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Wafer-scale synthesis of monolayer two-dimensional porphyrin polymers for hybrid superlattices

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Science  13 Dec 2019:
Vol. 366, Issue 6471, pp. 1379-1384
DOI: 10.1126/science.aax9385
  • Fig. 1 Wafer-scale monolayer 2DPs.

    (A) Schematic of monolayer 2DPs and corresponding chemical structures of the molecular precursors. (B) Absorption spectra of monolayer 2DPs on fused silica substrates. (C) Hyperspectral transmission images and resulting false-color images of 1-inch-square 2DP I on a 2-inch fused silica substrate. Transmission images taken at the wavelengths of 405, 420, and 440 nm were assigned red, green, and blue channels, respectively, to generate the false-color image. A linear transmission scale of 50 to 95% was applied to all of the channels. (D) False-color images of monolayer 2DPs covering entire 2-inch fused silica wafers. The same color code was applied in (C) and (D).

  • Fig. 2 Laminar assembly polymerization.

    (A) Schematic of a LAP reactor and in situ optical characterization apparatus. MSP, microsyringe pump. (B) Schematic of the LAP synthesis that involves three phases. (C) False-color images of 2DP I film at four different stages during growth. Images are individual frames extracted from movie S2 measured at the wavelength of 425 nm. The precursor was injected from the left side. The film was colored with purple. The view size is 6 mm by 24 mm. (D) Optical transmission images comparing monolayer films produced with and without Cu2+ ions before and after rinsing, measured at the wavelength of 425 nm. Image size is 0.67 cm by 1 cm. (E) (Left) Schematic of a linear growth model based on LAP. The film area increases linearly over time with a rate constant k = CN·A0·v·η/Neff, where CN is number concentration (i.e., the number of molecules per microliter) of the molecular precursor, A0 is the unit cell area of the 2DP I lattice, v is the volumetric injection rate, η is the monomer-to-monolayer yield, and Neff is the effective layer number. (Right) Relation between film area and volume of the injected precursor, measured for 2DP I. The dashed line indicates the theoretical curve for 100% monomer-to-monolayer conversion based on the lattice structure of 2DP I (η = 100%, Neff = 1). The data points were collected from movie S3. (F) False-color image of 2DP I/2DP III/2DP II lateral junctions. (Inset) Schematic of generating lateral heterostructures of 2DP I/2DP III/2DP II generated using three nozzles in LAP. (G) False-color images of 2DP I/2DP II lateral junctions with tunable stripe widths. (H) False-color image of overlapped 2DP I and 2DP II stripes. Scale bar, 500 μm.

  • Fig. 3 Structural characterizations of 2DPs.

    (A) SEM image of monolayer 2DP I on a holey silicon nitride TEM grid. The white arrow indicates a hole not covered by monolayer 2DP I. Scale bar, 5 μm. (Bottom left inset) Schematic of monolayer 2DP I suspended over a hole on a silicon nitride TEM grid. (Top right inset) Magnified SEM image of monolayer 2DP I suspended over a 2-μm hole. (B) AFM height image of monolayer 2DP I. Scale bar, 500 nm. (Inset) AFM height profile. (C) Experimental and calculated in-plane XRD profiles for 2DP II. The experiment was conducted on a stacked 2DP II of 147 layers on sapphire. (Inset) Crystal structure of 2DP II. (D) Constant-current STM topography image of a single-crystalline domain of monolayer 2DP II on a thin film of Au(111) on mica. (Inset) 2D FFT of the image. (E) Constant-current STM topography image of multiple-crystalline domains of monolayer 2DP II. Boundaries between different domains are manually identified by the white dashed line. (F) 2D FFT of (E) showing square lattices of three major orientations. (G) Color-coded inverse 2D FFT image generated using the three sets of square lattice spots in (F). One spot from each set is circled with the corresponding color in (F).

  • Fig. 4 2DP/TMD vertical superlattices.

    (A) (Left) Schematic of a 2DP/(MoS2)3 superlattice. (Middle) Cross-sectional ADF STEM image of a 2DP II/(MoS2)3 superlattice film transferred onto a SiO2/Si substrate. Each bright band consists of three MoS2 monolayers, and each dark layer between the bands is a monolayer 2DP II. (Right) Composite image of carbon (yellow) and oxygen (blue) EELS mapping and ADF STEM signal (green) taken from a different area on the sample shown in fig. S16. (B) Optical transmission image of a 2DP II/MoS2 heterostructure on fused silica taken at the wavelength of 405 nm. The diameter of the wafer is 1 inch. (C) (Left) Cross-sectional ADF STEM image of a 2DP III/(MoS2)2 superlattice film transferred onto a SiO2/Si substrate. Each bright layer consists of two layers of MoS2 stacked, and each dark layer is a 2DP III monolayer. (Right) EELS profiles of carbon and sulfur taken from a different area on the sample shown in fig. S16. Scale bar, 5 nm. (D) (Left) Structures of 2DP II/(MoS2)n vertical superlattices. (Middle) Normalized diffraction peaks corresponding to 2DP II /(MoS2)n superlattices measured by GIWAXS. (Right) 2D GIWAXS scattering patterns of 2DP II/(MoS2)n superlattices. Scale bar, 0.2 Å−1. (E) Schematic of vertical capacitor device arrays and individual device geometry. (F) Optical image of a 3-by-5 capacitor device array. Scale bar, 500 μm. (G) Reciprocal of area-normalized capacitance, 1/C′, as a function of N, the number of 2DP II layers in stacked (MoS2/2DP II)N(MoS2)6-N films. Each data point is averaged from 10 devices with corresponding stacked film structures shown above. Green, MoS2; yellow, 2DP II. The inset shows a capacitance histogram of 25 devices of N = 2.

Supplementary Materials

  • Wafer-scale synthesis of monolayer two-dimensional porphyrin polymers for hybrid superlattices

    Yu Zhong, Baorui Cheng, Chibeom Park, Ariana Ray, Sarah Brown, Fauzia Mujid, Jae-Ung Lee, Hua Zhou, Joonki Suh, Kan-Heng Lee, Andrew J. Mannix, Kibum Kang, S. J. Sibener, David A. Muller, Jiwoong Park

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

    Download Supplement
    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S20
    • Tables S1 to S3
    • Captions for Movies S1 to S3
    • References

    Images, Video, and Other Media

    Movie S1
    Formation of monolayer film at the injection point. The movie was taken in transmission mode at the injection end of a 1-inch by 2-inch reactor with 425 nm illumination for 2DP I growth. The complied avi file is played at 5× speed of the original recording. Injection rate: 10 μL/min. View size: 1 cm × 1 cm.
    Movie S2
    Laminar flow of film transport. The movie was taken in transmission mode at the center of a 1- inch by 5-inch reactor with 425 nm illumination for 2DP I growth. The precursor was injected from left side. The complied avi file is played at 5× speed of the original recording. Injection rate: 10 μL/min. View size: 2.5 cm × 2 cm.
    Movie S3
    Film formation and propagation with constant injection rate. The movie was taken at in transmission mode the upstream half of a 1-inch by 5-inch reactor with 425 nm illumination for 2DP I growth. The precursor was injected from left side. The complied avi file is played at 5× speed of the original recording. View size: 5 cm × 2 cm.

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