Hi, Research gate! I need HELP!
I'm trying to prepare nickel nanoparticles for my devices. I use the commonly used method from the article (DOI: 10.1002/adma.201405391). Briefly, 20 mmol Ni(NO3)2·6H2O were dissolved in 20 mL of deionized (DI) water to obtain a dark green solution. Then, 4 mL NaOH solution (10 mol L−1) was slowly added into the solution while stirring. After being stirred for 20 min, the colloidal precipitation was thoroughly washed with DI water three times and dried at 80 °C overnight under vacuum. The obtained green powder was then calcined at 270 °C for 2 h to obtain a dark-black powder. The NiOx NPs inks were prepared by dispersing the obtained NiOx NPs in DI water/IPA (3/1, v/v) with a concentration of 20 mg mL−1, stirred for 30 min.
However, the nanoparticles coagulate (precipitate). I can't seem to get the suspension.
What are the subtleties of synthesis? What am I missing? What should I pay attention to?