Researchers have set new efficiency records in a promising class of photovoltaic materials. These transition metal dichalcogenides, or TMDs, absorb extremely high levels of sunlight that strike their surface compared to other solar materials, such as silicon. It is far too heavy, bulky, and rigid for applications that require flexibility, lightness, and high power, such as wearable devices, sensors, autonomous drones, and electric vehicles.
The new prototype has a power conversion efficiency of 5.1 percent. Nonetheless, with optical and electrical optimizations, the researchers could achieve 27 percent efficiency (on par with the best solar panels on the market today, silicon included).
The new solar material is extremely thin, which reduces material usage and costs while also making TMD solar cells lightweight and flexible. TMDs can be shaped into irregular shapes, such as a car roof, an airplane wing, or the human body. The team created an active array that is only a few hundred nanometers thick. It consists of the photovoltaic TMD tungsten diselenide and gold contacts spanned by a single-atom-thick layer of conducting graphene sandwiched between a flexible, skin-like polymer and an anti-reflective coating that improves light absorption.
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