OPTICAL-PROPERTIES DUE TO ELECTRONIC-TRANSITIONS IN 2-DIMENSIONAL SEMICONDUCTORS (CNH2N + 1NH3)2PBI4
OPTICAL-PROPERTIES DUE TO ELECTRONIC-TRANSITIONS IN 2-DIMENSIONAL SEMICONDUCTORS (CNH2N + 1NH3)2PBI4
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DOI：
10.1103/physrevb.42.11099
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发表时间：
1990-12-15
影响因子：
3.7
通讯作者：
GOTO, T
中科院分区：
文献类型：
--
作者：
ISHIHARA, T;TAKAHASHI, J;GOTO, T
研究了层状钙钛矿化合物（CnH2n +1NH3）PbI4（n= 4，6，8，9，10和12）在可见光和紫外光区的光谱. PbI 4层之间的间距从n= 4的15.17 μ m变化到n= 12的24.51 μ m。尽管这些不同的间距，这些化合物的光谱几乎是相同的，这意味着层之间的相互作用是弱的。最低激子位于2.56 eV，在1.6 K，其振子强度和结合能分别为0.7每分子单位和320 meV。与三维模拟PbI 2相比，这些值非常大。大的振子强度和结合能可以用烷基铵“阻挡层”的小介电常数来解释，这加强了电子和空穴之间的库仑相互作用。
Optical spectra in the visible and uv regions are investigated in layer-type perovskite compounds (C n H 2 n+ 1 NH 3) PbI 4 with n= 4, 6, 8, 9, 10, and 12. The spacing between the PbI 4 layers changes from 15.17 Å for n= 4 to 24.51 Å for n= 12. In spite of these different spacings, the optical spectra are almost the same for these compounds, which means that the interaction between the layers is weak. The lowest exciton is located at 2.56 eV at 1.6 K, and its oscillator strength and binding energy are 0.7 per formula unit and 320 meV, respectively. These values are very large compared with those in a three-dimensional analog PbI 2. The large oscillator strength and binding energy can be explained by the small dielectric constant of the alkylammonium ‘‘barrier layer,’’which strengthens the Coulomb interaction between an electron and a hole.