We are using commercial screen-printed gold electrodes (SPGE) which have a low charge transfer resistance (RCT) deducted from the bare electrode measurement by electrochemical impedance spectroscopy (EIS).
We tried also to fabricate our own electrodes by sputtering, however, the RCT of the bare electrodes is much higher.
1/ Does this mean that our electrodes are worse than the SPGE?
2/ Can this be due to a smaller surface area of the WE?
3/ Is it better to use graphene oxide (GO) or reduced graphene oxide (rGO) to modify the SPGE? (rGO is more conductive than GO)
1-Higher resistance isn't necessarily "worse", especially if you want it to increase in response to a target. That said, no one wants to buy a higher resistance electrode.
2-yes. Resistance is inversely proportional to the cross-sectional area of the current flow.
3-What's better depends on your application. There's more than one redox reaction happening at your interface, and charge transfer resistance gives unspecific results from all of them. If you're just playing the usual game of "my graphite is better than yours" then sure, buy the more expensive stuff. If you actually want to detect an analyte, then only well-controlled experimentation will answer the question for your case. I found in one study that lower resistance "graphene" electrodes didn't react as much as higher-resistance carbon electrodes after functionalisation.
As an aside: why would you put carbon onto a gold electrode? It's cheaper and less risky to just buy carbon electrodes.
Thank you very much for your reply dear Anne Sawhney
Concerning your last question, you are right, but gold is used because it can accelerate electron transfer and enhance sensitivity, and it can be bonded to antibodies through the thiol group.
- Badges
- Science topic
- Similar topics
- Correction