Solliance and Miasolé’s record conversion for flexible solar cells

16 Sep 2019

23% efficiency achieved for flexible perovskite and CIGS-tandem design development.

Just nine months after the presentation of the first record breaking flexible solar cell, USA-based MiaSolé Hi-Tech and European Solliance Solar Research established what they call “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.

The partners add that 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 most infrared light to reach the bottom CIGS cell.

High potential

CIGS technology, added Solliance, “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 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 relatively 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.

The CIGS bottom cell was produced by MiaSolé Hi-Tech, a developer of CIGS production turn-key factories and manufacturer of CIGS flexible solar panels, located in Santa Clara, California. The CIGS 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 1.08 m².

”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,” commented Sjoerd Veenstra, Program Manager for Perovskite-based Solar Cells at Solliance," said Dmitry Poplavskyy, Director of Technology at MiaSolé Hi-Tech. “This significant tandem cell performance gain was achieved through process improvements in the bottom CIGS cell.”

”These process changes, implemented by MiaSolé, enable high efficiency CIGS cells with the spectral response better matched to the top perovskite cell. Further improvements in spectral matching as well as overall higher CIGS cell efficiency are expected to push the tandem architecture well beyond 23%.”

Perovskite PV white paper published

On September 9th, the European Perovskite Initiative – EPKI [click to access a download], announced the launch of its first white paper on perovskite-based photovoltaics technology and its prospects. The paper encompasses a description of the special features of this material and the overall progression roadmap that is planned by the research community within Europe.

The publication, entitled “Perovskite-based photovoltaics: A unique chance for European PV-industry”, also expresses the need for further commitment and support from European organizations as well as other relevant agencies within its member states to make this innovative technology a success story on the European continent.

Louis Huber, coordinator of EPKI, commented, “At EPKI, we strongly believe that perovskite PV represents a great opportunity which has just begun to reveal itself. Through the edition of this white paper, the European Perovskite Initiative is acting for all its partners, seeking further support with plans to raise awareness among investors and the industrial community.”