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

• Published in: The journal of physical chemistry letters Vol. 7; no. 24; pp. 5093 - 5100
• Main Authors: Diab, Hiba, Trippé-Allard, Gaëlle, Lédée, Ferdinand, Jemli, Khaoula, Vilar, Christèle, Bouchez, Guillaume, Jacques, Vincent L.R, Tejeda, Antonio, Even, Jacky, Lauret, Jean-Sébastien, Deleporte, Emmanuelle, Garrot, Damien
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15.12.2016
• Subjects: Chemical Sciences; Condensed Matter; Materials Science; or physical chemistry; Physics; Theoretical and
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.6b02261

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.