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Monocrystalline silicon solar cells

Series silicon solar cells, silicon cells can convert Dayang the most efficient, most mature technology. High-performance single crystal silicon cell is built on high-quality single crystal silicon and related materials into the thermal processing technology based on. Now the power to single crystal silicon technology has matured in recent in battery production, is generally used on the surface texture, firing passive zone, area, such as doping technology, the development of batteries are flat silicon cells and groove Monocrystalline silicon gate electrode buried in the battery. To improve the efficiency of conversion depends mainly on the surface of silicon micro-structure to deal with doping and zoning process. In this respect, Germany Fu Langhuo fee falaj Fort Solar System Research Institute maintains a leading position in the world. The technique photo-lithography technology to cell surface texture, made of inverted pyramid structure. And on the surface of a 13nm. Thickness of the oxide layer passivation and two-reflection coating by the combination. By improving the process of electroplating the gate to increase the ratio of width and height: more than a battery system conversion efficiency over 23%, the largest value of up to 23.3 percent. Kyocera Corporation prepared a large area (225cm2) single-crystal solar cell power conversion efficiency of 19.44 percent for domestic Beijing Solar Energy Research Institute is also active high-performance crystalline silicon solar cell research and development, the development of high-performance single crystal silicon flat battery (2cm X 2cm) reached 19.79 percent conversion efficiency, the groove gate electrode buried in crystalline silicon cells (5cm X 5cm) up 8.6 percent conversion efficiency.

Monocrystalline silicon solar cell conversion efficiency is the highest in the large-scale application and industrial production is still dominant, but because of the single crystal silicon material prices and the cumbersome process of the batteries affected, resulting in high cost single crystal silicon At least, to a significant reduction in the cost is very difficult. In order to save high-quality materials, single crystal silicon cells to find alternative products, the development of the thin film solar cells, polysilicon thin film solar cells and thin film amorphous silicon solar cells is a typical representative.

       Polysilicon thin film solar cells

The normally crystal silicon solar cells in the 350-450μm thickness of high-quality silicon made on this silicon or pulling from the casting of silicon ingots from the Juge. Therefore, the actual consumption of silicon material more. In order to save materials, from the mid-70 began in the low-cost polysilicon thin film deposited on the substrate, but because of the growth of silicon film grain size, not made of valuable solar cells. In order to obtain large-size grain of the film, people have never stopped, and a lot of ways. At present, preparation of polycrystalline silicon thin film batteries use chemical vapor deposition, including the low-pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD) process. In addition, the liquid phase epitaxy (LPPE) and the sputtering deposition could be made available for preparation of polycrystalline silicon thin film batteries.

Chemical vapor deposition is the main SiH2Cl2, SiHCl3, Sicl4 or SiH4, as the reaction gas, a certain degree of protection in an atmosphere of silicon atoms to form and deposited on the substrate heating, the choice of substrate materials in general Si, SiO2, Si3N4, and so on. But the study found that in non-silicon substrates is difficult to form a larger grain, and easily form a gap between grain. To solve this problem is first in LPCVD substrate Shen Chi-thin layer of amorphous silicon layer, and then this layer of amorphous silicon layer annealing, the greater the grain, and then in this layer on the seed Thick polysilicon thin film deposition, recrystallization technology is a very important aspect of the current technology are solid-phase crystallization of the law and the Central re-melt crystallization. In addition to the polysilicon thin film batteries using the re-crystallization process, also used almost all of the preparation of single crystal silicon solar cell technology, such a system, the conversion efficiency of solar cells has increased remarkably. Germany falaj Fort Hall area using solar energy research institute recrystallization technology in the FZ Si substrate on a silicon-cell conversion efficiency of 19%, Japan's Mitsubishi with the preparation of the battery, the effective rate was 16.42 percent.

Liquid phase epitaxy (LPE) is a principle of law by molten silicon in its mother's body, the lower the temperature of precipitation silicon membrane. Astropower U.S. companies LPE Preparation of the battery efficiency of 12.2%. China photovoltaic technology development center Chen Zheliang LPE method used in the metallurgical grade silicon on a silicon crystal growth, and a design similar to the crystalline silicon thin film solar cells a new type of solar cells, known as the "silicon tablets of" solar energy Battery, but the performance has not yet seen the report.

As the polysilicon thin film batteries used in the silicon single crystal silicon than the less efficient and no recession, and there may be low-cost substrate material on the preparation, the cost much lower than the single crystal silicon cells, and more efficient than amorphous Silicon thin film battery, polysilicon thin film solar cells will soon be in power to dominate the market.

Amorphous silicon thin film solar cells

The development of solar cells on two key issues: the conversion to increase efficiency and reduce costs. As the amorphous silicon thin film solar cells, low cost, ease of large-scale production, generally people's attention and rapid development, in fact, as early as in the early 1970s, Carlson, and so began the development of amorphous silicon cells, during the past few In its development has been rapid development of the world's been many companies in the production of this type of battery products.

Although the material as amorphous silicon solar battery is a good material, but because of its optical band gap is 1.7eV, making their own materials on the long-wave solar radiation spectrum of the region is not sensitive, so restrictions on the amorphous silicon solar cells The conversion efficiency. In addition, the efficiency of the photoelectric light as an extension of time and decay, the so-called photo-induced recession of the S-W effect, making the battery performance of instability. To address these issues in this track is prepared laminated solar cells, solar cells are stacked in the preparation of p, i, n single-junction solar cell layer and then deposited on one or more sub-Pin of a battery system. Tandem solar cells increase the conversion efficiency of single-junction cells do not resolve the key to the stability of the problem is: ① it to a different band gap of Materials group with Taiwan, in response to the increased scope of the spectrum; ② top of the i-thin battery , The light produced by small changes in the electric field strength to ensure that i layer of photo-induced carriers out; ③ generated at the end of the battery carrier is about one-half of the battery, reducing the effect of photo-induced recession; ④ tandem solar cells each child Battery is a series together.

Amorphous silicon thin film solar cells have a lot of preparation, response, including sputtering, PECVD method, LPCVD law, the response of raw materials for gas H2 diluted SiH4, and the glass substrate for the main piece of stainless steel, made of amorphous silicon Thin film battery technology through a different process can be a single-node tandem solar cells and batteries. At present, amorphous silicon solar cells made major progress in the study: First, the laminated structure of the three amorphous silicon solar cell conversion efficiency of 13%, setting a new record; in the second. Laminated three annual production capacity of solar cells up to 5MW. United Solar Energy Company (VSSC) obtained the highest single-junction solar cell conversion efficiency of 9.3 percent for the third band gap cell stack three highest conversion efficiency of 13%, see table 1

Above the highest conversion efficiency in a small area (0.25cm2) to get the battery. Had reported single-node amorphous silicon solar cell conversion efficiency of more than 12.5%, Academia Sinica, Japan adopted a series of new measures, a system of amorphous silicon cells for the conversion efficiency of 13.2 percent. With regard to domestic battery in particular, amorphous silicon thin film tandem solar cell research, Xinhua Geng's Nankai University, and other industrial materials used to back Al electrode prepared for the area 20X20cm2, to 8.28 percent conversion efficiency of a - Si / a-Si tandem solar cells.

As the amorphous silicon solar cells with high conversion efficiency and low cost and light weight, and other features, has a great potential. At the same time, but because of its stability is not high, a direct impact on its practical application. If you can solve problems and improve the stability of the conversion rate, then the sun can be amorphous silicon cell is the main development of solar products.
Solar photovoltaic cells (referred to as photovoltaic cells) used to direct the sun's light energy into electrical energy. At present, a large number of terrestrial photovoltaic system is based on the use of the silicon substrate for silicon solar cells can be divided into single crystal silicon, polycrystalline silicon, amorphous silicon solar cells. In the energy conversion efficiency and performance, and other aspects of life, better than the single crystal silicon and amorphous silicon cell battery. Polysilicon conversion efficiency is slightly lower than silicon, but the cheaper price.

       In accordance with application requirements, solar cells go through a combination of up to the required output power and the rated output voltage of a group of photovoltaic cells, called photovoltaic components. According to the size and scale photovoltaic power plant, photovoltaic components can be composed of a variety of different size of the array.
The advent of the first single crystal silicon solar cells are solar cells. Silicon is the Earth is a great deal of elements of a nearly everywhere silicon have a presence could be said to be inexhaustible. Used to manufacture silicon solar cells, has no shortage of raw materials. However, refining it is not easy, so people in the production of single crystal silicon solar cells at the same time, the polysilicon solar cell research and amorphous silicon solar cells, since commercial-scale production of solar cells, not yet out of a series of silicon. In fact, for the manufacture of solar cells, many semiconductor materials, with the materials industry, the solar cell will be more and more species. Has been At present, research & development of solar cells, with the exception of silicon series, there are CdS, gallium arsenide, copper indium selenium and many other types of list goes on, this election only a few of the more common solar cells for presentation.

       Monocrystalline silicon solar cell

       Monocrystalline silicon solar cell is the fastest development of a solar cell, its structure and production technology have stereotypes, the products have been widely used in space and on the ground. This high purity of the single crystal silicon solar cells to stick to raw materials, the purity of 99.999 percent requirement. In order to reduce production costs, ground applications such as solar cells using solar-grade silicon rods, materials performance has been relaxed. Some also use semiconductor materials and processing of waste at the beginning and end silicon materials, rehabilitation and Latin America through the exclusive use of single crystal silicon solar cells made of sticks.

       The single crystal silicon solar cell Tablets monomers made after a random test, according to the specifications required for assembly into a solar cell components (solar panels), serial and parallel with the method in some parts of the output voltage and current.

       Polycrystalline silicon solar cells

       At present, the use of polysilicon solar cell materials, most of the particles contain a large number of single-crystal aggregates, or waste time silicon materials and metallurgical grade silicon material from melting casting, and then into the graphite mold, to be gradually cooling solidification , That is, a polycrystalline silicon ingots. This can make a cube of silicon ingots, in order to slice processed into a square film solar cells, improve material utilization and to facilitate assembly. Polycrystalline silicon solar cell production process and almost single crystal silicon solar cell, its photoelectric conversion efficiency of about 12%, slightly lower than the single crystal silicon solar cells, but the material is simple, to save power consumption, with a total production costs than Low, it has been a large number of development.

       Amorphous silicon solar cell

       Amorphous silicon solar cells in 1976 is the emergence of a new type of thin film solar cell type, with single crystal silicon and polycrystalline silicon solar cell production method is completely different, very little silicon material consumption, lower power consumption, is very attractive.

       Amorphous silicon solar cells have different structures, of which there is a better structure called PiN battery, which is in the first substrate layer deposition of N-P-doped amorphous silicon and then a layer of sediment is not doped i Layer, and then deposited a layer of boron-doped amorphous silicon-based P, with the final electron beam evaporation by a layer of reflective film, and electrode silver evaporation. Such production process, a series of deposition chamber can be used in the production process constitutes a row in order to achieve high-volume production. At the same time, thin amorphous silicon solar cells can be made of laminated type, or integrated circuits produced in a plane, with the appropriate mask technology, the production of a number of batteries in series to achieve a higher voltage . Japan is now in series production of amorphous silicon solar cells up to 2.4 volts. Amorphous silicon solar cell problems in photoelectric conversion rate is low and unstable, so a lot yet to be used for large-scale solar power, for most, such as pocket-sized electronic calculators, electronic watches and clocks, and copiers, and so on.

       Multi-compound solar cells

       Multiple compounds refers to the solar cell is not a single element semiconductor materials made of solar cells. Now a wide variety of national studies, though not yet the majority of industrial production, but indicates that the photoelectric conversion Spring garden. There are CdS solar cells, gallium arsenide solar cells, solar cells are several copper indium selenium.

       Solar cells Condenser

       Solar concentrator solar cells is to reduce the use of a measure of the total cost. By condenser result of larger-sun together in a small, to form the "focal" or "focal zone" and will put solar cells "focal" or "focal zone" in order to Increase in light intensity, solar radiation to overcome the shortcomings of low density and thus more power output. Concentrator is usually greater than the rate of a few dozen of its structure may or lens-reflex. Condenser's optical tracking with automatic tracking in general. Can be a way of cooling water or air, water heater and some combination of both access to electricity, hot water to be.

       For condenser of monomer solar cells, solar cells and ordinary slightly different, because to be resistant to high-rate of solar radiation, particularly in the higher temperature of photovoltaic conversion performance to be assured that it is in the choice of semiconductor materials, batteries And the structure of the grid lines have to design some special consideration. The best material is gallium arsenide, followed by single crystal silicon material. In the cell structure, the general structure of the plane to make more use of solar cells, solar cells and condenser regular vertical structure in order to reduce the series resistance. At the same time, the condenser battery grid lines are more dense, typical of the condenser battery grid lines account for about 10% of the cell area to meet the high current density.

       Solar cells have the type of single-crystal silicon and amorphous silicon, multi-crystalline silicon three categories, and most of the applications currently on the market for single-crystal silicon and amorphous silicon.

       1. Single-crystal silicon solar cell

       The most common single-crystal silicon cells are used for power plants, charging systems, lighting and traffic signals, and so on, the electricity voltage and a wide range of high-efficiency, long service life, the world's leading manufacturers, such as Siemens of Germany, United Kingdom Oil and Japan's Sharp are the production of such single-crystal silicon-based solar cells, as the market share of about five, single-crystal silicon cell efficiency from 11% to 24% of the space level (-evaporation) chip from 16% to 24% efficiency, of course, the higher the price of its more expensive.

       2. Multi-crystalline silicon solar cell

       Polysilicon cell efficiency than the low-single-crystal silicon, but the process step is relatively simple, low-cost, single-crystal silicon cell less than 20%, so some of the power of low-power applications using polysilicon solar cells