Hello folks,
I am trying to make lead chalcogenide coatings over a glass slide using CBD. However, the coatings I got are very patchy and rough! I was wondering if this was an adhesion issue and should I clean my glass substrates more elaborately? (Currently, I ultrasonicate it in an ethanol/acetone mix for 20 mins and then clean it with DI water). Or does it have to do something with the precursors, pH and temp ? I have attached images of coatings for your reference. Thanks for taking the time out to read this and help me.
Your issue could be adhesion related - I'm not too familiar with your material, but it is advisable to etch your substrate rather than just cleaning it. You can use piranha solution (3:1 H2SO4:H2O2), but read carefully about safe handling as it is very corrosive. If you use this method, make sure to remove any organic material via cleaning and rinse with H2O multiple times under sonication before treatment
https://en.wikipedia.org/wiki/Piranha_solution
A clean surface is very important for thin film growth. You may check with the suggestion as Brian has provided. In addition, use a different substrate, say FTO-coated glass or Si etc after proper cleaning. The other substrates will give you an idea whether you should change your bath parameters. If the deposition still results in agglomeration, check with the precursor concentration, temperature, pH etc. Sometimes you might need to change the precursor salt.
Thanks for the insight guys!
I tried using Nochrome mix and it now I get better coatings. Still patchy though.So guess I'll try a different substrate as suggested by Chandan.
I came across a paper where they recommended soaking the acid cleaned glass substrate into a dilute Tin Chloride solution. Was wondering if you guys knew how this step would be helpful. Any insights?
Your best bet is, as Chandan suggested, using a high quality functionalized glass substrate like FTO, which is commercially available and not unreasonably pricey in small amounts. You could alternatively use a homemade metal oxide coating like SnO2, TiO2, ZrO2, etc. that have established synthetic procedures in the literature and are transparent when made with nanoparticles.
The transparent substrate will help you see the quality of your coating. After it is optimized then you can work out the kinks with regular substrate. I have not heard of tin chloride treatment, maybe this aims to functionalize with a thin tin oxide layer?
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Thin Films and Nanotechnology