Research ArticleMATERIALS SCIENCE

Two-dimensional hybrid perovskites sustaining strong polariton interactions at room temperature

See allHide authors and affiliations

Science Advances  31 May 2019:
Vol. 5, no. 5, eaav9967
DOI: 10.1126/sciadv.aav9967
  • Fig. 1 2D perovskite single crystal embedded in an optical cavity.

    (A) Schematic representation of a 2D perovskite single crystal embedded in an optical cavity formed by two DBRs; in 2D perovskite, inorganic layers are separated by organic ligands realizing an effective multiple layered QW structure. (B) Energy versus in-plane momentum k photoluminescence emission from the sample represented in (A), with k=2πλsinθ, θ being the emission angle; the white dashed and solid lines represent the cavity and the exciton uncoupled modes, respectively, and the orange line is a fit to the polariton lower mode with EX = 2.395 eV, EC = 2.385 eV, and ℏΩ = 170 meV.

  • Fig. 2 Nonlinearities in a cavity-embedded perovskite single crystal.

    (A) Transmittivity spectra obtained by cutting the dispersion in Fig. 1B in k = 0 and corresponding to different resonant excitation power for linear (A) and circular (B) polarized excitation laser. (C) Blueshift of the polariton modes in the case of a linear (L) and a circular (C) polarized laser; the dashed lines are linear fit to the experimental data with slopes of 1.75 and 0.83 meV/μW for C and L, respectively.

  • Fig. 3 2D perovskite single crystal grown on a glass substrate.

    (A) Schematic representation of the TIR configuration adopted for resonant blueshift measurements: An immersion oil objective (60×) is used to focus the excitation beam on a 2D PEAI single-crystal flake grown on a glass substrate; the same objective is used to collect the reflected light. (B) Energy and in-plane momentum k resolved reflectivity spectra of a thick single-crystal slab of PEAI; the dips in reflectivity correspond to lower polariton modes resulting from the coupling of the exciton mode to different optical modes; the white line represents the energy of the bare exciton mode; the red dashed lines represent lower polariton modes; the enhanced intensity for k ⩾ 10 μm1 corresponds to angles of incidence beyond the light line between air and the perovskite slab.

  • Fig. 4 Nonlinearities in a 2D perovskite single crystal.

    (A) Reflectivity spectra obtained for a PEAI single-crystal slab; the same excitonic mode is coupled to several optical modes of the slab; the two lower polariton modes highlighted by orange dashed lines originate from the coupling of the two optical modes (black dashed lines) to the excitonic mode (white solid line). (B) Energy shift of the lower polariton modes of (A) as a function of the incident power; the energy shift is measured at k ∼ 12.7 μm1 corresponding to the green region of (A). (C) Reversibility of the observed blueshift of the polariton modes; the red continuous curve corresponds to the energy of the polariton modes for low excitation power P = 10 μJ/cm2; the continuous blue curve shows the blueshifted modes at high excitation power P = 150 μJ/cm2; when the excitation power is reduced, the polariton modes recover the original energy (dashed red curve). (D) Hopfield coefficients showing the exciton (XLP1, XLP2) and photon (CLP1, CLP2) fraction of the two lower polariton modes of (A); the green vertical line represents the in-plane momentum of the resonantly created polariton, where LP1 has a larger exciton fraction than LP2.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/5/eaav9967/DC1

    Section S1. Material synthesis

    Section S2. Microcavity fabrication

    Section S3. Absorption and photoluminescence

    Section S4. Optical setup

    Section S5. Interaction constant

    Fig. S1. Absorption (blue) and photoluminescence (green) spectra measured on top of a PEAI single crystal with a 488-nm continuous-wave laser.

    Fig. S2. Optical setup used to measure the microcavity sample.

    Fig. S3. Exciton blueshift as a function of exciton density per QW obtained with a linearly polarized laser.

    Fig. S4. Microcavity-embedded single crystal.

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Material synthesis
    • Section S2. Microcavity fabrication
    • Section S3. Absorption and photoluminescence
    • Section S4. Optical setup
    • Section S5. Interaction constant
    • Fig. S1. Absorption (blue) and photoluminescence (green) spectra measured on top of a PEAI single crystal with a 488-nm continuous-wave laser.
    • Fig. S2. Optical setup used to measure the microcavity sample.
    • Fig. S3. Exciton blueshift as a function of exciton density per QW obtained with a linearly polarized laser.
    • Fig. S4. Microcavity-embedded single crystal.

    Download PDF

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article