{
  "patent_number": "US 9287431",
  "country": "US",
  "title": "How to Make High-Efficiency Solar Cells with Stacked Layers",
  "original_title": "Superstrate sub-cell voltage-matched multijunction solar cells",
  "summary": "This patent describes a solar cell design that stacks two different types of light-absorbing layers, cadmium telluride and silicon, connecting them in parallel to capture more sunlight efficiently.",
  "what_it_does": "This patent describes a special type of solar cell called a multijunction cell. It combines an \"upper sub-cell\" made of cadmium telluride (CdTe) with a \"lower sub-cell,\" often made of silicon (Si), as stated in claim 1 and claim 2. These two sub-cells are separated by a transparent insulating layer and are designed to be \"voltage-matched,\" meaning they produce similar electrical pressure. Crucially, they are connected in parallel (claim 1), which allows their currents to add up while maintaining a consistent voltage. Light enters through a transparent \"superstrate,\" like glass (claim 9), hitting the CdTe layer first, then passing through to the lower Si layer. For example, a solar panel could use this design to convert a broader spectrum of sunlight into electricity than a single-layer cell.",
  "what_it_does_not_cover": [
    "Solar cells where the different light-absorbing layers are connected in series, rather than in parallel.",
    "Multijunction solar cells that do not use a cadmium telluride (CdTe) upper sub-cell.",
    "Designs where the upper and lower sub-cells are not specifically \"voltage-matched.\"",
    "Solar cells that do not include a transparent insulating layer between the upper and lower sub-cells.",
    "Lower sub-cells that lack an interdigitated p-type and n-type back contact made of Si, as specified in claim 1."
  ],
  "filed": "2014-04-02",
  "granted": "2016-03-15",
  "expires": "2034-04-02",
  "status": "active",
  "holder": "Alliance for Sustainable Energy",
  "holder_url": "https://patentbrief.org/company/alliance-for-sustainable-energy",
  "inventors": [
    {
      "name": "Angelo Mascarenhas",
      "url": "https://patentbrief.org/inventor/angelo-mascarenhas"
    },
    {
      "name": "Kirstin Alberi",
      "url": "https://patentbrief.org/inventor/kirstin-alberi"
    }
  ],
  "times_cited": 18,
  "tags": [
    "renewable_energy",
    "semiconductors",
    "consumer_electronics",
    "materials"
  ],
  "abstract": "Voltage-matched thin film multijunction solar cell and methods of producing cells having upper CdTe pn junction layers formed on a transparent substrate which in the completed device is operatively positioned in a superstate configuration. The solar cell also includes a lower pn junction formed independently of the CdTe pn junction and an insulating layer between CdTe and lower pn junctions. The voltage-matched thin film multijunction solar cells further include a parallel connection between the CdTe pn junction and lower pn junctions to form a two-terminal photonic device. Methods of fabricating devices from independently produced upper CdTe junction layers and lower junction layers are also disclosed.",
  "url": "https://patentbrief.org/patent/us/9287431/superstrate-sub-cell-voltage-matched-multijunction-solar-cells",
  "markdown_url": "https://patentbrief.org/patent/us/9287431/superstrate-sub-cell-voltage-matched-multijunction-solar-cells/md",
  "google_patents_url": "https://patents.google.com/patent/US9287431",
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}