FAxCs1–xPbI3 Nanocrystals: Tuning Crystal Symmetry by A-Site Cation Composition,ACS Energy Letters

当前位置： X-MOL 学术 › ACS Energy Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

FAxCs1–xPbI3 Nanocrystals: Tuning Crystal Symmetry by A-Site Cation Composition
ACS Energy Letters ( IF 19.3 ) Pub Date : 2020-06-25 , DOI: 10.1021/acsenergylett.0c01069
Julian A. Vigil _{1,

2,

3} , Abhijit Hazarika _{1,

4} , Joseph M. Luther _{1,

4} , Michael F. Toney _{1,

3}

Affiliation

Nanoscale semiconductors show remarkably tunable properties. For metal halide perovskite (MHP) nanocrystals (NCs), surface energy and lattice strain stabilize desirable MHP compositions and crystallographic phases that are unstable in the bulk. We report an X-ray scattering study of the average room-temperature crystal structure of ∼15 nm FA_xCs_1–xPbI₃ (FA = formamidinium) NCs. All compositions crystallize in the perovskite structure; however, the average structure lowers in symmetry from the α (cubic) to β (tetragonal) to γ (orthorhombic) perovskite phases with decreasing x (Cs addition). The corresponding α- to β- and β- to γ-phase transitions occur between x = 0.75–0.5 and x = 0.25–0.1, respectively. Structural refinements also indicate large octahedral tilt angles (10–30°) in the β- and γ-phases and an increase in (pseudo)cubic unit cell volume upon FA addition. This work establishes the composition–structure relationship for FA_xCs_1–xPbI₃ NCs and demonstrates the ability to target average crystal symmetry with facile synthetic control.

中文翻译：

FA _x Cs _{1– x} PbI ₃纳米晶体：通过A站点阳离子组成调整晶体对称性

纳米级半导体显示出显着的可调谐特性。对于金属卤化物钙钛矿（MHP）纳米晶体（NC），表面能和晶格应变可稳定所需的MHP组成和晶体相，这些相在整体中不稳定。我们报告了〜15 nm FA _x Cs _{1– x} PbI ₃（FA = Formamidinium）NC的平均室温晶体结构的X射线散射研究。所有组合物均以钙钛矿结构结晶。但是，平均结构的对称性从钙钛矿相的α（立方）到β（四方）再到γ（斜方），降低了x（Cs加成）。在x = 0.75-0.5和x之间发生相应的从α-到β-和β-到γ的相变。分别为0.25–0.1。结构上的改进还表明，在β相和γ相中，八面体的倾斜角较大（10–30°），并且在添加FA后立方晶胞体积（伪）增加。这项工作建立了FA _x Cs _{1– x} PbI ₃ NCs的成分-结构关系，并证明了通过简便的合成控制达到目标平均晶体对称性的能力。

更新日期：2020-08-14

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11