knjiga solarna energija dobra

98 THE PHYSICS OF THE SOLAR CELL
0.90
4.0
0.85
FF
0.80
3.8
0.75
3.6
V OC
[V], FF
0.70
I SC
I SC
[A]
0.65
3.4
0.60
0.55
V OC
3.2
0.50
3.0
10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7
S BSF
[cm/s]
Figure 3.18 Effect of the back-surface field recombination velocity on solar cell performance. All
other parameters are from Table 3.2
Table 3.3
No grid (s = 0)
Full grid (s = 1)
Special cases of S F,eff
S F,eff = S F
S F,eff →∞
Dark (G = 0)
Short circuit (V = 0)
Vlarge(≈V OC )
S F,eff = S F + sD p /W N
1 − s
S F,eff = S F
S F,eff = S F + sD p /W N
1 − s
3.4.8 An Analogy for Understanding Solar Cell Operation:
A Partial Summary
The following analogy illustrates the importance of minimizing all sources of recombination
in the solar cell. 4 Imagine a funnel that has a variety of holes of different shapes
and sizes in it. It also has a stopcock at the bottom for controlling the flow of liquid
4 This analogy was developed on the basis of discussions with Professor Richard J. Schwartz of Purdue University,
West Lafayette, Indiana.