Researchers at Helmholtz-Zentrum Berlin and Humboldt-Universität zu Berlin in Germany have achieved a major milestone in solar energy technology, setting a new world record for tandem solar cell efficiency at 25.5%. While previously high efficiency rates had been achieved in microscopic cells with areas smaller than 1 cm², this study successfully demonstrated the record over an area of 1.081 cm², marking a critical step toward scalable photovoltaic technologies. By combining perovskite and CIGS layers, the achievement could pave the way for more flexible and efficient solar energy applications.
The researchers maximized the use of the solar spectrum by stacking two different materials in a “sandwich” structure within the tandem solar cell. The perovskite layer at the top converts high-energy blue light into electricity, while the copper, indium, gallium, and selenium (CIGS) layer underneath captures the lower-energy red and infrared light that passes through the perovskite layer. This precise engineering was made possible through the optimization of the CIGS absorber’s bandgap by Dr. Guillermo Farias Basulto and the adjustment of atomic coatings by chemist Wuai Zhang to prevent electrical leakage at internal interfaces.
The most significant aspect of this record is that it surpasses the 1 cm² threshold. Prestigious efficiency rankings known as the “Green Tables” require solar technologies to be tested on areas larger than 1 cm² to demonstrate their scalability. The Berlin team also moved beyond the laboratory scale by testing the technology in a 2.25 cm² mini-module, where it maintained an impressive efficiency of 19.7%.
According to the study published in the journal Joule, the thin-film technology can be integrated into curved surfaces, building windows, and vehicle roofs thanks to its lightweight and flexible structure. The researchers also reported that internal tests using the existing architecture have already achieved efficiency levels of 27.5%, suggesting that surpassing the 30% efficiency threshold could be within reach. This technological progress could expand the range of applications for solar energy and open the door to a new phase in the clean energy transition.
Source: Solarbaba – In Turkish
