I am performing cyclic voltammetry in an organic environment. My system is comprised of acetonitrile as my solvent with tetrabutylammonium hexafluorophosphate as my supporting electrolyte, and ferrocene as my internal reference. I am using a glassy carbon, Ag/AgCl, and Pt wire as my working, reference, and counter electrodes respectively.
The problem comes in with my calculating the HOMO/LUMO levels of P3HT and PCBM. I have found countless equations with different ways to make these calculations but either my system is flawed or the equations are, because I am unable to reproduce the literature values for P3HT or PCBM.
The most 'logical' of the methods that I have stumbled upon is this;
Eox(vs. Fc) = Eox(vs. Ag/AgCl) - 51/2(Fc vs. Ag/AgCl)
Eox(vs. SHE) = Eox(vs. Fc) + 0.4V
Eox(vs. vacuum) = Eox(vs. SHE) + 4.44V
E(HOMO) = e * Eox(vs. vacuum)
but I don't know if that is the "correct" method.
I've attatched some of my spectra for reference, with Taph being my supporting electrolyte.
Can anyone offer any guidance?
Dear James,
I am sending you one publication that might help you.
Regards
Marina
Ups, thats my paper :)
Well, you know I really dont like there are so many different results for CV measurements. You need to be consistent with your system and electrodes and so on. your calculations are ok, but your CV looks strange. Did you put both Fc and P3HT to the same solution? P3HT is a p type material you can measure Ionization potential (IP) and then you correct according to these values. I recently calculated electron affinity of PCBM film as 3.95. This may vary to the batch,purity of your PC60BM between 3.8-4.1 I guess. And people just report solution and film CVs mixed up, which is very misleading for all the other people.
hi james. Sorry to disturb you. Do you now another way to measure the HOMO/LUMO levels of P3HT except cyclic voltammetry؟
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