1 research outputs found
Homogeneous Emission Line Broadening in the Organo Lead Halide Perovskite CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub>
The organic–inorganic hybrid
perovskites methylammonium
lead iodide (CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>) and the
partially chlorine-substituted mixed halide CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> emit strong and broad photoluminescence (PL) around their
band gap energy of ∼1.6 eV. However, the nature of the radiative
decay channels behind the observed emission and, in particular, the
spectral broadening mechanisms are still unclear. Here we investigate
these processes for high-quality vapor-deposited films of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> using time- and excitation-energy dependent photoluminescence
spectroscopy. We show that the PL spectrum is homogenously broadened
with a line width of 103 meV most likely as a consequence of phonon
coupling effects. Further analysis reveals that defects or trap states
play a minor role in radiative decay channels. In terms of possible
lasing applications, the emission spectrum of the perovskite is sufficiently
broad to have potential for amplification of light pulses below 100
fs pulse duration