1 research outputs found
Controlling Exciton/Exciton Recombination in 2‑D Perovskite Using Exciton–Polariton Coupling
In this paper, we
demonstrate that exciton/exciton annihilation
in the 2D perovskite (PEA)2PbI4 (PEPI)a
major loss mechanism in solar cells and light-emitting diodes, can
be controlled through coupling of excitons with cavity polaritons.
We study the excited state dynamics using time-resolved transient
absorption spectroscopy and show that the system can be tuned through
a strong coupling regime by varying the cavity width through the PEPI
layer thickness. Remarkably, strong coupling occurs even when the
cavity quality factor remains poor, providing easy optical access.
We demonstrate that the observed derivative-like transient absorption
spectra can be modeled using a time-dependent Rabi splitting that
occurs because of transient bleaching of the excitonic states. When
PEPI is strongly coupled to the cavity, the exciton/exciton annihilation
rate is suppressed by 1 order of magnitude. A model that relies on
the partly photonic character of polaritons explains the results as
a function of detuning