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Patterned Amorphous Silicon Dopant Source For Interdigitated Back Contact (IBC) Solar Cells

National Renewable Energy Laboratory

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Technology Marketing Summary

The photovoltaic (PV) market today is dominated by silicon-based solar cells.  Increasing the efficiency of these types of solar cells at low cost is a high priority among silicon PV manufacturers; today, the most efficient type of silicon solar cells are constructed with an interdigitated back contact (“IBC”) process.  IBC type solar cells differ from standard silicon solar cells in that they have both electron- and hole-collecting contacts on the back of the cell, leaving the front side with no light-blocking, front-contact grid pattern. By avoiding shading losses incurred by the front-contact grid, IBC cells have improved efficiency compared to standard silicon-based PV cells.  Unfortunately, while IBC cells are highly efficient, they are also complicated to make, which increases their manufacturing cost.


Researchers at NREL have developed a novel method to manufacture highly efficient IBC solar cells at lower cost by simplifying the dopant patterning process on the back contacts and obviating the need for expensive high vacuum techniques such as ion implantation or plasma-based processes.  This new doping method involves layering of intrinsic (undoped) and patterned (doped) amorphous silicon films with subsequent annealing steps to enable dopants to cleanly diffuse into the underlying silicon film layers.  Importantly, this approach uses the same plasma assisted chemical deposition (PECVD) technique and tooling that are commonly used in the PV industry – only here, they’re used to cleanly deposit passivated n- and p-type contact layers for efficient function and production of the IBC technology.

  • A cleaner, simpler process for dopant patterning processes.
  • Savings in production steps.
  • No additional tooling or expensive techniques required.
  • Financial opportunities through process upgrades in IBC solar panel production
Applications and Industries
  • Residential and Commercial Solar Arrays
  • Distributed Energy Resources (DER)
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
ROI 17-08PrototypeAvailable07/16/201807/16/2018

Contact NREL About This Technology

To: Bill Hadley<>