I would say that it really depends on the specific applications. Nanoparticles (0d) and nanofilms (2d) also are widely used nanomaterials in a lot of areas. Some researchers use those nanowires perhaps because they are easy to be fabricated or even are commercially available. For 3D nanostructures, most of them need sophisticated nano-scale patterning technique, which are quite complicated.

Dear Sang-Yun Kim,

there are different reasons to coat 1-dimensional structures. This is the field of core-shell nanowires and I see the following reasons:

- A shell can reduce the surface recombination.The surface to core volume ratio is very high and dominates transport properties.

- A shell can effect carrier confinement like in the case of a quantum well. The wave function is localized in the center of the wire and minimizes the contact with the surface.

- The shell allows band structure engineering. Due to the difference in the lattice constant between shell and core you can realize a strain and consequently a shift of the band extrema what changes gap energies and band overlapping.

So, you have a tool box to influence wire properties in a wide range.

With Regards

R. Mitdank

1D materials can be coated over nanomaterials if you need directional percolation of electrons for various photocatalysis or sensing application. Otherwise nanoparticles and thinfilms can be applied as coatings for applications like corrosion protection.

Ramsha Khan Thank you for your answer. By the way I have other question. You mentioned 'directonal percolation'. Does it mean we can control the direction of 1D nanowire when we coat with 1d material? If possible, how? Normally in our lab we used dip-coating or spray coating or spin-coating. And All result showed random direction of 1d nanomaterials. If you have time, let me know then it will be very helpful for me. Thx.

Rüdiger Mitdank Your answer gives me new perspective. Thank you.

Yang Li Yeah.. That's right. Commercialized rGO flake's quality is not stable yet.. and if we use 0d meterials, maybe we need it a lot for making conductive network. It was very simple!! Thank you!

I read that in the following article:

T. J. Athauda, J. G. Ne, L. Sutherlin, U. Butt, and R. R. Ozer, “Systematic Study of the Structure − Property Relationships of Branched Hierarchical TiO 2 /ZnO Nanostructures,” 2012.

It might help you!