2D materials: introduction and market status

Recent research has shown that the incorporation of graphene-related materials improves the performance and stability of perovskite solar cells. Graphene is hydrophobic, which can enhance several properties of perovskite solar cells. Firstly, it can enhance stability and the passivation of electron traps at the perovskite’s crystalline domain interfaces. Graphene can also provide better energy level alignment, leading to more efficient devices.

In a recent study, Spain-based scientists used pristine graphene to improve the properties of MAPbI₃, a popular perovskite material. Pristine graphene was combined with the metal halide perovskite to form the active layer of the solar cells. By analyzing the resulting graphene/perovskite material, it was observed that an average efficiency value of 15% under high-stress conditions was achieved when the optimal amount of graphene was used.

Scientists studying two different configurations of bilayer graphene have detected electronic and optical interlayer resonances. In these resonant states, electrons bounce back and forth between the two atomic planes in the 2-D interface at the same frequency. By characterizing these states, they found that twisting one of the graphene layers by 30 degrees relative to the other, instead of stacking the layers directly on top of each other, shifts the resonance to a lower energy. From this result they deduced that the distance between the two layers increased significantly in the twisted configuration, compared to the stacked one. When this distance changes, so do the interlayer interactions, influencing how electrons move in the bilayer system. An understanding of this electron motion could inform the design of future quantum technologies for more powerful computing and more secure communication.

“Today’s computer chips are based on our knowledge of how electrons move in semiconductors, specifically silicon,” said first and co-corresponding author Zhongwei Dai, a postdoc in the Interface Science and Catalysis Group at the Center for Functional Nanomaterials (CFN) at the U.S. Department of Energy (DOE)’s Brookhaven National Laboratory. “But the physical properties of silicon are reaching a physical limit in terms of how small transistors can be made and how many can fit on a chip. If we can understand how electrons move at the small scale of a few nanometers in the reduced dimensions of 2-D materials, we may be able to unlock another way to utilize electrons for quantum information science.”