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Energy-Harvesting Chromogenic Devices

National Renewable Energy Laboratory

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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.


Researchers at NREL have developed a perovskite photovoltaic device that reversibly switches between a transparent and tinted state. In its first state the device is transparent and converts only non-visible spectrum light to current. When the device is sufficiently heated (i.e. in direct sunlight) its crystalline phase changes and it absorbs the visible portion of the solar spectrum, effectively becoming tinted. This invention is a significant step towards the economical production of solar windows that dynamically modulate absorption and transmission properties while converting sunlight into usable electricity.

This technology is within the Perovskite-based Reversibly Transparent Photovoltaic Devices category of NREL’s perovskite portfolio. For further information regarding NREL's broader perovskite portfolio, please visit NREL's Perovskite Patent Portfolio website.

The Perovskite-based Reversibly Transparent Photovoltaic Devices category consists of inventions enabling perovskite devices that switch between a transparent and tinted state in different environments. These technologies enable solar windows that modulate building lighting in addition to converting solar radiation into current.

  • Switchable between light absorbing and transparent states
  • Photovoltaically active in both absorbing and transparent state
  • Tunable switching temperature
Applications and Industries
  • Smart windows
  • Building integrated photovoltaics
  • Commercial and residential buildings
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL ROI 17-09PrototypeAvailable04/27/201803/28/2018

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To: Bill Hadley<>