Graphene-based multi-modal sensors

{
  "publication_number": "US9863885B2",
  "country": "US",
  "kind": "B2",
  "title": "Graphene-based multi-modal sensors",
  "abstract": "A method for fabricating a composite film structure, the method includes determining a desired morphology for a metallic layer of the composite film structure, selecting a first metal substrate based on the determining, transferring a graphene layer onto the first metal substrate, depositing the metallic layer on the graphene layer to achieve the desired morphology, and removing the first metal substrate from the graphene and the deposited metallic layer to form the composite film structure. A surface energy difference between the first metal substrate and the deposited metallic layer results in the desired morphology of the metallic layer.",
  "claims": [
    "1. A method for fabricating a composite film structure, the method comprising: determining a desired morphology for a metallic layer of the composite film structure; selecting a first metal substrate based on the determining; transferring a graphene layer onto the first metal substrate; depositing the metallic layer on the graphene layer to achieve the desired morphology, wherein a surface energy difference between the first metal substrate and the deposited metallic layer results in the desired morphology of the metallic layer, the desired morphology comprises a layer of nanoislands having controlled and uniform inter-nanoisland separation and a distance between edges of nanoislands in the metallic layer is on the order of about 2 Å to a few nanometers, and removing the first metal substrate from the graphene and the deposited metallic layer to form the composite film structure.",
    "2. The method of claim 1, wherein depositing the metallic layer comprises deposition of evaporated flux of metallic atoms.",
    "3. The method of claim 2, wherein the evaporated flux of metallic atoms self-assemble to yield the desired morphology.",
    "4. The method of claim 2, where in the evaporated flux of metallic atoms are produced by electron beam evaporation, thermal evaporation, or sputtering.",
    "5. The method of claim 1, wherein transferring the graphene layer onto the first metal substrate comprises exfoliating the graphene grown on a second metal substrate and placing the graphene layer onto the first metal substrate; and wherein the graphene comprises a single layer of graphene.",
    "6. The method of claim 5, wherein the graphene is grown on the second metal substrate using chemical vapor deposition.",
    "7. The method of claim 1, wherein the first metal substrate comprises a transition metal.",
    "8. The method of claim 7, wherein the transition metal comprises gold, silver, or nickel.",
    "9. A method of forming a substrate for surface-enhanced Raman scattering, the method comprising: depositing a graphene layer on a first metal substrate; depositing a plurality of metallic nanoislands on the graphene layer, wherein a surface energy difference between the first metal substrate and the deposited metallic nanoislands results in the desired morphology of the metallic nanoislands, the desired morphology comprises a layer of nanoislands having controlled and uniform inter-nanoisland separation and a distance between edges of nanoislands in the metallic layer is on the order of about 2 Å to a few nanometers; removing the first metal substrate from the graphene and the deposited plurality of metallic nanoislands to form the substrate for surface-enhanced Raman scattering.",
    "10. A method of performing surface-enhanced Raman scattering of an analyte, the method comprising: forming a substrate for surface-enhanced Raman scattering according to the method of claim 9; transferring the substrate on an optical fiber; coating the analyte on the substrate; and recording surface-enhanced Raman scattering signals from the analyte.",
    "11. The method of claim 10, wherein the plurality of metallic nanoislands comprises a plasmonically active metal.",
    "12. The method of claim 11, wherein the plasmatically active metal comprises copper, silver, palladium, gold, or platinum nanoislands.",
    "13. A method of performing surface-enhanced Raman scattering of an analyte, the method comprising: forming a substrate for surface-enhanced Raman scattering according to the method of claim 9; transferring the substrate on an optical fiber; placing the substrate into the analyte; and recording surface-enhanced Raman scattering signals from the analyte."
  ],
  "description_excerpt": "This invention relates to sensors.\n\nGraphene has several attractive characteristics. It is flexible and stretchable compared to metallic films, conductive, transparent, amenable to large-area growth and transfer to many substrates, and its crystalline grains can extend over dimensions reaching 1 cm.\n\nThe disclosed multimodal sensors can generate electrical responses to mechanical stimuli (tensile, compressive strains) as well as serve as surface-enhanced Raman scattering (SERS) substrates to evaluate local chemical environments by Raman spectroscopy.\n\nThe disclosed sensors and methods herein relate to a strain sensor having unprecedented high sensitivity (gauge factor ˜700 at 1% strain), a useful range from 0.001% strain to above 10% strain, and good cyclability.\n\nThe disclosed sensors and methods also include graphene-supported SERS substrates deposited onto tips of optical fibers that enable remote Raman sensing applications.\n\nThe systems and methods disclosed herein provide the first demonstration of measuring cardiomyocytes contractions using a mechanical strain sensor. By culturing cardiomyocytes on the sensor substrates, it is possible to record and analyze spontaneous and stimulated cardiomyocyte contractions using the sensors and methods disclosed herein. Strains sensors disclosed herein can also be used for structural health monitoring (civil engineering, aeronautics), biometrics acquisition (heart rate, motion detection), groundwater contamination testing, in-vivo biochemical analysis (optical fiber catheterization), and drug discovery (new drug screening, cardiotoxicity studies).",
  "cpc": [
    "G01N 21/658",
    "B82Y 15/00",
    "B82Y 40/00",
    "C23C 14/024",
    "C23C 14/04",
    "C23C 14/18",
    "C23C 14/30",
    "C23C 16/01",
    "C23C 16/0227",
    "C23C 16/26",
    "C23C 16/56",
    "G01B 7/18",
    "G01L 1/18",
    "G01N 2021/651",
    "G01N 27/028",
    "G01N 27/04"
  ],
  "ipc": [
    "C23C 14/18",
    "C23C 14/30",
    "C23C 16/01",
    "C23C 16/02",
    "C23C 16/26",
    "G01L 1/18",
    "G01N 21/65",
    "G01N 27/02"
  ],
  "assignees": [
    "University of California"
  ],
  "inventors": [
    "Aliaksandr Zaretski",
    "Darren J. Lipomi",
    "Alex Savtchenko",
    "Elena Molokanova",
    "Mark Mercola"
  ],
  "filing_date": "2016-10-07",
  "publication_date": "2018-01-09",
  "grant_date": "2018-01-09",
  "priority_date": "2015-10-07",
  "application_number": "US-201615288687-A",
  "family_id": "58488553",
  "cited_by_count": 118,
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}