Effective diffusion lengths for minority carriers in solar cells as determined from internal quantum efficiency analysis

We introduce a general relationship between the effective diffusion length LQ of solar cells derived from spectral quantum efficiency Q and the effective diffusion length LJ that determines the saturation current j0=qn0D/LJ of the diode in the dark. The general relation LQ⩾LJ holds in the presence of grain boundaries and of spatially nonhomogeneous doping profiles. We find the relation LQ=LJ for solar cells without potential fluctuations at the collecting junction.