Skip to Content
Find More Like This
Return to Search

Single-Walled Carbon Nanotube Buffer Layer for the Enhanced Performance of Perovskite Solar Cells

National Renewable Energy Laboratory

Contact NREL About This Technology

Technology Marketing Summary

Perovskite halides (e.g. CH3NH3PbI3 or MAPbI3) are a new class of light absorbers with exceptional and unparalleled progress in solar cell performance. A perovskite is any material with a specific ABX3 crystal structure, wherein an organic based cation is A, a metal cation is B, and a divalent halide anion is X. Work on solar cells using these perovskite materials has advanced rapidly as a result of the material’s excellent light absorption, charge-carrier mobilities, and lifetimes that result in high device efficiency with low-cost, industry-scalable technology. However, this potential for low cost and scalability requires overcoming barriers hindering the commercialization of perovskite devices related to perovskite stability, efficiency, and environmental compatibility. NREL researchers have made significant technical contributions within six areas critical to developing commercialized perovskite devices, which include increases in film efficiency and stability and innovations in perovskite film deposition methods, film chemistry, hole and electron extraction layer engineering, and device architecture.


NREL researchers have developed a novel process of inserting an ultrathin (e.g., 5-nm) layer of purely semiconducting single-wall carbon nanotubes (s-SWCNTs) between the perovskite and spiro-OMeTAD-based hole-transport layer. This process, which comprises depositing the s-SWCNT buffer layer through simple solution processing, is compatible with future low-cost manufacturing methods and has demonstrated through transient absorption dynamics to improve hole extraction efficiency. Furthermore, this process increases both short-circuit current (JSC) and fill factor and improves the conversion efficiency of MAPbI3 perovskites by about 2% when compared to a perovskite without an s-SWCNT buffer layer.

This technology is within the Hole and Extraction Layer Engineering category of NREL’s perovskite portfolio. For further information regarding NREL's broader perovskite portfolio, please visit NREL's Perovskite Patent Portfolio website.

The Hole and Electron Extraction Layer Engineering category comprises improvements to material layers in a perovskite solar cell device beyond the perovskite absorber layer itself. These technologies overcome the limitations of metal-organic device interfaces and spiro-OMeTAD interface layers.

  • 2% increase in conversion efficiency
  • Improves hole extraction efficiency
  • Increases JSC and fill factor
Applications and Industries
  • Perovskites
  • Photovoltaics
More Information

For further information on the status of the pending PCT application, please contact Bill Hadley.

Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL ROI 16-14PrototypeAvailable01/26/201701/26/2017

Contact NREL About This Technology

To: Bill Hadley<>