Liu Xing, Fu Jia, Chen Guangming
Shaanxi Key Laboratory of Material Processing Engineering, School of Material Science and Engineering, Xi'an Shiyou University Xi'an 710065 China
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University Xi'an 710072 PR China.
RSC Adv. 2020 May 5;10(29):17317-17326. doi: 10.1039/c9ra10735e. eCollection 2020 Apr 29.
The development of ABX-type advanced perovskite materials has become a focus for both scientific researchers and the material genome initiative (MGI). In addition to the traditional perovskite ABO and halide perovskite ABX, LaWN is discovered as a new ABX-type advanced perovskite structure. The elastic and optical properties of this novel LaWN structure are systematically studied DFT. Based on the calculated elastic constants, the bulk modulus, shear modulus, Young's modulus and Pugh modulus ratio are precisely obtained. Results show that (1) LaWN is an indirect bandgap semiconductor with a hybrid occuring near the Fermi level and the main contributions are La-d, W-d and N-p. (2) LaWN has a certain ductility. The optical constants, such as absorption spectrum, energy-loss spectrum, conductivity, dielectric function, reflectivity and refractive index, are analyzed and the static dielectric constant is 10.98 and the refractivity index is 3.31. (3) The optical constants of LaWN are higher than those of other existing ABX-type materials, showing very promising application as a functional perovskite in the future. The existence of this stable LaWN structure might widen the perovskite material's application, such as in photodetectors, light-emitting diodes, perovskite solar cells, fuel cells and so on.
ABX型先进钙钛矿材料的发展已成为科研人员和材料基因组计划（MGI）的关注焦点。除了传统的钙钛矿ABO和卤化物钙钛矿ABX外，LaWN被发现是一种新型的ABX型先进钙钛矿结构。利用密度泛函理论（DFT）对这种新型LaWN结构的弹性和光学性质进行了系统研究。基于计算得到的弹性常数，精确获得了体模量、剪切模量、杨氏模量和普格模量比。结果表明：（1）LaWN是一种间接带隙半导体，在费米能级附近存在杂化现象，主要贡献来自La-d、W-d和N-p。（2）LaWN具有一定的延展性。分析了吸收光谱、能量损失谱、电导率、介电函数、反射率和折射率等光学常数，静态介电常数为10.98，折射率为3.31。（3）LaWN的光学常数高于其他现有的ABX型材料，显示出未来作为功能性钙钛矿具有非常广阔的应用前景。这种稳定的LaWN结构的存在可能会拓宽钙钛矿材料的应用范围，如用于光电探测器、发光二极管、钙钛矿太阳能电池、燃料电池等。
