Numerical modeling of loss mechanisms resulting from non-uniform illumination in multijunction concentrator solar cells

AbstractQuasi-3D distributed emitter models utilizing a unit cell-based methodology have been successfully applied to the analysis of lateral current flow in solar cell emitter layers. However, the analysis of the specific loss mechanisms resulting from this flow has not been given adequate attention. In this work, a quasi-3D model for the simulation of effects related to the lateral flow of current in a solar cell emitter layer, particularly under non-uniform illumination, is developed. The model is applied to a specific case in which a GaInP/GaAs-like two-terminal solar cell is illuminated with a Lorentzian irradiance pattern, which is the expected pattern for parabolic trough concentrator. It is shown that bias-point loss, which results from the variation in the local operating condition of the cell, is significant under highly non-uniform illumination at low-moderate optical concentration. Understanding this loss mechanism is useful in considering trade-offs related to the design of the optical concentrator system, as well as, the design of a grid electrode pattern for maximum power output. Copyright © 2013 John Wiley & Sons, Ltd.