Solliance and MiaSolé set record 23% efficiency for flexible solar cells

Nine months after presenting the first record-breaking flexible solar cell, copper indium gallium diselenide (CIGS) thin-film photovoltaic solar cell and panel maker MiaSolé Hi-Tech Corp of Santa Clara, CA, USA (a subsidiary of Beijing-based renewable energy firm Hanergy) and Solliance Solar Research - a cross-border (Dutch-Flemish-German) public-private thin-film photovoltaic (TFPV) solar energy R&D consortium in the ELAT (Eindhoven-Leuven-Aachen) region - have set a new 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 CIGS cell.

Such a tandem solar cell has the potential for conversion efficiency exceeding single-junction solar cell performance due to tunable and complementary bandgaps of these individual thin-film solar cells.

To realize maximum conversion efficiencies, the absorption properties of the top perovskite cell and of the bottom CIGS cell can 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 a high-efficiency and stable solar technology and has entered high-volume manufacturing in multi-Gigawatt scale around the world. CIGS technology has been used to produce high-efficiency flexible and lightweight cells and modules, addressing 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.

Developed by MiaSolé Hi-Tech, the CIGS bottom cell used in this tandem architecture is based on a commercially available high-efficiency flexible solar cell technology fabricated on lightweight stainless-steel foil using a proprietary high-throughput roll-to-cell sputtering process. Recently, MiaSolé reported a flexible large-area certified module efficiency of 17.44% with an active area of 1.08m2.

“A highly efficient flexible hybrid solar cell is an outlook on how perovskite solar cell technology can innovate the established solar technology, leading to a different application area with improved performance,” says Sjoerd Veenstra, program manager for perovskite-based solar cells at Solliance.

“This significant tandem cell performance gain was achieved through process improvements in the bottom CIGS cell,” says Dmitry Poplavskyy, MiaSolé’s director of technology. “These process changes, implemented by MiaSolé, enable high-efficiency CIGS cells with the spectral response better matched to the top perovskite cell,” he adds. “Further improvements in spectral matching, as well as overall higher CIGS cell efficiency, are expected to push the tandem architecture well beyond 23%”.

See related items:

MiaSolé boosts its CIGS PV cell efficiency to 20.56%

Tags: MiaSolé Hanergy CIGS Solliance Thin-film PV

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