| Project/Area Number |
09650042
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied optics/Quantum optical engineering
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
KONDO Takashi The University of Tokyo, Graduate School, Division of Engineering, Associate Professor, 大学院・工学系研究科, 助教授 (60205557)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
EMA Kazuhiro Sophia University, Dept.Physics, Associate Professor, 理工学部, 助教授 (40194021)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Project Status |
Completed (Fiscal Year 1998)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
|
|---|
| Keywords | Self-Organized Quantum Well / Perovskite / Lead Iodide / Low-Dimensional Material / Exciton / Biexciton / Nonlinear Optics / Ultrafast Spectroscopy |
|---|
| Research Abstract |
We have performed linear and nonlinear spectroscopy on the following inorganic-organic perovskites : (C_6H_<13>NH_3)_2PbI_4 with monolayer inorganic sheets composed of PbI_6 octahedra, (C_6H_<13>NH_3)_2(CH_3NH_3)Pb_3I_<10> with trilayer inorganic sheets, (C_6H_<13>NH_3)_2(CH_3NH_3)_2Pb_3I_<10> with trilayer inorganic sheets, and (CH_3NH_3)PbI_3 with infinite inorganic sheets (i.e., three-dimensional perovskite).
1. Size Effects on Bandgaps and Excitonic Properties
We have performed magnetooptical absorption measurements on the four compound, and determined Bohr radius and binding energies of excitons and bandgap energies. With decreasing well layer thickness, the bandgap and the binding energy are drastically increased and the Bohr radius is decreased correspondingly. Although this size dependence can basically be understood as a result of the quantum confinement effect based on the effective mass approximation, tight binding models based on the molecular excitation picture seems to be m
… More
ore appropriate for compounds with thin well layers.
2. Exciton-Resonant Ultrafast Nonlinear Spectroscopy
We have performed four-wave mixing experiments on the exciton resonance region of (C_6H_<13>NH_3)_2PbI_4 and (C_6H_<13>NH_3)_2(CH_3NH_3)Pb_2I_7 using an OPA based on a Ti : Sapphire laser (pulse width-100 fs). x^<(3)>(omega ; omega, -omega, omega) of (C_6H_<13>NH_3)_2PbI_4 reaches 1.6 x lO^<-6>esu at the exciton resonance, and T_2=0.2 ps and T_1=7 ps. x^<(3)> of (C_6H_<13>NH_3)_2(CH_3NH_3)Pb_2I_7 have been found to be smaller than that of (C_6H_<13>NH_3)_2PbI_4 by about an order of magnitude, and T_2 be of the same order as that in (C_6H_<13>NH_3)_2PbL_4.
3. Two-Photon Resonant Spectroscopy
We have performed spectrally-resolved four-wave mixing experiments on (C_6H_<13>NH_3)_2PbI_4 and (C_6H_<13>NH_3)_<2-> (CH_3NH_3)Pb_2I_<7->. The spectra obtained have suggested that the two-exciton states in these compounds are composed of stabilized biexciton states and weakly-bound two-exciton states. Moreover, we have observed twophoton resonant hyper Raman signal in (C_6H_<13>NH_3)_2PbI_4, for the first time. Detailed experiments are now underway in order to clarify the two-photon resonant states in this unique system. Less
|
