Metal halide perovskite absorber materials have emerged as a potential new technology for large-scale low-cost photovoltaic solar power. One great advantage lies in the ability to tune their light absorption band across the visible to near infrared spectral regions, making it an ideal candidate for tandem solar cell applications, in combination with traditional crystalline silicon. For a multi-junction solar cell to operate at peak efficiency, the current generation in all junctions must closely match, especially for monolithically integrated tandem architectures. It is feasible to achieve such matching under a standardized solar spectrum with direct illumination. However, under real world conditions the spectrum of sun light, and the fraction of diffuse to direct sun light varies considerably depending upon the location and weather conditions. Hence, it is not directly obvious how much more efficient a multi-junction solar cell needs to be, in comparison to a single junction cell, before it will produce more electrical power under real world conditions. Here, we introduce a rigorous optical and device simulation to optimize perovskite-on-silicon tandem solar cells and identify feasibility of various optimisation parameters to achieve the highest possible efficiencies. Firstly, we determine that the ideal bandgap for a perovskite “top-cell” is 1.65 eV, which will deliver up to 32% efficiency when combined with a silicon rear cell. Furthermore, we calculate the annual energy yield under hourly spectrum changes at different locations and optimize the stack to show that tandem solar cells are yielding up to 30% more energy output than the single junction silicon. Most critically, the standardized air mass 1.5 efficiency measurement improvements observed for the tandems cells, translate almost entirely to the same fractional improvement in energy yield. Hence, the efficiency of the tandem cell is not significantly “de-rated” by real world spectral variations. We do observe however, that tandem solar cell stacks can deliver further improvements by optimising differently depending on the location of installation. Our results justify the drive towards monolithically integrated multi-junction solar cells, and will enable guidance to design the ideal perovskite tandem device and allow estimations for energy yield and hence the levelized cost of electricity.

中文翻译：

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预测和优化现实世界中硅钙钛矿串联太阳能电池的能量产量

金属卤化物钙钛矿吸收剂材料已经成为大规模低成本光伏太阳能的潜在新技术。一个很大的优势在于能够在可见光到近红外光谱范围内调节其光吸收带，使其与传统的晶体硅结合使用，成为串联太阳能电池应用的理想选择。为了使多结太阳能电池以最高效率工作，所有结中的电流必须紧密匹配，特别是对于单片集成的串联架构。在具有直接照明的标准化太阳光谱下实现这种匹配是可行的。但是，在实际条件下，太阳光的光谱以及从漫射到直接太阳光的比例随位置和天气条件的不同而有很大差异。因此，与单结电池相比，多结太阳能电池在现实世界条件下产生更多的电能之前需要提高多少效率尚不直接明显。在这里，我们介绍了严格的光学和器件仿真，以优化硅钙钛矿串联太阳能电池并确定各种优化参数的可行性，以实现最高的效率。首先，我们确定钙钛矿“顶部电池”的理想带隙为1.65 eV，当与硅质后电池组合使用时，其能提供高达32％的效率。此外，我们计算了在不同位置每小时频谱变化下的年发电量，并对堆进行了优化，以显示串联太阳能电池的发电量比单结硅高出30％。最关键的是 对双结电池所观察到的标准化空气质量1.5效率测量改进几乎完全转化为能量产率的同等改进。因此，串联电池的效率不会因现实世界中的光谱变化而明显“降低”。但是，我们确实观察到，串联太阳能电池堆可以根据安装位置进行不同的优化来实现进一步的改进。我们的结果证明了朝着单片集成多结太阳能电池发展的动力，并将为设计理想的钙钛矿串联设备提供指导，并可以估算出能量产量，从而实现平准化的电力成本。串联电池的效率不会因现实世界中的光谱变化而明显“降低”。但是，我们确实观察到，串联太阳能电池堆可以根据安装位置进行不同的优化来实现进一步的改进。我们的结果证明了朝着单片集成多结太阳能电池发展的动力，并将为设计理想的钙钛矿串联设备提供指导，并可以估算出能量产量，从而实现平准化的电力成本。串联电池的效率不会因现实世界中的光谱变化而明显“降低”。但是，我们确实观察到，串联太阳能电池堆可以根据安装位置进行不同的优化来实现进一步的改进。我们的结果证明了朝着单片集成多结太阳能电池发展的动力，并将为设计理想的钙钛矿串联设备提供指导，并可以估算出能量产量，从而实现平准化的电力成本。