Communications of the ACM
A New Family Member for 2-D Nanomaterials
Structural illustration of a large single-layer crystal. The researchers used X-ray diffraction and transmission electron microscopy to determine the crystal structure of the 2-D hybrid perovskites.
Credit: Peidong Yang Group / UC Berkeley
Popular in electronic devices including solar panels, silicon has its limits. Scientists are devising replacements to meet the technology demands of an energy-hungry nation. A team of researchers devised a new method to grow atomically thin films of a promising group of materials, known as hybrid perovskites. The material grew in well-defined, relatively large squares. For the first time, researchers have introduced an ionic semiconductor to the family of two-dimensional (2-D) nanomaterials. As an ionic material, it has special properties that graphene and other 2-D nanomaterials don't have.
The research is described in "Atomically Thin Two-Dimensional Organic-Inorganic Hybrid Perovskites," published in the journal Science. The study introduces a new family of materials, called planar hybrid perovskites, as a potential successor to silicon. The materials could lead to advanced solar cells, light-emitting electronics, photodetectors, and other optoelectronic devices. In addition, the study shows a way to manufacture these atomically thin semiconducting materials.
The scientists created the new form of hybrid organic-inorganic perovskites in atomically thin 2-D sheets. These hybrid perovskites have shown promise as semiconductor materials for photovoltaic applications. This new 2-D material could provide an alternative to other 2-D semiconductors that are widely studied as potential successors to silicon in future electronic devices. In other words, hybrid perovskite sheets could be an alternative to graphene, boron nitride, and molybdenum disulfide in future electronics.
Scientists grew the hybrid perovskite sheets from solution, yielding single layer and few-unit-cell-thick crystals. The thin crystals had a well-defined square shape and a relatively large lateral dimension (up to 10 micrometers). Unlike other 2-D materials, the hybrid perovskite sheets have an unusual atomic-scale structural relaxation. Advantageously, this subtle structural change in the 2-D material led to a noticeable shift in the electronic band gap. This shift in the band gap did not occur in the bulk (3-D) crystal of the same material.
Researchers discovered that the new 2-D crystals produce efficient photoluminescence and that color tuning of the emitted light could be achieved by changing the sheet thickness and composition.
This work was supported by funding from the U.S. Department of Energy (DOE) Office of Science; the National Center for Electron Microscopy and Molecular Foundry and Advanced Light Source, DOE Office of Science User Facilities; the National Institute for Health; the David and Lucile Packard Fellowship; the U.S. National Science Foundation; the Alfred P. Sloan Research Fellowship; they Camille and Henry Dreyfus Foundation; and Suzhou Industrial Park.
The Science article is authored by Letian Dou, Andrew B. Wong, Yi Yu, Minliang Lai, Nikolay Kornienko, Samuel W. Eaton, Anthony Fu, Connor G. Bischak, Jie Ma, Tina Ding, Naomi S. Ginsberg, Lin-Wang Wang, A. Paul Alivisatos, and Peidong Yang.
The study opens up opportunities for fundamental research into thin 2-D hybrid perovskites and introduces a new family of 2-D semiconductors for potential applications in advanced optoelectronic devices.
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