Experimental investigation and theoretical modeling of textured silicon solar cells with rear metallization

Abstract

Crystalline Silicon (c-Si) remains a dominant photovoltaic material in solar cell industry. Currently, scientific and technological advances enable producing the c-Si solar cells (SCs) efficiency close to the fundamental limit. Therefore, combining the experimental results and those of modeling becomes crucial to further progress in improving the efficiency and reducing the cost of photovoltaic systems. We carried out the experimental characterization of the highly-efficient c-Si SCs and compared with the results of modeling. For this purpose, we developed and applied to the samples under investigation the improved theoretical model to optimize characteristics of highly efficient textured solar cells. The model accounts for all recombination mechanisms, including nonradiative exciton recombination by the Auger mechanism via a deep recombination centers and recombination in the space-charge region. To compare the theoretical results with those of experiments, we proposed empirical formula for the external quantum efficiency (EQE), which describes its experimental spectral dependence near the long-wave absorption edge. The proposed approach allows modeling of the short-circuit current and photoconversion efficiency in the textured crystalline silicon solar cells. It has been ascertained that the dependences of the short-circuit current on the open-circuit voltage and the dark current on the applied voltage at V < 0.6 V coincide with each other. The theoretical results, as compared to the experimental ones, allowed us to validate the developed formalism, and were used to optimize the key parameters of SCs, such as the base thickness, doping level and others. In this work, we have further generalized and refined the analytical approach proposed and used by us earlier to analyze high-efficiency solar cells and model their characteristics.