Researchers Develop Multijunction Silicon Solar Cell with 36.1% Efficiency

The project was funded from the Fraunhofer ICON program

September 26, 2023


The Fraunhofer Institute for Solar Energy Research ISE (Fraunhofer ISE) and NWO-Institute AMOLF have developed a multijunction solar cell with an efficiency of 36.1%, beating previous records for silicon-based solar cells.

Silicon-based solar cells have long been a mainstay of the renewable energy landscape, but they usually face a fundamental efficiency limit of 29.4%.

To surmount this limitation, the researchers turned to the concept of multijunction solar cells. In these cells, multiple layers of light-absorbing materials are stacked on top of each other, allowing each layer to capture specific segments of the sunlight’s color spectrum efficiently.

The innovative approach offers the potential for significantly enhanced solar cell efficiency.

The record-breaking solar cell combines a “silicon TOPCon” solar cell, a novel high-efficiency cell design developed at Fraunhofer ISE, with two semiconductor layers composed of gallium indium phosphide (GaInP) and Gallium Indium Arsenide Phosphide (GaInAsP), also developed at Fraunhofer ISE.

The layer stack is further coated with a meticulously designed metal/polymer nanocoating developed at AMOLF and jointly fabricated by both research institutes.

The back reflector incorporated into the design enhances light trapping within the solar cell, marking the first time efficiency has been pushed beyond the 36% milestone.

The achievement was unveiled at the European Photovoltaic Solar Energy Conference (EU PVSEC) held in Lisbon last week and was made possible through funding from the Fraunhofer ICON program.

Paving the Way for New Applications

While these ultra-high-efficiency solar cells are currently more expensive to produce than conventional silicon solar cells, which typically achieve efficiencies of up to 27%, their potential applications hold promise.

The researchers explained that the multijunction cells are poised to shine in scenarios where space is limited and substantial solar power generation is essential. Examples of such applications include solar-powered electric cars, consumer products, and drones.

The innovative light management design also holds promise for other types of solar cells, such as silicon-perovskite multijunction solar cells.

Another recent study by Fraunhofer ISE has demonstrated the immense potential of triple-junction solar cells composed of perovskite-perovskite-silicon subcells.

In February, India partnered with Fraunhofer ISE on hydrogen and clean energy tech.