Suppressing Strong Exciton–Phonon Coupling in Blue Perovskite Nanoplatelet Solids by Binary Systems

Abstract

Quasi-two-dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates.H owever,s trong exciton-phonon interactions caused by mechanical softening of the surface act as abottlenecki ni mproving their suitability for aw ide range of lighting and displayapplications.Moreover,itisnot easily available to tune the phonon interactions in bulk films.H ere,w ea dopt bottom-up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids.By optimizing component domains,the phonon coupling strength can be reduced by afactor of 2driven by the delocalization of 2D excitons in out-of-plane orientations.I ts hows the picosecond energy transfer originated from the Fçrster resonance energy transfer (FRET) efficiently competes with the excitonphonon interactions in the binary system.