Room-Temperature Engineering of All-Inorganic Perovskite Nanocrsytals with Different Dimensionalities
Room-Temperature Engineering of All-Inorganic Perovskite Nanocrsytals with Different Dimensionalities
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DOI：
10.1021/acs.chemmater.7b04161
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发表时间：
2017-10
影响因子：
8.6
通讯作者：
Haoze Yang;Yuhai Zhang;J. Pan;Jun Yin;O. Bakr;O. Mohammed
中科院分区：
文献类型：
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作者：
Haoze Yang;Yuhai Zhang;J. Pan;Jun Yin;O. Bakr;O. Mohammed
钙钛矿基半导体纳米晶体由于其显著的光学性质，包括高光致发光量子产率（> 90%）、窄发射带（半峰全宽，fwhm< 30 nm）和可调带隙能量（400 - 800 nm），已成为光电应用中作为有源层材料的有希望的候选者。1− 11本质上，这些独特的物理性质源于晶体钙钛矿固体中存在的基本功能单元（即PbX 6八面体）的晶格结构。根据PbX 6八面体的连接方式，Cs基钙钛矿的维度分为零维（0 D）、二维（2D）和三维（3D）晶体结构。例如，0 D钙钛矿Cs4 PbBr 6在这些钙钛矿类似物中显示出最显著的量子限制效应（带隙= 3.90 eV）12，这是由于其PbX 6八面体的隔离性质，如图1所示。相比之下，3D钙钛矿CsPbBr 3由于其PbX 6八面体的耦合网络性质而显示出最小的限制，带隙为2.36 eV。理解维度和光学性质之间的内在相关性需要通过一般方法成功合成各种维度的钙钛矿。近年来，由于合成技术的进步，实现了对钙钛矿结构尺寸的精确控制。3D钙钛矿CsPbBr 3 NC通常通过热注入法合成，而钙钛矿CsPb 2Br 5 NC最近通过共沉淀法大规模生产。18− 22最近，我们的团队在室温下成功地从反相微乳液系统合成了0 D钙钛矿NC。尽管合成成功，但合成条件之间的巨大差异通常会导致所得材料的表面性质存在很大差异，并导致从这些所得样品获得的固有光学参数存在差异。例如，当分析使用不同方法合成的样品时，0 D Cs4 PbBr 6钙钛矿的激子结合能从171至353 meV变化。23，25这种戏剧性的差异对理解具有不同维度的钙钛矿的内在性质提出了严峻的挑战。为了定量评估钙钛矿的尺寸效应，高度期望同时提供相同的表面性质和尺寸控制的通用合成方法。
Perovskite-based semiconductor nanocrystals have become a promising candidate as active-layer materials in optoelectronic applications due to their remarkable optical properties, including high photoluminescence quantum yield (> 90%), narrow emission bands (full width at half-maximum, fwhm< 30 nm) and tunable bandgap energy (400− 800 nm). 1− 11 Intrinsically, these unique physical properties originate from the lattice structures of basic functional units (ie, PbX6 octahedra) existing in the crystalline perovskite solids. Based on the connection manner of the PbX6 octahedra, the dimensionality of Cs-based perovskite is classified into zerodimensional (0D), two-dimensional (2D) and three-dimensional (3D) crystal structures. For example, 0D perovskite Cs4PbBr6 displays the most significant quantum confinement effect (bandgap= 3.90 eV) 12 among these perovskite analogues due to its isolated nature of PbX6 octahedra as shown in Figure 1. In contrast, the 3D perovskite CsPbBr3 shows the least confinement with a bandgap of 2.36 eV due to its couplednetwork nature of PbX6 octahedra. 13 The understanding of the intrinsic correlation between dimensionality and optical property requires successful synthesis of various dimensional perovskites through a general method. The precise control over perovskite dimensionality has been realized due to the recent progress in synthetic technique. 3D perovskite CsPbBr3 NCs have commonly been synthesized by the hot-injection method, 13− 17 whereas perovskite CsPb2Br5 NCs were recently massively produced via a coprecipitation method. 18− 22 Very recently, our group successfully synthesized 0D perovskite NCs from a reverse microemulsion system at room temperature. 23, 24 Despite the success in synthesis, the large differences among synthetic conditions usually induce a large discrepancy in the surface property of as-obtained materials and an ensuing difference of intrinsic optical parameters derived from those obtained samples. For example, the exciton binding energy of 0D Cs4PbBr6 perovskite varies from 171 to 353 meV when samples synthesized using different methods are analyzed. 23, 25 Such dramatic discrepancy poses a severe challenge in understanding the intrinsic properties of perovskites with different dimensionalities. To quantitatively evaluate the dimensionality effect of perovskite, a general synthetic method simultaneously affording both identical surface properties and control over dimensionality is highly desired.