A new method for accurate measurements of the lumped series resistance of solar cells

Measurements of the series resistance R_S are important for the localisation of dominant loss mechanisms in photovoltaic devices. The new measurement technique presented in this work uses the measured “J_SC-V_OC curve” of a solar cell as an approximation to the unknown R_S-corrected I-V curve and determines the “lumped series resistance” in dark and illuminated operating conditions (R_s.dark and R_s.light) from the voltage shift between the “J_SC -V_OC curve” and the dark and illuminated I-V curve, respectively. Owing to multidimensional effects in practical devices, the lumped series resistance depends on the operating condition of the cell (i.e., dark or illuminated I-V measurements) and on the current density flowing through the device. This work not only provides a new, powerful method for the determination of the lumped series resistance of photovoltaic devices, but also considerably improves the general understanding of ohmic power loss effects in silicon solar cells