University of Vermont,
Keywords: Perovskite, printed, solar, grain
Summary:One of the largest problems facing humankind in the not-so-distant future is energy. This crisis is being tackled in a myriad of ways: wind, solar, tidal, geothermal, hydrogen, etc. With a global population rising from 7.6 to 9.7 billion in the next 30 years needing an estimated 10X increase in energy, 11% of the current population without electricity, CO2 emissions setting records of 33.3 Gt, and a dwindling supply of petroleum clean energy solutions are in a state where they need to grow at unprecedented rates. Lots of people see silicon solar cells (SCs) as a key component in combatting these issues, but they come with their own problems. First, Si SCs won’t be able to handle the whole problem itself, their production requires high energy consumption itself, 50% of the production is lost as “sawdust,” and their absorption spectra isn’t ideal which leads them to being thicker and heavier. Perovskite materials have been heralded as the challenger to Si in the last decade due to their high efficiency, facile production, weight, and durability. Several groups have shown it is possible to “print” off large amounts of perovskite SCs on a web, much like newspaper printing. There are problems with perovskites as well, the most significant of which is the relatively short lifetime when compared to Si. Instead of monocrystalline cells found in Si SCs, perovskites have a multitude of grains ranging up to 2 µm, where each grain boundary is potentially an avenue for film degradation. We are developing a technique to increase the grainsizes and hence the device lifetime while still being easy to print at high speeds and making is cost effective (< $0.50/W). Our technique should provide lightweight, flexible and highly efficient SCs to be used in situations where Si solar is not an option. In VT, 40% of houses have old roofs that cannot support traditional solar panels due to the weight requirements, Si panels cannot be placed on multidimensional surfaces as the radii of curvature are large. We plan to initially deploy our technology in these lower volume markets where lightweight and flexible modules are required.