Comparison of Terminal and Implied Open-Circuit Voltage Measurements

Illumination intensity dependent open-circuit voltage measurements, commonly known as Suns- $V_{{\rm{oc}}}$ , are often used to measure the current–voltage characteristic of a solar cell without the impact of series resistance. Deviations at high illumination levels between Suns- $V_{{\rm{oc}}}$ measurements and contactless measurements, such as injection-dependent photoluminescence, have previously been reported. These deviations are analyzed in detail in this paper and shown to cause significant errors when converting Suns- $V_{{\rm{oc}}}$ data to injection-dependent minority carrier lifetimes. Numerical modeling is used to identify shading and contact recombination as main causes of these deviations. Experimental data are used to demonstrate the magnitude of this effect for a range of different cell types.