Just 9 months after the presentation of the first record-breaking flexible solar cell, USA based MiaSolé Hi-Tech Corp and Eindhoven based Solliance Solar Research established a new world record power conversion efficiency of 23% on a flexible solar cell. The solar cell combines two thin-film solar cell technologies into a tandem solar cell stack: a top flexible semi-transparent perovskite solar cell with a bottom flexible copper indium gallium selenide (CIGS) cell.
Best of both worlds
A tandem solar cell, which combines a semi-transparent perovskite cell and a CIGS cell, has the potential for high conversion efficiency exceeding single-junction solar cell performance thanks to tunable and complementary bandgaps of these individual thin-film solar cells.
In order to realize maximum conversion efficiencies, the absorption properties of the top perovskite cell and of the bottom CIGS cell should be tuned to complement each other. The perovskite solar cell was deposited on a transparent and flexible substrate, employed transparent conductive electrodes, and was optimized for maximum visible light conversion efficiency and infrared light transparency to allow the majority of infrared light to reach the bottom CIGS cell.
CIGS technology has a proven track record as high efficiency and stable solar technology and has entered high volume manufacturing in a multi-GW scale around the world. CIGS technology has been successfully used to produce high efficiency flexible and lightweight cells and modules, which address markets where heavy and rigid panels cannot be used.
Perovskite solar cells, despite being a relatively young technology, have already achieved high efficiencies, and promise low-cost solar technology based on abundant materials. Combining both technologies in a flexible and lightweight package expands the horizon of high performance, flexible, and customizable solar technology, a spokesperson for Solliance states.