Voltage-Dependent Photocurrent and Crossover Behavior in Crystalline Silicon Solar Cells

Abstract

Contrary to the conventional assumption of voltage-independent photocurrent, we show that the photocurrent in monocrystalline silicon p-n junction solar cells depends explicitly on voltage. By applying physically realistic boundary conditions to the classical p-n junction solar-cell model, we derive an analytical expression for the photocurrent that incorporates both the built-in potential and the applied voltage. The model predicts a crossover point between the dark and illuminated $I-V$ characteristics, irrespective of illumination intensity. This prediction is experimentally validated by lock-in measurements on a commercial monocrystalline silicon solar cell. These results establish a more consistent understanding of the quantitative role of the built-in potential in the photovoltaic effect.

arXiv comment16 pages, 4 figures