C.3 Open circuit voltage for p-n junction solar
cells
The V oc for a p-n junction solar cell generating a photocurrent density J L is given by
With the expression for the saturation current density from Eq. (C.18), this becomes
For W ≪ L we can use the approximation tanh(W/L) ≈ W/L. Combined with Eq. (C.20),
we find
From this result we can draw an important conclusion: the thinner the base, the larger the
V oc !
cells
The V oc for a p-n junction solar cell generating a photocurrent density J L is given by
With the expression for the saturation current density from Eq. (C.18), this becomes
For W ≪ L we can use the approximation tanh(W/L) ≈ W/L. Combined with Eq. (C.20),
we find
From this result we can draw an important conclusion: the thinner the base, the larger the
V oc !