性能を犠牲にすることなく、持続可能な代替案を提供する画期的な製品です Breakthrough offers industry sustainable alternative without compromising performance
2022-08-30 ローレンスバークレー国立研究所(LBNL)
新しい強誘電体材料は、研究室で三臭化セシウムゲルマニウム（CsGeBr3またはCGB）から成長させたもので、太陽電池デバイスの製造がより容易になる道を開くものである。従来の太陽電池材料とは異なり、CGB結晶は本質的に分極しており、結晶の片面には正の電荷が、もう片面には負の電荷が蓄積され、ドーピングは不要である。
CGBの光吸収は、可視光から紫外線（1.6～3電子ボルト）までの範囲で調整可能であることがわかったのである。このような調整能力は、従来の強誘電体にはほとんど見られない。
＜関連情報＞
- https://newscenter.lbl.gov/2022/08/30/lead-free-solar-material/
- https://www.science.org/doi/10.1126/sciadv.abj5881
半導体全有機ハロゲン化物ペロブスカイトの強誘電性 Ferroelectricity in a semiconducting all-inorganic halide perovskite
Ye Zhang ,Eric Parsonnet,Abel Fernandez,Sinéad M. Griffin ,Huaixun Huyan,Chung-Kuan Lin ,Teng Lei,Jianbo Jin ,Edward S. Barnard ,Archana Raja,Piush Behera ,Xiaoqing Pan ,Ramamoorthy Ramesh,Peidong Yang
Science Advances Published:9 Feb 2022
DOI: 10.1126/sciadv.abj5881
Abstract
Ferroelectric semiconductors are rare materials with both spontaneous polarizations and visible light absorptions that are promising for designing functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics. The emerging halide perovskites with remarkable semiconducting properties also have the potential of being ferroelectric, yet the evidence of robust ferroelectricity in the typical three-dimensional hybrid halide perovskites has been elusive. Here, we report on the investigation of ferroelectricity in all-inorganic halide perovskites, CsGeX3, with bandgaps of 1.6 to 3.3 eV. Their ferroelectricity originates from the lone pair stereochemical activity in Ge (II) that promotes the ion displacement. This gives rise to their spontaneous polarizations of ~10 to 20 μC/cm2, evidenced by both ab initio calculations and key experiments including atomic-level ionic displacement vector mapping and ferroelectric hysteresis loop measurement. Furthermore, characteristic ferroelectric domain patterns on the well-defined CsGeBr3 nanoplates are imaged with both piezo-response force microscopy and nonlinear optical microscopic method.
