I would use a little higher kV (10-15 kV), probe size (smaller as possible), slow scan speed, and shorter working distance to get the targetted resolution. I would suggest you use a backscattered detector.
May I know which SEM machine you have?
One more thing to add, if you looking for Au in a biological specimen, you will destroy the specimen by increasing kV. So, you have to be careful while choosing the technique. I would suggest you go for TEM.
You did not specify what is your specimen. What is solution. It is better to replace solution with pure alcohol or distilled water (to "wash" particles) and use drop-cast method to prepare specimen for SEM. Gold is an easy material, you can use high voltages. I would start with something like 20 kV and see if lower voltages are OK. If you have and old non field emission SEM you can have problems in obtaining sharp images.