Differences and advantages between flexible amorphous silicon solar cells and ordinary solar cells.

There are two kinds of crystalline silicon photovoltaic cells: monocrystalline silicon and polycrystalline silicon. They are made of P-type (or N-type) silicon substrates and formed by phosphorus (or boron) diffusion. The production technology is mature and it is the leading product in the photovoltaic market. By adopting technologies such as buried electrode, surface passivation, enhanced light trapping, dense grid technology and optimization of back electrode and contact electrode, the photoelectric conversion efficiency has been greatly improved. , improve the carrier collection efficiency in the material, optimize the elbow-proof film, concave-convex surface and high reflection back electrode. The area of monocrystalline silicon photovoltaic cells is limited. At present, it is a wafer larger than 10 to 20 cm, with an annual production capacity of 46 MW/a. At present, the main task is to continue to expand the industrial scale, develop the ribbon silicon photovoltaic cell technology and improve the material utilization rate. Internationally recognized, the highest efficiency is 24% under the condition of AM 1.5, the high-quality space efficiency is about 13.5- 18% under the condition of AMO, and most of them are in11under the condition of AM 1. Replacing # crystalline silicon with cast polycrystalline silicon ingot grown by directional solidification method can reduce the cost, but the efficiency is low. Optimize the screen printing of silver paste and aluminum paste before and after electrodes, and do everything possible to further reduce costs and improve efficiency. The conversion efficiency of large-grain polysilicon photovoltaic cells is as high as 65438 08.6%.

Amorphous silicon photocell

A-Si (amorphous silicon) photovoltaic cells are usually formed by decomposing silane gas by high-frequency glow discharge. Due to the low deposition temperature, thin films with a thickness of about 1 micron can be deposited on glass, stainless steel plate, ceramic plate and flexible plastic sheet, which is easy to be large-scale (0.5 rn× L.0m) and low in cost, and most of them are structural. In order to improve efficiency and stability, it is sometimes made into a multilayer structure such as three layers in, or some transition layers are inserted. An integrated amorphous silicon photovoltaic module was developed. The effective area of laser cutting is more than 90%, the conversion efficiency of small area is improved to 14.6%, the mass production of large area is 8- 10%, and the highest efficiency of laminated structure is 2 1%. The research and development trend is to improve the film characteristics, accurately design the photovoltaic cell structure and control the thickness of each layer, and improve the interface state between layers in order to achieve high efficiency and high stability. Good weak light and low cost! Polycrystalline silicon photocell

P-Si (polycrystalline silicon, including micro-products) photovoltaic cells have no photo-induced degradation effect, and the degradation of material quality will not affect photovoltaic cells, which is an international frontier research hotspot. The conversion efficiency of P-Si photovoltaic cells prepared by liquid phase epitaxy on monocrystalline silicon substrate is 65438 05.3%, which can be improved to 23.7% by thinning the substrate and strengthening light trapping. The conversion efficiency of P-Si photovoltaic cells prepared by CVD method is about 12.6- 17.3%. The growth methods of P-Si thin films on cheap substrates include PECVD and hot filament method, or the low-temperature solid-state crystallization of A-Si: H thin films can be realized by post-annealing, and non-degenerate batteries with efficiency of 9.8% and 9.2% can be made respectively. The growth of microcrystalline silicon thin film is compatible with A-Si process, with high photoelectric performance and stability. The research has aroused great concern, but the effective rate is only 7.7%. The large-area low-temperature P-Si thin film and -Si constitute a laminated battery structure, which is an important way to improve the stability and conversion efficiency of A-S photovoltaic cells and can make full use of solar spectrum. Theoretical calculation shows that its efficiency can reach more than 28%, which will make a breakthrough in the performance of silicon-based thin film photovoltaic cells. CIS (copper lock selenium) thin film photovoltaic cell has the characteristics of high conversion efficiency (up to 17.7%), stable performance and low manufacturing cost, and has become a hot spot in international research and development. CIS photovoltaic cells are generally composed of multilayer films deposited on glass or other cheap substrates, and the thickness can reach 2-3 μ m.. CIS film plays a decisive role in battery performance. At present, many preparation methods have been developed, including reactive evaporation and selenization (sputtering, evaporation, electrodeposition, etc. ), and other outer layers are usually formed by vacuum evaporation or sputtering. The original wind that hinders its development is poor process repeatability, low yield of high-efficiency batteries, complex material composition and lack of analytical instruments to control the growth of thin films. CIS photovoltaic cells are attracting the attention of industry,