Dear Urvi Lad , it is actually possible to perform HRTEM of liquid samples and particularly water samples, but you would need a liquid cell holder for your sample, something that is not always available in most HRTEM facilities. Water will be vaporized under the high vacuum conditions of the TEM column and therefore the cell holder must be a vessel that safely seals the liquid sample. This sealed cell and the the liquid suspension must be transparent to the e-beam, so both the cell walls or membranes must be very thin and the liquid sample in between must be very thin too.

Often this kind of liquid cells are useful when you want to study some specimen which need the liquid (water) to observe the process we are interested on, generally biological samples.

Carbon nanodots should withstand the water removal process, then they could be dispersed in ethanol or other volatile solvent that allows to use a conventional TEM grid to deposit your sample, let it evaporate the solvent and proceed with the HRTEM analysis of a dry sample. This is the more common procedure and for instace what Papaioannou et al. reported in the following paper:

https://www.nature.com/articles/s41598-018-25012-8#Sec3

Hope it helps.

You can easily do the analysis of your sample by using TEM grids. you need to put a drop of your sample on the grid and let the water evaporate (oven @50 degrees).

Yes, you can do your HRTEM . Firstly you sonicate your samples and make a grid by putting a drop of your sample and wait for some time to dry out or evaporate the grid and then analyze your sample with the microscopy of TEM facility.