1 research outputs found
Electroabsorption Studies of Multicolored Lead Halide Perovskite Nanocrystalline Solid Films
Electroabsorption
(E-A) spectra of lead halide perovskites, that
is, CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Br<sub><i>x</i></sub> (<i>x</i> = 0–3),
which show large spectral shift depending on the ratio between iodine
and bromide, have been measured. By analyzing E-A spectra with the
integral method, spectral shape of the absorption spectra for the
first exciton band and binding energy of exciton have been determined.
Magnitudes of the change in electric dipole moment and molecular polarizability
following excitation into the exciton state have been also evaluated
in these perovskites. The binding energy of electron and hole in exciton
of these materials as well as the magnitude of change in electric
dipole moment following exciton absorption is roughly the same, suggesting
that the difference of the photoenergy conversion in photovoltaic
cells using these materials comes from the difference in light harvesting
effect and difference in carrier mobility, not from the difference
in carrier generation efficiency. The frequency-dependent third-order
nonlinear susceptibility χ<sup>(3)</sup> has also been calculated,
based on the E-A spectra