I want to use silver thin film on glass as electrode. How can I do cyclic voltammetry using this? What should be the setup?
Dear Venkatesh,
no problem. You simply have to contact the metal somehow, and eventually coat the contact areas to avoid electrochemical side reactions at the contacts. You will find a sketch of a cell that we have used for combined X-ray and electrochemical experiments as attachment (J. Electroanal. Chem. 381 (1995) 113). We simply glued a PTFE (Teflon) body on the thin film electrode to make the contact tight, and electrically contacted the electrode from the outside. The electrolyte compartment is closed by some mylar or Kapton (polyimide) windows to the fron and back, and the cell is open from the top to introduce the electrolyte as well as RE and CE electrodes. We also fabricated closed cells on the same basis with the opportunity to bubble the electrolyte with Ar or N2 to remove oxygen traces in the liquid.
I made some bad experience with evaporated films on glass and Si-wafers, because the adhesion of the films on the glass is poor. Simply by applying a potential to the thin film electrode, the stress substantially increases and the about 20-50 nm thin film peels off the substrate. Electrochemistry is hard then. You may improve the adhesion by a promoter such as some small amounts of Cr or Ti on the glass prior to the Ag evaporation, but still the cyclovoltammetry is difficult. However sputtering the Ag on the substrate gave good results - the adhesion is perfect, you may almost fully oxidize the silver without any peeling of the Ag from the substrate.
Hope this helps, good luck with your experiments, and let me know if you need further assistance
Dirk
Dear Venkatesh,
no problem. You simply have to contact the metal somehow, and eventually coat the contact areas to avoid electrochemical side reactions at the contacts. You will find a sketch of a cell that we have used for combined X-ray and electrochemical experiments as attachment (J. Electroanal. Chem. 381 (1995) 113). We simply glued a PTFE (Teflon) body on the thin film electrode to make the contact tight, and electrically contacted the electrode from the outside. The electrolyte compartment is closed by some mylar or Kapton (polyimide) windows to the fron and back, and the cell is open from the top to introduce the electrolyte as well as RE and CE electrodes. We also fabricated closed cells on the same basis with the opportunity to bubble the electrolyte with Ar or N2 to remove oxygen traces in the liquid.
I made some bad experience with evaporated films on glass and Si-wafers, because the adhesion of the films on the glass is poor. Simply by applying a potential to the thin film electrode, the stress substantially increases and the about 20-50 nm thin film peels off the substrate. Electrochemistry is hard then. You may improve the adhesion by a promoter such as some small amounts of Cr or Ti on the glass prior to the Ag evaporation, but still the cyclovoltammetry is difficult. However sputtering the Ag on the substrate gave good results - the adhesion is perfect, you may almost fully oxidize the silver without any peeling of the Ag from the substrate.
Hope this helps, good luck with your experiments, and let me know if you need further assistance
Dirk
How do you want coat the glass slides with silver? Remember that silver forms silver islands on glass slides, when deposited in a thin layer; such Silver Islands Films have much bigger surface to volume ratio than a planar electrode and also exhibit some other unique properties, like localized surface plasmon resonance, that can interfere with your experiment.
@ Nikodem: Yes, in principle you are right, but if the deposition parameters are correctly chosen in terms of substrate temperature during deposition, and a post deposition annealing, smooth films may be obtained either by evaporation and by sputtering for a thickness of about 20 nm at minimum. Thinner films are probably discontinuous with the problems mentioned by Nikodem, but thicker films are continuous revealing a roughness in the order of about 1-2 nm ...
Dirk is completely right, regarding the minimal thickness of the silver film, although this concerns only film deposited using physical vapor deposition techniques. Wet-chemistry methods, as reduction of silver nitrate onto a glass slide, might be tempting but they will result in a continuous, yet corrugated film, and no annealing nor any other similar process will change that (there are several works about SIF annealing in other to enhance its plasmonic properties).
Thanks a lot for the valuable input Dirk and Nikodem.
@Dirk- That is what exactly i want to do. I want to do cyclicvoltammetry with Silver thin film electrode. this silver film is 50nm and also has the Cr anchoring.
Is it possible to do it? any advice on the same?
I would start with open circuit potential, and small scan speed (1-5 mV/s), if the electrode "survives", i.e. if it does not peel off the surface, then you can try to increase the scan speed, or to apply voltage steps to do chronoamperometry etc. Good luck.
Use an alligator clip to attach to silver on glass material as working electrode and dip it in solution. I have tried gold and Cr on glass for CVs in ferrocene soln. The gold film actually becomes unstable, I could see color of film changing.
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