Solar energy is the inexhaustible renewable energy. Also clean energy, do not produce any pollution. In the effective use of solar energy, Can use is the sun arises in photoelectric the fastest, most vigorous development of research field, is one of the most of the project. Therefore, people and develop the solar cells. Make solar battery is mainly based on semiconductor materials, its working principle is using photoelectric material absorb the light after conversion reaction, according to the photoelectric from different materials and solar cell can be divided into: 1, silicon solar battery, 2 and inorganic salt as gallium arsenide III – V compounds, cadmium sulphide, copper indium selenium, multiple compound material for the battery, 3 and the sun arises functional polymer battery can, 4 and nanocrystalline solar battery, etc. In whatever material to produce batteries, solar battery materials general requirement is: 1, semiconductor materials with not too wide, ban 2, have higher photoelectric conversion efficiency: 3, material itself to the environment pollution, 4 and materials for industrial production and stable performance. Based on the above aspects into consideration, silicon solar battery is the most ideal material, which is mainly silicon solar cells are the main reasons. But along with the continuous development of new materials and related technology development, and in other mixture village on the basis of solar cells are also increasingly shows attractive prospect. This paper gives a review of the solar cell types and research status, and discusses the development and the trend of the solar cells.

1 in silicon solar cells
1.1 monocrystalline silicon solar battery
Silicon solar battery, monocrystalline silicon series batteries conversion efficiency is highest can sun arises, the most mature technology. High-performance monocrystalline cells is based on high quality materials and related silicon into hot processing technology. Now the electricity to process have monocrystalline nearly ripe, the battery production, generally using surface texture, launching district passivation, partition doped technology etc, are mainly develop battery planar monocrystalline cells and groove buried grid electrode monocrystalline cells. To improve the efficiency of conversion from mainly rely on silicon surface microstructure processing and partition doped process. In this aspect, Germany’s fee charges, huo solar system, maintains the world advanced level. This research USES camera battery technology will lithography surface texture, made inverted pyramid. And in the 13nm a surface. The thick with two layers passivation oxides coatings combined minus reflection. Through improved plating process increase screen width and height ratio: through the battery into more than 23% greater efficiency, it is worth of 23.3%. Kyocera company preparation of large 225cm2 (single crystal solar cell) power conversion efficiency for 19.44%, domestic Beijing institute of solar energy is also actively effectively crystalline silicon solar battery research and development, the development of planar efficient monocrystalline cells (2cm X 2cm) conversion efficiency reached 19.79% groove, silicon crystal buried grid electrode (5cm X 5cm) conversion efficiency of 8.6%.
Monocrystalline silicon solar battery conversion efficiency is undoubtedly the highest in large-scale application and industrial production is still the dominant, but because the price of materials and the corresponding monocrystalline trival, which affect the battery technology, high silicon cost greatly reduce the cost to think is very difficult. In order to save the high quality material, looking for alternative products monocrystalline cells, now developed film solar cells, including polycrystalline silicon thin film solar cells and amorphous silicon thin film solar cells is a typical representative.
1.2 polycrystalline silicon thin film solar cells
Usually the crystalline silicon solar cells in the thickness is 3.5-450 muon m high quality silicon wafer, and this made on from the ingot casting tiras or saw on. Therefore the actual amount of silicone material more. In order to save material, people from the mid-seventies began in cheap substrate polysilicon film, but because the sedimentary growth of silicon membrane grain size, not made valuable solar cells. In order to obtain large size of grain, people have been film hasn’t stopped research, and put forward many methods. There were more than batteries polysilicon film by chemical vapor deposition, including chemical vapor deposition (low LPCVD) and plasma enhanced chemical vapor deposition (PECVD) technique process. In addition, the liquid phase epitaxy (LPPE) and sputtering method can also be used for preparation of polysilicon film batteries.
Chemical vapor deposition is mainly SiH2Cl2, SiHCl3, Sicl4 or SiH4, for certain gases under the protective atmosphere reacts silicon atom and deposition in the heat of the substrate is generally selected Si substrate materials, etc., Si3N4 and SiO2 But the study found that in the silicon substrate to form larger grain, and easy in grain formed between the gap. To solve this problem is to use in the substrate LPCVD ablaze sink a thin layer of amorphous silicon, the layer of amorphous silicon layer of annealing, get bigger grain, and then again in the seeds deposited on the wafer polysilicon film thickness, therefore, recrystallization technology is an important part of the current technology, main solid-phase crystallization and central melting recrystallization method. Poly membrane batteries used in recrystallization processes, almost all other USES for the preparation of monocrystalline silicon solar energy cell technology
And so the solar cell can obviously improve the efficiency of conversion. Germany at the area of solar technology in library recrystallization FZ Si substrate of polysilicon battery conversion efficiency, mitsubishi Japan 19% in the preparation of battery, 16.42% efficiency.
Liquid phase epitaxy (LPE) method is melting in the silicon in the matrix, reduce temperature silicon membrane separation. American Astropower company adopts LPE preparation battery efficiency 12.2%. China photoelectric technology development center of ChenZheLiang using liquid extension method in metallurgical level on a silicon wafer growth of grain, and designed a kind of similar to the crystalline silicon thin film solar cells, called the “new solar battery silicon solar battery,” but the report could not see.
Poly membrane using silicon batteries due to less than monocrystalline silicon, and efficiency, and possible recession in the substrate, the preparation of cheap cost far below the higher efficiency, monocrystalline cells and amorphous silicon thin film battery, therefore, polycrystalline silicon solar battery will soon in the dominant power supply field.
130 amorphous silicon thin film solar cells
Development of solar battery, two key questions is: to improve efficiency and reduce cost. Because of amorphous silicon thin film solar cells with low cost, easy mass production, general attention and rapid development, early in the early 1970s, Carlson, etc have started to development of amorphous silicon cells in its research work, work have developed rapidly, the world has had many
Companies in the production of the battery products.
Amorphous silicon solar materials as though is a kind of very good battery materials, but due to its optical bandgap 1.7 for eV, and makes the material itself to solar radiation spectrum of long not sensitive areas, thus limiting amorphous silicon solar battery conversion efficiency. In addition, the photoelectric efficiency as the time of light and attenuation, namely the continuation of the so-called “S to a recession, battery performance W effect of instability. To solve these problems, the size is laminated solar battery, preparation of laminated solar battery consists in the preparation of n, p, single and solar battery on deposition of one or more p – I – n son batteries. Stack to improve conversion efficiency of solar cells, solve the stability of single “battery problem: (1) it is the width of the different section material in together, improve the spectral range of responses, 2 I layer top batteries are thin and light changed electric-field intensity of the light, I was born; spare carriers 3 of the battery for single battery charge carriers to recession effect, decreases, 4 the laminated solar battery is together.
Amorphous silicon thin film solar cells have lots of preparation methods, including the reaction PECVD sputtering, LPCVD method, method, the raw materials for H2 dilution of gas SiH4, mainly for the glass and stainless steel substrate, amorphous silicon thin film made by different batteries process can be made by batteries and laminated solar cells. Currently amorphous silicon solar battery has two big progress: first, three laminated structure of amorphous silicon solar battery conversion efficiency to set a new record; 13%, The second. Three laminated solar cell production capacity of 5MW. United solar companies (VSSC) system of single supreme conversion efficiency of solar cells for 9.3 per cent, the highest searc gap three laminated battery conversion efficiency 13%.
The conversion efficiency is highest in a small area (0.25 cm2) battery. Single and have been reported in the literature of amorphous silicon solar battery conversion efficiency, Japanese academia sinica than 12.5% adopted a series of new measures, the amorphous silicon cells for the conversion efficiency 13.2%. Domestic about amorphous silicon thin film solar cells, especially the study of laminated, nankai university GengXinHua of such materials, industrial aluminium was back electrode 20X20cm2 area for the conversion efficiency, 8.28% – - Si Si/laminated solar cells.
Amorphous silicon solar battery due to the high efficiency and low cost and weight etc, has great potential. But also because of its stability is not high, the direct impact of its practical application. If you can solve problems and further improve stability problem, so, conversion of amorphous silicon solar battery is undoubtedly the sun arises to the main product development is one of the battery.

2 multiple compound film solar cells
In order to find alternative monocrystalline cells, people in developed polysilicon, amorphous silicon thin film solar cells, and constantly develop other materials of solar cells. Include gallium arsenide iii-v compounds, cadmium sulphide, cadmium sulphide and copper Gu selenium film batteries etc. These cells, although the cadmium sulphide, tellurium polycrystalline cadmium battery efficiency is relatively thin film solar cells of amorphous silicon, high efficiency, low cost, and also monocrystalline cells to mass production, but due to cadmium has virulent, causing serious pollution of environment, therefore, not crystalline silicon solar battery ideal substitute gallium arsenide III – V compounds and copper indium selenium film batteries due to the high efficiency of the universal attention by people. GaAs belongs to iii-v semiconductor compound material, the gap of 1.4 eV, just as high absorptivity of sunshine, so, it is an ideal material for battery. GaAs etc III – V compounds were mainly adopts the technology, which MOVPE and MOVPE method LPE preparation of GaAs film substrate dislocation, battery by reaction pressure, III – V ratio, the influence of various parameters etc blade.
Besides, other III – GaAs Gasb, compounds such as V GaInP battery material also being developed. In 1998, Germany, solar system, the system of GaAs conversion efficiency of solar cells, for European record for 24.2%. The first preparation GaInP battery conversion efficiency for 14.7%. See table 2. In addition, the institute also adopts stack structure, preparation of GaAs Gasb battery, the battery is two independent battery stacked together, as the battery, GaAs battery Gasb is, the battery efficiency 31.1%.
Copper indium CuInSe2 selenium as CIC. The material can drop for CIS, suitable for leV employs 1. The sun photoelectric, moreover, CIS film solar cells, does not exist to recession. Therefore, high conversion efficiency of CIS used for film solar cells material also caused the people’s attention.
The preparation of CIS batteries are mainly vacuum film deposition method and selenide method. Vacuum deposition method is adopted their source of indium and steam copper, selenium, selenide method is used H2Se laminated film, but the selenium is composed of CIS have uniform. CIS film battery from the 1980s initially 8% of the conversion efficiency to the current development of about 15 per cent. Japan’s matsushita electric industrial company of development of CIS mixed gallium battery, the photoelectric conversion efficiency for 1cm2 area (15.3%). In 1995, American renewable energy laboratory developed conversion efficiency for 17. L % of CIS solar battery, this is by far the world’s highest conversion efficiency of the battery. Expected to 2000 CIS battery conversion efficiency will reach 20%, polycrystalline silicon solar energy cell.
CIS as solar cells semiconductor materials, low price and good performance has advantages such as simple process and development in the future, will become an important direction of solar cells. The only problem is, because the material sources of indium and selenium is rare elements are, therefore, this kind of cell development limited.

3 polymer layers modified electrodes solar cells
In the solar battery in polymer instead of inorganic materials are just beginning of a solar system dad research direction. Its principle is to use different supplies oxidation of different polymers, REDOX potential in conductive material (electrode) surface composite multi-layer made similar inorganic P, N – “one-way conductive device. One of the lining of the electrode potential by reduction of polymer modification, low layer of high polymer, electron transfer operation direction to the outer transfer only by lining, Another electrode modified opposite, and the first two electrodes are higher than the potential of polymer reduction of two kinds of polymer. When two modified electrodes into contain photosensitive of electrolytic waves hitting photoisomerization agent absorb light. After the electronic transfer to the reduction of potential lower electrode, the reduction in low electrode potential of electronic cannot transfer, only through the outer polymer/through the reduction of high potential to electrolyte, therefore electrodes in optical. /
Because organic material, make easy and flexible materials etc widely, cost advantages, and to utilize solar energy, cheap electricity has important significance. But with organic materials preparation of solar battery only just beginning, whether life, or the battery can and efficiency of inorganic materials, especially silicon. Can become a useful products, remains to be further study.

4 nanocrystalline chemical solar cells
In silicon solar cells in the development of solar battery is undoubtedly the most mature, but due to the high cost, cannot satisfy the requirement of large-scale promotion application. Therefore, people have been constantly in technology, the new material, the battery film etc are explored, and the recent development of nanometer TiO2 energy crystal solar cell and scientists.
The professor has successfully developed Gratzel Switzerland nanometer TiO2 chemical sun arises, domestic battery can some units are also on the research of this aspect. Nanocrystalline chemical solar battery) (hereinafter referred to as the NPC is composed of a kind of semiconductor material modification, the assembly to another large gap in the semiconductor, narrow the formation of semiconductor materials used in the transition metals such as the Os Ru sensitization dye, organic compounds big gap semiconductor materials for nanometer TiO2 and polycrystalline made electrode, besides NPCS batteries are still choose appropriate oxidation a reduction of electrolyte. Working principle: TiO2 nanocrystalline dye molecules absorb solar energy transition to excited excited, unstable, electronic quickly into adjacent TiO2, dye with lost quickly from electrolyte of electronic is compensated, TiO2 into the electricity in the final with conductive film and then enter through the outer loop current generated.
Nano TiO2 crystal solar cell’s advantage is that it is cheap cost and simple technology and stable performance. The photoelectric efficiency in production cost, only 10% for silicon solar cell 1/5 ~ 10. Life can reach 2O years. But because of this research and development of the battery has just started, estimates that the future will be progressively market.

5 the development trend of solar cells
From the above aspects, the discussion of solar cell materials, iii-v compounds and CIS by rare elements such as they made preparation, although the conversion efficiency of solar cells, but from sources, this kind of solar cells may not be dominant in the future. And the other two batteries nanocrystalline solar battery and polymer modified electrodes solar power to existing problems, their research, technology is mature, the conversion efficiency is low, the two kinds of batteries are still in the stage of exploration, inside short time should never replace of solar cells. Therefore, from the conversion efficiency and material sources, the key still is for the future development of silicon solar battery especially polysilicon and amorphous silicon thin film batteries. Because of polysilicon and amorphous silicon thin film batteries with high efficiency and low cost, relatively will eventually supplant monocrystalline cells, become the dominant products to the market.
To improve efficiency and reduce cost are considered in the preparation of solar cells are the two major factors, for the current silicon solar battery, is to further improve conversion efficiency is difficult. Therefore, the main research to develop new battery materials in how should focus on the lower cost and high efficiency of the existing in the solar battery is made of high quality slice, this is the most costly silicon solar battery. Therefore, how to ensure the high efficiency is lower the cost of substrate case is particularly important. But also the future development of solar cells to solve problems. Recently adopted some technology abroad have silicon strip as polysilicon film solar cells on the substrate, to reduce production cost, the effect is now.