1 research outputs found
Hydrogen-like Wannier–Mott Excitons in Single Crystal of Methylammonium Lead Bromide Perovskite
A thorough
investigation of exciton properties in bulk CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> perovskite single crystals was carried
out by recording the reflectance, steady-state and transient photoluminescence
spectra of submicron volumes across the crystal. The study included
an examination of the spectra profiles at various temperatures and
laser excitation fluencies. The results resolved the first and second
hydrogen-like Wannier–Mott exciton transitions at low temperatures,
from which the ground-state exciton’s binding energy of 15.33
meV and Bohr radius of ∼4.38 nm were derived. Furthermore,
the photoluminescence temperature dependence suggested dominance of
delayed exciton emission at elevated temperatures, originating from
detrapping of carriers from shallow traps or/and from retrapping of
electron–hole pairs into exciton states. The study revealed
knowledge about several currently controversial issues that have an
impact on functionality of perovskite materials in optoelectronic
devices