Comprehensive simulation study of industrially relevant silicon solar cell architectures for an optimal material parameter choice

Abstract

Solar cell production always requires a tradeoff between cell efficiency and production costs. This also concerns the choice of the silicon base material. In general, a long base lifetime is beneficial to achieve high conversion efficiency, but it strongly depends on the cell concept to which extent the cell performance is improved and whether a payback of the higher material costs can be expected. Therefore, in this comprehensive simulation study of various industrially relevant solar cell architectures, we present an investigation of the influence of the bulk lifetime and the resistivity of the base material on the cell performance. A consistent set of cell and simulation parameters is chosen to allow for a direct quantitative comparison of the different cell types. The parameters were chosen rather conservatively in order to describe realistic industrial cells and not record laboratory cells. The observed trends are analyzed using detailed loss breakdowns and are compared with experimental results. For various cell concepts, critical lifetimes τcrit can be observed for which the optimal material parameters change with increasing bulk lifetime when comparing materials of different base resistivity. The underlying physical reasons are explained in detail to accomplish two major aims: (i) generating a better understanding of limitations and challenges concerning different solar cell concepts and (ii) serving as a guide for an optimal material parameter choice for different cell architectures

Impact of bulk impurity contamination on the performance of high‐efficiency n‐type silicon solar cells

“…Rather similar conclusions were also drawn for the thickness variation. Such recombination‐induced effects on FF were already reported, for instance, for impurity recombination within the silicon bulk, for injection‐dependent surface recombination, or recombination in the (dark) perimeter of this small‐area solar cells embedded in a 4‐inch wafer …”

“…Although peak efficiency values in the range of 25% were observed for all studied variations, the I‐V parameters revealed significant trends as a function of W and ρ b (compare experimental data shown in Figure ). For instance, the efficiency was found to decrease with increasing resistivity, which was not expected as rather ρ b ‐independent efficiencies have been predicted . The observed efficiency reduction was found to correlate with an FF reduction, which is not caused by the series resistance of the cells or the parallel (shunt) resistance.…”

“…Crystalline silicon (c‐Si) wafers with a high electronic quality (ie, high charge carrier lifetime) are a basic requirement for wafer‐based silicon solar cells with high power conversion efficiencies. This was addressed recently by Steinkemper et al based on a comprehensive device simulation study for various c‐Si solar cell architectures . A high electronic quality of c‐Si wafers implicates a low concentration of recombination‐active crystal defects or impurities.…”

Revisiting thin silicon for photovoltaics: a technoeconomic perspective

“…Many of these advanced device concepts have two-or threedimensional architectures. We used device models with effective simulation parameters [15] in order to resemble the performance of these advanced concepts. Figure 2 shows the simulated module efficiencies depending on the Si wafer thickness.…”

Experimental Investigation of the Optimal Ingot Resistivity for both the Cell Performances and the Temperature Coefficients for Different Cell Architectures

“…The lifetime distribution, the resistivity and the dislocation density for mc-Si are the key parameters that are used to predict the solar cell performances. A high resistivity was shown to improve the cell performances for most cell architectures, except for some PERC designs where 3D carrier transport was happening [5]. Yet another study has shown that these results are to be considered cautiously as the lifetime limiting impurities present in the material have a great influence on the dependence of the cell efficiency with the resistivity [6].…”