  Hybrid Perovskites have shown a great potential for applications in
photovoltaics and light-emitting devices with high efficiency. Interaction
between defect-induced trapped excitons and phonons plays an important role in
understanding the emerging phenomena for such an excellent figure-of-merit.
Here we demonstrate hot polarons with narrow linewidth in
$\mathrm{CH_{3}NH_{3}PbBr_{3}}$ nanowires, which originate from the interaction
between trapped excitons and octahedra-twist phonons. The observation of hot
polarons in photoluminescence without gain methods indicates the large
interaction strength between excitons and phonons. The multiple hot polarons
are further confirmed by magneto-optical spectra with a Zeeman splitting of the
trapped excitons and a phonon energy increase with diamagnetic effect.
Furthermore, the phonons participating in the interaction are demonstrated to
be the octahedra-twist vibrations which are transverse optical phonons, while
the interaction between trapped excitons and longitudinal optical phonons is
weak. Our work demonstrates that trapped excitons in perovskites prefer to
interact with transverse rather than longitudinal optical phonons. Since bulk
materials usually interact with longitudinal optical phonons, this result
provides a physical explanation of the high tolerance of defects in
perovskites.
