Perovskite solar cells are significantly different from traditional silicon photovoltaic cells, in construction, efficiency, manufacturing, deployment and development costs, environmental impact, and the types of materials that can be used in the crystalline structures.
Overview
Perovskites come in several crystalline structures, including hybrid perovskites made of lead, iodine or bromine, and organic compounds. The inexpensive materials are rapidly advancing solar cell research and also has potential applications in advancing LEDs and lasers. In the past several years, perovskite solar cell efficiency has had a seven-fold increase. Silicon solar cell efficiencies have had very little improvement in the last couple of decades. Several labs have achieved efficiencies above 20 percent with hybrid perovskite solar cells, rivaling commercially available silicon solar cells.
Tandem and triple layer collector/converter hybrid perovskite solar cells have been demonstrated greatly improved stability and shows increased conversion efficiency in recent independently verified studies.
The addition of a titanium oxide layer also overcomes one of the key drawbacks of hybrid perovskite solar cells – humidity and related environmental factors. When the first findings were published in 2009, the conversion efficiency was just 3.8%, but in just seven years the efficiency has jumped to over 22% and a team in Tokyo announced a 44% efficiency hybrid cell in 2016.
Materials
The perovskite structure is adopted by many oxides that have the chemical formula ABO3.
Lead Halides: Many formulas are being tested utilizing materials like Lead Bromide, Lead Chloride, and many types of Iodides including Lead.
Titania Nanomaterials: A variety of oxides are being evaluated also, including Titania, Titanium, Titanium Dioxide, Titanium Isopropoxides.
Titania Precursors: Currently, the precursors are all based on various forms Titanium(IV) Isopropoxides or Titantium Diisopropoxide bis(acetylacetonate).
Hole Conductor Cobalt Dopants:
Several types of salts are being evaluated, including FK 102 Co(II & III) PF6, FK 102 Co(II & III) TFSI, FK 209 Co(II & III) TFSI, FK 209 Co(II & II) PF6, FK 269 Co(II & III) PF6, and FK 269 Co(II & III) TFSI.
Halide Sources:
Two types of acids in various purities and concentrations are being used at this time.
A) Hydriodic acid with purities ranging from 47% to 99.99%.
B) Hydrobromic acid with purities ranging from 48% to 99.99%.
Solar Conversion Efficiency
Single crystal silicon based solar cells had an efficiency of 14% in the mid-1970s and peaked at 25% in the mid-1990s. The best Silicon heterostructures (HIT) achieve 25.6%. Multicrystalline silicon structures had an efficiency of approximately 25% in the late 1980s and peaked at 27.6% in 2004. Multijunction cells have hit 46% in the past year. Emerging PV are hitting 22-26%, with some recent reports in 2016 showing efficiencies up to 44%.
Physics
The physics and chemistry involved are very detailed and require advanced technical knowledge. Please see the abstract and published article referenced later in this section for additional information concerning the physics involved with the development and advancement of perovskite solar cells.
"Organo-metal halide perovskite solar cells have shown remarkable progress in power conversion efficiencies in the past five years due to some amazing intrinsic properties such as long-range ambipolar transport characteristics, high dielectric constants, low exciton binding energies, and intrinsic ferroelectric polarizations. This review article discusses recent results with the focus on fundamental physics involved in internal photovoltaic processes in perovskite solar cells. The discussion includes charge transport, photoexcited carriers versus excitons, exciton binding energies, ferroelectric properties, and magnetic field effects. The objective of this review article is to provide the critical understanding for materials synthesis and device engineering to further advance photovoltaic actions in the state-of-the-art organo-metal halide perovskite solar cells."
Architecture
The Office of Energy Efficiency & Renewable Energy[1] has the SunShot Initiative which supports research and development projects aimed at increasing the efficiency and lifetime as well as evaluating new materials for hybrid organic-inorganic perovskite solar cells.
According to Energy.gov, one of the main environmental concerns for the current architecture is related to lead-based perovskite absorbers. Research is being conducted toward eliminating the toxicity of the lead-based absorbers or replacing the lead with current or future materials that do not negatively impact the environment.
Another type of structure that is showing great promise is tandem device architectures which use a combination of perovskite solar cells and multi-crystalline silicon cells. These take advantage of wide-gap high open voltage properties of perovskite solar cells.
The final challenge to widespread commercial deployment and use for clean energy production lies in scale-up and optimization of the deposition processes for duplicatable perovskite solar cell performance. The SunShot levelized cost of electricity (LCOE) target of $0.06 per kilowatt-hour, which perovskite solar cells can easily achieve once commercial scale-up can be implemented.
History
Power from the Sun has been a goal of humanity throughout history. Interestingly, it was during the Industrial Revolution that interest in alternative fuel sources because it was recognized at that point that relying on non-renewable fuel sources like coal and oil would eventually cripple the economy.
The first solar cell: French physicist Alexandre Edmond Becquerellar first demonstrated the photovoltaic effect. He is credited with developing the first solar cell that directly converted sunlight to electricity.
The first solar motor: Auguste Mouchout is credited with building the first device that directly converted solar radiation into mechanical power. His device used a solar reflector and a steam boiler to produce about 1/2 horsepower. He demonstrated it to Emperor Napoleon III in Paris, and received financial support to build a large solar engine in Algeria six years later. He refined his reflector, developed a truncated cone, built a tracking mechanism to keep the reflector following the sun and improved his boiler. The first solar icemaker:
In 1878, Auguste Mouchout demonstrated a new invention that used a redesigned version of his solar engine to run a condenser on a separate insulated box that was able to rapidly cool it down. He was awarded a medal for the accomplishment.
The first rooftop solar array: Charles Fritts is credited with building the world's first rooftop solar array in New York in 1883. Unfortunately, he used selenium combined with an extremely thin layer of gold for his solar cells. This had a conversion efficiency of only 1%. It was not until the middle of the 20th century that practical solar cells were developed.
The first spacecraft to use solar panels:
In 1958, the US Naval Research Laboratory launched Vanguard I. The US Government pioneered much of the early PV technology. Bell Labs developed the first modern photovoltaic cell in 1954. NASA launched the first satellite equipped with solar panels that tracked the Sun in 1964.
Power Tower Concept:
In 1860, William Adams pioneered the solar collection tower concept that is still used today. His award-winning book entitled Solar Heat: A Substitute for Fuel in Tropical Countries presented creative and practical improvements to Mouchout's system and new innovations. Adams advocated using small flat mirrors arranged in a semicircle that would each reflect the light to the central boiler mounted on a tower. The mirrors were mounted on a track that could be adjusted through the day to maximize collection.
The first non-reflecting/non-concentrating solar motor:
In 1885, Charles Tellier installed ten plates on his roof that used ammonia due to its lower boiling point and when heated by solar energy produced enough ammonia gas, which drove a water pump with enough power to pump 300 gallons per hour throughout the day. He is considered the father of modern refrigeration.
The first Parabolic Trough Collector system:
In 1870, Swedish-born engineer John Ericsson, developed a solar motor with similar design characteristics as Mouchout's. After that he built the first trough reflector collector system which is far easier to adjust and doesn't need complicated tracking mechanisms. His trough system is still used today as a great engineering compromise between peak collection and ease of use. John also developed the USS Monitor, improved propellers, and an independent hot air engine.
The first Perovskite Solar Cell:
In 2009, Myasaka and team published the first their report of their application of hybrid organic-inorganic perovskite absorbers in solar cells in 2006. The conversion efficiency was rather low, approximately 3.8%, due in part to the liquid electrolyte used and the open circuit voltage due to compromised interfacial chemistry and energetics.
Stability
Stability and longevity are two of the critical challenges to overcome before perovskite solar cells or more likely hybrid multijunction solar cells can be successfully deployed commercially and to the residential market.
Numerous research angles are proceeding evaluating a variety of photoactive layers, absorbers, balanced electron and hole transporting properties, resistance to humidity, mitigation or elimination of lead based components, and readily duplicatable flexible films with high efficiency.
Current benchmarks are achieving 16-25% efficiency with cells that are durable for a minimum of 1,000 hours. For commercial success, durability must be increased by orders of magnitude - a minimum of ten years service life with little or no maintenance.
Introduction
Perovskite solar cells are significantly different from traditional silicon photovoltaic cells, in construction, efficiency, manufacturing, deployment and development costs, environmental impact, and the types of materials that can be used in the crystalline structures.
Overview
Perovskites come in several crystalline structures, including hybrid perovskites made of lead, iodine or bromine, and organic compounds. The inexpensive materials are rapidly advancing solar cell research and also has potential applications in advancing LEDs and lasers. In the past several years, perovskite solar cell efficiency has had a seven-fold increase. Silicon solar cell efficiencies have had very little improvement in the last couple of decades. Several labs have achieved efficiencies above 20 percent with hybrid perovskite solar cells, rivaling commercially available silicon solar cells.
Contents
Introduction | Overview | Contents | Features | Materials | Solar Conversion Efficiency | Physics | Architecture | History | Stability | ReferencesFeatures
Tandem and triple layer collector/converter hybrid perovskite solar cells have been demonstrated greatly improved stability and shows increased conversion efficiency in recent independently verified studies.
The addition of a titanium oxide layer also overcomes one of the key drawbacks of hybrid perovskite solar cells – humidity and related environmental factors. When the first findings were published in 2009, the conversion efficiency was just 3.8%, but in just seven years the efficiency has jumped to over 22% and a team in Tokyo announced a 44% efficiency hybrid cell in 2016.
Materials
The perovskite structure is adopted by many oxides that have the chemical formula ABO3.
Lead Halides:
Many formulas are being tested utilizing materials like Lead Bromide, Lead Chloride, and many types of Iodides including Lead.
Organohlides:
Acetamidinium, Benzylammonium, Butylammonium, Diethylammonium, Ethylammonium, Formadidinium, Guanidinium, Imidazolium, Imidazolium, Methylamine, Phenethylammonium, and Propylammonium.
Titania Nanomaterials:
A variety of oxides are being evaluated also, including Titania, Titanium, Titanium Dioxide, Titanium Isopropoxides.
Titania Precursors:
Currently, the precursors are all based on various forms Titanium(IV) Isopropoxides or Titantium Diisopropoxide bis(acetylacetonate).
Hole Conductor Cobalt Dopants:
Several types of salts are being evaluated, including FK 102 Co(II & III) PF6, FK 102 Co(II & III) TFSI, FK 209 Co(II & III) TFSI, FK 209 Co(II & II) PF6, FK 269 Co(II & III) PF6, and FK 269 Co(II & III) TFSI.
Halide Sources:
Two types of acids in various purities and concentrations are being used at this time.
A) Hydriodic acid with purities ranging from 47% to 99.99%.
B) Hydrobromic acid with purities ranging from 48% to 99.99%.
Solar Conversion Efficiency
Single crystal silicon based solar cells had an efficiency of 14% in the mid-1970s and peaked at 25% in the mid-1990s. The best Silicon heterostructures (HIT) achieve 25.6%. Multicrystalline silicon structures had an efficiency of approximately 25% in the late 1980s and peaked at 27.6% in 2004. Multijunction cells have hit 46% in the past year. Emerging PV are hitting 22-26%, with some recent reports in 2016 showing efficiencies up to 44%.
Physics
The physics and chemistry involved are very detailed and require advanced technical knowledge. Please see the abstract and published article referenced later in this section for additional information concerning the physics involved with the development and advancement of perovskite solar cells.
In the Journal of Materials Chemistry A, Issue 30, 2015, an article published by Yu-Che Hsiao, et al.
"Organo-metal halide perovskite solar cells have shown remarkable progress in power conversion efficiencies in the past five years due to some amazing intrinsic properties such as long-range ambipolar transport characteristics, high dielectric constants, low exciton binding energies, and intrinsic ferroelectric polarizations. This review article discusses recent results with the focus on fundamental physics involved in internal photovoltaic processes in perovskite solar cells. The discussion includes charge transport, photoexcited carriers versus excitons, exciton binding energies, ferroelectric properties, and magnetic field effects. The objective of this review article is to provide the critical understanding for materials synthesis and device engineering to further advance photovoltaic actions in the state-of-the-art organo-metal halide perovskite solar cells."
Architecture
The Office of Energy Efficiency & Renewable Energy[1] has the SunShot Initiative which supports research and development projects aimed at increasing the efficiency and lifetime as well as evaluating new materials for hybrid organic-inorganic perovskite solar cells.
According to Energy.gov, one of the main environmental concerns for the current architecture is related to lead-based perovskite absorbers. Research is being conducted toward eliminating the toxicity of the lead-based absorbers or replacing the lead with current or future materials that do not negatively impact the environment.
Another type of structure that is showing great promise is tandem device architectures which use a combination of perovskite solar cells and multi-crystalline silicon cells. These take advantage of wide-gap high open voltage properties of perovskite solar cells.
The final challenge to widespread commercial deployment and use for clean energy production lies in scale-up and optimization of the deposition processes for duplicatable perovskite solar cell performance. The SunShot levelized cost of electricity (LCOE) target of $0.06 per kilowatt-hour, which perovskite solar cells can easily achieve once commercial scale-up can be implemented.
History
Power from the Sun has been a goal of humanity throughout history. Interestingly, it was during the Industrial Revolution that interest in alternative fuel sources because it was recognized at that point that relying on non-renewable fuel sources like coal and oil would eventually cripple the economy.
The first solar cell:
French physicist Alexandre Edmond Becquerellar first demonstrated the photovoltaic effect. He is credited with developing the first solar cell that directly converted sunlight to electricity.
The first solar motor:
Auguste Mouchout is credited with building the first device that directly converted solar radiation into mechanical power. His device used a solar reflector and a steam boiler to produce about 1/2 horsepower. He demonstrated it to Emperor Napoleon III in Paris, and received financial support to build a large solar engine in Algeria six years later. He refined his reflector, developed a truncated cone, built a tracking mechanism to keep the reflector following the sun and improved his boiler.
The first solar icemaker:
In 1878, Auguste Mouchout demonstrated a new invention that used a redesigned version of his solar engine to run a condenser on a separate insulated box that was able to rapidly cool it down. He was awarded a medal for the accomplishment.
The first rooftop solar array:
Charles Fritts is credited with building the world's first rooftop solar array in New York in 1883. Unfortunately, he used selenium combined with an extremely thin layer of gold for his solar cells. This had a conversion efficiency of only 1%. It was not until the middle of the 20th century that practical solar cells were developed.
The first spacecraft to use solar panels:
In 1958, the US Naval Research Laboratory launched Vanguard I. The US Government pioneered much of the early PV technology. Bell Labs developed the first modern photovoltaic cell in 1954. NASA launched the first satellite equipped with solar panels that tracked the Sun in 1964.
Power Tower Concept:
In 1860, William Adams pioneered the solar collection tower concept that is still used today. His award-winning book entitled Solar Heat: A Substitute for Fuel in Tropical Countries presented creative and practical improvements to Mouchout's system and new innovations. Adams advocated using small flat mirrors arranged in a semicircle that would each reflect the light to the central boiler mounted on a tower. The mirrors were mounted on a track that could be adjusted through the day to maximize collection.
The first non-reflecting/non-concentrating solar motor:
In 1885, Charles Tellier installed ten plates on his roof that used ammonia due to its lower boiling point and when heated by solar energy produced enough ammonia gas, which drove a water pump with enough power to pump 300 gallons per hour throughout the day. He is considered the father of modern refrigeration.
The first Parabolic Trough Collector system:
In 1870, Swedish-born engineer John Ericsson, developed a solar motor with similar design characteristics as Mouchout's. After that he built the first trough reflector collector system which is far easier to adjust and doesn't need complicated tracking mechanisms. His trough system is still used today as a great engineering compromise between peak collection and ease of use. John also developed the USS Monitor, improved propellers, and an independent hot air engine.
The first Perovskite Solar Cell:
In 2009, Myasaka and team published the first their report of their application of hybrid organic-inorganic perovskite absorbers in solar cells in 2006. The conversion efficiency was rather low, approximately 3.8%, due in part to the liquid electrolyte used and the open circuit voltage due to compromised interfacial chemistry and energetics.
Stability
Stability and longevity are two of the critical challenges to overcome before perovskite solar cells or more likely hybrid multijunction solar cells can be successfully deployed commercially and to the residential market.
Numerous research angles are proceeding evaluating a variety of photoactive layers, absorbers, balanced electron and hole transporting properties, resistance to humidity, mitigation or elimination of lead based components, and readily duplicatable flexible films with high efficiency.
Current benchmarks are achieving 16-25% efficiency with cells that are durable for a minimum of 1,000 hours. For commercial success, durability must be increased by orders of magnitude - a minimum of ten years service life with little or no maintenance.
References
http://uvutechnologymanagement.wikispaces.com/Photovoltaic+Cells
http://uvutechnologymanagement.wikispaces.com/Solar+Energy+and+the+Enviornemnt
http://pubs.acs.org/doi/abs/10.1021/acs.chemrev.5b00715?journalCode=chreay
https://en.wikipedia.org/wiki/Oxide
http://pubs.rsc.org/en/content/articlelanding/2015/ta/c5ta01376c#!divAbstract
http://www.energy.gov/eere/sunshot/hybrid-organic-inorganic-halide-perovskite-solar-cells
https://en.wikipedia.org/wiki/Edmond_Becquerel
https://en.wikipedia.org/wiki/Augustin_Mouchot
https://en.wikipedia.org/wiki/Charles_Fritts
https://en.wikipedia.org/wiki/William_Grylls_Adams
https://en.wikipedia.org/wiki/Charles_Tellier
https://en.wikipedia.org/wiki/John_Ericsson
https://www.ncbi.nlm.nih.gov/pubmed/19366264