I have CdSe/Zns and CdSe QDs. The ligand is OA (Oliec Acid) and the QDs are dispersed in nonpolar solvant (like: Hexane,chloroform)
I want to form QD layer (up to 200nm) on the surface of ZnO thin film, but the QDs don't like the surface of ZnO.
I have the same problem with ZnO nanowires, the adsorption/loading of QDs to nanowires is very low.
I know that it is the ligand which is playing the big role here?
Can any one recommend a suitable ligand and accordingly a simple solution based ligand exchange process to me?
Thanks
You can try it by electrodeposition. We have deposited thin layer of Ni on the top surface of Ag nanowires. Check our recent paper:
https://www.researchgate.net/publication/263393150_AgNi_CoreShell_Nanowire_Network_for_Robust_Transparent_Electrodes_Against_Oxidation_and_Sulfurization
Article Ag@Ni Core–Shell Nanowire Network for Robust Transparent Ele...
essentially you need a ligand that has a carboxyl group (to attach to the ZnO) and a thiol group to attach to the Cd. Try mercaptopropanoic acid, works like a charm!
Carboxyl group react with ZnO and forms zinc carboxylate at the surface. Ligands that have carboxyl group dissolve zinc ions. I don't think these ligands work for this purpose. Oleic acid also has carboxyl groups but, it does not show good attachment to ZnO surface.
Please see references below:
1. Studies of the Adsorption Process of Ru Complexes in Nanoporous ZnO Electrodes
2. Phase transitions of adsorbed carboxylic acids on zinc oxide and of zinc soaps.
Infrarcd and X-ray diffraction investigations
I have attached CdSe QDs on ZnO nanorods using mercaptopropanoic acid. It was very effective, with good mechanically as well as electronic properties (effective charge transfer). Details are available in my PhD thesis and one of my publications, both are available for download in RG.
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