He Xin, Singh David J, Boon-On Patsorn, Lee Ming-Way, Zhang Lijun
State Key Laboratory of Superhard Materials, Key Laboratory of Automobile Materials of MOE, and School of Materials Science , Jilin University , Changchun 130012 , China.
Department of Physics and Astronomy , University of Missouri , Columbia , Missouri 65211-7010 , United States.
J Am Chem Soc. 2018 Dec 26;140(51):18058-18065. doi: 10.1021/jacs.8b10685. Epub 2018 Dec 14.
Dielectric screening plays an important role in reducing the strength of carrier scattering and trapping by point defects for many semiconductors such as the halide perovskite solar materials. However, it was rarely considered as a screen to find new electronic semiconductors. We performed a material search study using the dielectric properties as a screen to identify potential electronic materials in the class of metal-pnictide ternary sulfosalts, containing Bi or Sb. These salts are basically ionic due to the electronegativity difference between the S and both the metal and pnictogen elements. However, we do find significant cross-gap hybridization between the S p-derived valence bands and pnictogen p-derived conduction bands in many of the materials. This leads to enhanced Born effective charges and, in several cases, highly enhanced dielectric constants. We find a chemical rule for high dielectric constants in terms of the bond connectivity of the pnictogen-chalcogen part of the crystal structure. We additionally find a series of compounds with low effective mass, high dielectric constant, and other properties that suggest good performance as electronic materials and also several potential thermoelectric compounds. Experimental optical data and solar conversion efficiency are reported for Sn-Sb-S samples, and results in accord with predicted good performance are found. The results illustrate the utility of dielectric properties as a screen for identifying complex semiconductors.
对于许多半导体，如卤化物钙钛矿太阳能材料，介电屏蔽在降低点缺陷对载流子的散射和俘获强度方面起着重要作用。然而，它很少被视为寻找新型电子半导体的筛选标准。我们进行了一项材料搜索研究，以介电性质作为筛选标准，在含铋或锑的金属磷族三元硫盐类中识别潜在的电子材料。由于硫与金属和磷族元素之间的电负性差异，这些盐基本上是离子性的。然而，我们确实在许多材料中发现了硫的p轨道衍生价带与磷族元素的p轨道衍生导带之间存在显著的跨能隙杂化。这导致了增强的玻恩有效电荷，在某些情况下，还导致了高度增强的介电常数。我们根据晶体结构中磷族元素-硫族元素部分的键连性，找到了高介电常数的化学规律。我们还发现了一系列具有低有效质量、高介电常数以及其他表明作为电子材料具有良好性能的性质的化合物，以及几种潜在的热电化合物。报道了Sn-Sb-S样品的实验光学数据和太阳能转换效率，并且发现结果与预测的良好性能相符。这些结果说明了介电性质作为筛选复杂半导体的一种手段的实用性。
