A Predictive Optical Simulation Model for the Rear-Surface Roughness of Passivated Silicon Solar Cells

作者：Woehrle Nico; Greulich Johannes; Schwab Christoph; Glatthaar Markus; Rein Stefan

来源：IEEE Journal of Photovoltaics, 2013, 3(1): 175-182.

DOI：10.1109/JPHOTOV.2012.2215013

• Dielectric films
• free carrier absorption (FCA)
• optical losses
• optical reflection
• ray tracing
• rough surfaces

In this paper, we introduce a predictive, physics-based model, i.e., the so-called tilted-mirror model (tm-model), for optical modeling of rough rear surfaces on silicon solar cells. An enhanced method of using transfer matrices at the rear-side interface of solar cells is developed and combined with Monte Carlo ray tracing. As a result, a physically consistent and precise simulation of the spectral reflectance is achieved, thus leading to a predictive quality of the simulations that could previously not be reached for solar cells with a remaining irregular rear-surface roughness. This advance in optical simulation enables the researcher to directly analyze the effects of varying rear-side passivation materials and thicknesses, as well as the impact of different surface morphologies on the gained charge-carrier generation rate of a solar cell. A comparison with the Phong model shows that the tm-model is able to simulate the generated photocurrent J(ph) more accurately, as it is shown that the Phong model tends to overestimate this value due to imprecise calculation of charge-carrier generation. In an application of the tm-model to passivated emitter and rear cells, it is shown that a strong planarization of the rear surface leads to an improvement in photogenerated current up to 0.13 mA/cm(2) compared with a weak planarization.

• 出版日期2013-1