Solar Energy (Solar Energy), which generally refers to the radiant energy of sunlight, is generally used in modern times to generate electricity. Since the formation of the Earth, living creatures have survived mainly on the heat and light provided by the sun, and since ancient times humans have known how to dry objects with sunlight and use it as a way to preserve food, such as making salt and drying salted fish. However, it is only with the reduction of fossil fuels that solar energy has been intentionally developed further. Solar energy can be utilized in two ways: passive use (photothermal conversion) and photovoltaic conversion. Solar power an emerging renewable energy source. Solar energy in a broad sense is a source of many energies on earth such as wind energy, chemical energy, potential energy of water etc.
Edit
History
The term "photovoltaics" is derived from the Greek words meaning light, volts, and electrical, and comes from the name of the Italian physicist Alessandro Volt, after whom the term "volt" was used. After Alessandro Volt, "volt" was used as a unit of voltage.
Solar cells (18)
In terms of the history of solar energy development, the behavior of "photoelectricity" caused by light irradiation on materials was discovered as early as the 19th century.
In 1839, the photovoltaic effect was first discovered by French physicist A.E. Becquerel. The term "photovoltaic" appeared in English only in 1849.
The first solar cell was prepared in 1883 by Charles Fritts, who used a germanium semiconductor with a very thin layer of gold to form a semiconductor-metal junction, with an efficiency of only 1%.
By the 1930s, the principle of photoelectric behavior was widely used in camera exposure meters.
In 1946 Russell Ohl patented the manufacture of modern solar cells.
To the 1950s, with the gradual understanding of the physical properties of semiconductors, as well as advances in processing technology, in 1954, when the United States of America's Bell Labs experiments with semiconductors found in the silicon doped with a certain amount of impurities in the more sensitive to the phenomenon of light, the first solar cell in 1954 was born in Bell Labs. The era of solar cell technology has finally arrived.
Beginning in the 1960s, U.S. satellites were launched that utilized solar cells as a source of energy.
When the energy crisis hit in the 1970s, it made the world realize the importance of energy development.
With the oil crisis in 1973, people began to shift the application of solar cells to general livelihood uses.
Currently, in countries such as the United States, Japan and Israel, solar installations have been used in large quantities, and are moving toward the goal of commercialization.
In these countries, the United States in 1983 in California to establish the world's largest solar power plant, it can be as high as 16 megawatts of power generation. South Africa, Botswana, Namibia and other countries in southern Africa have also set up programs to encourage the installation of low-cost solar cell power systems in remote rural areas.
The most active country in the promotion of solar power is Japan, which implemented a subsidy incentive program in 1994 to promote a 3,000-watt "utility-parallel type solar power system" for each household. In the first year, the government subsidizes 49% of the cost, and the subsidy decreases every year thereafter. The "utility-connected solar power system" is a system in which solar cells provide power to the home load when there is sufficient sunlight, and any excess power is stored separately. If there is excess power, it is stored separately. When there is insufficient or no power generation, the required power is supplied by the power company. By 1996, 2,600 households in Japan had installed solar power systems, with a total installed capacity of 8 megawatts. One year later, 9,400 households had installed solar power systems, with a total installed capacity of 32 megawatts. In recent years, due to the rise in environmental awareness and the government's subsidy system, it is expected that the demand for solar cells for residential use in Japan will also increase rapidly.
In China, the solar power industry has also received strong encouragement and funding from the government, with the Ministry of Finance announcing in March 2009 that it would subsidize large-scale solar projects such as solar photovoltaic buildings.
Editorial
Principle of solar cells
Sunlight in the semiconductor p-n junction, the formation of new hole-electron pairs, in the p-n junction under the action of the electric field, holes from the p area flow to the n area, electrons from the n area flow to the p area, connected to a circuit to form a current. This is the working principle of photoelectric effect solar cells. Solar green energy solar power generation in two ways, one is the light - heat - electricity conversion method, the other is the light - electricity direct conversion method.
Photo-thermal-electrical conversion
(1) Photo-thermal-electrical conversion method generates electricity by utilizing the thermal energy produced by solar radiation, generally by solar collectors to convert the absorbed thermal energy into the steam of the work material, and then drive the turbine to Generation of electricity. The former process is the light - heat conversion process; the latter process is the heat - electricity conversion process, as with ordinary thermal power generation. The disadvantage of solar thermal power generation is that the efficiency is very low and the cost is very high, it is estimated that its investment is at least 5 to 10 times more expensive than ordinary thermal power plants. A 1000MW solar thermal power plant requires an investment of 2 to 2.5 billion dollars, with an average investment of 2,000 to 2,500 dollars for 1kW. Therefore, it can only be used on a small scale for special occasions at present, while large-scale utilization is economically uneconomical and cannot yet compete with ordinary thermal or nuclear power plants.
Photoelectricity direct conversion
(2) photoelectricity direct conversion mode the way is to use the photoelectric effect, the sun's radiant energy is directly converted into electrical energy, photoelectricity conversion of the basic device is the solar cell. Solar cell is a device that directly converts the sun's light energy into electrical energy due to the photovoltaic effect, a semiconductor photodiode, when the sun shines on the photodiode, the photodiode turns the sun's light energy into electrical energy and generates an electric current. When many cells are connected in series or parallel can become a relatively large output power of the solar cell array. Solar cells are a promising new type of power source with three major advantages: permanence, cleanliness and flexibility. Solar cells have a long life, as long as the sun exists, solar cells can be an investment and long-term use; compared with thermal power, nuclear power generation, solar cells do not cause environmental pollution; solar cells can be large and small and large, large to millions of kilowatts of medium-sized power stations, small to just for a household with a solar panel, which is unmatched by other power
Edit
Subject to the current situation of the solar energy industry
Subject to the current situation of the solar energy industry
Subject to the current situation of the solar energy industry
The current stage of the photoelectric effect of thin-film solar cells work as the mainstream, while the photochemical effect of wet solar cells are still in the embryonic stage.
Global solar cell industry status
According to Dataquest's statistics, at present, the world*** has 136 countries into the popularization of the application of solar cells in the boom, of which 95 countries are in large-scale research and development of solar cells, and actively produce a variety of related energy-saving new products. 1998, the world's production of In 1998, the total power generation capacity of solar cells produced worldwide amounted to 100 megawatts (MW) of photovoltaic (PV) power generation, and in 1999 it reached 2,850 MW. According to the forecast of European Photovoltaic Industry Association (EPIA) in 2008, if the global installed capacity is 2.4GW in 2007, the global annual installed capacity will reach 6.9GW in 2010, 56GW and 281GW in 2020 and 2030, respectively, and the global cumulative installed capacity will be 25.4GW in 2010, and it is expected to reach 278GW in 2020 and 278GW in 2030. In 2010, the global cumulative installed capacity was 25.4GW, and is expected to reach 278GW in 2020 and 1,864GW in 2030.
At present, many countries are formulating medium- and long-term solar energy development plans to prepare for large-scale development of solar energy in the 21st century.
The U.S. Department of Energy has launched its National Photovoltaic Energy (NPV) Program, and Japan has launched its Sunshine Program. The NREL PV program is an important element of the U.S. National Photovoltaic Program, which carries out research in five areas: monocrystalline silicon and advanced devices, thin-film photovoltaic (PV) technology, PVMaT, PV modules, and system performance, solar cell automotive and engineering, and PV applications and market development.
The U.S. has also launched a "solar streetlight program" aimed at making part of the U.S. city's streetlights solar-powered, according to the plan, each streetlight can save 800 degrees of electricity each year. Japan is also implementing solar energy "70,000 sets of project plan", Japan is ready to popularize the solar energy residential power generation system, mainly installed on the roof of the home of the solar battery power generation equipment, the family with the remaining electricity can also be sold to the power company. A standard household can install a system that generates 3,000 watts of electricity. Europe will be the research and development of solar cells in the famous "Eureka" high-tech program, launched the "100,000 sets of engineering programs." These popularization of the application of photovoltaic cells as the main content of the "solar energy project" program is currently promoting the solar photovoltaic cell industry, one of the important driving forces of the development.
Japan, South Korea and the European region, the total **** 8 countries recently decided to work together, inland Asia and the African desert region to build the world's largest solar power station, their goal is to account for about 1/4 of the global land area of the desert area of the long hours of sunshine resources effectively utilized for 300,000 users to provide 1 million kilowatts of electricity. The plan will begin in 2001 and take four years to complete.
Currently, the U.S. and Japan hold the largest market shares in the world photovoltaic market. The United States has the world's largest photovoltaic power plant, its power for 7MW, Japan has also built a power generation power of 1MW photovoltaic power plant. There are 230,000 photovoltaic power plants in the world, with Israel, Australia and New Zealand leading the way.
Since the 1990s, the global solar cell industry has continued to grow at an annual rate of 15%. According to Dataquest released the latest statistics and forecasts show that the United States, Japan and Western European industrialized countries in the research and development of solar energy in the total investment in 1998 amounted to 57 billion U.S. dollars; in 1999, 64.6 billion U.S. dollars; in 2000, 70 billion U.S. dollars; in 2001, it will be 82 billion U.S. dollars; 2002 is expected to break through the 100 billion U.S. dollars.
China's solar cell industry status
China attaches great importance to the research and development of solar cells, as early as during the 7th Five-Year Plan period, amorphous silicon semiconductor research has been included in the major national issues; the 8th Five-Year Plan and the 9th Five-Year Plan period, China's research and development focus on large-area solar cells, etc. In October 2003, the National Development and Reform Commission (NDRC) and the Ministry of Science and Technology (MOST) formulated a plan for solar resource development for the next five years. In October 2003, the National Development and Reform Commission and the Ministry of Science and Technology formulated a plan for the development of solar energy resources in the next five years, and the NDRC's "Brightness Project" will raise 10 billion yuan for the promotion of the application of solar power generation technology, with the plan that by 2015 the total installed capacity of solar power generation systems in the country will reach 300 MW. China has become the world's largest manufacturer of photovoltaic products, China's upcoming "new energy revitalization plan", China's installed capacity of photovoltaic power generation is planned for 2020 to reach 20GW, is the original "medium- and long-term plan for renewable energy," more than 10 times the 1.8GW.
In 2002, the relevant state ministries and commissions launched the "Western provinces and districts without electricity townships electricity program", through solar energy and small wind power to solve the western seven provinces and districts without electricity townships polycrystalline silicon solar cell power problems. This project has greatly stimulated the start of the solar power industry, the domestic construction of several solar cell packaging line, so that the rapid increase in the annual production of solar cells. According to expert forecasts, China's photovoltaic market demand is currently 5MW per year, 2001 to 2010, the annual demand will reach 10MW, from 2011, China's photovoltaic market annual demand will be greater than 20MW.
Currently, the domestic solar energy silicon production enterprises are mainly located in Luoyang monocrystalline silicon plant, Hebei Ningjin monocrystalline silicon base and Sichuan Emei semiconductor materials factory and other manufacturers, of which Hebei Ningjin monocrystalline silicon base is the world's largest solar monocrystalline silicon production base, accounting for about 25% of the world solar monocrystalline silicon market share.
In the downstream market of solar cell materials, the current domestic production of solar cells are mainly Hongwei Group, Wuxi Suntech, Hairun Photovoltaic, Nanjing CLP, Baoding Yingli, Hebei JA, Linyang New Energy, Suzhou Atlas, Changzhou Trina, Tuorigi Xinneng, Yunnan Tianta Photovoltaic Technology, Ningbo solar energy power supply, KYOCERA (Tianjin) solar energy, etc., with a total annual production capacity of 800 MW The total annual production capacity is more than 800MW.
In 2009, the State Council, according to the report provided by the Ministry of Industry and Information Technology pointed out that polysilicon overcapacity, the actual industry people do not recognize, the Ministry of Science and Technology has taken the position that polysilicon production capacity is not excessive [1].
Solar cells and solar power prospects
At present, the application of solar cells from the military field, aerospace into industry, commerce, agriculture, communications, household appliances, and utilities, etc., especially can be decentralized in remote areas, mountains, deserts, islands and rural areas to save the cost of very expensive transmission lines. But at the present stage, its cost is still very high, send out 1kW of electricity need to invest tens of thousands of dollars, so the large-scale use is still subject to economic constraints.
But in the long run, with the improvement of solar cell manufacturing technology and the invention of new light-to-electricity conversion devices, the protection of the environment and the huge demand for renewable clean energy, solar cells will continue to be a more practical way to utilize the sun's radiant energy, which can open up broad prospects for the future of large-scale use of solar energy for mankind.
Editorial
Classification of Solar Cells
Solar Cells Classification Introduction
Solar cells can be classified into two major categories according to the state of crystallization: crystalline thin film and non-crystalline thin film (hereinafter referred to as a-), which are divided into mono-crystalline and poly-crystalline forms.
By material can be divided into silicon thin film form, compound semiconductor thin film form and organic film form, and compound semiconductor thin film form is divided into amorphous form (a-Si:H, a-Si:H:F, a-SixGel-x:H, etc.), Ⅲ V (GaAs, InP, etc.), Ⅱ Ⅵ (Cds system) and zinc phosphide (Zn 3 p 2 ) and so on.
Solar cells according to the different materials used, solar cells can also be divided into: silicon solar cells, multicompound thin-film solar cells, polymer multilayer modified electrode-type solar cells, nanocrystalline solar cells, organic solar cells, of which the silicon solar cell is currently the most mature development, the dominant position in the application.
(1) silicon solar cells
Silicon solar cells are divided into monocrystalline silicon solar cells, polycrystalline silicon thin film solar cells and amorphous silicon thin film solar cells.
Monocrystalline silicon solar cells have the highest conversion efficiency and the most mature technology. The highest conversion efficiency in the laboratory is 24.7%, and the efficiency in large-scale production is 15%. In large-scale applications and industrial production is still dominant, but due to the high cost of monocrystalline silicon cost price, significantly reduce its cost is very difficult, in order to save silicon materials, the development of polycrystalline silicon thin film and amorphous silicon thin film for monocrystalline silicon solar cells as an alternative product.
Polycrystalline silicon thin film solar cells and monocrystalline silicon comparison, low cost, and efficiency is higher than amorphous silicon thin film batteries, the highest conversion efficiency of its laboratory 18%, industrial-scale production of conversion efficiency of 10%. Therefore, polycrystalline silicon thin-film batteries will soon be International Space Station solar panels dominate the market for solar power.
Amorphous silicon thin-film solar cells are low-cost and lightweight, high conversion efficiency, easy to mass production, has great potential. But subject to its material-induced photoelectric efficiency decline effect, stability is not high, directly affecting its practical applications. If we can further solve the stability problem and improve the conversion rate problem, then, amorphous silicon solar cells is undoubtedly one of the main development of solar cells.
(2) multi-compound thin film solar cells
Multi-compound thin film solar cell materials for inorganic salts, including gallium arsenide III-V compounds, cadmium sulfide, cadmium sulfide and copper selenium thin film batteries.
Cadmium sulfide, cadmium telluride polycrystalline thin-film battery efficiency than amorphous silicon thin-film solar cell efficiency, lower cost than monocrystalline silicon batteries, and is also easy to large-scale production, but due to the cadmium has a high degree of toxicity, will cause serious pollution of the environment, so it is not the most ideal alternative to the crystalline silicon solar cells.
Gallium arsenide (GaAs) III-V compound battery conversion efficiency of up to 28%, GaAs compound material has a very ideal optical band gap and high absorption efficiency, anti-irradiation ability, heat insensitive, suitable for the manufacture of high-efficiency monojunction battery. However, the price of GaAs materials is not expensive, thus limiting the popularity of GaAs batteries to a large extent.
Copper indium selenide thin-film batteries (CIS) are suitable for photovoltaic conversion, there is no photoelectric degradation, and the conversion efficiency is the same as that of polycrystalline silicon. With the advantages of low price, good performance and process simplicity, it will become an important direction for the development of solar cells in the future. The only problem is the source of materials, due to indium and selenium are relatively rare elements, so the development of such batteries is bound to be limited again.
(3) polymer multilayer modified electrode-type solar cells
Organic polymers instead of inorganic materials is just beginning a solar cell manufacturing research direction. Due to the advantages of organic materials such as good flexibility, easy to fabricate, wide range of material sources, and low cost, thus it is important for large-scale utilization of solar energy to provide cheap electricity. However, organic materials to prepare solar cell research has only just begun, whether it is the service life, or battery efficiency can not be compared with inorganic materials, especially silicon batteries. Whether it can be developed into a practical significance of the product, but also to be further research and exploration.
(4) nanocrystalline solar cells
Nanometer TiO2 crystal chemical energy solar cells are newly developed, the advantage lies in its cheap cost and simple process and stable performance. Its photovoltaic efficiency is stable at more than 10%, the production cost is only 1/5 ~ 1/10 of the silicon solar cells. life expectancy can reach more than 20 years.
The research and development of such batteries has just begun, and they will gradually come to the market in the near future.
(5) organic solar cells
Organic solar cells, that is, organic materials constitute the core part of the solar cell. It makes sense that people are not familiar with organic solar cells. More than 95 percent of today's mass-produced solar cells are silicon-based, and less than 5 percent of the rest are also made from other inorganic materials.
Editorial
Solar cell (module) production process
Encapsulation
Module line, also known as the encapsulation line, encapsulation is a key step in the production of solar cells, no good encapsulation process, how good the battery will not produce a good module board. The encapsulation of the battery not only ensures the life of the battery, but also enhances the impact strength of the battery. The high quality and life span of the product is the key to win can customer satisfaction, so the encapsulation quality of the component board is very important.
Process:
1.Battery inspection - 2.Front side welding-inspection - 3.Back side stringing-inspection - 4.Laying (glass cleaning, material Cutting, glass pretreatment, laying) --5, lamination --6, de-burr (de-burr, cleaning) --7, mounting frame (glue, mounting corner key, punching, mounting frame, scrubbing residual glue) --8, welding junction box - 9, high-voltage test - 10, component testing - appearance inspection - 11 Packaging and warehousing
How to ensure high efficiency and high life of the module:
1, high conversion efficiency, high quality cells;
2, high quality raw materials, such as: high cross-linking degree of EVA, high bonding strength of encapsulant (neutral silicone resin glue), high transmittance of high-strength toughened glass and so on;
3, reasonable encapsulation process
4, the staff's rigorous work style;
Because the solar cell is a high-tech products, the production process of some of the details of the problem, some inconspicuous issues such as should be wearing gloves and do not wear, should be uniformly coated with reagents and scribbling, etc. is the enemy of product quality, so in addition to the development of a reasonable production process, the staff's conscientiousness and rigor is very important.
Edit paragraph
Solar cell assembly process introduction:
Here is only a brief introduction to the role of the process, to give you a perceptual understanding.
1, battery test:
Because of the randomness of the battery cell production conditions, the production of battery performance is not the same, so in order to effectively combine the performance of the same or similar batteries, so it should be categorized according to its performance parameters; battery test that is, through the testing of the size of the battery's output parameters (current and voltage) for its classification. In order to improve the utilization rate of the battery, to make the quality of qualified battery components.
2, Positive welding:
Welding is the confluence band to the front of the battery (negative) on the main grid line, the confluence band is tinned copper tape, we use the welding machine can be welded in the form of multi-point welding band on the main grid line. The heat source for welding is an infrared lamp (utilizing the thermal effect of infrared rays). The length of the strip is approximately twice the length of the battery side. Extra welding tape in the back welding with the back of the battery cells behind the back of the electrode connected
3, the back of the string:
Back welding is the 36 pieces of batteries in series together to form a component string, we are currently using the process is manual, the battery is positioned mainly by a film with a board, there are 36 placed in the battery cell groove, the size of the groove and the size of the battery corresponds to the groove position has been designed, different sizes of cells, and the location of the groove is designed. Position has been designed, different specifications of the components use different templates, the operator uses a soldering iron and solder wire will be "front battery" of the front electrode (negative) welded to the "back battery" of the back electrode (positive), so that the 36 pieces of the series connected together and in the module string of solar panels, so that the 36 pieces of the series connected together and in the module string of solar panels. Together and in the component string Solar panels of the positive and negative welding out of the lead.
4, laminated laying:
Back series connected and passed the inspection, the component string, glass and cut EVA, fiberglass, backplane in accordance with a certain level of laying, ready to laminate. The glass is coated with a layer of reagent (primer) to increase the adhesive strength of the glass and EVA. Ensure that the relative position of the battery string and the glass and other materials when laying, adjust the distance between the batteries, to lay a good foundation for the lamination. (Laying level: from the bottom up: tempered glass, EVA, battery sheet, EVA, fiberglass, back plate).
5, component lamination:
Put the laid battery into the laminator, extract the air inside the component by vacuuming, and then heat the EVA to melt to bond the battery, the glass and the back plate together; finally, cool down and take out the component. The lamination process is a critical step in the production of the module. The lamination temperature and time are determined by the nature of the EVA. When we use fast curing EVA, the lamination cycle time is about 25 minutes. The curing temperature is 150°C.
6, trimming:
Laminating EVA melted due to pressure and extended outward curing to form a burr, so laminating should be removed.
7, framing:
Similar to installing a frame for glass; installing an aluminum frame for glass components increases the strength of the components, further seals the battery components, and prolongs the service life of the battery. The gap between the frame and the glass component is filled with silicone resin. Each bezel is connected to each other with an angle key.
8. Welding junction box:
Welding a box on the back of the module at the lead wire to facilitate the connection between the battery and other equipment or battery.
9, high-voltage test:
High-voltage test means applying a certain voltage between the module frame and electrode leads to test the module's voltage resistance and insulation strength to ensure that the module will not be damaged under harsh natural conditions (lightning strikes, etc.).
10, component testing:
The purpose of the test is to calibrate the output power of the battery, test its output characteristics, and determine the quality level of the component. At present, the main test is to simulate the sunlight Standard test condition (STC), generally a panel requires a test time of about 7-8 seconds.
Solar array design steps
1. Calculate the load 24h consumption capacity P
P=H/V
V - load rated power
2. Select the number of hours of sunshine per day T (H).
3. Calculate the solar array operating current.
IP=P(1+Q)/T
Q - according to the richness factor of cloudy and rainy period, Q=0.21~1.00
4. Determine the battery float voltage VF.
Cadmium-nickel (GN) and lead-acid (CS) batteries have a single float voltage of 1.4~1.6V and 2.2V respectively. 1.6V and 2.2V.
5. Solar cell temperature compensation voltage VT.
VT=2.1/430(T-25)VF
6. Calculate solar cell array operating voltage VP.
VP=VF+VD+VT
Which is VD=0.5 to 0.7
Approximately equal to VF
7. Solar cell array output power WP?Flat plate solar panel.
WP=IP×UP
8. According to VP, WP in the silicon cell flat panel combination series table, determine the number of standard specifications of the series block and parallel group.
Solar cell development market
New solar cells
Currently on the market in large quantities of monocrystalline silicon and polycrystalline silicon solar cells average efficiency of about 15% or less, that is to say, such solar cells can only be converted into 15% of the incident solar energy available electricity, the remaining 85% are wasted into useless heat. Therefore, strictly speaking, today's solar cells are also a certain type of "waste of energy". Of course, theoretically, as long as we can effectively inhibit the energy exchange between carriers and phonons in the solar cell, in other words, effectively inhibit the release of energy within or between the energy bands of the carriers, we can effectively avoid the generation of useless heat energy in the solar cell, and dramatically improve the efficiency of the solar cell, and even reach the ultra-high efficiency of the operation. While such a simple theoretical conception, in the actual technology, it is possible to use different methods to implement such a principle. The technological development of ultra-high efficiency solar cells (third generation solar cells), in addition to the use of novel structural design of components to try to break through its physical limitations, may also be due to the introduction of new materials to achieve a substantial increase in the conversion efficiency of the purpose.
Thin film solar cells include amorphous silicon solar cells, CdTe and CIGS (copper indium gallium selenide) cells. Although the conversion efficiency of most mass-produced thin-film solar cells is still not able to compete with that of crystalline silicon solar cells, their low manufacturing cost still gives them a place in the market, and their market share will continue to grow in the future.
Dye-sensitized solar cell
Dye-sensitized solar cell (DSSC) is a new type of solar cell that has been developed recently. DSsC is also known as Gr?tzel cell because it was published by Gr?tzel et al. in 1991 and its structure is different from that of a general photovoltaic cell. The substrate is usually glass, or transparent and bendable polymer foil (polymer foil), with a layer of transparent conducting oxide (TCO) on the glass (usually FTO (SnO2:F)), and then a layer of porous nano-sized TiO2 particles (about 10 to 10 μm thick), with a thickness of about 10 μm. TiO2 particles (~10-20 nm) to form a nano-porous film. A layer of dye is then applied to attach to the TiO2 particles. Usually, the dye is ruthenium polypyridyl complex, and the upper electrode is also coated with a layer of platinum as the catalyst for the electrolyte reaction, in addition to glass and TCO, and the electrodes between the two electrodes are injected and filled with an iodide/triiodide electrolyte. Although the current maximum conversion efficiency of DSC battery is about 12% (theoretical maximum 29%), but the manufacturing process is simple, so it is generally recognized that it will significantly reduce the production cost, but also reduce the cost of electricity per kilowatt-hour.
Tandem Cells
Tandem Cells are a type of battery that utilizes a novel original structure, which is designed to optimize absorption efficiency by designing multiple layers of solar cells with different energy gaps. Currently, theoretical calculations show that if more layers of cells are placed in the structure, the efficiency of the cell can be gradually increased, and even reach a conversion efficiency of 50 percent.
Edit paragraph
Transparent solar cells
According to the American Physicists Organization network recently reported, the U.S. Department of Energy Brookhaven National Laboratory and Los Alamos National Laboratory scientists developed a can absorb light and will be converted to a large area into a new type of transparent thin film of electrical energy. The film is made of semiconductors and fullerenes and has a microcellular structure. Published in the latest issue of the journal Chemistry of Materials, the paper says the technology could be used to develop transparent solar panels, and even windows that generate electricity could be made from the material. The material consists of a semiconducting polymer doped with carbon-fullerene. Under tightly controlled conditions, the material can be self-assembled to unfold from a micrometer-scale hexagonal structure into a millimeter-sized flat surface filled with microhoneycomb structures.
Mircha Cartwright, a physical chemist at the Center for Multifunctional Nanomaterials at Brookhaven National Laboratory in the U.S., who was in charge of the research, said that while the honeycomb-like film was made using a process similar to that used for traditional polymers such as polystyrene, it was the first time that semiconductors and fullerenes were used as raw materials and made to be capable of absorbing light and generating an electrical charge.
It is said that the material can still be transparent in appearance because the polymer chains are closely linked only to the edges of the hexagon, while the rest of the structure is simpler and thinner outward from the center of the connection point. This structure serves as a connector and also has a strong ability to absorb light and conduct electricity, while the rest of the structure is relatively thin and more transparent, acting mainly as a light transmitter.
The researchers wove the honeycomb film in a very unique way: first, they added a very thin layer of micrometer-scale droplets to a solution that included polymers as well as fullerenes. These droplets self-assemble into large arrays when they come into contact with the polymer solution, and when the solvent evaporates completely, a large hexagonal honeycomb-like plane is formed. In addition, the researchers found that the formation of the polymer is closely related to the rate of evaporation of the solvent, which in turn determines the rate of charge transfer in the final material. The slower the solvent evaporates, the more compact the polymer is and the faster the charge transfer rate.
"This is a cost-effective and remarkably efficient preparation method that has great potential for application from the laboratory to large-scale commercial production." Cartwright said.
Through scanning probe-based electron microscopy and fluorescent ****-focused scanning microscopy, the researchers confirmed the homogeneity of the new material's honeycomb structure and tested its optical properties and charge generation at different parts (edges, centers, and nodes).
Cartwright said, "Our work provides a deeper understanding of the optical characteristics of honeycomb structures. Our next step is to apply this material to the fabrication of transparent and rollable flexible solar cells and other devices to push this honeycomb film into practical use as soon as possible."