Unraveling exciton-phonon coupling in individual FAPbI(3) nanocrystals emitting near-infrared single photons

作者：Fu Ming; Tamarat Philippe; Trebbia Jean Baptiste; Bodnarchuk Maryna I; Kovalenko Maksym V; Even Jacky; Lounis Brahim^*

来源：Nature Communications, 2018, 9(1): 3318.

DOI：10.1038/s41467-018-05876-0

Formamidinium lead iodide (FAPbI(3)) exhibits the narrowest bandgap energy among lead halide perovskites, thus playing a pivotal role for the development of photovoltaics and near-infrared classical or quantum light sources. Here, we unveil the fundamental properties of FAPbI(3) by spectroscopic investigations of nanocrystals of this material at the single-particle level. We show that these nanocrystals deliver near-infrared single photons suitable for quantum communication. Moreover, the low temperature photoluminescence spectra of FAPbI(3) nanocrystals reveal the optical phonon modes responsible for the emission line broadening with temperature and a vanishing exciton-acoustic phonon interaction in these soft materials. The photoluminescence decays are governed by thermal mixing between fine structure states, with a two-optical phonon Raman scattering process. These results point to a strong Frolich interaction and to a phonon glass character that weakens the interactions of charge carriers with acoustic phonons and thus impacts their relaxation and mobility in these perovskites.

• 出版日期2018-8-20