I am depositing TiO2 thin film onto glass/FTO using spin coating technique.I am using 2gm of TiO2 powder,8ml ethanol,2 ml acetyl actone and 1ml titanium isopropoxide.The solution is stirred for 8 hr using magnetic stirrer and then using a spin coater (600 to 3400rpm) I am coating the film on glass/fto.I am getting very thin and uniform thickness film if
TiO2 but when annealed the film for several hrs at about 250 to 300 degree celsius the film deposited is not able to adhere to the substrate.When touched with finger the film is developing scratches.Can anyone tell me solution to this problem.
I would recommend that you try treating the surface of the substrates with UV-ozone which usually improves the surface energy and coatibility of the substrates. 10 minutes should be enough.
Are you sure about cleanness of your substrate? Any contamination on the substrate surface can cause interfere in film adhering. Also pretreatment of substrate as @Gunel Huseynova said, may be helping.
Also let the substrate to be cold in the furnace medium, after the treatment.
Yes I am sure about cleanliness of substrate but still I will take care about the said.Thank you for your valuable suggestions.
Dear Sachin Padwal
Are you using absolute ethanol or ethanol 96%?
Best regards
Yes dear, you should change to ethanol 96% .The 4% water in ethanol is necessary for titanium isopropoxide hydrolysis completion:
Hydrolysis reaction
Ti(OR)4 + 4H2O → Ti(OH)4 + 4ROH
where R is i-propyl
Best regards
Dear Sachin Padwal,
can you test a way to slow down, before the annealing, thermal pre-treatment processing ?
In other words, can you
1) increase the oven's Temperature very slowly, and/or can you
2) cover your sample, in order to protect it from a (possible) Temperature overshooting ?
I will do the things as per your suggestion dear sir@Ioannis Samaras.
I am attaching one good article from Beijing University for your kind reference. Hope it help.
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