Visualization of the microscope suggestion exposing material to terahertz light. The colors on the material represent the light-scattering information, and the blue and red lines represent the terahertz waves. They developed a microscopic lense that uses terahertz waves to gather information on material samples. The microscope uses the terahertz range of electromagnetic frequencies to gather data on products. Considering that the information gathered on a sample is a reading of how the light scatters when the material is exposed to the terahertz waves, they expected a consistent low-level of light scatter throughout the product.
Visualization of the microscopic lense suggestion exposing product to terahertz light. The colors on the product represent the light-scattering information, and the red and blue lines represent the terahertz waves. Credit: U. S. Department of Energy Ames National Lab
A brand-new characterization tool was developed by a group of researchers, permitting them to gain unique insight into a possible alternative material for solar batteries. They established a microscopic lense that uses terahertz waves to gather information on material samples. The team, from the Department of Energys Ames National Laboratory, working under the leadership of senior researcher Jigang Wang, then utilized their microscope to check out Methylammonium Lead Iodide (MAPbI3) perovskite, a product that could possibly change silicon in solar cells.
The microscope uses the terahertz range of electromagnetic frequencies to gather data on products. The terahertz light is shined through a sharp metal tip that boosts the microscopic lenses capabilities toward nanometer-length scales.
” Normally if you have a light wave, you can not see things smaller sized than the wavelength of the light youre utilizing. And for this terahertz light, the wavelength has to do with a millimeter, so its quite large,” explained Kim. “But here we used this sharp metal tip with an apex that is sharpened to a 20-nanometer radius curvature, and this functions as our antenna to see things smaller than the wavelength that we were using.”
Utilizing this brand-new microscopic lense, the group investigated a perovskite material, MAPbI3, that has actually recently become of interest to researchers as an option to silicon in solar batteries. When it is exposed to visible light, perovskites are an unique type of semiconductor that carries an electric charge. The primary challenge to utilizing MAPbI3 in solar batteries is that it degrades quickly when exposed to elements like heat and wetness.
According to Wang and Kim, the team expected MAPbI3 to behave like an insulator when they exposed it to the terahertz light. Given that the information gathered on a sample is a reading of how the light scatters when the product is exposed to the terahertz waves, they anticipated a constant low-level of light scatter throughout the material. What they found, nevertheless, was that there was a great deal of variation in light scattering along the border in between the grains.
Kim explained that conductive products, like metals, would have a top-level of light spreading while less-conductive products, like insulators, would not have as much. The wide variation of light scattering detected along the grain limits in MAPbI3 clarifies the materials degradation problem.
Throughout a week, the group continued to collect data on the material, and data collected because time showed the destruction process through modifications in the levels of light scatterings. This details can be helpful for controling the product and enhancing in the future.
” We believe that today study shows a powerful microscopy tool to envision, comprehend and possibly reduce grain boundary deterioration, flaw traps, and materials deterioration,” stated Wang. “Better understanding of these concerns may make it possible for developing highly effective perovskite-based photovoltaic devices for several years to come.”
The samples of MAPbI3 were supplied by the University of Toledo. This research study is further discussed in the paper “Terahertz Nanoimaging of Perovskite Solar Cell Materials,” composed by Richard H. J. Kim, Zhaoyu Liu, Chuankun Huang, Joong-Mok Park, Samuel J. Haeuser, Zhaoning Song, Yanfa Yan, Yongxin Yao, Liang Luo, and Jigang Wang, and released in the ACS Photonics.
Referral: “Terahertz Nanoimaging of Perovskite Solar Cell Materials” by Richard H. J. Kim, Zhaoyu Liu, Chuankun Huang, Joong-Mok Park, Samuel J. Haeuser, Zhaoning Song, Yanfa Yan, Yongxin Yao, Liang Luo and Jigang Wang, 17 October 2022, ACS Photonics.DOI: 10.1021/ acsphotonics.2 c00861.