What is perovskite
Perovskites and"Faceless"Similar approach but similar effect,In fact, calcium,titanium,The words "mine" have nothing to do with each other.,What is called in photovoltaic field"perovskite",Refers to a class related to perovskite(CaTiO3)The crystal structure is similar to"ABX3"compound.This structure looks like this:
The perovskite structure can be represented by ABX3,in short,Perovskite materials do not refer to the narrow sense"perovskite"Made of materials,It is a general term for materials with a specific structure..To avoid ambiguity,described below"perovskite",If no special instructions,Both refer to photovoltaic materials with this perovskite-like structure.,rather than a literal perovskite(CaTiO3).
Year 2009,When Japanese scientist Tsutomu Miyasaka first used perovskite solar cells to generate electricity,Photoelectric conversion efficiency is only 3.8%,At that time, the conversion efficiency of the crystalline silicon battery laboratory had reached about 18%..Only 12 years have passed,Perovskite laboratory conversion efficiency record has reached 29.8%,Exceeding the most efficient heterojunction currently available,The efficiency limits of crystalline silicon technologies such as TOPCon,A few steps ahead of other technical routes for thin film batteries.
Advantages of perovskite photovoltaic cells
1.Compared to crystalline silicon,Perovskite materials are designable.
The ability to continuously iterate materials is the biggest advantage of perovskites.1954,The advent of silicon transistors,from then to today,Crystalline silicon material has never changed at all,Perovskites are different.Year 2009,Japanese scientists use perovskite solar cells to generate electricity for the first time,the next ten years,Its recipe has been changed many times,Earth-shaking changes have taken place.
Perovskite photoelectric conversion efficiency is a gradual process,But compared to crystalline silicon,The speed of evolution is much faster.As shown below,Perovskite took about 10 years,Increased conversion efficiency from the initial 3.8% to the current laboratory efficiency record of over 29%(end of 21),Catching up with the development of crystalline silicon over the past forty or fifty years,This is in the history of the development of photovoltaic technology,never had.Support this rapid progress,It is the continuous improvement of perovskite materials and structures that
2. High photoelectric conversion efficiency limit.
After decades of improvements,Solar cells have encountered major bottlenecks in continuing to improve the conversion efficiency of crystalline silicon cells;Photovoltaic materials have a limit in converting solar energy into electricity.The level of this limit depends on their"Bandgap",i.e. releasing electrons from a material,making it the energy required for charge carriers to flow in a circuit.Crystalline silicon has a band gap of 1.1 eV,it means from the sun,Photons with energy less than 1.1 eV cannot release electrons,Photons above 1.1 eV can still generate charge carriers,But part of the photon energy exceeding 1.1 eV will be wasted in the form of heat energy.Since Bell Labs in the United States developed the first practical crystalline silicon solar cell in 1954,,The highest conversion efficiency that can be achieved in the laboratory is around 27%.
At present, the theoretical limits of different technologies for crystalline silicon modules are:
Theoretical limit efficiency of crystalline silicon solar cells:29.43%;
The maximum efficiency of ordinary monocrystalline silicon cells under ideal conditions is 24.5%;
The maximum efficiency of TOPCon battery under ideal conditions is 27.5%;
HJT batteries have a higher efficiency upper limit:28.2%-28.7%
Perovskites are direct bandgap materials,The light absorption capacity is much higher than that of crystalline silicon materials.The single-layer theoretical efficiency of new perovskite photovoltaic cells can reach 31%,Perovskite double-junction tandem battery conversion efficiency can reach 35%,The theoretical efficiency of perovskite triple-junction tandem cells can reach more than 45%.And if new materials are doped,The conversion efficiency of perovskite cells can reach an astonishing 50%,It is about 2 times that of current crystalline silicon cells.
3. From the production side,Important advantages of perovskite cells——Significantly shorten the industrial chain.
at present, According to GCL Optoelectronics:100 MW single perovskite cell factory,from glass,Adhesive film,Target material,Chemical raw materials entry,to component molding,Only takes 45 minutes in total.
For crystalline silicon,silicon material,silicon wafer,Battery,Components require production and processing in more than four different factories,If all links are seamlessly connected,It takes about three days to complete a component.,The time taken varies greatly.
4. From the perspective of production capacity investment,Perovskite cells have huge advantages
Compare with 1GW capacity investment,Crystalline silicon material,silicon wafer,Battery,Add all components together,Need about 900 million,Investment scale close to 1 billion yuan,The perovskite production capacity investment of 1GW,After reaching a certain maturity,About 500 million yuan,It is 1/2 of crystalline silicon
5. Raw material advantages
From a raw material perspective,Perovskites are direct bandgap materials,The light absorption capacity is much higher than that of crystalline silicon materials.Silicon wafers in crystalline silicon modules,Thickness is typically 180 microns,In perovskite components,The thickness of the perovskite layer is about 0.3 microns,There is a difference of three orders of magnitude.Contrast crystalline silicon,If 500,000 tons of silicon material were completely replaced by perovskite,About 1,000 tons can meet the demand,so,Perovskite raw materials have no bottlenecks,First, the dosage is small,Second, there is no scarcity
6. Low purity requirements,Low energy consumption
Solar grade silicon,Purity needs to reach 99.9999%(6 nines),Now there are standards that have raised the purity to 99.99999%(7 9s).But for perovskites,Just need 1 9(95%)can meet the needs of use,This one 9,Not only will it reduce energy consumption,At the same time, there will be a fundamental improvement in stability..
From the perspective of energy consumption,There is a number for comparison——Energy consumption per 1 watt of monocrystalline module manufacturing,About 1.52KWh,The energy consumption of perovskite modules is 0.12KWh,Energy consumption per watt is only 1/10 of crystalline silicon,This is a significant advantage.
7. Low manufacturing cost
From a comprehensive cost perspective,Compared to crystalline silicon,Perovskites also have great advantages——Monolithic module cost structure,Perovskite materials account for only about 5%,The total cost is about 5 cents to 6 cents,It is 50% of the limit cost of crystalline silicon.
8. High actual power generation efficiency
From the perspective of temperature coefficient,Crystalline silicon components are about -0.3,this means,Every 1 degree increase in temperature,Power will drop by 0.3%.That is to say,If the factory calibration is 20% efficiency,In practical applications,When the temperature rises to 75 degrees,The efficiency is only about 16%,17%.The temperature coefficient of perovskite is -0.001,very close to 0,Therefore, its actual power generation efficiency will be significantly higher than that of crystalline silicon...
Disadvantages of perovskite cells????
Now many friends who know something about perovskite photovoltaic cells should know the two biggest problems of perovskite photovoltaic cells 1. Stability(attenuation)2. Toxicity: What is the actual situation of these problems??
1. Stability
If someone wants to judge the efficiency or stability of perovskites,Then please ask one more question——Which perovskite are you talking about??first two years,Perovskite performance is indeed unstable,But to this day,The stability of perovskite is no worse than that of crystalline silicon.
Everyone questions the stability of perovskite,This actually stems from doubts about the crystal structure.Crystalline silicon is a diamond structure,It can be heated to more than 1,400 degrees before it starts to melt.,Perovskite is a hexagonal ionic crystal structure,Its decomposition temperature is about 200 degrees Celsius - 300 degrees Celsius.More than 1,000 degrees,It does seem like a big difference.,But if we look at it from a practical perspective,We can get another conclusion.we know,Solar cells used on the Earth's surface,It is difficult for the temperature to exceed the range of 75 degrees to 85 degrees,so,Two or three Baidus are enough,And 1400 degrees becomes a huge redundancy. CCTC®
Apply barrel effect,Crystalline silicon’s high temperature resistance of 1400 degrees,It's a long, long board,But to a certain extent,It doesn’t make much sense,The shortcomings of crystalline silicon are also obvious.——Impurity tolerance is too low.Light decay of crystalline silicon,For example, the light decay of PERC batteries,In fact, it comes from the boron-oxygen pair,Even the presence of boron-oxygen pairs in parts per million,It will also cause the crystalline silicon to melt at 75 degrees,Produces 1%~4% efficiency attenuation,Perovskites can tolerate impurities at the 1% level,This is the difference between one millionth and one hundredth.
in fact,The stability of perovskite is improving year by year.
2016,A university conducted an experiment on a palm-sized perovskite component.——under standard light source,Let the component work continuously for 12,000 hours,The result is no attenuation.However, some domestic media have misinterpreted it——They thought perovskites had a lifespan of only 12,000 hours,thus making erroneous reports
2019,A newer advancement has emerged.
This improvement is at the material formula level,Recipes become more complex,Also added some liquid,at 70 degrees continuously,400 hours of light,without any attenuation,Test extended to 1800 hours,Attenuation is still less than 5%,This data is very positive,No crystalline silicon can do this.
Because of different packages,Will bring different attenuation effects,2020,Kunshan GCL Optoelectronics has conducted a series of work and experiments around packaging,Discover components that are not well packaged,Will decay soon,But well-encapsulated components,In double 85(85℃,85%RH)under conditions,No degradation within 2000 hours
end of 2020,A more robust experimental data also demonstrates the competitiveness of perovskites.Under the crystalline silicon IEC61215 standard,Perovskite module works continuously for 9,000 hours without any degradation,It can be said clearly,This result,Likewise, no crystalline silicon can achieve so,On the stability of perovskite solar cells,Perovskites are superior in terms of stability,Or,This is probably an advantage of perovskites.
From the end of September to early November 2019,GCL conducts 75-degree cooling on 45×65 modules,More than 1,000 hours of continuous actual testing,You can see the red power curve in the picture above,There is also no attenuation
2. Toxicity(Lead content)
In addition to stability,There is another issue that is often questioned about perovskites.——Lead content.I have some academic friends,They want to work on developing a lead-free perovskite.This may be due to their insufficient understanding of the crystalline silicon industry,they feel,Perovskite contains lead,It's a big sin,So try to replace it with something else if possible.
But in fact,If research is done on crystalline silicon,It will be found that the amount of lead used in the crystalline silicon industry far exceeds that of perovskite——Although silicon wafers do not contain lead,But the soldering tape is copper foil coated with lead.,There are approximately 18 grams of lead in each standard size crystalline silicon module,And perovskite modules of the same size,Contains no more than two grams of lead,The lead content of perovskite is only 1/10 of that of crystalline silicon,so,About the controversial lead content,Actually it’s a pseudo question
The global development status of perovskite photovoltaic cells
1 USA
1. U.S. government policy on perovskite photovoltaic cells
a. The U.S. Department of Energy’s Solar Technology Office supports various perovskite startups at different stages of development through different programs.These companies include Beyond Silicon,BlueDot Photonics,CubicPV,Energy Materials Company,First Solar,GVD Corporation,Nanosonic,nTact,Optigon,Swift Solar and Tandem PV.To increase the diversity of companies working on perovskite commercialization,U.S. Department of Energy’s Solar Energy Technologies Office launches Perovskite Entrepreneurship Awards,for new company(Established after October 16, 2020)Provide seed funding.More mature startups are eligible for the Small Business Innovation Research (SBIR) grant program run jointly by the Office of Science and the U.S. Department of Energy’s Solar Energy Technologies Office and Competitiveness Team.
b. April 25, 2021,The U.S. Department of Energy (DOE) announced the 2021 perovskite solar cell R&D and mass production funding project on its website: ( Web link )
The total amount of OE funding reached US$40 million.(About 270 million yuan),22 funded projects.Funding projects are divided into:First group:Device R&D(Conversion efficiency and stability)(TOPIC AREA 1: Device R&D (Efficiency and Stability));Second Group:Mass production development(TOPIC AREA 2: Manufacturing R&D);The third group:Verification and Financing Center(TOPIC AREA 3: Validation and Bankability Center).These projects will promote the development of perovskite photovoltaic devices and manufacturing R&D,and neutralize the performance of new perovskite devices through a new $14 million test center,independent verification.
2. Relevant information about American perovskite battery companies
April 2022,U.S. perovskite company Tandem PV completes first half of $12 million Series A financing,previously,The company said the $6 million in funding will be used to build a pilot production plant at its headquarters in San Jose, California..US market-focused Tandem PV will use the investment to produce its first commercial-grade tandem solar modules,Designed to provide customers with more efficient,More affordable solar power
Tandem PV specializes in"Super efficient"Tandem metal perovskite solar module production.By utilizing perovskite-coated front glass,Transforming silicon solar modules into highly efficient tandem solar modules
Tandem PV is the brainchild of Colin Bailie, Ph.D. in Materials and solar industry stalwart,Co-founded by Chris Eberspacher, former CTO of Hanwha Solar
Co-founder and CEO Bailie said,"We secured residential solar installers,end user,Strong market drivers from equipment distributors and utility companies.The industry strives to use more sustainable,More efficient and economical solar modules are ready."
Eberspacher said:"Tandem PV is being developed rapidly across the United States and globally,Demonstrate and commercialize perovskite and silicon tandem solar modules."
Tandem said in a media report,The round was led by early-stage venture capital firm Bioeconomy Capital through its new Planetary Technologies fund,Participants include an international solar manufacturer and a U.S. utility company.
2 South Korea
1. The Korean government’s policy on perovskite photovoltaic cells
Korea trade,ministry of industry and energy(MOTIE)A new roadmap has been released for the domestic solar module industry,The roadmap plans to invest heavily in efficient,expensive product,For example, panels based on tandem solar cells
.According to the document,Domestic solar manufacturers and research institutions in South Korea expect tandem solar cell technology based on silicon and perovskite to be the most promising candidate for the next generation of photovoltaics..According to MOTIE,The Korean semiconductor and display industry may benefit from providing its expertise in silicon product and thin film development,play a decisive role in this transition
MOTIE said,The next five years,About 190 billion won($159.7 million)of public investment will go into research into tandem photovoltaic technology,Hopes to reach 26% efficiency by 2023,Achieve 35% efficiency by 2030.also,Plans to allocate another 25 billion won,Construction of 100 MW research and development facility,To test TOPCon,Heterojunction and tandem solar technologies.
2. Related information about Korean perovskite battery companies
2021,South Korean solar module manufacturer Hanwha QCells will invest 1.5 trillion won over the next five years(US$1.28 billion),To expand solar module manufacturing capabilities,and increase R&D activities in their home countries.Part of this investment commitment will be invested in TOPCon and tandem perovskite technology,Expanded production capabilities will include perovskite and TOPCon production lines,However, the specific production capacity is not yet certain.,No further details were provided.
December 2021,Hanwha Q Cells-led perovskite-crystalline silicon stacked cell technology selected for a three-year South Korean national project,Develop and commercialize perovskite crystalline silicon solar cells with high durability and efficiency
The Korean industry generally believes that,By connecting perovskite cells in series on the surface of crystalline silicon cells,Can maximize the use of solar spectrum energy,Obtain higher photoelectric conversion efficiency than pure crystalline silicon cells or perovskite cells.This is also considered to be the perfect combination of third-generation solar cell technology and second-generation solar cell technology.,Simply connect individual cells in series,Ensure that the current through each battery is the same.Current mainstream perovskite industrialization research focuses on the future of stacked-layer batteries,Crystalline silicon technology researcher,In particular, heterojunction cell technology researchers also highly recognize perovskite-crystalline silicon stack technology.
Hanwha Q Cells is one of the top ten overseas players in the world in crystalline silicon module shipments,The original purpose of acquiring Q CELLS was to maintain the leading edge in battery technology,But in recent years, in addition to the cooperation with Longi,Jinko and others have repeatedly struggled with foreign companies for PERC patent rights.,Other technological breakthroughs are rare.To ensure the competitive advantage of Korean photovoltaic technology,Korea Institute of Energy Technology Evaluation and Planning (KETEP) and two research institutions,Three universities and more sign an agreement with Hanwha,Joint research on perovskite-crystalline silicon battery stack technology,Securing Korea’s original technology for basic materials,Promote the commercialization of next-generation solar modules,Improve competitiveness in the global solar market.
3 Japan
1. The Japanese government’s policy on perovskite photovoltaic cells
2021,The Senate of the Japanese Diet formally passed the revised《Global Warming Countermeasures Promotion Act》,The Japanese government’s goal of achieving carbon neutrality by 2050 has been clarified in the form of legislation..Become another photovoltaic powerhouse to announce a carbon neutrality deadline
in key tasks,《Global Warming Countermeasures Promotion Act》Opinions on photovoltaic development,It is believed that the research and development of promising next-generation solar cell technologies including perovskite solar cells should be accelerated,Demonstration and deployment;Increase the deployment scale of solar buildings,Promote the development of solar building integration
Perovskite solar cells belong to the third generation of solar cells,Solar cells using perovskite-type organic metal halide semiconductors as light-absorbing materials,It is quite different from the current mainstream crystalline silicon solar cells in terms of cost and technical route CCTC®
Japan wants to boost carbon neutrality goals by developing perovskite solar cells,It is very likely that it contains the intention to avoid Chinese photovoltaic companies.,However, there is currently no leading company in perovskite solar cells.
2.Related information about Japanese perovskite battery companies
November 2019,Japan's Panasonic's perovskite module achieves record efficiency,Obtain 16.1% photoelectric conversion efficiency on a module area of 800-6500cm².
Japanese electronics manufacturer Toshiba announced in September 2021,The photoelectric conversion efficiency of polymer thin film perovskite photovoltaic modules based on 703 cm² reached 15.1%
4 Europe
The European photovoltaic industry is continuing to lose ground.The number of photovoltaic cell and module manufacturers in Europe is currently in the low double digits.The number of bankruptcies continues to rise.European Perovskite Initiative(EPKI)of member states believe perovskite technology can bridge this gap.Considering the disastrous record of the European PV industry over the past 10-12 years,There are currently too few European companies willing to invest in photovoltaic technology.in the EU,Perovskite research is dispersed across many countries,Among them, there are more than 65 research institutions under the EPKI umbrella.
5 China
1. Chinese government’s policies on perovskite photovoltaic cells
China's National Energy Administration and the Ministry of Science and Technology released the 14th Five-Year Plan for Science and Technology Innovation in the Energy Sector in April 2022.
Among them, in solar power generation technology, it is clearly pointed out that high-efficiency perovskite cell preparation and industrial production technology should be carried out.
China’s Ministry of Science and Technology announced the national key research and development plan in early 2022"High-end functions and smart materials"Key special projects
The first project is led by Southern University of Science and Technology,Kunshan GCL Optoelectronic Materials Co., Ltd.,Hefei Institute of Physical Sciences, Chinese Academy of Sciences,Institute of Physics, Chinese Academy of Sciences,Huazhong University of Science and Technology serves as the project undertaking unit,CATL New Energy Technology Co., Ltd.,Beijing University,Tianjin University,Shanghai Jiao Tong University is a participating unit of the 2021 National Key Research and Development Plan"High-end functions and smart materials"Key projects,"Key materials and macro-scale preparation technology for new generation perovskite solar cells"(Project number 2021YFB3800100),Recently received project announcement.The total project budget exceeds 90 million yuan,GCL Optoelectronics undertakes sub-projects"Pilot production of hundreds of megawatt perovskite modules"research tasks
The core of perovskite photovoltaic cells——"equipment".
Two problems currently existing in perovskite photovoltaic cells:
First, the efficiency of large areas is not as good as that of small areas.,The main reason is:Uneven coating,Coating equipment needs breakthrough.
Second , the issue of stability,The main reason is:Magnetron sputtering method for depositing TCO films(PVD),Too much energy,Causes roughness on the surface of the film layer,Not conducive to stability.From the device side,The current industrialization idea is to use reactive plasma deposition method(RPD)Alternative to magnetron sputtering(PVD),Because the TCO membrane produced by RPD,Has low ion bombardment damage and high mobility,High quality film properties.
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