Huang Weiqi, Zhang Xu, Li Yanqiang, Zhou Yang, Chen Xin, Li Xiaoqi, Wu Fafa, Hong Maochun, Luo Junhua, Zhao Sangen
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
School of Science, Jiangxi University of Science and Technology, Ganzhou, 341000, China.
Angew Chem Int Ed Engl. 2022 May 23;61(22):e202202746. doi: 10.1002/anie.202202746. Epub 2022 Mar 30.
Birefringent crystals that can modulate the polarization of light play a significant role in modern optical devices including polarizing microscopes, optical isolators, and achromatic quarter-wave plates. To date, commercial birefringent crystals are exclusively limited to purely inorganic compounds. Here we report a new organic-inorganic hybrid halide, MLAPbBr (MLA=melamine), which features a (110)-oriented layered perovskite structure. Although the 6s lone-pair electrons of Pb cations are stereochemically inert, MLAPbBr exhibits a birefringence of 0.322@550 nm, which exceeds those of all commercial birefringent crystals. The first-principles calculations reveal that this birefringence should be ascribed to the highly dislocated π-conjugation of MLA cations and high distortion of PbBr octahedra. This work highlights the persistently neglected great potential of hybrid halide perovskites as birefringent crystals.
能够调制光偏振的双折射晶体在包括偏光显微镜、光隔离器和消色差四分之一波片在内的现代光学器件中发挥着重要作用。迄今为止，商业双折射晶体仅限于纯无机化合物。在此，我们报道了一种新型有机-无机杂化卤化物MLAPbBr（MLA = 三聚氰胺），其具有（110）取向的层状钙钛矿结构。尽管Pb阳离子的6s孤对电子在立体化学上是惰性的，但MLAPbBr在550 nm处表现出0.322的双折射，超过了所有商业双折射晶体。第一性原理计算表明，这种双折射应归因于MLA阳离子高度错位的π共轭和PbBr八面体的高畸变。这项工作突出了杂化卤化物钙钛矿作为双折射晶体一直被忽视的巨大潜力。
