Exploring the Stability of Mixed-Halide Vacancy-Ordered Quadruple Perovskites
Exploring the Stability of Mixed-Halide Vacancy-Ordered Quadruple Perovskites
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DOI：
10.1021/acs.chemmater.0c04951
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发表时间：
2021-03-12
影响因子：
8.6
通讯作者：
Woodward, Patrick M.
中科院分区：
文献类型：
--
作者：
Gray, Matthew B.;Majher, Jackson D.;Woodward, Patrick M.
本文研究了Br-和I-在（Cs_4MM_2Cl_（12））-M-II-Cl-III（M-II = Cd ~（2+），Mn ~（2+）; M-III = Bi ~（3+），Sb ~（3+））中的卤代反应的结构和光学性质。所有组分均为< 111 >层状空位有序四重钙钛矿结构，具有R（3）过barm空间群对称性。通过增量卤化物取代反应，我们表明，显着的溴化物掺入是可能的（>25%的含镉2+的结构）。较大的卤素离子（Br-或I-）优先占据邻近阳离子空位层的阴离子位点。在这些组合物中，其中M-II是Cd 2+，溴离子的掺入导致大量的M-II/空位反位无序，这是伴随着一个更均匀的分布在两个化学上不同的阴离子位点的溴取代。（Cs4 CdM 2Cl 12）-Cl-III化合物可以掺入两倍于类似的含Mn 2+化合物的溴化物量，对于Cs4 CdSb 2Cl 12发现最大29（2）%的溴化物取代。碘化物的掺入更受限制，Cs4 CdBi 2Cl 12的最大卤化物取代量接近6%。较重的、电负性较低的Br-和I-离子的掺入导致以Vegard定律类型的方式的光吸收的开始的红移。对Cs4 CdBi 2Cl 12-zXz的影响最大，其中随着组成从Cs4 CdBi 2Cl 12改变为Cs4CdBi2Cl8.9Br3.1，吸收起始从3.20（1）eV移动到2.99（1）eV。正如论文中所讨论的，这些结果为稳定空位有序四重钙钛矿结构的因素提供了一些见解。
The structural and optical properties of the halide substitutions of Br- and I- into (Cs4MM2Cl12)-M-II-Cl-III (M-II = Cd2+, Mn2+; M-III = Bi3+, Sb3+) have been investigated. All compositions adopt the < 111 > layered vacancy-ordered quadruple perovskite structure with R (3) over barm space group symmetry. Through incremental halide substitution reactions, we show that significant bromide incorporation is possible (>25% for Cd2+-containing structures). The larger halide ions (Br- or I-) preferentially occupy the anion sites adjacent to the cation-vacancy layer. In those compositions where M-II is Cd2+, incorporation of bromide ions leads to substantial M-II/vacancy antisite disorder, which is accompanied by a more even distribution of bromide substitution over the two chemically distinct anion sites. The (Cs4CdM2Cl12)-Cl-III compounds can incorporate over twice the amount of bromide as analogous Mn2+-containing compounds, with a maximum of 29(2)% bromide substitution found for Cs4CdSb2Cl12. Iodide incorporation is more limited, with a maximum of similar to 6% halide substitution for Cs4CdBi2Cl12. The incorporation of the heavier, less electronegative Br- and I- ions results in a red shift of the onset of optical absorption in a Vegard's Law type fashion. The effect is largest for Cs4CdBi2Cl12-zXz, where the absorption onset shifts from 3.20(1) eV to 2.99(1) eV as the composition changes from Cs4CdBi2Cl12 to Cs4CdBi2Cl8.9Br3.1. As discussed in the paper, these results offer some insights into the factors that stabilize the vacancy-ordered quadruple perovskite structure.