How to improve the efficiency of solar power generation?

Energy shortage and environmental pollution are major problems facing my country's sustainable economic development. The use of solar power generation is expected to change my country's energy structure and fundamentally solve the environmental problems faced by my country. However, how to improve the "work efficiency" of such perovskite solar cells is a common headache for scientific researchers.

Recently, the team of Professor Qin Tianshi from the Advanced Materials Research Institute of Nanjing University of Technology recently used an anion-cation pair material to repair the two "holes" of the perovskite "crystal building". Defect passivation, changing chemical properties, so as to achieve both efficiency and stability, the relevant research results were recently published in "Matter".

"In the context of carbon neutralization and carbon peaking, a new type of perovskite solar cell has emerged, and improving the environmental stability of perovskite materials and cells is crucial for the commercialization of perovskite solar cells." Qin Tianshi introduced that perovskite solar cells have high power conversion efficiency, which is comparable to the current commercial silicon solar cells, but because of its simple, more economical and environmentally friendly production process, it has become the "darling" of scientists around the world. It is expected to contribute to the realization of the dual carbon goal. The headache for researchers is that the current perovskite solar cells are still very sensitive to humidity, temperature, light and other environments. When perovskite solar cells are exposed to these environments, they are prone to degradation and have outstanding problems such as poor stability.

At present, the research work on the market mainly focuses on solving one-sided problems to improve the efficiency and stability of solar cells. Usually, only one component of the perovskite material is optimized, or the optimization of a single chemical environment is used to achieve efficiency and stability. Synchronized enhancement of sex. Wang Aifei, the co-first author and associate researcher of the paper, said: "This research result of our team uses the synergistic effect of adding anion and cation pairs to passivate the defects of perovskite materials in many aspects and all directions, and change the chemical properties to achieve The best of both worlds in efficiency and stability.”

"Perovskite materials, like our common salt, are a kind of crystal composed of anions and cations." Qin Tianshi introduced vividly. In the microscopic world, there are many defective holes in this "crystal building", which will allow external water vapor to enter the building through the holes. With the continuous increase of water storage, the building will eventually collapse. From a macroscopic point of view, this perovskite crystal is decomposed and destroyed. So scientists have developed a variety of materials to repair the building's flaws and protect it from outside water vapor. Just as anions and cations form crystals together, the perovskite "crystal building" also has two "holes", anion defects and cation defects. The previous work of international colleagues only repaired one type of hole. Using an anion-cation pair material, the two "holes" of the perovskite "crystal building" are repaired at the same time. The resulting perovskite solar cells have greatly improved efficiency and stability compared to previously reported ones.

Doctoral student Wang Jungan said: "The results of this research can achieve a photoelectric conversion efficiency of more than 23% under a standard sunlight, which is very close to or even exceeds the efficiency of current commercial silicon solar cells. At the same time, the synergy of the anions and cations builds two A waterproof isolation layer can effectively improve the stability of perovskite solar cells, thereby extending the operating time of the cells and achieving environmental stability of more than 1,000 hours under continuous light."

"Through this research, one strategy solves the pain points of multiple perovskite solar cells at the same time, and also increases confidence in trying to fabricate larger-area solar cells and prepares for the commercialization of perovskite solar cells." Commented by Professor Qin Tianshi road.

It is reported that this work has been supported by the General Project of the National Natural Science Foundation of China and the General Project of the Natural Science Foundation of Jiangsu Province.