Gaury Benoit, Haney Paul M
† Center for Nanoscale Science and Technology, National Institute for Standards and Technology, Gaithersburg, MD 20899, USA.
‡ Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA.
ACS Appl Energy Mater. 2019;2(1). doi: 10.1021/acsaem.8b01246.
Thin film polycrystalline photovoltaics are a mature, commercially-relevant technology. However, basic questions persist about the role of grain boundaries in the performance of these materials, and the extent to which these defects may limit further progress. In this work, we first extend previous analysis of columnar grain boundaries to develop a model of the recombination current of "tilted" grain boundaries. We then consider systems with multiple, intersecting grain boundaries and numerically determine the parameter space for which our analytical model accurately describes the recombination current. We find that for material parameters relevant for thin film photovoltaics, our model can be applied to compute the open-circuit voltage of materials with networks of inhomogeneous grain boundaries. This model bridges the gap between the distribution of grain boundary properties observed with nanoscale characterization and their influence on the macroscale device open-circuit voltage.
薄膜多晶光伏是一项成熟的、具有商业相关性的技术。然而，关于晶界在这些材料性能中的作用以及这些缺陷可能限制进一步进展的程度等基本问题仍然存在。在这项工作中，我们首先扩展了先前对柱状晶界的分析，以建立一个“倾斜”晶界复合电流的模型。然后我们考虑具有多个相交晶界的系统，并通过数值方法确定我们的分析模型能够准确描述复合电流的参数空间。我们发现，对于与薄膜光伏相关的材料参数，我们的模型可用于计算具有不均匀晶界网络的材料的开路电压。该模型弥合了通过纳米级表征观察到的晶界特性分布与其对宏观器件开路电压的影响之间的差距。
