Semiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions, High Mobilities, and Near-Infrared Photoluminescent Properties
Semiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions, High Mobilities, and Near-Infrared Photoluminescent Properties
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DOI：
10.1021/ic401215x
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发表时间：
2013-08-05
影响因子：
4.6
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
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作者：
Stoumpos, Constantinos C.;Malliakas, Christos D.;Kanatzidis, Mercouri G.
报道了一类广泛的有机-无机杂化金属碘化钙钛矿系列，其一般分子式为AMI(3)，其中A为甲基铵（CH3NH3+）或甲脒(HC(NH2)（2)(+)）阳离子，M为Sn（1和2）或Pb（3和4）。通过各种合成方法制备了这些化合物，并从其热稳定性和光学和电子性能方面讨论了所得材料的性质。我们发现这些材料的化学和物理性质与制备方法有很大的关系。对1-4的单晶x射线衍射分析将化合物划分为钙钛矿结构族。在100-400 K范围内，用温度相关的单晶x射线衍射观察和研究了结构相变。讨论了材料的电荷输运特性，并结合中红外区域的漫反射研究，显示了典型的吸收特征。温度依赖性研究表明，电阻率作为晶体结构的函数有很强的依赖性。光吸收测量表明，1-4表现为直接隙半导体，能带隙分布在1.25-1.75 eV范围内。在室温下，化合物在700 ~ 1000 nm （1.1 ~ 1.7 eV）范围内表现出强烈的近红外光致发光（PL）。我们发现锡和铅化合物之间的固溶体在整个组成范围内都很容易接近。CH3NH3Sn1-xPbxI3等结构系列固溶体的光学性质，如能带隙、发射强度和波长可以很容易地控制(5)。用塞贝克系数和霍尔效应测量表征了这些材料中的电荷输运类型。根据制备方法的不同，化合物表现为p型或n型半导体。载体浓度最低的样品由溶液制备，为n型；p型样品可以通过可控暴露在空气中的固态反应得到。在Sri化合物的情况下，有一个容易氧化的趋势，导致材料掺杂Sn4+，从而表现为p型半导体，显示类似金属的导电性。这些化合物似乎具有非常高的电子和空穴迁移率，分别超过2000 cm(2)/(V s)和300 cm(2)/(V s)，如CH3NH3SnI3(1)所示。我们还将标题杂化材料的性能与采用相同合成方法制备的无机CsSnI3和CsPbI3的性能进行了比较。
A broad organic-inorganic series of hybrid metal iodide perovskites with the general formulation AMI(3), where A is the methylammonium (CH3NH3+) or formamidinium (HC(NH2)(2)(+)) cation and M is Sn (1 and 2) or Pb (3 and 4) are reported. The compounds have been prepared through a variety of synthetic approaches, and the nature of the resulting materials is discussed in terms of their thermal stability and optical and electronic properties. We find that the chemical and physical properties of these materials strongly depend on the preparation method. Single crystal X-ray diffraction analysis of 1-4 classifies the compounds in the perovskite structural family. Structural phase transitions were observed and investigated by temperature-dependent single crystal X-ray diffraction in the 100-400 K range. The charge transport properties of the materials are discussed in conjunction with diffuse reflectance studies in the mid-IR region that display characteristic absorption features. Temperature-dependent studies show a strong dependence of the resistivity as a function of the crystal structure. Optical absorption measurements indicate that 1-4 behave as direct-gap semiconductors with energy band gaps distributed in the range of 1.25-1.75 eV. The compounds exhibit an intense near-IR photoluminescence (PL) emission in the 700-1000 nm range (1.1-1.7 eV) at room temperature. We show that solid solutions between the Sn and Pb compounds are readily accessible throughout the composition range. The optical properties such as energy band gap, emission intensity, and wavelength can be readily controlled as we show for the isostructural series of solid solutions CH3NH3Sn1-xPbxI3 (5). The charge transport type in these materials was characterized by Seebeck coefficient and Hall-effect measurements. The compounds behave as p- or n-type semiconductors depending on the preparation method. The samples with the lowest carrier concentration are prepared from solution and are n-type; p-type samples can be obtained through solid state reactions exposed in air in a controllable manner. In the case of Sri compounds, there is a facile tendency toward oxidation which causes the materials to be doped with Sn4+ and thus behave as p-type semiconductors displaying metal-like conductivity. The compounds appear to possess very high estimated electron and hole mobilities that exceed 2000 cm(2)/(V s) and 300 cm(2)/(V s), respectively, as shown in the case of CH3NH3SnI3 (1). We also compare the properties of the title hybrid materials with those of the all inorganic CsSnI3 and CsPbI3 prepared using identical synthetic methods.