What the future of the solar industry needs innovative technologies?

Currently, the global installation of solar panels continued rapid growth, but due to oversupply, resulting in the solar panel manufacturing industry in a downturn. Recently, at the meeting of IEEE optoelectronic experts held in Florida, the industry insiders still optimistic about the development prospects of the entire solar energy industry. Although the innovation momentum in the solar energy market has weakened, many studies have made progress. Since the 19th century scientists discovered the semiconductor properties of crystalline silicon, it has changed almost the entire world. Today, the traditional solar cell is still the main use of crystalline silicon technology. A few years ago, the cost of a silicon solar panel was $ 4 / watt. A well-known researcher in the field, Professor Martin Green of the University of New South Wales in Australia, claimed that the cost of a silicon solar panel could never be less than $ 1 per watt. But to talk about it now, he said: "The cost has dropped to about 50 cents / watt, and it is still possible to drop to 36 cents / watt." The United States Department of Energy had planned to achieve overall solar panel system installation costs of less than 11 cents / watt by 2020. This goal not only refers to the cost of solar panels, but also covers utilities' facility costs to make up for the intermittent nature of sunlight (depending on how much solar power is used and other factors). Green believes that the solar industry is likely to complete the goal ahead of schedule. By then, the direct cost of solar energy is expected to drop to 6 cents / kWh, lower than the cost of supplying new natural gas power plants. The global silicon solar panel industry has been seeking ways to cut manufacturing costs and increase panel output. In the 1990s, Professor Green's lab developed a record conversion solar cell, the record has remained so far. In order to maintain the conversion rate, the battery had to use expensive lithography to make fine enough wires to adhere to the crystalline silicon to collect the current generated by the solar cell. With technological innovations, scientists now can use screen printing technology to create fine wires. Recent research shows that screen printing technology can produce a wire width of only 30 microns, which is similar to Professor Green's wire width, but at a much lower cost. Through the composite technology, people are expected to use more convenient and cheap methods to mass-produce high-efficiency solar cells in the production line, and the conversion rate can reach the standards of the predecessor. At present, the company has developed a technology to manufacture the metal contacts of the front part of the solar cell. However, the design of the back-end electronic contacts is more complicated and difficult and no result has been achieved yet. Meanwhile, researchers at the National Renewable Energy Laboratory (NREL) have created a flexible solar cell on a new type of glass. Made of Corning Incorporated, this glass has ultra-thin and highly curved features. The flexible thin-film cadmium telluride solar cells, is currently the only one in the production scale with the traditional silicon solar cells to contend with the product. In the production process, the flexible battery attached to a bendable glass, just like print newspapers, can be manufactured in volume-to-volume fashion continuously, thus reducing costs by increasing output. Dr. Zhao Jianhua, co-founder and CTO of China's solar panel manufacturer China Sunergy, was a student and research associate of Professor Green. Not long ago, Zhao Jianhua announced that CLP PV is building a trial production line for "double-sided solar" batteries that can absorb sunlight on both sides before and after production. This solar cell is designed to reflect sunlight between rows of solar panels to the back of the panel during the daytime when the sun is well lit. If the light is absorbed, then energy is added Out This technology is particularly suitable for use in desert areas where there is strong reflectivity of sunlight. The data shows that the study is particularly well suited for use in the desert, where sunlight is very reflective. Single-sided solar panels generate 340 watts of electricity, while double-sided panels generate up to 400 watts. Zhao Jianhua predicts that these panels can produce 10% -20% more energy per year. Not hard to imagine, these double-sided solar panels will be mounted vertically like a fence. Solar panels absorb sunlight in the morning and sunlight in the afternoon, making it a device that can also use solar power in limited spaces. For example, use them as noise barriers on highways. This arrangement will be more advantageous in areas with dusty weather. Many countries in the Middle East seem to be ideally placed to use such solar panels. Because, in addition to these regions in the light of the strong advantages, the ordinary sandstorms will affect the solar panel power output. Vertical installation of the panels will not accumulate too much dust, but may make the entire solar power system more economical and feasible. In the long run, Professor Green still favors those based on crystalline silicon technology. He hoped to be able to silicon by one or several other semiconductors, which can greatly improve the efficiency of silicon solar panels to further reduce manufacturing costs. All kinds of semiconductor materials as additives should have the characteristic of selectively absorbing part of the light in the solar spectrum and converting it into electrical energy to make up for the deficiency that silicon can not effectively absorb the full-spectrum light source. Experiments show that the addition of one kind of semiconductor can increase the photoelectric conversion rate of the solar panel from the current 25% to 40%, and increase the conversion of another semiconductor to 50%. In the case of the same total output, you can reduce the installation of at least half of the solar panels. At present, the main challenge of combining such semiconductor materials is the arrangement of silicon atoms in crystalline silicon.