Four thin film solar cells
1. Amorphous silicon. Amorphous silicon film is one of the core raw materials of solar cells, also known as microcrystalline silicon. According to the different materials, the current silicon solar cells can be divided into three categories: monocrystalline silicon solar cells, polycrystalline silicon solar cells, and thin film solar cells. An amorphous silicon film is relative to monocrystalline silicon and polysilicon. As a new type of solar cell, a thin film solar cell has a broad market prospect due to its wide source of raw materials, low production cost, and ease of large-scale production. Thin-film batteries are basically classified into three types: non-microcrystalline silicon thin film batteries, CIGS thin film batteries, and CdTe thin film batteries. Among them, the conversion efficiency of GIGS is the highest, about 10% to 12%, the conversion efficiency of CdTe is the second, about 8.5% to 10.5%, the lowest is non-microcrystalline battery, generally 6% to 8%; but from raw materials In terms of availability, the raw material of non-microcrystalline cells is silane, which is the most common, while the raw materials of the other two kinds of cells contain rare-element compounds, and the availability is low. In recent years, amorphous silicon thin film solar cells have gradually emerged from various types of solar cells, setting off an investment boom worldwide. Large-size glass substrate thin-film solar cells are put into the market, which will greatly accelerate the promotion and popularization of photovoltaic building integration, rooftop grid-connected power generation systems, and photovoltaic power stations. At the same time, amorphous silicon thin-film batteries attenuate weakly at high temperatures, so they are also suitable for high-temperature, desert areas.
2. Copper indium gallium selenide panels. CIGS is a shorthand for solar thin film battery CuInxGa(1-x)Se2, which has the advantages of good stability, good radiation resistance, low cost, and high efficiency. The highest conversion efficiency of the small sample CIGS thin-film solar cells was refreshed to 21.7% in December 2014, and was prepared by the German Solar Energy and Hydrogen Research Institute ZSW using the co-evaporation method. The conversion efficiency and output of large-area battery modules vary according to the preparation process of each company, and is generally in the range of 10% to 15%. The copper indium gallium selenide thin film solar cell has the characteristics of low production cost, small pollution, no recession, and good low light performance. The photoelectric conversion efficiency ranks first among various thin film solar cells and is close to a crystalline silicon solar cell, while the cost is a crystalline silicon cell. One-third of it is internationally known as "a very promising new type of thin film solar cell in the next era." In addition, the battery has a soft, uniform black appearance, and is ideal for places with high requirements for appearance, such as glass curtain walls of large buildings, and has a large market in modern high-rise buildings and other fields. Although CIGS battery has the advantages of high efficiency and low material cost, he also faces three main problems: (1) complicated process and high investment cost (2) insufficient supply of key raw materials (3) buffer layer CdS has potential toxicity .
3. Cadmium telluride. CdTe is a II-VI compound semiconductor with a bandgap of 1.5 eV, which is very compatible with the solar spectrum and is most suitable for photoelectric energy conversion. It is a good PV material with high theoretical efficiency (28%) and stable performance. Has always been valued by the photovoltaic industry, is a relatively rapid development of a thin film battery. Cadmium telluride is easily deposited into large-area thin films with high deposition rates. CdTe thin-film solar cells are the easiest to manufacture in solar cells, and as a result, they have achieved the fastest commercialization. To improve the efficiency is to optimize the cell structure and the material process of each layer, appropriately thinning the thickness of the window layer CdS, can reduce the loss of incident light, thereby increasing the short-wave response of the battery to increase the short-circuit current density, higher conversion efficiency of CdTe battery The use of a thin CdS window layer has set a record. To reduce costs, it is necessary to reduce the deposition temperature of CdTe to 550°C or lower to make it suitable for use as a substrate for inexpensive glass; the achievement of laboratories in the industry must go through the process of designing, researching, and optimizing components and production models.
4. Organic thin film solar cells. Organic solar cells, as the name suggests, are solar cells that are made of organic materials. Mainly organic materials with photosensitive properties are used as semiconductor materials, and a voltage is generated by a photovoltaic effect to form a current, thereby realizing the effect of solar power generation. Organic thin-film solar cells have the potential advantages of low material cost, easy processing, large area film formation, designability of molecular and thin film properties, light weight, flexibility, and the like, but carrier mobility of organic semiconductors is lower than that of inorganic semiconductors. Poor stability. At present, the photoelectric conversion efficiency of organic solar cells is very low, and it is only possible to increase the photoelectric conversion efficiency to 5% or more.