As the most popular renewable energy industry, competition in the field of solar energy is very fierce. Currently, solar cells with the highest market share are silicon cells such as polycrystalline silicon and monocrystalline silicon. However, as the Yangtze River waves push forward and the emerging perovskite cells are staring intently The city's No. 1. The team at Brown University and the University of Nebraska Lincoln (UNL) is also working to improve the performance of perovskite cells and to find materials that take the place of toxic materials, lead.
Perovskite batteries are cheaper and easier to manufacture. Their photoelectric conversion efficiency has also risen from 3.81% in 2009 to 22% in comparison with silicon cells. Recent research has increased to 26%. However, in perovskite batteries Of the lead substance is toxic and may be harmful to the environment and the environment, so chemists are looking for ways to replace or detoxify lead.
NitinPadture, a professor of electrical engineering at Brown University, said: 'One of the current focuses of perovskite research is finding alternative, nontoxic and stable materials. We use computer simulations to think of a material that contains cesium, titanium and halogen (bromine or iodine ) Of the perovskite battery is a good candidate material, and for now we are testing his properties.
Rather than directly replacing perovskite cells with silicon cells, the team attempted to combine the two to create 'tandem' solar cells in which the perovskite thin film was located above the silicon layer, Is a translucent material that allows some light to penetrate below the silicon layer, and the two work together to convert more light into electricity.
Perovskites and silicon cells have their own advantages and disadvantages, the research team hopes that by designing multi-layer, different energy gap materials to enhance the photoelectric conversion efficiency, Padture said that at present there is no plan to replace the existing silicon technology, But the team is working hard to improve its performance, and if it can make a stable, lead-free tandem cell, we'll be the winner in the future, and the new material looks great.
Researchers created a 1.8-volt wide-bandgap titanium-perovskite thin film that absorbs higher-energy photons, while other photons are absorbed by the underlying silicon layer, although the current photovoltaic efficiency is only 3.3%, well below the silicon Batteries or other perovskite batteries, but researchers say there are plenty of room for improvement on this first attempt.
Michael McGehee, a professor of materials science and engineering at Stanford University in the United States, also proposed a similar battery design earlier this year (2018). According to his research, tandem cells are 10% more efficient than typical silicon cells, which may be perovskite Material into the market one way.
Nor is it the first time researchers have looked for alternatives to lead, but the team said the titanium is much more rust-proof and offers more voltage than any other material.In other lead-free material experiments, Open-circuit voltage is typically only 0.6 volts, while tin metal experiences the rust problem.
The open circuit voltage is the voltage between the positive and negative terminals of the battery under no load. Padture said that this voltage is usually used to evaluate the potential of solar cell materials. From the very beginning there is such a high voltage that the future should be promising .
