Three-parameter tube model of current spreading in solar cells

This paper improved three-parameter model for calculating the IV-curves of photovoltaic converters is proposed. The model is based on dividing the solar cell into current tubes, each of which contains a $p$–$n$-junction and three resistances – vertical, lateral and an additionally introduced. To determine the model parameters, dark IV-curves and electroluminescence (EL) maps obtained by passing current through the edge of the upper contact grid of a solar cell are used. Using the model, the experimental characteristics of two Ga$_{0.79}$In$_{0.21}$As photovoltaic converters with different current collection bus geometries were analyzed and it was shown that the model allows one to describe experimental IV-curves and determine parameters characterizing the quality of the contact grid.