Characteristics of solar cells
Many advantages of solar photovoltaic power generation are very needed for future energy. It has the following characteristics: ①It is not restricted by region and can generate electricity when there is sunlight; ②The power generation process is a simple physical process, and there is basically no impact on the environment without any waste gas discharge; ③The solar cell runs statically, with no moving parts, no wear, high reliability, and no noise; ④The power generation power is determined by the solar battery, which can be assembled into any size according to the required power; ⑤It is convenient to be used as an independent energy source, but also can be used in networking with other power sources; ⑥Long life (up to 20 years); ⑦The solar cell has light weight, stable performance and high sensitivity; ⑧The solar life span is 6 billion years, so solar power generation is relatively infinite energy. It is a universal power technology that can be used in many large or small fields, can be used in any place with sunlight, and can be installed on any surface, can also be integrated into the building structure, making it easy to realize unmanned and fully automated. Because of these characteristics, solar cells are widely used in space technology in various countries. Among the renewable energy sources is mainly bio-energy, solar energy accounts for a small proportion, but by 2050 the proportion of conventional energy and nuclear energy will drop to 47%, and renewable energy will rise to 53%. Among renewable energy sources, solar energy (including solar thermal utilization and solar power generation) will occupy the first place, accounting for 29% of the total energy. It is particularly worth pointing out that solar power generation alone accounts for 25% of the total energy. The forecast of solar power generation in the energy market from 2020 to 2100 is shown in Figure 1.
Classification of solar cells
Throughout the development process of solar cells, people have successively developed batteries with different structures and different materials. According to these two different aspects, it can be subdivided into different types of solar cells. In terms of structure, there are mainly homogeneous PN junction batteries, Schottky (MS) batteries, MIS batteries, MINP batteries, heterojunction batteries, etc., among which homogeneous PN junction batteries have always been dominant. In terms of materials, there are mainly silicon-based solar cells, multi-component compound thin-film solar cells, organic semiconductor thin-film solar cells, and nanocrystalline chemical solar cells. In terms of material appearance characteristics, they can be divided into bulk materials and thin-film materials.
Among them, crystalline silicon solar cells can be divided into monocrystalline silicon solar cells and polycrystalline silicon solar cells. According to the materials used to prepare solar cells, thin film solar cells can be divided into five categories: multi-element compound thin film solar cells, organic semiconductor thin film solar cells, dye-sensitized nano thin film solar cells, amorphous silicon thin film solar cells and polycrystalline silicon thin film solar cells. The following articles will detail the solar cells under each category.