front metal contact (Ag, Al or Au)
solar cell such
Ag/SnO2/Si/Al
I presume you mean the front contact grid of a silicon solar cell ( but that is not mentioned in the question).
For such contacts, the area must be minimised ( see response from T Walther above). In addition, for any silicon device, Au is always avoided since it is a mid-gap trap in silicon i.e. the rate of (deleterious) electron hole recombination is high. Au will therefore cause progressive degradation of silicon solar cells.
Due to their good conductivity the penetration depth of EM waves into metals is small and their reflectivity high (>>90%). So they are commonly used as back contacts; any coverage on the front side will mean a lowering of the DQE by about the fraction covered and should hence remain minimal (
Metalization of solar cells influence the solar cell behaviour. Not only from the geometrical point of view (optical) but also the recombination rates, local field etc....depending of the material used.
You might want a low specific resistivity for your metal contacts. If you are working below 250°C (no or just low temperature annealing) conductive silver, gold or platinum show almost the same low specific resisitvities. Working with temperatures >250°C concerning the specific resistivity you should stick to conductive gold!
For all other influences concerning the solar cell see the answers above.
Screen-printing provides an economically attractive means for making Ag electrical contacts to Si solar cells . but the use of Ag substantiates a significant manufacturing cost, and the glass frit used in the paste to enable contact formation contains Pb. To achieve optimal electrical performance and to develop pastes with alternative, abundant and non-toxic materials, a better understanding the contact formation process during firing is required.
I presume you mean the front contact grid of a silicon solar cell ( but that is not mentioned in the question).
For such contacts, the area must be minimised ( see response from T Walther above). In addition, for any silicon device, Au is always avoided since it is a mid-gap trap in silicon i.e. the rate of (deleterious) electron hole recombination is high. Au will therefore cause progressive degradation of silicon solar cells.
Yes, it can changes the parameters of solar cells, as Voc, Jsc, F.F, Rs and Rsh, because of its different work function, conductivity, interface traps and so on. As it mentioned above it depends on the material you used for solar cells.
Simple answer, YES.
Please, first read up on work function, electron affinity and electrochemical potential (Fermi energy).
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