My samples (solar cell) have graphene on the two sides, but the back face is full of oxides and impurities. I imagine that the conductivity is poor on that side compare to the other one, clean and quasi-perfect. What will happened if I try to measure the characteristics of the cell on short current and open circuit voltage ? How the charges (electron and holes) will distribute themselves on the two faces ?
I suspect that the result would be like examining the output of a large number of small parallel connected cells all with different characteristics. I doubt whether it would give much useful information. It will be impossible to determine which parts of the IV plot are being produced by which part of the cell.
We struck a similar problem with the rear contact type Sunpower panels some years ago. The solution was to ground the positive at the inverter to act as a 'drain'. Ultimately the panels simply reduced supply to nil. In the end there was no current flow at all.
I am not sure if this is the same problem but it might help.
Dear Yann,
welcome ,
Adding to the colleagues, if i understood you correctly, The backside of your cells suffers from the presence of layer with high resistivity.
The effect of this high resistivity layer is to act as a relatively high resistance in series with the rest of the cell. If the rest of the cell is working properly with a good rectifying junction then your short circuit may be smaller than the photocurrent. The open circuit voltage will be not affected, the fill factor will suffer very much and the I-V curve in the forth quadrant will tend to triangular case.
Best wishes
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