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New Technology and New Varieties of Photovoltaic Cells

Author: Source: Datetime: 2016-10-04 11:42:08
Solar power batteries according to their development stage can be divided into three generations. Is now from the first generation of silicon-based technology to the solar cell based on semiconductor thin film technology to the second generation of semiconductor solar cell transition. The first generation of solar cells is mainly based on silicon and gallium arsenide materials, is characterized by high conversion efficiency, long life and good stability, but the cost is higher. Most of the current production of commercial batteries is still the first generation of monocrystalline silicon and polycrystalline silicon solar cells. The second generation of solar cells based on thin film technology, that is, a thin layer of photovoltaic materials in the non-silicon substrate, greatly reducing the consumption of semiconductor materials, reducing the cost of solar cells. Thin film solar cells are polysilicon, amorphous silicon, cadmium telluride and copper indium selenium and other thin film solar cells. But to improve the conversion efficiency is the main problem to be solved. The third generation of solar cells is still in the research and development stage, the goal is to improve the photoelectric conversion efficiency, reduce production costs, according to the "multi-layer laminated semiconductor materials a quantum well material a quantum dot material" route.

So far, this chapter has briefly explained the basic principle of the solar power batteries with monocrystalline silicon semiconductor as an example. Monocrystalline silicon cells using silicon single crystal material, the photovoltaic effect is the use of ordinary PN junction. In order to apply photovoltaic cells to different environments (such as space) is required for photovoltaic cells with different performance indicators and technical characteristics, the formation of different new products and series. At the same time on the existing products also need in the performance 1: [such as conversion efficiency) replacement. So the photovoltaic cell technology is still a fast-growing high-tech fields. In addition to monocrystalline silicon photovoltaic cells, there are many varieties of photovoltaic cells, new varieties are also constantly born. In terms of battery materials, in addition to silicon material, there are a variety of other semiconductor and organic materials can be used for the production of photovoltaic cells. Even the use of silicon materials, there are monocrystalline silicon, polycrystalline silicon and amorphous silicon cells of the points. In the battery structure can also be used, including the new structure called the junction, including a variety of special designs, the performance of photovoltaic cells produce special effects.
The closer the photon energy is to the bandgap, the more efficient it is to absorb the energy, and one way to absorb more photons in the sun is to add multiple junctions with different bandgaps. A relatively large bandgap is placed on the upper surface of the solar power batteries for solar powered portable generator, and high energy photons are absorbed more efficiently on this layer. While the lower bandgap or even smaller junctions will be more effective in absorbing low-energy photons.

This phenomenon can be overcome by using so-called heterojunctions. The heterojunction is a composite junction composed of two materials which are closely matched by a crystal lattice. The band gap of the material near the surface of the cell is larger than the band gap near the bonded portion. The high band gap surface portion is transparent to the low energy photon solar powered portable generator, The photons then penetrate to the lower bandgap region and generate electron-hole pairs there, which can be collected prior to recombination. A heterojunction of indium tin oxide - silicon photovoltaic cells, copper sulfide - cadmium sulfide photovoltaic cells. If the lattice structure of two heterogeneous materials is similar, the lattice matching at the interface is better, it is called heterogeneous surface photovoltaic cell. Such as aluminum gallium arsenide gallium arsenide heterojunction solar power batteries.

Metal and semiconductor contact to form a "Schottky barrier" of the solar power batteries for solar powered portable generator, also known as the elbow 8 p hotovoltaic cells. The principle is based on the metal - semiconductor contact under certain conditions can produce rectified contact Schottky effect. At present, the so-called metal-oxide-semiconductor photovoltaic cells, namely, 10 ^ 5 photovoltaic cells; metal-insulator-semiconductor photovoltaic cells, that thief 13 photovoltaic cells. Such as cobalt - silicon Schottky photovoltaic cells, aluminum - silicon Schottky solar power batteries. TAG: Deployment Fixed SMA Tesvolt Unlimited Volt Army Sonnen Multi-Storage Reliability Shell Manganese 200MW Ørsted Micro