HOMO and LUMO energy levels determination is un important step to confirme organic materials application in OSCs
Cyclic Voltammetry data provides you one of the simplest method to know the HOMO and LUMO energy levels. Thus, once you have the two onset potentials (let us assume you are using the ferrocene redox pair as reference), the following empirical equations can be used:
HOMO = 4.8 + Eox(vs.ferrocene) [eV]
LUMO = 4.8 + Ered(vs. ferrocene) [eV]
However, I've seen -5.1 eV reported as the experimental constant for ferrocene, instead -4.8 eV
For further reference and a more detailed explanation you might consult the following paper:
https://www.researchgate.net/publication/264269067
Hope this answer will be useful for you.
As has been said, Cyclic Voltammetry and Differential Pulse Voltammetry are good ways to know the HOMO and LUMO, if your compound is in solution. Have you tried to dissolve your compound in uncommon solvents? Try with dichlorobenzene, DMF or DMSO, even if they are not always used for electrochemical analysis. If your compound is not soluble you can try with diffuse reflectance spectroscopy, which will give you an approximate band-gap.
I have worked finding the HOMO-LUMO energy levels of some molecules using different approaches::
Article Electric-field Induced Bistability in Single-Molecule Conduc...
Article Multiscale Approach to the Study of the Electronic Propertie...
Also, I found the following article very clarifying about band-gaps, HOMO-LUMO levels and related terminology:
Article Mind the gap!
Thank for your halpful informations, we worked with the CV method and it provided us with very efficient results for the determination of HOMO and LUMO levels, where the analyzed molecules showed their remarkable performance in organic solar cells as active layers or as buffer layers, here are some articles published :
- DOI:10.1142/S0218625X18501160
- DOI: 10.1142/S0218625X15500250
- DOI: 0.1051/epjap/2015140184
- DOI: 10.1016/j.sse.2014.11.006
the difficulty I encounter is that the CV method is reserved only for soluble molecules and polymers, however I wish to determine the HOMO and LUMU levels of the non-soluble organic molecules that I deposit in a thin layer with the technique of vacuum sublimation
By Cycle Voltammetry can provide very important information about HOMO and LUMO levels .
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