Biomineral-inspired mechanically tough perovskite solar cells with enhanced stability

钙钛矿太阳能电池(PSC)是溶液可加工的，具有高效率，并承诺低成本的可再生电力。不幸的是，由于长期稳定性差，PSCs的广泛应用受到了阻碍。他们的老牌竞争对手，晶硅太阳能电池，提供了25年的运行寿命。然而，高效率的PSC的运行稳定性不到6个月。钙钛矿具有非常低的机械韧性，这是因为分离钙钛矿晶体所需的能量很低。太阳能电池的工作寿命随着机械韧性的增加而增加，我们的目标是利用这种关系来极大地提高高效PSCs的稳定性。受高度坚韧的天然生物材料(如珍珠岩)的启发，我们将使用粘合蛋白的合成类似物将晶体粘合在一起，并增加钙钛矿的机械韧性。我们的新粒子是超变形纳米大小的凝胶粒子(称为超低交联纳米凝胶，ULC纳米凝胶)。在我们早期工作的基础上，传统的纳米凝胶提高了铅-PSC的稳定性，将制备新型的ULC纳米凝胶，以共面覆盖和连接钙钛矿晶体。它们会变平，变得超薄，允许电荷在晶体之间畅通无阻地移动。我们还将研究无铅、锡钙钛矿，并通过改善化学稳定性和机械韧性来提高它们的操作稳定性。机械韧性和PSC稳定性之间的联系将通过实验和使用最先进的建模技术进行研究。还将利用建模来研究化学降解所涉及的能量变化，以便为具有更高稳定性的PSC建立材料设计规则。该项目的成功成果将有助于更好地从根本上了解钙钛矿机械韧性和稳定性之间的相互作用，以及一个预计运行寿命为8年的高效演示器(S)。这样的结果将使钙钛矿型光伏发电的大规模部署更接近于无二氧化碳发电，并增加能源安全。

Perovskite solar cells (PSCs) are solution processable, have high efficiencies and promise low cost renewable electricity. Unfortunately, the widespread application of PSCs is being held back by their poor long-term stability. Their established rivals, crystalline-silicon solar cells, offer a 25 year operational lifetime. However, high efficiency PSCs are operationally stable for less than 6 months. Perovskites have very low mechanical toughness due to the intrinsically low energy required to separate perovskite crystals. Solar cell operation lifetime increases with mechanical toughness and we aim to exploit this relationship to greatly enhance the stability of high efficiency PSCs. Taking inspiration from highly tough natural biomaterials (such as nacre) we will use synthetic analogues of adhesive proteins to glue the crystals together and increase perovskite mechanical toughness. Our new particles are ultra-deformable nanometre-sized gel particles (termed ultra-low crosslinked nanogels, ULC nanogels). Building on our earlier work where conventional nanogels improved lead-PSC stability, novel ULC nanogels will be prepared that conformally coat and interlink perovskite crystals. They will flatten to become ultra-thin and allow charges to move unhindered between crystals. We will also study lead-free, tin-perovskites and increase their operational stability by a combination of improvements in chemical stability and mechanical toughness. The link between the mechanical toughness and PSC stability will be investigated experimentally and using state-of-the-art modelling techniques. Modelling will also be used to study the energy changes involved in chemical degradation so as to establish materials design rules for PSCs with enhanced stability. A successful outcome to this project would provide improved fundamental understanding of the interplay between perovskite mechanical toughness and stability as well as a high efficiency demonstrator(s) with a projected operation lifetime of 8 years. Such a result would bring the large-scale deployment of perovskite photovoltaics for CO2-free electricity generation closer and increase energy security.