I do not want to enter the discussion about the definition of nano, but more the one about the sample characterization.

As it was mentioned above, and in quite some of other topics here, make sure that you are aware of the fact that XRD can indeed give you acces to a size (e.g. via Scherrer's formula), but it is the CRYSTALLINE(coherent) part size, which is not necessarily the particle size (the 'particles' can have an 'amorphous' part as well, or can be composed of several smaller crystalline grains, ...). So a discrepancy between TEM/SEM (let's call it particle size) and XRD (size of crystallites) is not always a contradiction, since you are not necessarily looking at the same thing. Also, as it was mentionned above, SAXS experiments could give you acess to sizes, and, most importantly to corresponding distributions, all this with much better statistics than TEM/SEM, for which only a small area is investigated. In an X-ray experiment, areas of several 100 microns^2 up to several mm^2 can easily be illuminated and contribute to the signal.

Various techniques can give you various informations, it is always a good idea (in my opinion) to investigate your sample using several techniques if available, just making sure that you extract the right piece of information from each. And hopefully this will only make more 'complete' the image that you can get about your sample

Regards

cristian

XRD spectrum gives different crystal orientation and crystalline size, but not the particle size. Therefore you need to see your sample under SEM or as you did with TEM. Under SEM you can see the grown nano particles over a substrate or as a powder. SEM is better than TEM because the difficult preparation and handling of TEM samples.

There is no mention of the material form. Nevertheless, XRD does not give particle size. It gives a GLOBAL AVERAGE of all the crystallites within the diffraction volume. Where as TEM are local probes, it gives fine and all details, but confined to a small local region of your sample. A direct comparison thus is little inappropriate, rather people used them as supplementary techniques. And yeah SEM can give details of agglomerate in you are interested in that.

Wow tbis question gets asked a lot and the same wrong answers are given. On ce again SAXS will provide particle size shape and distribution for sizes between 1nm and 10 microns. Grain size and shape can also be determined at the same time. There is a lot more to xrd than line broadening.

Particle size can be determined using Zetasizer Nano ZS. This instrument will give you the average particle size of your materials.

You also can use SEM/TEM to confirm the resluts.

I'm not sure how many times I have to keep saying this but SAXS gives you the particle size distribution not the average, and it gives you the shape. SEM/TEM are not 3D measurements, so in order to get a volume from an area you must make unrealistic assumptions about 3D shape. X-ray results can confirm SEM/TEM results but not the other way around. There seems to be a large misunderstanding of what modern x-ray techniques can measure.

Dear Jasper,

I think you can try the NanoSight technique for size determination of your particles. However, your particles need to be in suspension and the minimum size limit for NS is 10 - 40 nm, so if your material is smaller it might not be good to use NS. I think, if you have a possibility, you can use technique like that.

Best regards,

Michal W

SEM or TEM is the best method. XRD can be used as back up.

You can see the synthesis techniques as well as use of nanostructured metal oxides in papers mentioned below.

Integration of ZnO nanostructures with MEMS for ethanol sensor

H J Pandya, Sudhir Chandra, A L Vyas

http://www.sciencedirect.com/science/article/pii/S0925400511010689

A Simple Technique to Grow Long and Vertically Aligned CuO Nanowires on Oxidized Silicon Substrate

Hardik J. Pandya, Sudhir Chandra, A.L. Vyas

http://www.ingentaconnect.com/content/asp/nnl/2011/00000003/00000006/art00007

SEM and TEM are unable to give any information about 3D volume or shape. It is a 2D measurement. X-rays are able to probe a 3D volume with nanometer accuracy. What exactly don't you get about this basic fact? Again if you are ignorant about a particular technique, please do not comment. It will save you a lot of embarrassment and others a lot of misinformation.

my suggestion is: you should prepare a liquid dispersion (a colloidal dispersion) and apply Laser Doppler spectroscopy or DLS.

Dear friend, whether your material has a crystal size of 5 or 100 nm, it is still nanomaterial. By definition it is.

actually the definition of nano is

actually it is "< 100 nm", but I don't mind

no it's

I don't disagree, < 50 nm is also nano, sure ...

above 50 nm is not technically defined as nano. If you think about it, it makes sense.

XRD is not giving particles size . and it is not a suitable to measure particles size. some cases only XRD acceptable........go to DLS and FESEM, TEM.....in general DLS gives larger particles size than SEM and TEM, due to hydrodynamic radius was measured in DLS. but going to FESEM and TEM directly is not good idea because FESEM , TEM is per sample u may have to pay money so before going to imaging do DLS if u r getting particles size nearlly what u are expecting then go SEM, and TEM......but accurate particles size will be SEM because in TEM very smaall number or only few particles will observed but in SEM u can observed nearly more than 1000 particles atleast so consider it as particles size..........if u also get more than 1000 particles in TEM u can consider it also. it depends on ur particles size and sample.

i am sure there are lot of confusion in XRD....particles size, crystall size, grain size.....and finnaly confuse the researcher.

First and foremost you have to have some basic idea of what kind of materials do you expect to get out of your chemical synthesis is it, nanorods, nanoparticles or tubes etc. TEM / SEM may show agglomeration of you nanomaterials and XRD does not differentiate between an agglomeration, dispersed nanoparticle or a crystallite.

DLS as discussed before will give the hydrodynamic radius rather than the actual size.

As Lawrence discussed TEM is a 2D measurement and by that logic if your cylinders are standing upright then you may see circles distributed. But per your questions TEM result gives much larger particles than XRD. Just to make things clear, or you measuring your particle size using Scherrer's formula ?

Raj,

SAXS gives particle size as well as grain size. The misconception has been discussed in multiple questions here. X-rays are a much more powerful and accurate tool for determining particle and grain size distributions, shapes, clustering, etc on a statistically significant volume.

XRD data it is possible to calculate the crystallite size, particle size, not. or the particle size I recommend that you use TEM or SEM.

As you said you have particles between 5 and 50 nm, I recommend that you characterize your material for distribution of particle sizes of particles.

Wow. Just wow. I feel like im wasting my time.

I do not want to enter the discussion about the definition of nano, but more the one about the sample characterization.

As it was mentioned above, and in quite some of other topics here, make sure that you are aware of the fact that XRD can indeed give you acces to a size (e.g. via Scherrer's formula), but it is the CRYSTALLINE(coherent) part size, which is not necessarily the particle size (the 'particles' can have an 'amorphous' part as well, or can be composed of several smaller crystalline grains, ...). So a discrepancy between TEM/SEM (let's call it particle size) and XRD (size of crystallites) is not always a contradiction, since you are not necessarily looking at the same thing. Also, as it was mentionned above, SAXS experiments could give you acess to sizes, and, most importantly to corresponding distributions, all this with much better statistics than TEM/SEM, for which only a small area is investigated. In an X-ray experiment, areas of several 100 microns^2 up to several mm^2 can easily be illuminated and contribute to the signal.

Various techniques can give you various informations, it is always a good idea (in my opinion) to investigate your sample using several techniques if available, just making sure that you extract the right piece of information from each. And hopefully this will only make more 'complete' the image that you can get about your sample

Regards

cristian

you can also have a look at the topic

https://www.researchgate.net/post/Can_any_one_explain_the_broadening_of_XRD_peaks_of_nanoparticles_compared_to_those_of_the_corresponding_raw_materials?_trid=53a35f54d039b105168b4629_30

which gives also a lot of hints related to your question

Thank you Cristian, for bringing back sanity to this discussion.

Thank you all.

Using Scherrer's formula you may not take the values accurate. It gives the range. But in TEM we can measure very accurately about a particular particle. The particles size may not be uniform so the average size of the particle may vary in a range.  

I also want to know the answer

I would like to repeat for those who have not seen previous answers:

- XRD and Scherrer's formula can not tell you anything about *particle* size, but everything about *crystalline* structure and (with limited significance) *crystallite* size;

- for determining what is the *particle* size, you need to combine SEM or TEM and (in order to differentiate agglomerate from aggregate structures) Laser Doppler (or light scattering) in dispersions of your material.

And "nano" material are defined so that if particle size is