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Oriented Perovskite Crystals and Methods of Making the Same

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.

Description

In the last five years, scientists and engineers have revolutionized perovskites by incorporating formamidinium (HC(NH2)2+, FA+) cation into organic-inorganic lead halide devices. Perovskites containing FA+ show improved structural/chemical/opto-electronic properties, wider absorption spectral window into the NIR range, and longer charge carrier diffusion length. While these devices show great promise, some have already demonstrated efficiencies above 20%, they have so far shown excellent performance only when adopting a mesoscopic architecture. To successfully adopt FA-based perovskite layers in planer device geometries for various applications, alternative procedures for forming thick, uniform, material with enhanced charge transport will be necessary.

Researchers at NREL have created a FA-based perovskite device using an oriented crystal growth approach. Although this has traditionally been accomplished by incorporating chlorine, this approach has not been applied as successfully in FA-based perovskite devices due differences in reaction rates during sublimation. Researchers instead fabricated a uniaxially-oriented high-crystalline perovskite layer by utilizing a facile and simple topotactic oriented attachment (TOA) process. The resulting device exhibits unprecedented high 9 GHz charge-carrier mobility (up to 70.8 cm2V-1s-1) and an efficiency of 19.7%, comparable to that of mesoscopic perovskite structures.

This technology is within the Film Efficiency and Film Deposition groups of NREL’s perovskite portfolio. For further information regarding NREL's broader perovskite portfolio, please visit NREL's Perovskite Patent Portfolio website.

The Film Efficiency category consists of film deposition methods, chemistry improvements, and engineering of device layer and architecture to push commercial perovskite device efficiencies to 20% and beyond.

The Film Deposition category consists of novel methods for more rapid, less expensive, and more effective means of depositing perovskite films. These techniques have been published in multiple peer-reviewed journals and are prepared for scaling to commercial levels.

Benefits
  • Enables high performance FA-based perovskite planar heterojunction devices
  • Improved charge carrier mobility
  • Versatile process for other alloys including state-of-the-art triple cation and mixed halide perovskite compositions
Applications and Industries
  • Perovskites
  • Photovoltaics
More Information

WO 2018/071890

Oriented Perovskite Crystals and Methods of Making the Same

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018071890

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Application 20180105543
Application
20180105543
ORIENTED PEROVSKITE CRYSTALS AND METHODS OF MAKING THE SAME
An aspect of the present disclosure is a method that includes combining a first organic salt (A.sup.1X.sup.1), a first metal salt) a second organic salt (A.sup.2X.sup.3), a second metal salt (M.sup.2Cl.sub.2), and a solvent to form a primary solution, where A.sup.1X.sup.1 and M.sup.1(X.sup.2).sub.2 are present in the primary solution at a first ratio between about 0.5 to 1.0 and about 1.5 to 1.0, and A.sup.2X.sup.3 to M.sup.2Cl.sub.2 are present in the primary solution at a second ratio between about 2.0 to 1.0 and about 4.0 to 1.0. In some embodiments of the present disclosure, at least one of A.sup.1 or A.sup.2 may include at least one of an alkyl ammonium, an alkyl diamine, cesium, and/or rubidium.
National Renewable Energy Laboratory 10/16/2017
Filed
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL ROI 16-120PrototypeAvailable04/27/201803/28/2018

Contact NREL About This Technology

To: Bill Hadley<bill.hadley@nrel.gov>