Study on Excitons and biexcitons in Lead-Iodide-Based Perovskite-Type Low-Dimensional Crystals

碘化铅基钙钛矿型低维晶体中激子和双激子的研究

• 批准号: 12440081
• 负责人: KONDO Takeashi
• 金额: $ 9.28万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440081/
• 关键词: Self-organized quantum well; Perovskite-type crystal; Lead halogenide; Low-dimensional material; Exciton; Biexciton; Nonlinear spectroscopy; Modulation spectroscopy; ヨウ化鉛

1. Two-three-dimensional crystalsWe have shown that lowest excitons in a "monolayer" two-dimensional crystal (C_6H_<13>NH_3)_2PblI_4 are nearly ideal two-dimensional Wannier excitons. The large binding energy of the lowest exciton is enhanced effectively by the so-called dielectric confinement effect. In addition, we have investigated excitons in a variety of 23-dimensional crystals, and have verified that the spatial and the dielectric confinements affects the Coulomb interlaction between electons and holes in the excitons. Moreover, we have successfully understood almost whole electronic structures in these crystals by group-theory analysis and first-principle band calculations. Based on this picture, we suggest three excitons (one allowed for E ⊥L c, one aloowed for E ‖ c, one forbiden (triplet)) exist and the triplet excitons affect,the relaxation process of the biexcitons.2. One-dimensional crystalsWe have measured optical spectra of the "corner-sharing" one-dimensional crystal [CH_3 CS(=NH_2)NH_2]_3 PbI_5, and have found lowest excitons with very strong one-dimensional characters. Based on the group-theory analysis, we have attributed all the structures (excitons) in the spectra including their polarization dependences. Excitons in this crystal are self-trapped ones and exhibit large Stokes shift. Exchange energy of the excitons have proved to be 70 meV which indicates the strong one-dimensionality of the system. Moreover, band calculations have shown that "sharing class" (corner-, line-, or face-sharing) and the lattice deformation strongly affect the bandgap energy of the lead-iodide-based one-dimensional crystals

1.我们证明了在“单层”二维晶体（C_6H_NH_3）_2PbI_4中的最低激子<13>是近似理想的二维Wannier激子。最低激子的大结合能被所谓的介电限制效应有效地增强。此外，我们还研究了各种23维晶体中的激子，并证实了空间和介电约束影响激子中电子和空穴之间的库仑相互作用。此外，我们已经成功地了解了几乎整个电子结构在这些晶体中的群论分析和第一性原理能带计算。基于这一图像，我们提出了三个激子（一个允许E_xL_c，一个允许E_xL_c，一个禁止（三重态））的存在，并且三重态激子影响双激子的弛豫过程.一维晶体我们测量了[CH_3CS（=NH_2）NH_2]_3PbI_5的光谱，发现了具有很强一维特征的最低激子。基于群论分析，我们归属了光谱中的所有结构（激子），包括它们的偏振依赖性。该晶体中的激子是自陷激子，具有较大的斯托克斯位移。激子的交换能已被证明是70 meV，这表明该系统的强一维性。此外，能带计算表明，“共享类”（角共享、线共享或面共享）和晶格变形强烈影响碘化铅基一维晶体的带隙能量

项目成果

K.Tanaka, F.Sano, T.Takahashi, T.Kondo, R.Ito, K.Ema: "Twq-Dimensional Wannier Excitons in a Layered-Perovskite-Type Crystal (C_6H_<13>NH_3)_2PbI_4"Solid State Commun.. (印刷中). (2002)

K.Tanaka、F.Sano、T.Takahashi、T.Kondo、R.Ito、K.Ema：“层状钙钛矿型晶体中的 Twq 维万尼尔激子 (C_6H_<13>NH_3)_2PbI_4”固态通讯..（正在出版）（2002）。

K. Ema, J. Ishi, H. Kunugita, T. Ban and T. Kondo: "All-Optical Serial-to-Parallel Conversion of Thits/s Signals Using a Four-Wave-Mixing Process"Opt. Quantum Elecron. 33. 1077-1087 (2001)

K. Ema、J. Ishi、H. Kunugita、T. Ban 和 T. Kondo：“使用四波混合过程对 Thits/s 信号进行全光串并转换”选项。

J.Ishi,H.Kunugita,K.Ema,T.Ban,and T.Kondo: "Time-to-Space Conversion of Tbits/s Optical Pulses Using a Self-Organized Quantum-Well Material"Appl.Phys.Lett.. 77. 3487-3489 (2000)

J.Ishi、H.Kunugita、K.Ema、T.Ban 和 T.Kondo：“使用自组织量子阱材料进行 Tbits/s 光脉冲的时空转换”Appl.Phys.Lett。

K.Ema,J.Ishi,H.Kunugita,T.Ban and T.Kondo: "All-Optical Serial-to-Parallel Conversion of Tbits/s Signals Using a Four-Wave-Mixing Process"Optical and Quantum Electronics. (印刷中). (2001)

K.Ema、J.Ishi、H.Kunugita、T.Ban 和 T.Kondo：“使用四波混合过程的 Tbits/s 信号的全光串行到并行转换”光学和量子电子学（正在出版）（2001）。

J Ishi, H.Kunugita, K.Ema T.Ban, T.Kondo: "Time-to-Space Conversion of Tbits/s Optical Pulses Using a Self-Organized Quantum-Well Material"Appl. Phys. Lett.. 77. 3487-3489 (2000)

J Ishi、H.Kunugita、K.Ema T.Ban、T.Kondo：“使用自组织量子阱材料进行 Tbits/s 光脉冲的时空转换”Appl。