Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica
Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica
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DOI：
10.1021/jacs.6b05608
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发表时间：
2016-10-26
影响因子：
15
通讯作者：
Yamauchi, Yusuke
中科院分区：
文献类型：
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作者：
Malgras, Victor;Tominaka, Satoshi;Yamauchi, Yusuke
杂化有机-无机金属卤化物钙钛矿具有令人着迷的电子性能，并已在各种器件中实现。尽管大块金属卤化物钙钛矿的行为已被广泛研究，但钙钛矿纳米晶体的性质尚不清楚，因为它们的合成仍然非常具有挑战性，部分原因是稳定性。在这里，我们展示了一种在介孔二氧化硅模板内生长单分散CH3NH3PbBrxIx-3钙钛矿纳米晶体的简单而通用的方法。纳米晶体的大小取决于模板的孔径大小（3.3、3.7、4.2、6.2和7.1 nm）。深入的结构分析表明，纳米晶体保持了钙钛矿的晶体结构，但略有扭曲。通过模板调整粒子的大小来观察量子约束。这种方法提供了一种额外的途径来调整纳米晶体的光学带隙。量子约束水平的建模考虑了棒状纳米晶体的尺寸和它们在模板通道内的紧密包装。对CH3NH3PbBr的光致发光测量清楚地表明，随着孔径的减小，该材料由绿色向蓝色转变。在模板中合成钙钛矿纳米结构提高了它们的稳定性，并通过量子限制实现了可调的电子特性。这些结构可以作为参考材料与其他钙钛矿进行比较，或作为所有固态发光二极管的功能材料。
Hybrid organic-inorganic metal halide perovskites have fascinating electronic properties and have already been implemented in various devices. Although the behavior of bulk metal halide perovskites has been widely studied, the properties of perovskite nanocrystals are less well-understood because synthesizing them is still very challenging, in part because of stability. Here we demonstrate a simple and versatile method to grow monodisperse CH3NH3PbBrxIx-3 perovskite nanocrystals inside mesoporous silica templates. The size of the nanocrystal is governed by the pore size of the templates (3.3, 3.7, 4.2, 6.2, and 7.1 nm). In-depth structural analysis shows that the nanocrystals maintain the perovskite crystal structure, but it is slightly distorted. Quantum confinement was observed by tuning the size of the particles via the template. This approach provides an additional route to tune the optical bandgap of the nanocrystal. The level of quantum confinement was modeled taking into account the dimensions of the rod-shaped nanocrystals and their close packing inside the channels of the template. Photoluminescence measurements on CH3NH3PbBr clearly show a shift from green to blue as the pore size is decreased. Synthesizing perovskite nanostructures in templates improves their stability and enables tunable electronic properties via quantum confinement. These structures may be useful as reference materials for comparison with other perovskites, or as functional materials in all solid-state light-emitting diodes.