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The entire photovoltaic clean renewable energy development has played a huge role in promoting. Amorphous silicon solar cell technology has become more sophisticated as to enhance the awareness of clean renewable energy photovoltaic energy can substitute for conventional one-time confidence. Amorphous silicon solar cell development is the main vivid, complex and tortuous. A comprehensive summary of the lessons learned to further promote the amorphous silicon thin film solar cell in the field of science and technology and related high-tech industry is of great significance. Moreover, because of its material from the amorphous silicon solar cell research to the development of new industries related to science and technology into productive forces of the typical examples. One of the laws of other emerging areas of science and technology and related industries will also be useful inspiration. This article will be chasing fans of amorphous silicon solar cells in the development process. A brief commentary in which fans of the key points. Pointed out the direction for further development.
First, the birth of amorphous silicon solar cells
1, the social needs of the birth of a-Si solar cells
The birth of solar cells in the mid-1970s, should be seen, scientists trying to invent themselves to adapt to engage in scientific research: the demand would be an example. In their report the invention of the amorphous solar cells two major goals: Aung responsible for the J-Japanese battery Crystal Silicon competition; the use of amorphous silicon solar cells for power generation, and conventional energy competition. The 1970s, there have been a well-known energy crisis; Against this background, urging the scientists on the a-Si materials to study the general application of low-cost solar cell technology innovation, this innovation is in fact to the amorphous semiconductor crystals of the semiconductor third challenge . Crystalline silicon solar cell is in the field of application, Challenger said, although the solar cell is a high-grade optoelectronic devices, but do not have to use Aung responsible for the manufacture of crystal semiconductor materials, low-cost amorphous silicon thin film materials can also be qualified.
2. Amorphous silicon solar cells based on the theory and technology to establish
Amorphous materials for the first time in the field of optoelectronic devices emerge in 1950. At that time, people are looking for apply to the television camera tube and copying equipment used in the photoconductive material found amorphous selenium (a-Se) and amorphous three antimony sulfide (a one SbS3). At that time, there is still amorphous materials and the concept of the field, and semiconductor crystals one by one on the basis of the theory of energy band theory, as early as the 1930s had matured. Transistor has been invented. Crystal optical properties of semiconductor devices and development is the hot spot. And a-Se and a-SbS3 even in the absence of such materials on the basis of the theory developed into a production value in the billions of dollars in major industries, amorphous materials for the first time that this challenge is successful, start of the amorphous materials science Technology Research. Spear in 1957 to measure the success of the a-Se material drift mobility, in 1958 the United States for the first time in the Anderson paper pointed out that amorphous system, the existence of local electronic effects. In 1960, the former Soviet Union were about to fly with the Heat Nagel entitled "amorphous, amorphous semiconductors and liquid electronic" in the article, put forward the theory of amorphous semiconductors that are important arguments, that is, the decision of solid Electronics are the basic characteristics of metal or semiconductor or insulator of the main factors constitute a short-range atomic structure of condensed matter, that is, the nearest neighbor atoms of the coordination situation. From 1960 onwards, it is committed to the preparation of a start-Si and thin film materials aGe. Previously used mainly sputtering. At the same time, it was systematically studied the optical properties of these films. Sterling in 1965 and others for the first time using glow discharge (GD) or plasma enhanced chemical vapor deposition (for Jane PECVD) prepared hydrogenated amorphous silicon (a-si: H) films. This method of using radio frequency electromagnetic fields incentives such as low pressure silane gas, glow discharge chemical decomposition in a substrate to form a thin film Si. This is the later of a Si solar cell using a material of the main methods of preparation.
In 1960 took place in the amorphous semiconductor device applications in the field of semiconductor crystals to the second challenge. That is when the Americans found Rysinski Ou Fu-S amorphous semiconductor materials with electronic storage switch roles. This found that although the application: not a success, but it has the academic value of a breakthrough. Mott said the Nobel laureates than the invention of the transistor is also important. Scientists interested in it from the traditional crystal semiconductor materials into the amorphous semiconductor materials. Set off a study of amorphous: the upsurge of semiconductor materials. China is also in the late 1960s began working in this field of study. From 1966 to 1969 related to the scientists carried out an in-depth fundamental research to address the amorphous semiconductor energy band theory. Electronics made to sub-state; Mott cloth CF0 a migration model and the ideological side.
E-band theory of semiconductor materials and devices on the basis of the theory. It can guide the design of semiconductor devices and processes, sub-16f1i4fo device performance. At present, amorphous silicon can do together with the theory is not perfect, there are also controversial, but after all, for the amorphous semiconductor devices provides a theoretical basis.
3, a-Si solar cell's basic structure
On the a-Si thin film doped in order to control the conductivity of the number conductance and the type of work, for the first time in 1975 by Lai Kangbo Spear and achieve. At the same time, it achieved a-Si PN-end production. In fact, because of a-Si more of the characteristics of the defect, often doped to further increase the density of defects, a-Si solar cell basic structure of the PN junction is not binding but PIN. The formation of boron-doped P areas, the formation of N-P-doped areas, I impurities or non-B-doped light of the intrinsic layer (non-doped a-Si is a weak-N). Re-doped P, N zone in the formation of built-in internal battery power to collect the charge. At the same time, both with conductive electrode to form ohmic contact, in order to provide an external electric power. I was light district area. Photoconductive / dark conductivity than in the 105 - 106. This area of photo-electronic hole is a source of photovoltaic power. Non-silicon crystal structure of the long-term damage to a disorderly transition of crystalline silicon photonics selection rule. So that from the indirect band gap material into a direct band gap materials. Photon absorption of the high sensitivity of the absorption spectrum domain away. Therefore, P / I / N structure of a-Si battery check the thickness of about 5000Å, and as a death ray absorption area of P, N thickness 100Å weight limit.
In short, amorphous silicon solar cell is the application of the product is amorphous semiconductor technology and explore the theoretical basis of the results of the study. Scientific and technological innovation and social needs arising from a combination of great value. Each of today's scientific and technological innovation include technical and fundamental research to explore two aspects, one of which can be neglected. Of course, a different subject or the subject of different stages of development, the focus will be different. In the history of science and technology development, some in the field to form the basis of theory, after waiting for a mature technology bear fruit. Some also have a first in the field of applied technology, and technology to promote the development of fundamental research, the results have a theory. The establishment of the guiding theory and application of technology to mature.
Second, the early stages of the development of amorphous silicon solar cells
The initial technical progress and prosperity
Semiconductor giant electronic device - the amorphous silicon solar cells can be used cheap materials and production process, which inspired scientists, research institutions have invested in this area of study, also attracted attention and business in many countries of concern to the Government And attention. This has brought great development of amorphous silicon solar cells. Amorphous silicon solar cells quickly out of the laboratory, went into the test line and large-scale production line. From a technical point of view, amorphous silicon solar cell at this stage of the progress of the main problems: (1) from the simple IT0/P/I/N (a-Si) / Al develop into Sn02 (F) / Pa-SiC / I an a-Si / N-a-Si / AI such a complex structure of the utility. Sn0: transparent conductive film IT0 than the more stable, lower cost, easy-to-achieve texture, thus increasing the absorption of solar light. Use asIC: H-P as the window layer, the band gap wider, a decrease of P layer of light absorption loss, to make better use of the incident solar energy. (2) a-Si thin layer and the two electrodes were realized split laser line, the realization of the integrated components of the production. (3) the emergence of mass production of single-and multi-empty room of the production of amorphous silicon thin film of water in two ways. In the production also appeared in a transparent conductive glass substrate for the production of components and flexible materials (such as stainless steel) as a substrate of the two components batteries of production. Many of the world to a solar-S1 for the main products of the enterprises or enterprise branch. For example, the United States CHR0NAR, s0LAREx, ECD, and so on, in Japan Sanyo, Fujitsu, such as the Cape. CHR0NAR solar asl is the vanguard of industrial development, not only have their own production lines, but also to other countries in the export surplus MW-class production line. The United States and Japan also use their products were installed outside the power generation test station. Have the largest capacity of 100 kilowatts. In the mid-1980s, the world's total solar cell sales in the possession of amorphous silicon 40%. Emergence of amorphous silicon, polycrystalline silicon and silicon on the three pillars of power.
a-Si solar cell edge
Technology to the productivity of such a high-speed conversion on the amorphous silicon solar cell has a unique advantage. The main advantage of these in the following areas:
1. Materials and low-cost manufacturing process. This is because the substrate materials, such as glass, stainless steel, plastic, and so cheap. Only Egypt and thousands of silicon thin film thickness, the Ngong responsible for very little amount of pure silicon. Process technology for the production of low-temperature (100-300 ℃), the production of small power / energy recovery time is short.
2. Easy to form large-scale production capacity. This is because nuclear: Heart Technology for the production of large holders of non-structural defects of a-Si alloy film; just change the composition of gas or gas flow will be able to achieve balance and the corresponding PIN Diego layer structure; the entire production process automation.
3. Varieties, use widely. A-Si thin film solar cells easy to achieve sub-integrated. Power devices, the output voltage, output current are free to design and manufacture, can more easily create more demand for different varieties of products. As the light absorption, dark conductivity, low-liang, suitable for the production of indoors with
The low-power power supplies, batteries such as watches, calculators, such as batteries. Si a result of a silicon membrane structure of the mechanical properties of solid network. Suitable for flexible substrates to produce light of the large "battery.'s Flexible manufacturing methods can be integrated manufacturer of construction of the battery for power plant operators to use the roof installation.
Momentum setback
Although the amorphous silicon solar cells as on a number of advantages, disadvantages are also obvious. The main initial photoelectric conversion efficiency is low, less stable. The initial products in the early solar cell efficiency of 5% 6%, strong sunlight exposure standard after one year, the stability of the efficiency of 3% to 4% in a poor light under the application, of course, not be a problem. However, outdoor light, as the use of power generation, stability has become more serious. Power generation of power plant performance tests of short-lived recession has seriously affected the confidence of consumers, resulting in difficulties in the market, closing down some production lines, such as CHR0NAR company.
The first phase of a-Si solar cell performance recession in fact there are two aspects, namely, packaging and pose a battery of a-Si material instability problems. Packaging is the main issue: the aging packaging materials and packaging defective, the environments harmful to the atmosphere of the battery electrode materials and electrode contact damage, so that a significant decline in battery performance and even failure. To address this problem by improving the packaging technology, has adopted a package laminated glass (which refers to the glass substrate of the cell) and multi-layer protection of the hot package (stainless steel substrate on the battery), basically to resolve The packaging problem. At present, the service life of solar cells has reached more than 10 years.
a-Si thin film in the bright light (usually a standard light of the sun, 100mW/cm2) irradiation for a few hours, photoconductive gradual decline in light after dark conductivity can be a decline in the number of children and to maintain a relatively stable level; light of the samples in 160 ℃ Annealing, the conductivity restore original value. This is a well-known Sri Lanka do not pull all the way too Angsi Ji effect, referred to as SWE. Alanniusi characteristics of the dark conductivity measurements show that light can be activated when the conductivity increased. This means that the fee level can not move from side to bring the central band gap. Described as the first band gap resulted in the Department of metastable state, or be able to produce a metastable defect center. Such metastable annealing can eliminate the defects, according to the Semiconductor carrier have a complex theory, the central band of metastable center complex likely the largest, with Mr. reduce the carrier's role in life; it at the same time as a carrier of Xianjie , The space charge arising from the increase, in layer 1 to reduce the electric field strength, so that Mr. carrier free of drift to shorten the distance to reduce the carrier collection efficiency. This decline in the performance of solar cells, compared with the consensus view is that the light-induced recession and the effects of a-Si materials in the hydrogen-related move.
PECvD widely used method of deposition of a-Si film containing hydrogen 1OI5 were spoon, on the one hand, so that the key has been suspended silicon better compensation; On the other hand, such a high content of hydrogen than the density of silicon hanging keys. He is certain that the hydrogen in a-Si materials in the possession of activation energy of a variety of different locations, of which compensation is a key hanging. The other is at a lower activation energy. A-si ideal material should be neither empty, and other micro-defects, there is no SiH2, (SiH2) n, SiH3 the keys fit, and so on. The density of the material should be close to the ideal of the density of crystalline silicon, silicon dangling bonds have been entirely appropriate compensation for the hydrogen, making low-density gap, to maintain the highest structural stability, to find the ideal low-cost technology to achieve such an ideal structure, Should be able to eliminate photo-induced recession, this is a very difficult task.
a-Si solar cell efficiency of the reasons
Amorphous silicon solar cells belonging to the semiconductor junction solar cell. Junction solar cell can be based on the model of its ideal performance photovoltaic estimated.
Photoelectric conversion efficiency
One Voc, Isc and FF were open circuit voltage, short-circuit current and fill factor, the incident can usually get a standard of solar energy for 100mW/cm2, equal to short-circuit current photocurrent Il, Isc = Il = qφΙhv> Egn = l The big difference between the ideal situation.
a solar-St area of P and N areas of high resistivity, TC0 / P-a-Si (or N-a-Si) higher contact resistance, or even the existence of barriers to the interface, which brings additional energy loss . These issues must be new measures to address, which constitute the next phase of the development of amorphous silicon solar cell's main tasks.
三. Further development of amorphous silicon solar cells with the status quo
1. Amorphous silicon solar cell technology to improve and increase
As the momentum back in the 1980s is not in the early 1990s, the development of amorphous silicon solar cells has gone through a restructuring, improving and enhancing the period. On the one hand, people stepped up exploration and research, on the one hand, in preparation for a higher level of technology for large-scale industrial development. The central task is to improve the efficiency of the stability of the battery. To explore the structure of the new devices, new materials, new techniques and new technology. The core is the perfect balance of technology and battery technology stack. In the exploration success on the basis of the mid-1990s, there have been more large-scale industrialization of high tide. Has established more than a few megawatts to 10 megawatts a high level of battery components production line, an area of square magnitude components, to achieve fully automated production processes, product assembly area in square meters order of magnitude. The introduction of a new package branch operation, product components in more than 10 years of life. The production of components to the perfect balance of technology and technology-based cell stack. The efficiency of product components to achieve 6 8 pilot component (the area around 900CM2) a 9% effective rate of 11%; small battery maximum effective rate of 14.6%.
2. Perfect balance technology
Technology is the perfect balance of the following combination of technology, (1) with a texture of the composite S102/Sn02/Zn0 transparent conductive film instead of single-Sn02 or IT0 transparent conductive electrodes. Composite membrane electrode with a block-ion pollution, increased absorption of incident light and hang plasma reduction. (2) TC0 / P interface insert 6-doped layer in order to overcome barriers interface. (3) P-wide band-gap materials using high-conductivity of the film ceramics, such as μc-Slc, can reduce P layers of light absorption loss; to reduce the series resistance of the battery. (4) To reduce the P / I interface defects, reduce the diode quality factor in the P / I interface insert C content slowly decreasing level. This level of preparation is the best turn of the deposition and hydrogen treatment. (5) low-defect low hydrogen content of the I layer. Using precise control of dopant concentration gradient of doping law, so that from the impurities of the formation of light and space charge arising from the metastable space charge and maintain stability in the uniform of the built-in electric field. This is a device from the structure of light to eliminate the effects of the recession and a program. (6) 1 / N interface slowly in order to reduce the interface defects. (7) pc using a n-S1 can reduce the series resistance of the battery at the same time reducing the long-wavelength light of the loss. (8) use of ZnO / AI composite electrodes to strengthen the back of a long wavelength of light reflection, increasing the battery in the optical path, thereby increasing the absorption of solar light to use. It is worth mentioning that in my eight. Five research in the use of such technology, to achieve a large area (900CM2) pieces of battery efficiency and stability of 6.55 percent. Small open-end single-battery power of up to 1.12 volts.
3. Laminated cell technology
I cited a thinning of a solar cell layer can enhance the degree of built-in library field, Mr. reduce carrier through the band-gap defect centers and / or Mr. metastable Center complex risk, but also increase the rate of the mobile carrier, at the same time to increase The quantum efficiency of the battery collection and stability: If, however, a thin layer will absorb the full impact of the incident, leading to a decline in the efficiency of the battery, in order to avoid people think of a number of thin-layer structure of the battery Xiangdie. NN is the first of the two end of the stack, that is, a one Si / a-Si layer battery, which has improved efficiency and stability of our country to make use of the structure of the battery components (400CM2) stability in the effective rate of 7.35 percent.
A solar material can be used than the wavelength 1.24/Eg (μM) to the short spectrum of light energy domain. If we have the same band gap (that is) thin-film battery materials stack can use a broader spectrum of light energy domain. This can increase the efficiency of solar cells. Heterojunction solar cell stack, the gap Broadband use of the material for battery-top, short-wavelength light energy into electrical energy; the use of narrow-band material for the end of the battery, the long-wavelength light energy into electrical energy. Due to more fully utilize the sun's spectrum domain, heterogeneous cell stack Yang should have a higher photoelectric transfer efficiency of use and at the same time inhibit photo-back Michael.
Heterogeneity of the formation of the solar cell laminated materials band gap must have the right to match could be the most nephew. At present, handcuffed flow of amorphous silicon-based solar cell stack heterogeneous better match the band gap of 1.8eV, 1.6eV, 1.4eV. In addition to matching the band gap requirements, the composition of the solar cell stack in the first sub-current of the battery should be basically the same; between battery-P / N should be higher conductivity of the high transmission tunnel junction.
4. To explore new materials
To explore the wide band-gap materials are, amorphous carbon, oxygen amorphous silicon, microcrystalline silicon, silicon-carbon-ceramic, and so on. These materials in the main window layer. The top cell layer is a wide band-gap amorphous silicon and amorphous carbon. The most important narrow-band-gap material non-silicon germanium. Change in the silicon germanium alloy of germanium content of the materials band gap in the range of 1.7eV to 1.leV adjustable. Silicon and germanium atoms in the next small, bonding to different keys. Amorphous silicon germanium film defects more often than amorphous silicon. Film and silicon germanium atoms together is not evenly distributed. Hydride, optional hydrogen bonding silicon with worry. To overcome these difficulties, the key is to use diluted hydrogen fluoride deposition and doped. The optoelectronic properties of these materials can do a good job. However, hydrogen content is usually high, light-induced recession of the material still exists. Laminated structure to a certain extent, curbed its battery performance.
5. To explore new technologies
In order to improve the efficiency of the initial amorphous silicon solar cells and light conditions, the stability of the people to explore many new materials appropriate technology. The new process is more important: the chemical annealing, the light pulse according to law lice, hydrogen dilution, alternating with the deposition of hydrogen Methodist law, fluorine-doped, intrinsic level of trace boron-doped law, and so on. In addition, in order to increase the a-Si thin films of the efficiency of boron-doped with boron in place of two-diethyl-boron doping for the source of gas. In order to obtain a-Si film deposition of high-speed, the use of silicon-diethyl-kang in place of a silane gas as the source.
The so-called chemical annealing, that is, in a step by step growth of a thin film Si intervals, with hydrogen atoms, or the activation of Ar, He atoms to deal with the film, so that the surface structure of the relaxation, thus reducing defects and excess hydrogen, while ensuring low Gap density of states at the same time, lower the effects of the recession here, to deal with chemical particles are produced by additional equipment.
Hydrogen dilution law to adopt a large number (several times) silicon kang diluted hydrogen gas as the source of a-Si alloy deposition film, in fact, the film side of the meter on the side of the film on the surface for handling hydrogen, the same principle, a simpler method and the results quite basic.
Alternating with the deposition of hydrogen is to deal with: the repeated turn of the thin film deposition and hydrogen plasma treatment. This is a combination of the two sides to. Neon light pulse is in a layer of a-Si thin film growth of every other question, the cycle pulse with neon light toot Department membrane surface, the stability improved significantly. In the preparation of a-Si source of gas to add appropriate amount of silicon tetrafluoride can in order to achieve a-Si. Fluorine-doped so that the plot structure of the network more stable. Intrinsic 8si-N was weak, the incorporation of trace boron costs can be shifted to energy band gap of the Central, will help enhance the light sensitivity can be addressed to reduce the recession.
6. Preparation of the new technology to explore
RF plasma CVD is strong in today's commonly used in the preparation of a one Sl alloy film. Its main priority, the right is: can the lower substrate temperature (200 ℃ or so) can be re-replication big area of uniform thin film, a system of hydrogenated a-Si alloy film without structural defects, a good step rehabilitation benefits, Low-density gap, optoelectronics with the large area solar cell characteristics. The main disadvantage of this method is also a fatal drawback is that the preparation of a-Si film with a high hydrogen, usually some 10% -5% hydrogen content. Photo-induced recession more serious. As a result, on the one hand, people use this method to achieve a large-scale production; on the other hand, continuous efforts to explore new technical preparation.
RF-PECVD with the nearest neighbor of the technology, ultra-high vacuum PECVD technology, very high frequency (VHF) PECVD and microwave technologies (including ECR) PECVD technology. Plasma-photon excitation of the electromagnetic wave energy, gas will break down the energy particles, particles to survive life, the film production and film on the surface of the mechanism to deal with different generation of membrane structure, electronic properties and stability will be different. yHF and PECVD microwave ceramics in the preparation of silicon that there are certain advantages.
Other new technologies are the main, ion beam deposition a-si thin film technology, H0M0 a hot filament CVD technology and CVD technology. Ion Beam Deposition a-Si alloy films, including silane gas, the first reaction from the ionization chamber of decomposition, and then the formation of ion beam, deposition to the substrate to form a stable structure of the strangulation of a Sl alloy film . H0M0 a CVD technology bo hot gas, thermal decomposition of the instrument, and then break down particles deposited on the substrate. Film of the first class of rough-life principals, the electronic properties of a good film, a low hydrogen content, better stability. The two film technical quality, though good, but difficult to form the industrialization of technology. Hot Wire CVD technique is more promising high-quality silicon thin film of high-speed preparation techniques.
Fourth, the future development of amorphous silicon solar cells
1. Existing solar cell industry has cited a market development
Amorphous silicon solar cells in terms of academic or industry have been a huge success. World gold production capacity of 50 megawatts. In colleges and universities account for about half the level of operation. The largest-scale production line for components with an annual output of 10MW. Such large-scale high-grade production lines at full capacity the normal operation of the production costs have been as low as 1.1 U.S. dollars / peak watt or so. It is predicted that if the cost of solar cells below the peak watt per dollar, more than 20 years of life, power generation system cost less than 2 U.S. dollars per peak watt, photovoltaic power generation will be able to compete with conventional electricity. Compared with other varieties of solar cells, amorphous silicon solar cells closer to the ideal. Dayang amorphous silicon cells currently can not compete with conventional electricity, but many of the special conditions, not only can be used as power generation, and has more obvious advantages, for example, relying on the roof of the building power plants, because of its Not an area of chaos from an area of expenditure, lower the cost of power generation. As a networking power, no energy storage equipment, the cost of solar power generation in China has the largest proportion of low-cost solar cell will bring low-cost electricity. At present, the world's total sales of amorphous silicon solar cells less than half of its production capacity. In addition to the application of a small number of large-scale power plants outside the test is still to small and power-based indoor low-light power. Although the cost of production of crystalline silicon solar cells is a-Si double the battery, but the power generation market is still crystal silicon-based batteries. This shows that the photovoltaic power generation market has not really matured. On the other hand, amorphous silicon solar cells have to cross a "threshold" in order to enter the photovoltaic market that once crossed the "threshold", the market demand will drive the expansion of industry, and the larger the lower the cost of production. To break through the "threshold", on the one hand have to step up marketing efforts to strengthen the marketing measures; on the other hand, the Government should give the user an appropriate subsidy to encourage and stimulate the expansion of the market. Are being implemented in many developed countries such as the "roof of the millions of" this type of photovoltaic applications, is a concrete manifestation of this effort.
2, further technological development
On the one hand, amorphous silicon solar cells to face the high-performance low-cost anti-crystalline silicon cells to the challenges facing him on the one hand, the price of other thin film solar cell industry has become more sophisticated technology challenges. For further development, so as to the future of photovoltaic energy in the occupied prominent positions, in addition to efforts should be made to open up the market, the existing level of technology products to large-scale power generation applications, should also further develop its crystal Silicon cells in the cost and price advantages of other thin film solar cells more mature branch operation advantages in efforts to overcome their weaknesses. Further improve the efficiency and stability of the product components, to extend the service life of the product. More specific direction is as follows.
(1) strengthen the material basis of a-Si metastable characteristics and study ways to overcome, to basically eliminate the silicon thin film solar photo-induced recession of the performance.
(2) to strengthen the crystalline silicon thin film of material to explore technology and research, the future of the film products cutting solar cells have only a-Si thin film solar cells take advantage of lower costs of crystalline silicon solar cells also have a long life and high stability, high-performance advantages .
(3) with a-Si components alloy film or a-Si has a low-cost characteristics of the hybrid cell stack, the a-Si solar cells and other advantages of the advantages of solar cells grafted together.
(4) of her best pieces of the new technique means husband is not the time to carry out the industrialization of technological development. At a higher level of technology on a larger scale to achieve the solar industry and commercial markets. Meeting the photovoltaic energy era.
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