[Science and technology frontier] If there is a race between human beings and energy issues, then solar cell research is like a race of 100 meters. Every number after the Decimal separator point is the focus of scientists. The Wang Rui team of Westlake University, who has been committed to the research of new perovskite solar cells, once again achieved a breakthrough after the Decimal separator point. Recently, Nature magazine published the latest research results of Wang Rui's laboratory online. They found a new method of formamidine lead iodide perovskite oriented nucleation - adding an "additive" called "pentamidine" can bring better crystallinity and lower defects, which also means higher photoelectric efficiency and greater stability, expanding more space for the conversion efficiency of perovskite solar cells. The stability of the "star material" perovskite is insufficient. Regarding solar cells, everyone's first impression is that the "blue roofs" that can be seen everywhere in many cities and villages in China are silicon solar cells, which have been around for many years. Why do scientists still strive to study perovskite solar cells? In recent years, perovskite batteries have achieved a single small area photoelectric conversion rate of 25% or even higher in the laboratory, comparable to the development speed of silicon solar cells in 40 years. In theory, perovskite solar cells can achieve a photoelectric conversion rate of over 40% through the stacking method, and are lighter, more efficient, low-cost, and even flexible compared to silicon solar cell materials. Imagine a future where, like painting a wall, applying perovskite solar cells to the outside of a building can provide power to the house. But this "star material", which scientists have high hopes for, has a fatal flaw, which is insufficient stability. It forms at low temperatures and is prone to decomposition at low temperatures, and is afraid of water and oxygen. Therefore, most operations in Wang Rui's laboratory need to be completed in the Glovebox, where nitrogen is filled to isolate water and oxygen. Our task is to find the right medicine to improve the conversion rate and stability of perovskite solar cells until they can truly enter and change human life, "said Wang Rui. The "long tail" pentamidine has special effects. Currently, the photoactive black phase formamidine lead iodide perovskite (FAPbI3) is the most promising material for efficient perovskite photovoltaics. Interestingly, the performance of perovskite can be seen from its "surface phase". The well grown formamidine lead iodine perovskite appears black and is technically called the "black phase"; Crystals that do not grow well will appear yellow, technically known as "yellow phase". The "black phase" means a neat and complete perovskite crystal structure, allowing for unobstructed current generation. However, during the formation process of formamidine lead iodine perovskite crystals, there is often a phenomenon of "black yellow phase". Although previous researchers have developed some methods to avoid such mixing, the crystallization rate of formamidine lead iodide perovskite is too fast, which can be completed in seconds, making it difficult for people to "see" the mechanism of changes in the crystallization process. How to control the production of only "pure black phase" formamidine lead iodide perovskite in this process? In 2019, when Wang Rui's team was conducting research on the secondary growth of perovskite surfaces, they noticed that a substance called "oil ammonium iodine" could help crystals grow better. Ammonium iodide is an organic compound with a long tail