I am working on dilute magnetic semiconductors, cobalt doped ZnO prepared using sol gel spin coating method. when I use DMF (dimethylformamide) as solvent , I get easily dissolving up to 15% without heating and without any stabilizer. Is there any way that I could use DMF as solvent instead of traditional ethanols? And can I use my thin film samples to study them for magnetic characterization?
I have not seen any paper reporting magnetism with DMF as far as my survey is concerned, only with methoxyethanol.
Indeed the solubility of zinc acetate in ethanol is low, and it increses gradually with the addition of water. I do not think there is any restriction of water addition for the synthesis of DMS (speially for Co-doped ZnO). The magnetic behavour of the sample should not change substantially on adding water in the sol.
On the other hand, fabrication of metal oxide NPs using DMF as solvent has been demostrated by Prof. Diaz´s group (Prof. David Diaz, Facultad de Quimica, UNAM, Mexico; e-mail: [email protected]). However, selection of solvant affects the grain size, and the final size of NPs (in case of coolidal samples). The princpal reason for using a particular solvent for thin film fabrication (using sol-gel technique) is to adjust the viscocity of the gel.
Solubility of compounds always varies from solvent to solvent. Instead of ethanol, if DMF is used there should be problem in gel formation.
Please be sure that water content in the two solvents is not a drawback.
Indeed the solubility of zinc acetate in ethanol is low, and it increses gradually with the addition of water. I do not think there is any restriction of water addition for the synthesis of DMS (speially for Co-doped ZnO). The magnetic behavour of the sample should not change substantially on adding water in the sol.
On the other hand, fabrication of metal oxide NPs using DMF as solvent has been demostrated by Prof. Diaz´s group (Prof. David Diaz, Facultad de Quimica, UNAM, Mexico; e-mail: [email protected]). However, selection of solvant affects the grain size, and the final size of NPs (in case of coolidal samples). The princpal reason for using a particular solvent for thin film fabrication (using sol-gel technique) is to adjust the viscocity of the gel.
thank you all for your worthy responses..
@Arindham: my motive is constrained upto sol formation only for coating as i am working on thin films. do you think that the transparent sol i get after stirring the salt in DMF with some aging will not be sufficient for coating?
@Umapada pal:sir please provide me the link for the paper you mentioned. and you have said that addition of water will not change the magnetic behavior. but actually i am taking pure solvent only. DMF does dissolve it completely and the sol stays transparent even after the aging of more than a week. do you want to say that if i use methoxyethanol as a solvent then i should add water to make the solute dissolve completely without any suspension or colloid. but as far as i have seen papers.. nobody talks about the addition of water when dealing with adding acetate salt for cobalt and zinc in methoxyethanol.. they all simply drop the sol on substrate. how the gel come into the play??
You can try to use cobalt(II) acetate tetrahydrate which is very soluble in water (380 g/L at 20 ºC) or to use as solvent a mixture with ethylene-glycol /water (1:3)
@virginia: mam, i have heard that ethylene glycol precipitates the mixture of zinc and cobalt acetate. but i need to prepare a clear sol for thin film deposition. the proportion you suggested (water and EG 3:1) will yield me a transparent sol that can be spin coated? please suggest me your valuable comment.
@Sunil Kumar: Here is a reference on the use of DMF for ZnO NP synthesis. "J. Németh, G. Rodríguez-Gattorno, D. Díaz, A. R. Vázquez-Olmos, I. Dékány* Synthesis of ZnO Nanoparticles on Clay Mineral Surface in Dimethyl Sulfoxide Medium. Langmuir. (2004) 20, 2855-2860".
As I mentioned earlier, using DMF control of viscosity of the sol might be difficult. But the hydrolysis of zinc acetate can proceed to grow ZnO.
May I ask you if you know why would not be soluble my dihydrated zinc acetate . I asume 1st. It is not 100% and 2nd. It is adulterated but with what?
Thanks in advance for your attention and response.
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