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The optical duality of tellurium nanoparticles for broadband solar energy harvesting and efficient photothermal conversion

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Science Advances  10 Aug 2018:
Vol. 4, no. 8, eaas9894
DOI: 10.1126/sciadv.aas9894
  • Fig. 1 Typical morphology and structure characterization results of Te nanoparticles prepared by ns-LAL.

    (A) SEM image of Te nanoparticles. (B) TEM image of a Te nanoparticle. (C and D) Corresponding HRTEM micrographs. (E and F) SAED and EDS patterns of the Te nanoparticle. (The Cu signal in EDS pattern originated from the Cu grid.) (G) XRD pattern of Te nanoparticles deposited on a Si substrate. (H) Raman spectrum of Te nanoparticles.

  • Fig. 2 Scattering spectra of individual Te nanoparticles.

    (A) Solid curves: Experimental backward scattering spectra of Te nanoparticles with diameters of 106.0 nm (black), 120.6 nm (red), 137.5 nm (blue), 156.1 nm (pink), and 178.4 nm (green). Dashed curves: Measurement results of the same Te nanoparticles after exposure to air for about 2 months. Insets: Corresponding SEM images of Te nanoparticles, respectively. Scale bar, 200 nm. a.u., arbitrary units. (B) Simulated backward scattering spectra of Te nanoparticles with diameters of 100 nm (black curve), 120 nm (red curve), 140 nm (blue curve), 160 nm (pink curve), and 180 nm (green curve). (C) Corresponding simulated absorption spectra of Te nanoparticles in (B).

  • Fig. 3 Optical duality of Te nanoparticles.

    (A) Real part of permittivity of Te compared with Au (a plasmonic material) and Si (an all-dielectric material). (B) Plasmonic-like behavior of Te nanoparticles with diameters smaller than 120 nm. (C) All-dielectric behavior of Te nanoparticles with diameters ranging from 120 to 340 nm. (D to F) Contributions of ED and MD to the scattering efficiency of Te nanoparticles embedded in air and water with diameters of 100, 200, and 300 nm, respectively.

  • Fig. 4 Photothermal effect of a Te nanoparticle layer deposited on the Si substrate.

    (A) SEM image of self-assembly of Te nanoparticles. (B) Size distribution based on the SEM image in (A) (statistic data from 500 particles). (C) Photograph of a bare Si wafer (left) and Te nanoparticle layer deposited on Si substrate (right). (D) Absorption spectrum (red curve) of the Te nanoparticle absorber. The blue area is the solar radiation spectrum. (E) Schematic diagram of Te nanoparticle layer irradiated by sunlight. (F) Time-dependent temperature variation of the bare Si wafer (black curve) and Te nanoparticle absorber (red curve). (G and H) Steady-state thermal images of the bare Si wafer and Te nanoparticle absorber, respectively.

  • Fig. 5 Perfect absorption of the Te nanoparticle layer.

    (A) Imaginary part of permittivity of Te compared with Au, Si, and Ge. (B) Schematic diagram of Te nanoparticle oligomer containing particles ranging from 25 to 300 nm. Inset: Perfect Te nanoparticle absorber. (C to H) Electric field enhancements of the oligomer at a broadband range from 300 to 2000 nm.

  • Fig. 6 Te nanoparticles used for water evaporation.

    (A) Measured UV-vis–NIR absorption spectrum of Te nanoparticle colloid solution (5 μg/ml). Inset: Gray Te nanoparticle colloid solution synthesized by ns-LAL. (B) ICP-AES analysis results of Te in the water before and after evaporation. The deionized water is used for reference. The dashed boxes indicate that the concentration is lower than the detection limit of ~0.05 μg/ml. (C) Vaporized weight of Te nanoparticle solutions with different concentrations under the illumination of simulated sunlight at 78.9 mW/cm2. (D) Vaporized weight of Te nanoparticle solutions (10 μg/ml) under different illuminations of simulated sunlight.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/8/eaas9894/DC1

    Fig. S1. Typical morphology and structure characterization of Te nanoparticles prepared by ns-LAL.

    Fig. S2. Scattering spectra of individual TeO2 nanoparticles.

    Fig. S3. Scattering and absorption spectra of Te nanoparticle oligomers.

    Fig. S4. The real part and imaginary part of the refractive index of Te, Au, and Si.

    Fig. S5. The scattering spectra of Au nanoparticles and Si nanoparticles.

    Fig. S6. The electric field enhancements of the Au nanoparticle oligomer.

    Fig. S7. Typical morphology and structure characterization of Te nanoparticles after working in steam generation for about 2 months.

    Fig. S8. Water evaporation using Te nanoparticles that have been working in steam generation for about 2 months.

    Fig. S9. An intuitive diagram illustrating the flow of energy in a photoexcited semiconductor.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Typical morphology and structure characterization of Te nanoparticles prepared by ns-LAL.
    • Fig. S2. Scattering spectra of individual TeO2 nanoparticles.
    • Fig. S3. Scattering and absorption spectra of Te nanoparticle oligomers.
    • Fig. S4. The real part and imaginary part of the refractive index of Te, Au, and Si.
    • Fig. S5. The scattering spectra of Au nanoparticles and Si nanoparticles.
    • Fig. S6. The electric field enhancements of the Au nanoparticle oligomer.
    • Fig. S7. Typical morphology and structure characterization of Te nanoparticles after working in steam generation for about 2 months.
    • Fig. S8. Water evaporation using Te nanoparticles that have been working in steam generation for about 2 months.
    • Fig. S9. An intuitive diagram illustrating the flow of energy in a photoexcited semiconductor.

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