Single-Photon Emission from Single Microplate MAPbI_3 Nanocrystals with Ultranarrow Photoluminescence Linewidths and Exciton Fine Structures

摘要

Stimulated by the superior performance of organic–inorganic MAPbI_3perovskite films in photovoltaic devices, a lot of research interest is nowbeing devoted to their low-dimensional nanocrystals (NCs) to extend theoptoelectronic functionalities as well as to promote the potential applicationsin quantum information technologies. Compared to other organic–inorganicand all-inorganic counterparts that have been intensively studied, theMAPbI_3 NCs suffer from the optical and chemical instabilities so that theirsingle-particle photophysical properties have been largely unexplored up tonow. Here, the authors have synthesized single MAPbI_3 microplates froma two-step method and characterize their optical properties mainly at thecryogenic temperature, showing that localized optical emitters are universallypresent with the quantum feature of single-photon emission. Photoluminescence(PL) linewidth measured for such a single quantum emittercan be as narrow as ≈200 μeV, as a direct consequence of its embedmentinside the microplate with the spectral diffusion effect being greatly suppressed.This has allowed them to resolve the exciton fine structures fromsome of the studied single quantum emitters, each of which is manifestedas a PL doublet with the energy separation of ≈600 μeV and the orthogonallylinear polarizations.