Generally, in inorganic solar cell (eg, Si), if number of grains increases, the open circuit voltage decreases due to increase in the recombination losses of charge carries at grain boundaries. While in perovskite solar cell open circuit voltage is increase with increasing the number of grains?
Dear Firoz,
welcome,
Would you please give a citation to follow the details of the subject in order to give a correct account on this findings.
I think that the most effective parameter here is the dependence of the energy gap on the grain size when the size enters in the manometer range. As the grain size decreases the energy band increases. Since the the open circuit voltage depends on the energy gap where it is specifically increases with the energy gap, so as the grain gets finer the open circuit voltage increases.
In case of the grain size sufficiently large not to affect the energy gap, the grain size will only increase the recombination current if the grain boundaries are not passivated and thereby decrease the open circuit voltage.
So, such phenomenon can be observed also metallic material. Therefore i asked you to give a reference to see exactly what is the grain size.
Best wishes
Dear Mr. Khan,
in the field of EMC the grain size effect is very important. We have the great EMC absorption effect over the relaxation dependence. With a increasing the grain size we have a great dampring effect over the relaxation term in the landau system.
This effect may be is analoge effect in the solar technics.
Sincerely Yours
F. Gräbner
In DSSC the increase of Voc with the increase of cation size can be related to the
decrease
of the recombination of electrons in the conduction band of
TiO2 with I3
in the electrolyte at the vicinity of the TiO2 electrode and also to the shift of the conduction band edge which result by the adsorption of cation
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