Collaboration with UCLA: Research on Perovskite-CIGS tandem solar cells yields 24.9 percent efficiency

Based on a commercial CIGS solar cell, Midsummer engineers, by working with researchers at Prof. Yang Yang’s laboratory of University of California, Los Angeles (UCLA), have demonstrated a four-terminal perovskite-CIGS tandem solar cell reaching 24.9 percent efficiency.

[Los Angeles, CA, USA, March 19, 2023.] Based on a commercial CIGS solar cell, Midsummer engineers, by working with researchers at Prof. Yang Yang's laboratory of University of California, Los Angeles (UCLA), have demonstrated a four-terminal perovskite-CIGS tandem solar cell reaching 24.9 percent efficiency.


Midsummer is a leading Swedish developer and manufacturer of thin film CIGS solar cells. Recently, by a joint project with Prof. Yang, they have demonstrated a 4-terminal perovskite-CIGS tandem solar cell. It is based on a perovskite top cell that has been optimized for integration with Midsummer's CIGS cells that are utilized in their commercial suite of BIPV products.

The cell has shown an efficiency of 24.9 percent as a 4-terminal device architecture. It consists of a top layer of wide bandgap perovskite cell and a bottom layer of the CIGS cell. The research continues with the aim of a two-terminal perovskite-CIGS cell which will render this particular solar cell highly competitive and suitable for mass production.

This work shows the feasibility of building a tandem cell on a breakthrough production proven process developed at Midsummer and using the Midsummer DUO machine. The DUO production system developed by Midsummer is able to provide high performance CIGS solar cells with dimensions of 156 mm x 156 mm on a flexible stainless steel substrate. This form factor is ideally suited for subsequent processing of perovskite films on the company's current BIPV product suite (SLIM; WAVE; and BOLD).

"We feel fortunate to be working with Professor Yang's group at UCLA which has demonstrated key advances in perovskites," said Leon Chiu, President, Pioneer Materials, Inc. which is a key supplier for compound sputtering targets used in Midsummer's novel processing for CIGS on stainless steel. "Integrating Midsummer's production proven CIGS processing with Yang's Lab tailored perovskite shows a clear path toward expanding the reach of BIPV by improving efficiency and lowering costs."

"Perovskite-CIGS tandem cells have great future potential and Midsummer's solar panel design has by far the best conditions for building a commercial product for this type of solar panel, e.g since it contains a diode between each solar cell," comments Sven Lindström, CEO, Midsummer.

Quote by Professor Yang Yang: "We are thrilled to have this opportunity to work with Midsummer and PMI. Our ultimate goal is to demonstrate two-terminal perovskite/CIGS tandem cells, suitable for mass production."

About Midsummer
Midsummer is a Swedish solar energy company that develops and markets equipment for the production of thin film solar cells and also manufactures, sells and installs solar roofs. The solar cells are of CIGS technology and thin, light, flexible, discreet and with a minimal carbon footprint compared with other solar panels.

The solar roofs are produced in Sweden using the company's own unique DUO system which has taken the position as the most widespread manufacturing tool for flexible CIGS solar cells in the world. The Company's shares (MIDS) are traded on Nasdaq First North Growth Market with G&W Fondkommission as Certified Adviser. For more information, please visit: midsummer.se

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