The development process of solar cells
Solar cells are the core technology that restricts the use of solar energy. Since the invention of solar cells in 1954, scientists around the world have made unremitting efforts and have now entered the third-generation development period.
The first generation of solar cells uses wafer technology, and the material is mainly silicon. Its technology is quite mature and currently accounts for more than 98% of the total output. The service life of its components has exceeded 25 years, and its highest efficiency is 24, 7 %. At present, the solar cells on the mainstream market are low-priced polysilicon solar cells with an efficiency of about 20%. Group III-V materials can produce higher-efficiency (>25%) solar cells, but their high cost has led to the development of high-efficiency concentrating cells.
The second-generation solar cell adopts thin film technology, and its manufacturing process is more varied than silicon round technology and its manufacturing cost is lower. Only CIS batteries are used to achieve power supply, which are currently mass-produced in Europe, with an efficiency of about 13%. Other low-cost but medium-efficiency solar cells include microcrystalline (about 8%), amorphous silicon (about 10%), and II-VI groups (about 10%), which have been widely used in consumer electronic products, such as watches and computers. There are also a variety of flexible products available.
The third-generation solar cell includes all new solar photovoltaic technologies that are being innovated and enlightened. It has been divided into two categories. The first day is a new type of solar cell with extremely high efficiency (>31%). It is mainly composed of GaSb, GalnSb and other thermal energy conversion crystals added to GaAs photovoltaic cells, which can achieve an efficiency of 30%. In terms of solar cells, its theoretical simulation of titanium quantum dots is expected to reach a high efficiency of 63.2% in GaP or GaAs, but it needs to be tested by experiments. The second category is cheap organic solar cells that can be made into a large area, represented by dye-sensitized thin-film solar cells, containing liquid electrolyte, the efficiency of the cell laboratory reaches 11%, and the commercial efficiency reaches 8%. The 15-year life span is guaranteed. If the commercialization efficiency reaches 10%, the cost is expected to be reduced to 25 US dollars/m2, which meets the requirements of generalization.
The development trend of solar cells
The large-scale application of solar cells needs to solve two major problems:-is to improve the photoelectric conversion efficiency; the second is to reduce the production cost. Since the 21st century, the development of solar cells has entered a new stage, and solar cells have obtained new developments in terms of structure and material technology. The so-called new solar cells refer to solar cells manufactured with new materials, new structures and new processes. At present, crystalline silicon high-efficiency solar cells and various thin-film solar cells are the two hotspots and focal points in the research and development of new-type solar cells in the world. The photoelectric conversion efficiency of high-efficiency monocrystalline silicon solar cells is close to 25%, and the photoelectric conversion efficiency of high-efficiency polycrystalline silicon solar cells has exceeded 20%. The research work of thin-film solar cells is mainly concentrated on amorphous silicon thin-film batteries, CdTe-based thin-film batteries, CIS-based thin-film batteries and polycrystalline silicon thin-film batteries. The research and development of amorphous silicon thin-film batteries focuses on solving the problems of light-induced degradation and efficiency improvement of the battery. After hard work, there have been many new breakthroughs, and the stable efficiency of the laboratory has reached 15%. The laboratory efficiency of CdTe-based thin-film batteries has reached 16.4%, and the laboratory efficiency of CIS-based thin-film batteries has reached 19.2%, and a pilot-scale production line with an efficiency of more than 10% has been established. The rapid development of polycrystalline silicon thin-film batteries, the current laboratory efficiency has exceeded 17%, has become a new hot spot that has attracted the attention of the world’s photovoltaic industry, and the prospects are promising.