We have performed pump-and-probe measurements to investigate ultrafast excitonic non-linearity expected in an inorganic-organic compound (C6H5C 2H4NH3)2PbI4, which has huge exciton binding energy (220 meV) and oscillator strength (0.5 per formula unit) by virture of the small dielectric constant in the barrier layer (the dielectric confinement or image charge effect). When the pump photon energy is set at the exciton level at 2.37 eV or above the band gap, the absorption decreases immediately after the pump due to the phase space filling effect and retrieves in a few ps. The retrieval time is ascribed to the ultrafast radiative lifetime of the exciton level. The second exciton absorption at 2.39 eV exhibits induced absorption when the pump is at the first exciton band, which may provide a hint to the origin of the band.
|Number of pages||4|
|Journal||International Journal of Modern Physics B|
|Publication status||Published - 2001 Dec 10|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Condensed Matter Physics