Accurate opto-electrical modeling of multi-crystalline silicon wafer-based solar cells

• Realistic input parameters for opto-electrical modeling of multi-crystalline silicon solar cells were extracted by fitting measured characteristics of a fabricated cell.
• Auger, Shockley-Read-Hall, radiative, surface recombination mechanisms and Fermi-Dirac statistics were taken into account in the ASA-based iterative calibration procedure.
• Extracted values of front surface recombination velocity, Auger coefficients, minority carrier diffusion length were in good agreement with theory.
• Opto-electrical losses in the investigated mc-Si solar cell were determined and quantified.
• Major electrical losses: emitter Auger recombination and front surface recombination. Major optical losses: optical reflectance and parasitic rear side absorption.

Modeling of multi-crystalline silicon solar cells has been recently widely used for fast and cost-effective performance improvements. The optimization of device performance requires deep understanding of the opto-electrical losses in a fabricated solar cell. To carry out trustworthy simulations for performance analysis and optimization, the simulation program has to be calibrated to the performance of the fabricated device. In this article an accurate opto-electrical modeling of multi-crystalline silicon solar cells is presented. Specific issues that arose during the calibration process were addressed, such as the optical model describing light scattering due to wafer texturing, the electrical modeling of heavily doped emitter and the opto-electrical modeling of the back surface field. Calibrated model parameters, obtained from theory or measurements, led to an excellent simultaneous matching between simulated and measured reflectance spectrum, internal and external quantum efficiencies and dark and illuminated current–voltage characteristics of the multi-crystalline silicon solar cells. In addition, opto-electrical losses in the investigated solar cells were determined and quantified.