Researchers at the Visvesvaraya National Institute of Technology in India have unveiled an innovative solar cell design that utilizes tungsten disulfide (WS2) as a back surface field (BSF) layer in copper indium gallium diselenide (CIGS) solar cells. This advancement promises to enhance efficiency while lowering the costs associated with the materials used in solar cell production.
The BSF layer, typically a highly doped region at the rear of solar cells, is essential for boosting the voltage of the device. WS2, known for its slick, durable properties, serves not only as an electron transport layer but also as a buffer. Its nanosheets and nanoparticles have found applications in various fields, including nanoelectronics and energy storage.
Sushama M. Giripunje, the lead author of the study, highlighted that this research marks a significant milestone, achieving a remarkable 25.7% efficiency with an ultra-thin CIGS absorber layer of just 200 nm and a 50 nm BSF layer. This design aims to minimize the use of rare earth materials, such as indium and gallium, thereby reducing the cost per watt of solar energy. “This kind of structure is not reported earlier to the best of the authors’ knowledge,” Giripunje stated.
The researchers employed SCAPS-1D solar cell simulation software, developed by the University of Ghent, to model the new configuration, which includes nickel for the back contact, a PEDOT
layer, the CIGS absorber, WS2 buffer, zinc oxide window layer, and an aluminum front electrode. The simulations showed promising results: a power conversion efficiency of 25.7%, an open-circuit voltage of 0.81 V, a short-circuit current density of 39.33 mA/cm², and a fill factor of 79.89%.
The study, titled “Designing and Simulating of New Highly Efficient Ultra-thin CIGS Solar Cell Device Structure: Plan to Minimize Cost per Watt Price,” was published in the Journal of Physics and Chemistry of Solids, offering a glimpse into the future of cost-effective solar technology.
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