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用第一性原理方法,计算了空间群分别为Pbca和P21/a的杂合物(C4H9NH3)2SnI4、(C12H25NH3)2SnI4。计算结果表明,费米面附近的能带来自无机元中各原子的原子轨道,无机元的结构直接决定了带隙的大小,其中桥位碘连接的Sn—I—Sn键角对带隙大小有明显影响,该键角偏离180°幅度越大,带隙就越大。有机元的原子轨道对费米面附近的能带无贡献,不直接对带隙产生影响。但有机元对无机元有模板作用,不同有机元的氨基头与无机层之间的夹角不同,与无机层中的碘原子形成不同氢键。氢键的大小与方向会引起Sn—I—Sn键角的变化,从而间接地改变带隙。
The first-principle method was used to calculate the hybrids (C4H9NH3) 2SnI4 and (C12H25NH3) 2SnI4 with space groups Pbca and P21 / a, respectively. The calculated results show that the energy band near the Fermi surface originates from the atomic orbitals of the atoms in the inorganic element. The structure of the inorganic element directly determines the size of the bandgap. The Sn-I-Sn bond angle of the iodine- Significantly affect the key angle deviation from the greater the 180 °, the greater the band gap. The atomic orbitals of organic elements do not contribute to the band near the Fermi surface and do not directly affect the bandgap. However, the organic element has a template effect on the inorganic element. The angle between the amino head of the different organic element and the inorganic layer is different and forms different hydrogen bonds with the iodine atom in the inorganic layer. The size and orientation of the hydrogen bond can cause a change in the Sn-I-Sn bond angle, thereby indirectly changing the band gap.