Interface Engineering for Terawatt Scale Deployment of Perovskite-on-Silicon Tandem Solar Cells

太瓦（TW）可再生能源的部署对世界实现净零排放至关重要。太阳能发电是最有前途的可再生能源发电技术之一，拥有最大的可开发资源。为了将太阳能发电提升到太瓦的水平，我们必须加快新技术的发展，实现更高的效率。目前，占主导地位的硅技术已接近其实际效率极限。为了获得更高的性能，其他半导体吸收器必须采用所谓的串联结构：将两个或更多的光吸收器集成在彼此的顶部，以更好地利用高能可见光子，减少热化损失并将更高比例的太阳能转换为电能。在这些新的吸收剂中，混合有机-无机金属卤化物钙钛矿半导体最近取得了前所未有的进展，是最有希望集成到串联装置中的技术。将钙钛矿与硅集成在一起以制造高效率的串联已经取得了重大进展，但迄今为止的努力几乎无处不在地使用高端硅异质结后电池，这并不代表主流的量产硅光伏技术。在这个项目中，我们将在成本最低的“PERC”和“TOPCon”硅电池的基础上开发钙钛矿-硅串联太阳能电池。我们的目标是提供一种新的串联技术，该技术具有扩展到TW水平的潜力，因为它不再使用稀有材料，而是采用完全可扩展的制造方法，用于硅和钙钛矿电池。将硅电池生产的巨大装机容量“升级”到钙钛矿串联技术，将加速钙钛矿-硅串联技术的部署，这在目前的设计中是不可能的。最重要的是，向可扩展串联的转变将产生每平方米高达45%的能量捕获（从24%到35%）的阶梯式变化，而额外的成本微乎其微。由于光伏制造过程中有一半的二氧化碳排放量来自硅生产，因此更高的效率大大减少了单位能源产生的碳足迹，这可能是迄今为止所有发电技术中最低的。

Terawatt (TW) deployment of renewable energy is critical for the world to achieve net-zero emissions. Solar power is one of the most promising technologies for renewable electricity generation and has the largest available resource for exploitation. To boost solar electricity to TW levels, we must accelerate the development of new technologies enabling ever higher efficiencies. At present, the dominant silicon technology is close to reaching its practical efficiency limit. For higher performance to be unlocked, other semiconductor absorbers must be adopted in what is known as a tandem architecture: where two or more light absorbers are integrated on top of each other to make better use of high energy visible photons, reduce thermalisation losses and convert a higher fraction of the solar energy into electrical energy. Among such new absorbers, mixed organic-inorganic metal halide perovskite semiconductors have recently witnessed unprecedented progress and are the most promising technology to integrate into a tandem device. Significant advances have already been made integrating perovskites with silicon to make high efficiency tandems, but efforts so far have almost ubiquitously employed high-end silicon heterojunction rear cells, which do not represent the main-stream mass-produced Si PV technology. In this project, we will tackle the development of perovskite-on-silicon tandem solar cells based on the lowest cost "PERC" and "TOPCon" silicon cells. Our goal is to deliver a novel tandem technology with the potential to scale up to TW levels, due to moving away from the use of rare materials, and employing fully-scalable manufacturing methodologies, for both the silicon and perovskite cells. Enabling the vast installed capacity for silicon cell production to "upgrade" to perovskite tandem technology will accelerate deployment of perovskite-on-silicon tandems in a way that it is not yet possible with current designs. Most importantly, a shift towards scalable tandems will produce a step change in energy capture per metre square as high as 45%rel (from 24% to 35%abs), at a marginal extra cost. Because half the CO2 emissions of PV manufacturing come from silicon production, tandem higher efficiencies greatly reduce the carbon footprint per unit energy generated, potentially to the lowest level of any electricity generating technology to date.