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Narrow Linewidth Excitonic Emission in Organic-Inorganic Lead Iodide Perovskite Single Crystals

Published on - Journal of Physical Chemistry Letters

Authors: Hiba Diab, Gaelle Trippe-Allard, Ferdinand Lédée, Khaoula Jemli, Christèle Vilar, Guillaume Bouchez, Vincent L.R Jacques, Antonio Tejeda, Jacky Even, Jean‐sébastien Lauret, Emmanuelle Deleporte, Damien Garrot

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Hybrid perovskite thin films have demonstrated impressive performance for solar energy conversion and optoelectronic applications. However, further progress will benefit from a better knowledge of the intrinsic photophysics of materials. Here, the temperature-dependent emission properties of CH3NH3PbI3 single crystals are investigated and compared to those of thin polycrystalline films by means of steady-state and time-resolved photoluminescence spectroscopy. Single crystals photoluminescence present a sharp excitonic emission at high energy, with full width at half maximum of only 5 meV, assigned to free excitonic recombination. We highlight a strong thermal broadening of the free excitonic emission, due to exciton–LO-phonon coupling. The emission turned to be very short-lived with a subnanosecond dynamics, mainly induced by the fast trapping of the excitons. The free excitonic emission is completely absent of the thin film spectra, which are dominated by trap state bands.