Abstract
We investigate the impact of phonon excitations on the photoexcited carrier dynamics in a lead-halide perovskite CH_{3}NH_{3}PbI_{3}, which hosts unique low-energy phonons that can be directly excited by terahertz pulses. Our time-resolved photoluminescence measurements reveal that strong terahertz excitation prolongs the cooling time of hot carriers, providing direct evidence for the hot-phonon bottleneck effect. In contrast to the previous studies where phonons are treated as a passive heat bath, our results demonstrate that phonon excitation can significantly perturb the carrier relaxation dynamics in halide perovskites through the coupling between transverse- and longitudinal-optical phonons.
Highlights
Lead-halide perovskites are promising materials for future optoelectronic devices such as low-cost but highperformance solar cells and light-emitting diodes [1,2,3,4,5,6]
We investigated the influence of a THzinduced phonon population on the hot-carrier relaxation dynamics in MAPbI3 by performing time-resolved photoluminescence (PL) measurements
Upon THz excitations, we observed an ultrafast quench of the total PL intensity and a simultaneous enhancement of the PL intensity on the high-energy side, revealing that long-lived hot carriers are generated by THz pulses
Summary
Lead-halide perovskites are promising materials for future optoelectronic devices such as low-cost but highperformance solar cells and light-emitting diodes [1,2,3,4,5,6]. The cooling dynamics of the hot carriers depends on the THz-excitation intensity, with slower time constant at higher THz intensities under the same carrier density. The THz excitation brings carriers to higher energy states with lower PL efficiencies, but subsequent carrier cooling by carrier-phonon interactions results in the recovery of Itotal.
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