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Perovskite Patent Portfolio

NREL's perovskite patent portfolio focuses on eight technology areas that are critical to the development of a commercial perovskite solar cell device.

A perovskite solar cell.

These patents reflect perovskite device development from an applied perspective, capitalizing on NREL's world-class foundational perovskite research. Contact Bill Hadley to learn more about NREL's licensing process and ways to partner with NREL to further commercialize these technologies.

Key patents in these eight areas are listed below by patent number and title, each followed by a summary of the technology.

Unique Perovskite Deposition Processes

These patents consist of novel methods for growth and deposition of high-quality perovskite films. These techniques have been published in multiple peer-reviewed journals and are prepared for scaling to commercial levels.

Technology ID: 14-88
U.S. Patent: 9,701,696

A simple, low-temperature synthesis for preparing single-crystal mixed-halide perovskites such as MAPb(Br1-xClx)3. Single-crystal perovskites may be useful for multiple applications in lasers, photodetectors, or photovoltaic devices and the halide content can be tuned to optimize the material bandgap for the intended use.

Find additional information about this patent on the U.S. Department of Energy's (DOE's) Lab Partnering Service website.

Publications

A Facile Solvothermal Growth of Single Crystal Mixed Halide Perovskite CH3NH3Pb(Br1-xClx)3, Chemical Communications (2015)

Technology ID: 15-20
U.S. Patent Application: 15/574,611
European Patent Application: 16797238.9

This method of perovskite deposition uses a solvent-solvent (or "anti-solvent") crystallization step wherein a polar solution-dissolved perovskite complex in the presence of an excess methylammonium halide is bathed in a second nonpolar solvent, causing the perovskite complex to rapidly crystallize because of its lack of miscibility in the second solvent. Perovskite photovoltaic devices made with this method exhibit a 2%–3% increase in absolute photovoltaic conversion efficiency compared with standard deposition mechanisms and improved crystal grain morphology and uniformity. In addition, they can be rapidly formed on large-area substrates.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Room-Temperature Crystallization of Hybrid-Perovskite Thin Films via Solvent–Solvent Extraction for High-Performance Solar Cells, Journal of Materials Chemistry A (2015)

Square‐Centimeter Solution‐Processed Planar CH3NH3PbI3 Perovskite Solar Cells with Efficiency Exceeding 15%, Advanced Materials (2015)

Technology ID: 16-120
U.S. Patent Application: 15/784,251
Patent Cooperation Treaty Patent Application: PCT/US17/56729

A method of depositing an oriented polycrystalline perovskite film wherein each crystal grain is grown perpendicular to the growth substrate, allowing for significantly enhanced carrier lifetime (2.8 μs compared to 1.0 μs) and mobility (71 cm2 V-1 s-1 compared to 25 cm2 V-1 s-1) when compared to standard polycrystalline perovskite films. Formamidinium-based planar heterojunction photovoltaic devices fabricated using this method demonstrated an efficiency of 19.7% compared with an efficiency of 15.7% for films grown via a control method.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

300% Enhancement of Carrier Mobility in Uniaxial‐Oriented Perovskite Films Formed by Topotactic‐Oriented Attachment, Advanced Materials (2017)

Technology ID: 16-133
U.S. Patent Application: 15/934,656
Patent Cooperation Treaty Patent Application: PCT/US18/24140

Research at NREL has shown that perovskite photovoltaic devices may operate via the bulk photovoltaic effect, whereby charge carriers are separated by an induced internal dipole, rather than a p-n junction. This allows for open-circuit voltages in excess of the perovskite bandgap and could enable radically new perovskite device architectures.

Find additional information about this patent on DOE's Lab Partnering Service website.

Technology ID: 19-29
U.S. Provisional Patent Application: 16/801,398

By incorporating a multi-step application process called “self-seeding growth” (SSG), thin film perovskite devices yield far fewer defects than those produced via typical one-step precursor application processes. The process takes typically one-step perovskite precursor solutions and applies them to substrates over several steps where each successive application produces improved film quality and performance that has been “seeded” from the preceding step. SSG devices exhibit reduced defect densities, improved charge-carrier transport and lifetime, and enhanced hydrophobic properties that enable stable power conversion efficiencies above 20%. The process can be applied with different perovskite compositions and solvents, thus making it a versatile new method for preparing high-quality perovskite films with superior improvements to stability.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Perovskites at Scale

These patents consist of techniques and processes that enable rapid, inexpensive deposition of high-quality perovskite films. These inventions allow perovskite photovoltaics to be manufactured consistently and cost-effectively in an industrial environment.

Technology ID: 14-51
U.S. Patent Application: 15/312,714
European Patent: EP 3 149 765 B1
European Patent Applications: 18168162.8, 19193865.3

This invention relates to one- and two-step methods for the solution growth of methylammonium lead halide (e.g., MAPbI3) perovskite films involving the introduction of excess methylammonium chloride to the perovskite precursor solution. Importantly, the combination of the addition of excess methylammonium chloride methylammonium chloride, as well as the use of a mixed NMP/DMF precursor solvent, increases the processing window for anti-solvent-based film crystallization from only a few seconds to nearly eight minutes. This opens the door for consistent, reliable, roll-to-roll-based deposition of perovskite films using an anti-solvent approach. Moreover, these methods improve both the open-circuit voltage and the short-circuit current density of perovskite films and enhance crystal growth.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Perovskite Ink with Wide Processing Window for Scalable High-Efficiency Solar Cells, Nature Energy (2017)

Technology ID: 17-92
Patent Cooperation Treaty Patent Application: PCT/US18/54370 

Realizing practical applications of perovskite-based photovoltaic devices will likely require large-area perovskite solar modules that integrate multiple sub-cells. A major difference between small-area cells and large-area modules is the lack of interconnecting contacts between individual sub-cells. Because a module always consists of multiple interconnected sub-cells, and a large photocurrent is concentrated at the relatively narrow interconnections, the interface behavior at the interconnections becomes critically important to the performance of the module. This invention relates to methods for depositing and scribing large-area perovskite modules. By use of these techniques, a highly-efficient mixed-cation mini-module has been demonstrated with a power conversion efficiency of 15.6% over an aperture area of 10.36 cm2. This corresponds to an active area module conversion of 17.9% with a geometric fill factor of 87.3%.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Highly Efficient Perovskite Solar Modules by Scalable Fabrication and Interconnection Optimization, ACS Energy Letters (2018)

Technology ID: 18-27
U.S. Provisional Patent Application: 62/779,618

Recent work at NREL has shown that, over time, perovskite precursor inks using a DMF solvent degrade, resulting in a number of undesirable side products that may be subsequently incorporated into the deposited perovskite film. For instance, perovskite films deposited from a precursor ink on Day 1 achieved an 18.2% power conversion efficiency, while films deposited from the same precursor ink on Day 52 achieved only a 4.28% power conversion efficiency. Storage of perovskite precursor materials is critical to industrial deposition processes, which may use large amounts of precursor material. This technology describes solutions that enable storage of perovskite precursors for up to 31 days without any signs of degraded film performance.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Degradation of Highly Alloyed Metal Halide Perovskite Precursor Inks: Mechanism and Storage Solutions, ACS Energy Letters (2018)

Technology ID: 18-24
U.S. Patent Application: 16/297,539
Patent Cooperation Treaty Patent Application: PCT/US19/21496

Researchers at NREL have developed a method to manufacture perovskite photovoltaic devices that allows the top and bottom sections of a device to be fabricated independently. This method enables new device architectures (including those using perovskite heterojunctions) and may improve overall device stability and performance. It can also be performed at low pressures, making it suitable for high-volume roll-to-roll manufacturing.

Find additional information about this patent on DOE's Lab Partnering Service website. 

Publications

Curtailing Perovskite Processing Limitations via Lamination at the Perovskite/Perovskite Interface, ACS Energy Letters (2018)

Perovskite Chemistry

These patents consist of alternative thin film and quantum dot chemistries to the common methylammonium lead halide (CH3NH3PbI3) perovskite devices. These alternative compositions include novel organic, inorganic, and hybrid compositions for cations in the ABX3 perovskite crystalline structure and have been shown to improve the performance of perovskite films by demonstrating both increased stability and efficiency.

Technology ID: 15-105
U.S. Patent: 10,411,209
European Patent Application: 17747052.0
Chinese Patent Application: 201780019004.6
Indian Patent Application: 20182033346

Although most research has been centered around methylammonium lead halide perovskites (e.g., MAPbI3), formamidinium lead halide perovskite films (e.g., FAPbI3) in which the methylammonium cation is replaced, in whole or in part, with a formamidinium cation are also of significant interest because of their lower bandgap (1.45 eV compared to 1.55 eV) and increased thermal stability. Unfortunately, the morphology of FA-perovskites is much more difficult to control, making growth of FA-perovskites challenging. The invention here is a simple, effective method of performing a cation-exchange reaction on as-deposited films to change an MA-based perovskite film to an FA-based film while retaining the morphological character of the film. In this way, the benefits of MA-perovskite growth are retained for FA-based films.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Exceptional Morphology-Preserving Evolution of Formamidinium Lead Triiodide Perovskite Thin Films via Organic-Cation Displacement, Journal of the American Chemical Society (2016)

Technology ID: 16-81
U.S. Patent: 10,273,403

This invention relates to synthesis of optoelectronic devices using quantum dots composed of inorganic CsPbI3 perovskite materials. Photovoltaic devices produced from this approach have the highest power conversion efficiency and stabilized power output of any all-inorganic perovskite absorber, produce 1.23 V at open circuit (among the best of any perovskite device), and also function as light-emitting diodes emitting visible red light with low turn-on voltage. Compared with other CsPbX3 thin-film perovskite devices, NREL's quantum dot devices have improved power conversion efficiency (13.43% versus 9.8%), operational stability, and humidity tolerance. The open-circuit voltage of 1.23 V (at a bandgap of 1.73 eV) is remarkable compared with that of other quantum dot solar cells (˜0.7 V) and is among the highest VOC reported for all perovskite devices at a sub-2.0 eV bandgap. Based on their performance, CsPbI3 quantum dot films produced in this fashion may be desirable for both LEDs or as the high-bandgap cell in a tandem photovoltaic device.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Quantum Dot–Induced Phase Stabilization of α-CsPbI3 Perovskite for High-Efficiency Photovoltaics, Science (2016)

Enhanced Mobility CsPbI3 Quantum Dot Arrays for Record-Efficiency, High-Voltage Photovoltaic Cells, Science Advances (2017)

Technology ID: 18-43
U.S. Patent Application: 16/271,358
Patent Cooperation Treaty Patent Application: PCT/US19/17312

Recent work at NREL has demonstrated that CsPbBr3 nanocrystals, when exposed to a variety of complexing salts in solution, may form quasi-2-D networked nanocrystalline sheets that exhibit blueshifted emission because of disruption of the three-dimensional perovskite lattice. These sheets exhibit outstanding emissive properties, which are tunable by virtue of thermodynamic control over the solution composition.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Dynamic Evolution of 2D Layers within Perovskite Nanocrystals via Salt Pair Extraction and Reinsertion, The Journal of Physical Chemistry (2018)

Technology ID: 18-104
U.S. Patent Application: 16/540,592
Patent Cooperation Treaty Patent Application: PCT/US19/46520

Researchers at NREL have developed a process that involves routine synthesis of two compositions of perovskite quantum dots [formamadinium lead triiodide (FAPbI3) and cesium lead triiodide (CsPbI3)] that are then mixed together and heated to activate a cation-exchange reaction, resulting in a mixed-cation composition of (FAxCs1-x)PbI3 perovskite quantum dots with two distinct advantages. First, synthesis of previously unachievable (FAxCs1-x)PbI3 quantum dots with >50% cesium incorporation is now available, thus expanding the range of bandgaps, size, and material properties available in the (FAxCs1-x)PbI3 material system. Second, (FAxCs1-x)PbI3 quantum dots synthesized by this process exhibit open-circuit voltages approaching 90% of the theoretical thermodynamic limit, compared with ˜70% for identical materials synthesized by other means. This opens the door to exceptionally well-performing (FAxCs1-x)PbI3 quantum dot photovoltaic devices and optoelectronic structures.

Find additional information about this patent on DOE's Lab Partnering Service website. 

Publications

Perovskite Quantum Dot Photovoltaic Materials beyond the Reach of Thin Films: Full-Range Tuning of A-Site Cation Composition, ACS Nano (2018)

Technology ID: 18-106
U.S. Patent Application: 16/571,344
Patent Cooperation Treaty Patent Application: PCT/US19/51235

Researchers at NREL have developed performance benefits to various perovskite compositions by adding PEA+ and SCN- together to passivate defect densities and energy disorders at grain boundaries of perovskite layers.  Such a process merges performance efficiency and stability advantages of 3D and 2D perovskites respectively to optimize charge carrier mobility between layers and extend solar cell lifetime.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 18-113
Provisional U.S. Patent Application: 62/779,763

NREL researchers have developed novel additive enhancements to acetonitrile/methylamine perovskite inks to prevent the formation of microscopic cracks and defects during deposition processes. Such improvements enable lead-halide perovskite inks to be deposited on large-area substrates in one step with homogeneity and elimination of irregular drying patterns.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 19-03
Provisional U.S. Patent Application: 62/757,244

This invention introduces the novel incorporation of dimethylammonium ((CH₃)₂NH, or “DMA”) into the fractional composition of the ‘A’ site cation in perovskite films. Incorporation of DMA into the film improves film performance and stability at wide band gaps, ranging from 1.7-1.9 eV. A previous perovskite chemistry constraint has been the requirement for a high fractional percentage of Bromine (i.e. >20%) at the ‘X’ site which, while enabling access to higher band gaps, also greatly destabilized the perovskite film to a tendency for the ‘X’ site anions to phase segregate into iodine-rich and bromine-rich regions within the film. The inclusion of DMA into the composition eliminates this constraint, enabling access to stable, high-performance, wide bandgap perovskite devices with only a minimal fractional percentage of Bromine.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Perovskite Film Performance

These patents consist of film deposition methods, chemistry improvements, and engineering of the perovskite active layer and device architecture to push commercial perovskite device efficiencies to 20% and beyond.

Technology ID: 14-51
U.S. Patent Application: 15/312,714
European Patent: EP 3 149 765 B1
European Patent Applications: 18168162.8, 19193865.3

This invention relates to one- and two-step methods for the solution growth of methylammonium lead halide (e.g., MAPbI3) perovskite films involving the introduction of excess methylammonium chloride to the perovskite precursor solution. Importantly, the combination of the addition of excess methylammonium chloride methylammonium chloride, as well as the use of a mixed NMP/DMF precursor solvent, increases the processing window for anti-solvent-based film crystallization from only a few seconds to nearly eight minutes. This opens the door for consistent, reliable, roll-to-roll-based deposition of perovskite films using an anti-solvent approach. Moreover, these methods improve both the open-circuit voltage and the short-circuit current density of perovskite films and enhance crystal growth.

Find additional information about this patent on DOE's Lab Partnering Service Website.

Publications

Perovskite Ink with Wide Processing Window for Scalable High-Efficiency Solar Cells, Nature Energy (2017)

Technology ID: 15-105
U.S. Patent: 10,411,209

Although most research has been centered around methylammonium lead halide perovskites (e.g., MAPbI3), formamidinium lead halide perovskite films (e.g., FAPbI3) in which the methylammonium cation is replaced, in whole or in part, with a formamidinium cation are also of significant interest because of their lower bandgap (1.45 eV compared to 1.55 eV) and increased thermal stability. Unfortunately, the morphology of FA-perovskites is much more difficult to control, making growth of FA-perovskites challenging. The invention here is a simple, effective method of performing a cation-exchange reaction on as-deposited films to change an MA-based perovskite film to an FA-based film while retaining the morphological character of the film. In this way, the benefits of MA-perovskite growth are retained for FA-based films.

Find additional information about this patent on DOE's Lab Partnering Service Website.

Publications

Exceptional Morphology-Preserving Evolution of Formamidinium Lead Triiodide Perovskite Thin Films via Organic-Cation Displacement, Journal of the American Chemical Society (2016)

Technology ID: 15-40
U.S. Patent Application: 15/777,275
European Patent Application: 16867100.6

Because of the sensitivity of perovskite crystallization to processing conditions (temperature, humidity, pressure, anti-solvent application timing, etc.), the quality of MAPbI3 films may vary significantly from research lab to research lab (or production line to production line), resulting in perovskite photovoltaic devices with variable performance characteristics. Accordingly, it is desirable to develop a method for obtaining higher-quality perovskite films that are not subject to delicate processing controls. The present invention is a facile post-treatment that "heals" mediocre MAPbI3 films to form highly improved mixed-halide MAPbI3-XBrX films. Using this method, MAPbI3 films exhibiting mediocre 14%–16% power conversion efficiency were reliably converted to MAPbI3-XBrX films exhibiting power conversion efficiencies in excess of 19%.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Facile Fabrication of Large-Grain CH3NH3PbI3-XBrX Films for High-Efficiency Solar Cells via CH3NH3Br-Selective Ostwald Ripening, Nature Communications (2016)

Technology ID: 15-60
U.S. Patent Application: 15/762,500
European Patent Application: 16852820.6

Work at NREL has shown that the substrate on which a perovskite active layer is grown can have important effects on the deposited perovskite film. Capitalizing on this discovery, this invention relates to a perovskite photovoltaic device architecture that incorporates an interdigitated contact geometry of alternating lateral p-n junctions across the perovskite active layer. This architecture maximizes photocarrier collection and can be implemented through direct-write, high-throughput electronic printing or through traditional photolithograph processes. In addition, NREL researchers have used metal wires as the electrode and substrate for electron- or hole-transport layers to create threads that, when woven together, form flexible, defect-tolerant fabric with photovoltaic functionality.

Find additional information about this patent on DOE's Lab Partnering Service website.

Technology ID: 16-120
U.S. Patent Application: 15/784,251
Patent Cooperation Treaty Patent Application: PCT/US17/56729

A method of depositing an oriented polycrystalline perovskite film wherein each crystal grain is grown perpendicular to the growth substrate, allowing for significantly enhanced carrier lifetime (2.8 μs compared to 1.0 μs) and mobility (71 cm2 V-1 s-1 compared to 25 cm2 V-1 s-1) when compared to standard polycrystalline perovskite films. Formamidinium-based planar heterojunction photovoltaic devices fabricated using this method demonstrated an efficiency of 19.7% compared with an efficiency of 15.7% for films grown via a control method.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

300% Enhancement of Carrier Mobility in Uniaxial‐Oriented Perovskite Films Formed by Topotactic‐Oriented Attachment, Advanced Materials (2017)

Technology ID: 16-133
U.S. Patent Application: 15/934,656

Research at NREL has shown that perovskite photovoltaic devices may operate via the bulk photovoltaic effect, whereby charge carriers are separated by an induced internal dipole, rather than a p-n junction. This allows for open-circuit voltages in excess of the perovskite bandgap and could enable radically new perovskite device architectures.

Find additional information about this patent on DOE's Lab Partnering Service website. 

Technology ID: 17-100
Patent Cooperation Treaty Patent Application: PCT/US18/49489 

NREL researchers have developed methods to create wide-bandgap FA0.83Cs0.17Pb(I0.6Br0.4)3 perovskite solar cells with improved properties for tandem applications. When non-stoichiometric precursors with excess methylammonium halides were used during device fabrication, NREL researchers were able to create a device with a wide-bandgap (1.75 eV) absorber layer and improved crystallographic properties without affecting the final perovskite composition. These wide-bandgap perovskite films are of particular interest when paired in tandem photovoltaics with smaller bandgap (e.g., Si) solar cells.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Effect of Non-Stoichiometric Solution Chemistry on Improving the Performance of Wide-Bandgap Perovskite Solar Cells, Materials Today Energy (2018)

Perovskite Film Stability

These patents comprise technologies that improve perovskite device resistance to performance degradation over time. These technologies include methods of depositing perovskite films, encapsulant coatings, contact layer compositions, and novel film chemistries.

Technology ID: 15-106
U.S. Patent Application: 15/487,988

NREL researchers have developed a method to make a perovskite device with enhanced stability that is hermetically protected from degradation. This method consists of coating a perovskite device with a specialized hybrid organic-inorganic sol-gel epoxide encapsulant layer.

Find additional information about this patent on DOE's Lab Partnering Service website.

Technology ID: 15-40
U.S. Patent Application: 15/777,275
European Patent Application: 16867100.6

Because of the sensitivity of perovskite crystallization to processing conditions (temperature, humidity, pressure, anti-solvent application timing, etc.), the quality of MAPbI3 films may vary significantly from research lab to research lab (or production line to production line), resulting in perovskite photovoltaic devices with variable performance characteristics. Accordingly, it is desirable to develop a method for obtaining higher-quality perovskite films that are not subject to delicate processing controls. The present invention is a facile post-treatment that "heals" mediocre MAPbI3 films to form highly improved mixed-halide MAPbI3-XBrX films. Using this method, MAPbI3 films exhibiting mediocre 14%–16% power conversion efficiency were reliably converted to MAPbI3-XBrX films exhibiting power conversion efficiencies in excess of 19%.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Facile Fabrication of Large-Grain CH3NH3PbI3-XBrX Films for High-Efficiency Solar Cells via CH3NH3Br-Selective Ostwald Ripening, Nature Communications (2016)

Technology ID: 16-81
U.S. Patent: 10,273,403

This invention relates to synthesis of optoelectronic devices using quantum dots composed of inorganic CsPbI3 perovskite materials. Photovoltaic devices produced from this approach have the highest power conversion efficiency and stabilized power output of any all-inorganic perovskite absorber, produce 1.23 V at open circuit (among the best of any perovskite device), and also function as light-emitting diodes emitting visible red light with low turn-on voltage. Compared with other CsPbX3 thin-film perovskite devices, NREL's quantum dot devices have improved power conversion efficiency (13.43% versus 9.8%), operational stability, and humidity tolerance. The open-circuit voltage of 1.23 V (at a bandgap of 1.73 eV) is remarkable compared with that of other quantum dot solar cells (˜0.7 V) and is among the highest VOC reported for all perovskite devices at a sub-2.0 eV bandgap. Based on their performance, CsPbI3 quantum dot films produced in this fashion may be desirable for both LEDs or as the high-bandgap cell in a tandem photovoltaic device.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Quantum Dot–Induced Phase Stabilization of α-CsPbI3 Perovskite for High-Efficiency Photovoltaics, Science (2016)

Enhanced Mobility CsPbI3 Quantum Dot Arrays for Record-Efficiency, High-Voltage Photovoltaic Cells, Science Advances (2017)

Technology ID: 18-113
Provisional U.S. Patent Application: 62/779,763

NREL researchers have developed novel additive enhancements to acetonitrile/methylamine perovskite inks to prevent the formation of microscopic cracks and defects during deposition processes. Such improvements enable lead-halide perovskite inks to be deposited on large-area substrates in one step with homogeneity and elimination of irregular drying patterns.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 18-118
U.S. Patent Application: 16/585,843
Patent Cooperation Treaty Patent Application: PCT/US19/51235
Provisional U.S. Patent Application: 62/826,126

Researchers at NREL have developed a protective nucleation layer for perovskite solar devices and other semiconducting materials that helps to prevent damage to underlying layers from solvent applications during solar cell production and from exposure degradation due to ambient, humidity, oxygen, and reactive metal electrodes. 

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 19-03
Provisional U.S. Patent Application: 62/757,244

This invention introduces the novel incorporation of dimethylammonium ((CH₃)₂NH, or “DMA”) into the fractional composition of the ‘A’ site cation in perovskite films. Incorporation of DMA into the film improves film performance and stability at wide band gaps, ranging from 1.7-1.9 eV. A previous perovskite chemistry constraint has been the requirement for a high fractional percentage of Bromine (i.e. >20%) at the ‘X’ site which, while enabling access to higher band gaps, also greatly destabilized the perovskite film to a tendency for the ‘X’ site anions to phase segregate into iodine-rich and bromine-rich regions within the film. The inclusion of DMA into the composition eliminates this constraint, enabling access to stable, high-performance, wide bandgap perovskite devices with only a minimal fractional percentage of Bromine.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 19-21
Provisional U.S. Patent Application: 62/818,989

This technology improves on proven, stable architectures for perovskite photovoltaic modules by inverting the traditional layering structure on the substrate so that it takes on a Glass/Carbon_black/Perovskite/ETL/TCO structure. This novel approach enables three improved benefits: the removal of the constraint for perovskite ink to crystallize through small pores of a zirconium oxide layer, the enabled illumination of the device from the top rather than through the substrate, and enhanced stability through encapsulation via the Transparent Conductive Oxide (TCO) layer. 

Find additional information about this patent on DOE’s Lab Partnering Service website.

Technology ID: 19-29
U.S. Provisional Patent Application: 62/801,398

By incorporating a multi-step application process called “self-seeding growth” (SSG), thin film perovskite devices yield far fewer defects than those produced via typical one-step precursor application processes. The process takes typically one-step perovskite precursor solutions and applies them to substrates over several steps where each successive application produces improved film quality and performance that has been “seeded” from the preceding step. SSG devices exhibit reduced defect densities, improved charge-carrier transport and lifetime, and enhanced hydrophobic properties that enable stable power conversion efficiencies above 20%. The process can be applied with different perovskite compositions and solvents, thus making it a versatile new method for preparing high-quality perovskite films with superior improvements to stability.

Find additional information about this patent on DOE’s Lab Partnering Service website.

Perovskite Film Contact Layers

These patents comprise improvements to hole-selective, electron-selective, or other material layers found in perovskite-based optoelectronic devices.

Technology ID: 16-14
U.S. Patent Application: 15/777,841
European Patent Application: 16871398.0 

Despite their importance, the time scales and mechanics for charge extraction from perovskite absorber layers are generally poorly understood. This has the effect of creating ambiguity between the effects of perovskite absorber layer interfacial modifications on device performance and the fundamental mechanisms underlying that performance. Recent work at NREL has shown that the application of ultra-thin (5nm) interfacial layers of semiconducting single-walled carbon nanotubes (s-SWCNT) deposited between the perovskite absorber layer and the adjacent hole- and electron-selective contact layers can greatly improve perovskite photovoltaic device performance because of the performance of the s-SWCNT layers in preferentially extracting holes from the perovskite absorber layer, thereby reducing exciton recombination in the absorber layer itself and providing an enhanced driving force for electron extraction. Test devices using a single 5nm s-SWCNT interlayer deposited between a perovskite absorber and a spiro-OMeTAD hole-extraction layer have exhibited a 2% absolute efficiency gain when compared with control devices. Moreover, because of the favorable energetics of the s-SWCNT layers, design flexibility around novel contact layers outside of spiro-OMeTAD or TiO2 may be possible.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Efficient Charge Extraction and Slow Recombination in Organic–Inorganic Perovskites Capped with Semiconducting Single-Walled Carbon Nanotubes, Energy and Environmental Science (2016)

Charge Transfer Dynamics between Carbon Nanotubes and Hybrid Organic Metal Halide Perovskite Films, The Journal of Physical Chemistry Letters (2016)

Technology ID: 16-98
U.S. Patent: 10,332,688

One of the key components of a perovskite photovoltaic device is the hole transport layer that is in contact with the perovskite absorber to extract photogenerated holes. To perform this function, hole transport layers must have a relatively high conductivity and an affinity for holes. Although various hole transport layer materials have been studied, spiro-OMeTAD is currently the dominant hole transport material for high-efficiency perovskite devices. Despite its emergence, spiro-OMeTAD suffers from relatively low conductivity and requires extrinsic p-type doping, usually by Li-TFSI to achieve acceptable levels of conductivity. Further complicating the matter, it may take Li-TFSI thousands of hours to effectively dope spiro-OMeTAD to acceptable performance. To address these shortcomings, work at NREL has shown that the addition of moderate acids to the combination of spiro-OMeTAD and Li-TFSI noticeably improves the overall conductivity of the hole transport layer and significantly decreases the time to which full conductivity is reached. In a test of 30 devices using a non-acid-based spiro-OMeTAD hole transport layer and 50 devices including an acid additive to the spiro-OMeTAD hole transport layer, the devices with the acid additive exhibited an average power conversion efficiency of 17.1%, compared with the control devices' 14.5%.

Find additional information about this patent on DOE's Lab Partnering Service website.

Publications

Acid Additives Enhancing the Conductivity of Spiro‐OMeTAD toward High‐Efficiency and Hysteresis‐Less Planar Perovskite Solar Cells, Advanced Energy Materials (2016)

Technology ID: 16-97
U.S. Patent Application: 15/997,403
Patent Cooperation Treaty Patent Application: PCT/US18/35872 

Work at NREL has shown that the deposition conditions by which materials contacting a perovskite active layer are deposited can have significant impacts on the performance of the completed device—perhaps as significant as the nature of the contact layer material itself. The present invention describes methods of depositing contact layers on a perovskite active layer without compromising the performance of the overall device.

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Technology ID: 18-118
U.S. Patent Application: 16/585,843
Patent Cooperation Treaty Patent Application: PCT/US19/51235
Provisional U.S. Patent Application: 62/826,126

Researchers at NREL have developed a protective nucleation layer for perovskite solar devices and other semiconducting materials that helps to prevent damage to underlying layers from solvent applications during solar cell production and from exposure degradation due to ambient, humidity, oxygen, and reactive metal electrodes. 

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Perovskite Device Architecture

These patents comprise new perovskite solar cell device designs, such as interdigitated back-contact perovskite solar cell devices, that capitalize on the unique properties of the perovskite layer to create low-cost devices with improved efficiency and reliability.

Technology ID: 15-60
U.S. Patent Application: 15/762,500
European Patent Application: 16852820.6

Work at NREL has shown that the substrate on which a perovskite active layer is grown can have important effects on the deposited perovskite film. Capitalizing on this discovery, this invention relates to a perovskite photovoltaic device architecture that incorporates an interdigitated contact geometry of alternating lateral p-n junctions across the perovskite active layer. This architecture maximizes photocarrier collection and can be implemented through direct-write, high-throughput electronic printing or through traditional photolithograph processes. In addition, NREL researchers have used metal wires as the electrode and substrate for electron- or hole-transport layers to create threads that, when woven together, form flexible, defect-tolerant fabric with photovoltaic functionality.

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Technology ID: 17-92
Patent Cooperation Treaty Patent Application: PCT/US18/54370

Realizing practical applications of perovskite-based photovoltaic devices will likely require large-area perovskite solar modules that integrate multiple sub-cells. A major difference between small-area cells and large-area modules is the lack of interconnecting contacts between individual sub-cells. Because a module always consists of multiple interconnected sub-cells, and a large photocurrent is concentrated at the relatively narrow interconnections, the interface behavior at the interconnections becomes critically important to the performance of the module. This invention relates to methods for depositing and scribing large-area perovskite modules. By use of these techniques, a highly-efficient mixed-cation mini-module has been demonstrated with a power conversion efficiency of 15.6% over an aperture area of 10.36 cm2. This corresponds to an active area module conversion of 17.9% with a geometric fill factor of 87.3%.

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Publications

Highly Efficient Perovskite Solar Modules by Scalable Fabrication and Interconnection Optimization, ACS Energy Letters (2018)

Technology ID: 18-24

U.S. Patent Application: 16/297,539
Patent Cooperation Treaty Patent Application: PCT/US19/21496

Researchers at NREL have developed a method to manufacture perovskite photovoltaic devices that allows the top and bottom sections of a device to be fabricated independently. This method enables new device architectures (including those using perovskite heterojunctions) and may improve overall device stability and performance. It can also be performed at low pressures, making it suitable for high-volume roll-to-roll manufacturing.

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Publications

Curtailing Perovskite Processing Limitations via Lamination at the Perovskite/Perovskite Interface, ACS Energy Letters (2018)

Technology ID: 19-21
Provisional U.S. Patent Application: 62/818,989

This technology improves on proven, stable architectures for perovskite photovoltaic modules by inverting the traditional layering structure on the substrate so that it takes on a Glass/Carbon_black/Perovskite/ETL/TCO structure. This novel approach enables three improved benefits: the removal of the constraint for perovskite ink to crystallize through small pores of a zirconium oxide layer, the enabled illumination of the device from the top rather than through the substrate, and enhanced stability through encapsulation via the Transparent Conductive Oxide (TCO) layer. 

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Perovskite-Based Reversibly Transparent Photovoltaic Devices

These patents comprise inventions enabling perovskite devices that reversibly switch between a transparent and tinted state. These patent applications enable semi-transparent, photovoltaically active windows that modulate building thermal load while simultaneously converting solar radiation to power.

Technology ID: 15-108
U.S. Patent: 10,253,559 B2

European Patent Application: 16852492.4 
Saudi Arabia Patent Application: 518391212
United Arab Emirates Patent Application: P60000439/2018 

Work at NREL has combined the functionality of a thermochromic window with a photovoltaic cell to produce a "switchable" window implementing a MAPbI3 active layer that undergoes a reversible change from an optically transparent state to a shaded, photovoltaically active tinted state when illuminated by sunlight. This extraordinary technology thereby combines the benefits of both an electrochromic window (potential for 2.1 quads of energy savings by 2030) with a photovoltaic solar window (potential for 2.9 quads of energy generation by 2030) with an early estimated cost of about $6/m2 of glass coverage.

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Publications

NREL Scientists Are Developing Windows That Can Generate Electricity and Provide Their Own Shade, The Denver Post (2017)

Switchable Photovoltaic Windows Enabled by Reversible Photothermal Complex Dissociation from Methylammonium Lead Iodide, Nature Communication (2017)

Technology ID: 17-09
U.S. Patent Application: 15/906,696 

Additional work on switchable thermochromic windows at NREL has identified an alternative, all-inorganic, perovskite absorber layer—CsPbI3-xBrx—that also exhibits thermochromic behavior. Importantly, the CsPbI3-xBrx absorber does not use an intercalating species to induce its color change, relying instead on a crystallographic phase-change that may be more resilient to both environmental degradation and repeated cycling through multiple light-dark phases.

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Publications

Thermochromic Halide Perovskite Solar Cells, Nature Materials (2018)

Technology ID: 17-54
U.S. Patent Application: 15/976,108
Patent Cooperation Treaty Patent Application: PCT/US18/32088 

Further work on switchable thermochromic windows at NREL has developed improvements to the contact layers for these devices in which their transparency, conductivity, and gas permeability are improved.

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Technology ID: 18-23

U.S. Patent Application: 16/231,571

Patent Cooperation Treaty Patent Application: PCT/US18/67435

Yet further improvements on MAPbI3 switchable thermochromic windows relating to improved photovoltaic efficiency over repeated light/dark cycles.

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Contact

Bill Hadley | 303-275-3015