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  • What is perovskite?
    Perovskite refers to a class of materials that share the mineral perovskite's crystalline structure. They are sensitive to wavelengths of light that conventional silicon solar panels do not efficiently convert to electricity. Combining perovskite with conventional silicon solar cells can increase their efficiency for a tandem technology that can also lower the cost of solar energy.
  • What is the efficiency of Tandem PV's perovskite panels?
    Tandem PV stacks conventional silicon solar cells with thin-film perovskite materials for tandem panels with 26% efficiency, which is roughly 25% more powerful than the average silicon solar panel. Tandem PV’s stacked design distinguishes the company from most competitors, who deposit perovskite directly on silicon cells to make monolithic tandem cells.
  • What is the durability of Tandem PV's panels?
    Tandem PV has demonstrated the equivalent of decades of projected durability in the lab, although its newest and highest performing panels are still undergoing testing. We plan to provide independent industry-standard validation of efficiency and durability, expected to rise further, during 2024.
  • Why is durability as important as efficiency for a commercial-grade perovskite solar panel?
    Perovskites can degrade when they react with moisture and oxygen or with extended exposure to light, heat or voltage (just as silicon-based solar panels can). However, Tandem PV is drawing on years of solar industry experience and patented technology to demonstrate extended durability through a variety of technology and design innovations. A perovskite panel that combines robust durability and high efficiency is required for commercial success.
  • Why are perovskite modules simpler than silicon solar panels to manufacture?
    Manufacturing perovskite panels is less like making a silicon panel, which entails producing a multitude of silicon solar cells, each processed at very high temperatures, requiring high energy use, and more like making a window or television. Making the latter involves coating a single surface at lower temperatures and comparatively low energy use.
  • Why is perovskite technology described as the future of solar energy?
    Primarily because perovskite solar products are less expensive to produce and manufacture and will ultimately have much higher performance than traditional silicon solar panels. Perovskite also holds the possibility of new uses because it is a thinner, more flexible material.
  • Why are perovskite panels cheaper to make than conventional silicon panels?
    The synthetic perovskite materials used for solar technology are low cost and less material is needed because perovskite coatings are 200 times thinner than conventional silicon solar cells. Tandem panels have the potential to produce up to 45% efficiency. Silicon solar technology is limited to the high 20s. Our panels are also cheaper and more sustainable to manufacture because they require roughly one tenth the energy. Silicon must be heated up to roughly 1,500 Celsius. Our process runs around 150 Celsius.
  • When will perovskite technology reach its full potential and why has it been taking so long to commercialize?
    The development of perovskite solar technology is progressing much faster than silicon solar tech. The latter took some 50 years to reach its current status, whereas the former is on track for commercial viability within a year or two, after about one decade of industrial development.
  • But isn't conventional solar becoming more powerful, abundant and cheaper by the day?
    Silicon cannot match perovskite’s eventual performance for reasons related to the limitation of physics. Also, perovskite technology can turbocharge the rapid growth of conventional solar, plus, there is elasticity of demand for electricity. As the price goes down, demand will go up. So it's not just about replacing what we use but making a lot more of it. The only way to do that is to make it a lot more affordable.
  • How do perovskite solar panels have a lighter environmental footprint than conventional solar technology?
    Lead is the main element in perovskite, but the amount of lead in a single auxiliary car battery can produce 5 megawatts of perovskite solar power—enough to power a small town. Also, perovskite solar manufacturing requires about ten times less energy than silicon cell production and Tandem PV’s panels use about 15 times less lead than traditional silicon solar panels. We have patents to help advance tandem-panel lead recycling industry wide, as well.
  • How can perovskite panels accelerate the shift to a renewable energy economy?
    Predominantly by not only offering a lower-cost alternative to fossil fuels, but an even lower cost alternative to silicon-based solar panels. There is near unlimited demand and applications for increased global electricity consumption, and perovskites will be critical to satisfying that demand and to sustaining improved living standards for all people.
  • How will Tandem PV's panels be used? Who will be its first customers?
    We will initially focus on utility-scale projects, with utilities as our first customers. For other applications, please contact us at
  • How is Tandem PV testing efficiency and durability?
    Our experts in materials science, engineering and operations are increasingly conducting indoor and outdoor performance and durability testing. Our indoor testing simulates exterior conditions including light, temperature and moisture variations.
  • Will Tandem PV panels include warranties?
    We expect to provide a standard industry warranty for our panels.
  • Can perovskite panels be sourced and manufactured in the United States?
    Yes, because they can be produced synthetically in a lab. Policies such as the Inflation Reduction Act are incentivizing domestic manufacturing.
  • Can perovskite technology be developed for applications beyond solar panels?
    Yes. In addition to holding the promise of lower cost and higher efficiency, perovskites are being developed for integration into window glass and building facades, due to their flexibility. The technology is also better at capturing light inside buildings, thus could provide renewable power where access to direct sunlight is limited. Perovskite is also being developed for LEDs, x-ray detectors and other non-solar uses.
  • What does the PV in Tandem PV stand for?
  • When was Tandem PV founded?
    Tandem PV, a VC-backed startup based in Silicon Valley, was founded in 2016.
  • Who founded Tandem PV?
    Tandem PV was founded by its CTO, Colin Bailie, who published the first peer-reviewed studies on perovskite-silicon tandem solar panels as a Stanford University doctoral candidate. (Studies can be found here and here). Tandem's co-founder is Chris Eberspacher, an industry pioneer who has led technology at some of the world's largest solar companies. Tandem's co-founder, Chris Eberspacher, is an industry pioneer who has led technology at some of the world's largest solar companies. Bailie and Eberspacher launched the company while at the Cyclotron Road startup accelerator, the U.S. Department of Energy’s prestigious entrepreneurial fellowship at Lawrence Berkeley National Laboratory supporting innovations with the potential for global impact.
  • Has Tandem PV received governmental funding?
    Tandem PV has received a total of $8 million in public funding as well as technical and other support from 15 grant awards, including from the U.S. Department of Energy, the National Science Foundation and the California Energy Commission. The company has raised a total of $26 million to date in venture capital and government support.
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