Temperature-Dependent Electroabsorption Spectra and Exciton Binding Energy in a Perovskite CH3NH3PbI3Nanocrystalline Film

Morihiko Hamada, Shailesh Rana, Effat Jokar, Kamlesh Awasthi, Wei-Guang Diau, Nobuhiro Ohta*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    1 Scopus citations

    Abstract

    Temperature-dependent electroabsorption (E-A) spectra of methylammonium lead tri-iodide (MAPbI3) solid film, which result from the quadratic Stark effect of the exciton absorption band, have been analyzed with an integral method. The change in the electric dipole moment (Δμ) and polarizability (Δα) following exciton absorption was determined at each temperature; the absorption profile was separated into an exciton band and a continuum band caused by a transition from the valence band to the conduction band, and the position and the linewidth of the exciton absorption band were determined at each temperature. As the temperature decreased, a phase transition occurred from a tetragonal phase to an orthorhombic phase; the temperature dependence of Δμ and Δα differed greatly between the two phases. We have evaluated the exciton binding energy (EB) of MAPbI3 polycrystalline film with the following three methods: (1) fitting the temperature-dependent absorption profile; (2) fitting the temperature-dependent linewidth of the exciton absorption profile; and (3) fitting the photoluminescence intensity as a function of temperature. The EB values thus determined for samples fabricated with the same procedure are compared. Our estimated binding energies for an exciton of a MAPbI3 nanocrystalline film are also compared with those reported in the literature.

    Original languageEnglish
    Pages (from-to)11830-11840
    Number of pages11
    JournalACS Applied Energy Materials
    DOIs
    StatePublished - 28 Dec 2020

    Keywords

    • exciton binding energy
    • integral method analysis
    • methylammonium lead iodide perovskite
    • perovskite solar cells
    • temperature-dependent electroabsorption spectra

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