Two-photon absorption and hydrostatic pressure effects on exciton states in one-dimensional crystal C5H10NH2PbI3

In order to identify the electronic structure of a one-dimensional crystal C5H10NH2PbI3, we investigate two-photon absorption and hydrostatic pressure effects on its optical spectra. In the two-photon excitation spectra of photoluminescence from the self-trapped exciton, prominent absorption peak is observed at 3.61 or 0.36 eV above the lowest exciton Level, which is attributed to the two-photon absorption to the exciton state having relative motion of odd parity. From the energy difference, exciton binding energy is estimated to be 0.36 eV. As the hydrostatic pressure is applied, the PL peak shifts to the blue at a rate of 63 meV/GPa while the PL width increases. By fitting the spectra, the relevant phonon energy is found to increase from 12.7 meV at the ambient pressure to 14.6 meV at 1.9 GPa. (C) 2000 Published by Elsevier Science B.V. All rights reserved.