D. Macdonald et A. Cuevas, Reduced fill factors in multicrystalline silicon solar cells due to injection-level dependent bulk recombination lifetimes, PROG PHOTOV, 8(4), 2000, pp. 363-375
Recombination lifetimes of multicrystalline silicon solar cell precursors h
ave been measured experimentally, as a function of injection-level, and mod
eled using Shockley-Read-Hall statistics, The expressions for the variable
lifetimes are then used to predict the final cell open-circuit voltages and
fill factors using a simple analytic method, When accurate recombination l
ifetimes measurements are possible, the predicted parameters match well wit
h the measured values on finished cells. The cells ave shown to be limited
by the presence of bulk recombination, which not only limits the open-circu
it voltage through lower lifetimes, but also reduces the fill factor due to
a strong injection-level dependence around one-sun maximum-power condition
s, It is shown that such non-ideal behaviour cannot be adequately explained
by junction recombination. The specific effect of interstitial iron, an im
portant impurity in silicon, on voltages and fill factors is modeled numeri
cally and discussed, Copyright (C) 2000 John Wiley & Sons, Ltd.