Hybrid organic-inorganic perovskite has already demonstrated high photovoltaic efficiencies of over 25%. Widely known in this field, organic (carbon and hydrogen-containing) molecules in the material are thought to suppress defect-supporting carrier recombination and are therefore important for achieving this impressive performance. It means that there is.
New study at the University of California, Santa Barbara material Not only is this assumption incorrect, but the department has shown that all inorganic materials can perform better than hybrids. Perovskite.. The findings are published in the article “All Inorganic Halide Perovskite as a Candidate for Efficient Solar Cells” on the cover of the October 20th issue of the journal. Cell Reports Physics..
“We ran a comprehensive simulation of the recombination mechanism to compare the materials,” explained Xie Zhang, lead researcher for the study. “When the solar cell material is exposed to light, the photogenic carriers generate current. Recombination at the defects destroys some of these carriers and reduces efficiency. Therefore, defects reduce efficiency. Let me do it. “
To compare inorganic perovskite with hybrid perovskite, researchers studied two prototype materials.Both materials contain lead and iodine atoms, but in one material Crystal structure Is completed by the inorganic element cesium, but other elements have organic methylammonium molecules.
It is very difficult to experimentally classify these processes, but thanks to a new methodology developed by Chris Van de Walle’s group of UCSB Materials Professors who acknowledged Mark’s achievements, state-of-the-art quantum mechanical calculations. You can accurately predict the recombination rate with. Turiansky, a senior graduate student in the group, is helping to write code to calculate the recombination rate.
“Our method is very powerful in determining which defects cause carrier loss,” Turiansky said. “It’s exciting to see this approach applied to one of the key issues of our time: the efficient generation of renewable energy.”
Simulations have shown that defects common to both materials cause similar (and relatively benign) levels of recombination. However, the organic molecules of hybrid perovskite can be degraded. When a hydrogen atom is lost, the resulting “vacancy” significantly reduces efficiency. Therefore, the presence of molecules is a disadvantage, not an asset, to the overall efficiency of the material.
So why was this not noticed experimentally? The main reason is that it is more difficult to grow a high quality layer of all inorganic materials. They tend to adopt other crystal structures and promoting the formation of the desired structure requires greater experimental effort. However, recent studies have shown that achieving a favorable structure is undoubtedly feasible. Still, this difficulty explains why all-inorganic perovskite has never received so much attention.
“We hope that our findings on the expected efficiency will stimulate more activity towards the production of inorganic perovskite,” Vandeware concludes.
Xie Zhang et al, All Inorganic Halide Perovskite as a Candidate for Efficient Solar Cells, Cell Reports Physics (2021). DOI: 10.1016 / j.xcrp.2021.100604
University of California, Santa Barbara
Quote: Team improves solar efficiency (October 14, 2021) obtained on October 14, 2021 from https: //phys.org/news/2021-10-team-great-all-inorganic- Shows great expectations for all-inorganic perovskite solar cells to be perovskite-solar.html
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The team shows great expectations for all-inorganic perovskite solar cells to improve the efficiency of solar cells
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