I am studying about different shape of nanoparticles in molecular imaging and I need to confirm the shape forming after each synthesis of nanoparticles. I am looking for cheap and more routine analysis method which can confirm the shape of nanoparticles accurately (except TEM and SEM analysis).
Thanks
Can you specific "shape"? What is it, what you are interested in? The size (diameter) or approximately round particles, or lenght or detect irregularities from a specific form/size/shape? Also, what approximate size (or range of sizes) you interested in, because nanoparticles come in sizes from literally nm up to hundreds of nm (or even microns). Lastly, it is a question of material.
Depending on your answers of the questions above, optical spectroscopy methods (Raman, PL, etc.) may can provide a routinely, easy to apply method to determine the approximate shape/size of a large ensemble of nanoparticles in a sample. Basically, you need to compare the spectral response of a unknown sample, with some pre-established spectra (or fingerprint). But, if the spectrum is influenced by the shape, depends on a lot of properties, i.e. what size ranges you expect, what shapes there are, what material you have and most important what accuracy you need. Finnally it is also a question of application. If you want to pick very specific particles from a large number of particles, spectroscopy might not be the best tool, but if you are interested in a general trend in a larger sample, it is better suited.
Since you are asking except SEM and TEM, you may use AFM without complications of prior sample preparation. I shall not suggest Raman, PL, DLS etc. because these are indirect methods where the result may be affected by several parameters.
Dear Parisa Fatehbasharzad Madam,
We can measure the Particle Size (PS) by using TEM for thin film samples and its thickness should be less than 1 μg, but for SEM, sample must be conductive and sputter coated.
Other than, AFM is also used for measure P S and sample should stick to substrate. But this is not cost effective.
Photon Correlation Spectroscopy (PCS), Nanoparticle Surface Area Monitor (NSAM), Aerosol Particle Mass Analyzer (APM), Nanoparticle Tracking Analysis (NTA) are the instruments to find the shape of particle size.
Photon Correlation Spectroscopy (PCS) is the cheap and more routine.
Be in your situation, I would decide for TEM tomography. This is pretty nice way how to reveal the shape of nanoparticles.
Michael Rüsing I am working with 50 nm cube gold nanoparticles and I am looking for the technique which can confirm this shape after each synthesis.
Then TEM tomography should be your choice. Another techique is imaging these nanoparticles in reciprocal space. Cubic form could be visible also on diffraction spot pattern.
Most easiest way to check particle shape and size for 50nm particles or less is through TEM ( because if particles are agglomerated, you can't differentiate without HR imaging so in short TEM is most precise technique and now very easy to access)
To be very specific to your question ( except TEM and SEM) , so yes . you can do it. Parisa Fatehbasharzad
Ans: NPs have unique optoelectronic properties and NPs of Alkali and noble metals like Cu, Ag and Au have broad absorption band in visible zone. Size of nano particles can influence the physico-chemical properties e.g. optical properties. So for example : 20nm NPs of Alkali and noble metals ( in your case gold NPs) will have wine red , yellowish gray, black and dark black colors. So Variation of color will occur due to change in % Au conc, aspect ratio and nano shell thickness.
Partially agree with Ankur. He has rightly said about size dependent optoelectronic properties, but on the reverse way shape and size cannot be confirmed from such properties, rather, it can only be correlated. I agree with Ankur about selecting TEM considering identification of shapes from agglomeration. If possible, it can also be ultrasonicated during sample preparation to avoid much agglomeration.
Since Parisa does not have the choice of SEM and TEM, shape and size can also be determined from the bulk nanoparticles from log[I(q)] vs. q plot using SAXS, which I have forgot to mention earlier.
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