Cheap dye-sensitized solar cells go commercial

Easy-to-prepare solar cells use dyes to capture light and have received an impressive array of scientific awards, including the Millennium Technology Prize in 2010. However, they have no commercial impact. They were invented in 1988.

Researchers at Northwestern University reported last week that a new design could change the situation. The equipment produced eliminates the inherent deficiencies of dye-sensitized solar cells: they are prone to leaks and corrosive. Liquid electrolytes.

Solar Dyes: The colored windows on the left are in the Seoul Government Building in South Korea. These windows can generate electricity. The technology used comes from Australian dye-based solar developer, Dasso.

Unlike thin-film and silicon plates, dye solar panels can be manufactured using inexpensive roll-to-roll processes similar to printing. Therefore, even if their efficiency is lower than silicon solar cells, they are indeed cost-effective.

Northwestern University's development is the latest, with a series of advancements. Michael, director of the Center for Advanced Molecular Photovoltaics at Stanford University? ? Michael McGehee recently called a "rejuvenation" dye-sensitized battery. In this area, these latest developments can eventually transform elegant scientific ideas into practical power generation equipment.

In dye-sensitized solar cells, incident light activates a porous layer of titanium dioxide (titania). This layer of titanium dioxide is coated with a dye that produces positive and negative charges. The negative charge is the excited electron that will flow out of the cell through the titanium dioxide, and the positive charge will flow into the liquid electrolyte. Leakage is an ever-present danger for alkaline batteries filled with electrolytes, especially since solar panels can be exposed to extreme weather conditions. When the electrolyte is heated to 80°C (for example, on a roof), it expands, breaking the seal on the panel. The iodine electrolyte of the dye battery is also highly corrosive and can be worn through rust-resistant metals such as aluminum and stainless steel.

Northwestern University chemist Mercouri Kanatzidis, material scientist Robert Chang, and two graduate students who replaced the liquid electrolyte of the dye cell, using solid-state iodine-based semiconductors . Although previous solid-state designs reduced the output power of the dye cells, Northwestern University's design actually improved performance, the researchers said, because cesium-tin-iodine semiconductors replace liquid electrolytes. Absorb light. "Actually, our materials absorb more light than the dye itself," said Karnatis.

In a report in Nature last week, the Northwest University team claimed that their batteries can convert 10.2% of incident light into electricity, far exceeding 7% efficiency, which is the best existing solid-state dye battery. effectiveness. Sean Shaheen, an expert in organic solar cells at Denver University in the United States, said that the efficiency of solar cells at Northwestern University is closer to 8%, which is the case under standard measurement conditions. However, Sahin said that this is still an important advance for dye batteries.

Canachtis said that it is possible to commercialize this design as long as the battery efficiency can be advanced to more than 11%. This is less than 12% to 16% of the commercial thin-film solar panel efficiency, but also far below the efficiency of the silicon plate. However, the cost of making dye batteries should also be low.

Australian solar developer Dyesol is looking to use low-cost processes to promote traditional dye solar technologies, including liquid electrolytes. Its strategy is to integrate dye-based solar energy into building materials such as high-rise glass panels and steel structural roof panels. In March of this year, Timothy Technology, a Korean joint venture partner of the DS company, installed glass panels on a building in Seoul. The Dysol company is working with Tata Steel of India to develop a steel structure roof with a dye solar cell coating.

Damion Milliken, research and development manager at Desal, insists that liquid electrolytes can be included. "Dysol and other companies have produced some equipment that has excellent long-term stability and has been accelerated, equivalent to 25 years of service life, or even longer," Milliken said. "This technology is commercially viable."