Two-dimensional carbon graphyne (GD) is a full-carbon superstructure with a two-dimensional planar network formed by conjugated benzene rings by 1,3-diyne bonds. It has rich carbon chemical bonds, large conjugated systems, and wide faces. Pitch, excellent chemical stability and semiconductor performance have been widely used in various fields such as biology, energy, catalysis, information technology, energy storage, etc., and it is the first carbon material with independent intellectual property rights in China. Graphyne has a natural band gap and is a class of intrinsic semiconductors with high charge transport capabilities. Because of its special electronic structure and excellent silicon-like semiconductor properties, it has gained important applications in many fields of energy and solar cells.
The huge global demand for renewable energy has promoted the vigorous development of perovskite solar cell research. At present, the common hysteresis effects and stability problems of perovskite solar cells have seriously hindered their realization of large-scale industrial applications. How to prepare a battery device with excellent performance and good stability is an urgent problem to be solved. Under the guidance of Li Yuliang, an academician of the Chinese Academy of Sciences, the Jiutong Steel team of the Qingdao Institute of Bioenergy and Process of the Chinese Academy of Sciences first used graphyne as the main material of the battery active layer. When the content of the graphyne active material is 25%, the perovskite solar energy Battery efficiency is up to 21.01%. The study found that when graphyne is used as the host material, the graphene-rich π electrons have significant coordination with the lead in the perovskite precursor solution, thereby delaying the crystallization rate of perovskite, achieving large grain size, Perfect combination of fewer grain boundaries and high crystallinity. At the same time that the photoelectric performance is improved, the hysteresis effect and stability have also been greatly improved.
Subsequently, the researchers explored the reasons for the device performance improvement from the aspects of transient fluorescence, exciton generation rate, and conductivity. The results showed that the introduction of graphyne effectively reduced the grain boundaries and suppressed the recombination of charges at the grain boundaries. The charge transfer is effectively improved, and these effects are conducive to the improvement of device fill factor and short-circuit current density, thereby improving device performance. At the same time, as the quality of the perovskite film is improved and the density of defect states is reduced, the hysteresis effect and stability of the device are also greatly improved.
This study shows that this is the first time that carbon materials can be used as host materials for solar cells. Graphene as a perovskite host material has great potential for improving the performance of perovskite solar cell devices. Work provides a whole new way of thinking