Newswise — The Science
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 (2D) nanomaterials. As an ionic material, it has special properties that graphene and other 2D nanomaterials don’t have.
This study introduces a potential successor to silicon. This new family of materials, called planar hybrid perovskites, could lead to advanced solar cells, light-emitting electronics, photodetectors, and other optoelectronic devices. In addition, this study shows a way to manufacture these atomically thin semiconducting materials.
Scientists created a new form of hybrid organic-inorganic perovskites in atomically thin 2D sheets. These hybrid perovskites have shown promise as semiconductor materials for photovoltaic applications. This new 2D material could provide an alternative to other 2D 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 2D materials, the hybrid perovskite sheets have an unusual atomic-scale structural relaxation. Advantageously, this subtle structural change in the 2D material led to a noticeable shift in the electronic band gap. This shift in the band gap did not occur in the bulk (3D) crystal of the same material. Researchers discovered that the new 2D crystals produce efficient photoluminescence and that color tuning of the emitted light could be achieved by changing the sheet thickness and composition. This study opens up opportunities for fundamental research into thin 2D hybrid perovskites and introduces a new family of 2D semiconductors for potential applications in advanced optoelectronic devices.
This work was supported by the U.S. Department of Energy (DOE) Office of Science (Office of Basic Energy Sciences) (theoretical calculations); National Center for Electron Microscopy and Molecular Foundry (transmission electron microscopy and cathodoluminescence microscopy) and Advanced Light Source (grazing-incidence wide-angle x-ray scattering), DOE Office of Science User Facilities; National Institute for Health (X-ray crystallography); David and Lucile Packard Fellowship (cathodoluminescence microscopy); National Science Foundation; Alfred P. Sloan Research Fellowship; Camille and Henry Dreyfus Foundation; and Suzhou Industrial Park.
L. Dou, A. Wong, Y. Yu, M. Lai, N. Kornienko, S. Eaton, A. Fu, C. Bischak, J. Ma, T. Ding, N. Ginsberg, L. Wang, A. Alivisatos, and P. Yang, “Atomically thin two-dimensional organic-inorganic hybrid perovskites.” Science 349, 1518 (2015). [DOI: 10.1126/science.aac7660]