High-Temperature Equilibrium of 3D and 2D Chalcogenide Perovskites
High-Temperature Equilibrium of 3D and 2D Chalcogenide Perovskites
复制标题
3D 和 2D 硫系钙钛矿的高温平衡
DOI：
10.1002/solr.202201078
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发表时间：
2023
期刊：
影响因子：
7.9
通讯作者：
Kayastha P
中科院分区：
文献类型：
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作者：
Kayastha P
硫系钙钛矿是一种新型的光伏吸收材料。BaZrS_3是该家族中研究最多的化合物，表现出高的吸收系数，约1.8 eV的带隙，以及良好的稳定性。除了三维钙钛矿型BaZrS3外，Ba-Zr-S组成空间还含有最近报道的各种二维Ruddlesden-Popper相Ban+ 1ZrnS3n+ 1(n= 1，2，3)。结果表明，在高温下，3D和2D钙钛矿的Gibbs自由能非常接近，这表明在高温下容易形成2D相。在不同的化学计量比条件下，BaS和ZrS_2的固相反应产物为BaZrS_3和Ba4Zr3S_(10)的混合物。为了仔细解析组成，X射线衍射、扫描电子显微镜和能量色散X射线光谱分析与拉曼光谱相辅相成。为此，计算了3D和2D硫系钙钛矿以及二元前驱体的声子色散和随后的拉曼光谱。这种彻底的表征表明了通过固相合成形成相纯的硫系钙钛矿的热力学限制和实验困难，以及使用多种技术来合理地确定这些材料的组成的重要性。
Chalcogenide perovskites have been recently proposed as novel absorber materials for photovoltaic applications. BaZrS3, the most investigated compound of this family, shows a high absorption coefficient, a bandgap of around 1.8 eV, and excellent stability. In addition to the 3D perovskite BaZrS3, the Ba–Zr–S compositional space contains various 2D Ruddlesden–Popper phases Ban+ 1ZrnS3n+ 1(withn= 1, 2, 3) which have recently been reported. Herein, it is shown that at high temperature the Gibbs free energies of 3D and 2D perovskites are very close, suggesting that 2D phases can be easily formed at high temperatures. The product of the BaS and ZrS2solid‐state reaction, in different stoichiometric conditions, presents a mixture of BaZrS3and Ba4Zr3S10. To carefully resolve the composition, X‐ray diffraction, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy analysis are complemented with Raman spectroscopy. For this purpose, the phonon dispersions, and the consequent Raman spectra, are calculated for the 3D and 2D chalcogenide perovskites, as well as for the binary precursors. This thorough characterization demonstrates the thermodynamic limitations and experimental difficulties in forming phase‐pure chalcogenide perovskites through solid‐state synthesis and the importance of using multiple techniques to soundly resolve the composition of these materials.