by Robert Schreiber
Berlin, Germany (SPX) Dec 14, 2025
Researchers in Munich and worldwide companions have raised the effectivity of perovskite-silicon tandem photo voltaic cells to 31.4 p.c by tailoring the molecular contacts on the interface between the absorber and cost assortment layers. The staff studies the outcome within the journal Joule and notes that the tandem cell was manufactured completely within the Munich area on crystalline silicon backside cells which might be consultant of commercial gadgets. The work concerned scientists from Ludwig-Maximilians-Universitat Munchen (LMU), the Southern College of Science and Know-how (SUSTech) in Shenzhen, the Metropolis College of Hong Kong, and King Abdullah College of Science and Know-how (KAUST) in Saudi Arabia.
Perovskite-silicon tandem cells cut up the photo voltaic spectrum between two absorbers, with the perovskite high cell capturing high-energy blue gentle whereas the silicon cell beneath converts the crimson portion. Through the use of two supplies with completely different bandgaps, these tandem buildings can convert a bigger share of incident daylight into electrical energy than single-junction silicon cells. The general efficiency relies upon strongly on the interfaces, the place photogenerated fees should be effectively extracted with minimal recombination losses.
A central element on this structure is the self-assembled monolayer, or SAM, which varieties an ultrathin molecular contact just a few nanometers thick. This SAM is designed to facilitate cost transport from the perovskite into the underlying cost assortment layers. On pyramidally textured silicon surfaces, nonetheless, normal SAM molecules with easy alkyl chains can prepare inconsistently, leaving gaps and inhomogeneous protection that scale back gadget effectivity.
To beat this limitation, the researchers synthesized a molecule engineered for textured, tough surfaces, enabling extra uniform protection and secure digital contact. This tailor-made molecular construction improves cost transport throughout the interface and establishes a extra sturdy junction between the perovskite and silicon subcells. Throughout detailed evaluation of the interface chemistry, the staff observed {that a} commercially obtainable SAM precursor contained hint quantities of bromine-bearing impurities.
These brominated species turned out to be helpful as a result of they passivated defects on the interface and raised the effectivity of the tandem cells. “That such a small chemical change can have such a big impact stunned even us,” explains challenge chief Aydin. “This discovery reveals how decisive the exact interaction of supplies on the molecular stage is for the power yield of rising photo voltaic cells.” Constructing on this discovering, the researchers intentionally mixed brominated and non-brominated molecules to harness the defect-passivating impact with out sacrificing total chemical stability.
The ensuing SAM design permits denser packing of molecules on the textured floor and higher passivation of digital defects on the perovskite-silicon interface. This denser layer enhances cost extraction, will increase gadget stability, and helps greater working efficiencies. By fine-tuning the molecular composition of the contact, the group created situations the place photogenerated carriers transfer extra successfully into {the electrical} circuit fairly than recombining on the interface.
Utilizing this optimized SAM, the tandem gadgets reached a licensed effectivity of 31.4 p.c, inserting the LMU-led collaboration among the many laboratories pushing the efficiency of perovskite-silicon tandems. The truth that the outcome was achieved on industrially related crystalline silicon backside cells underscores the potential for transferring the method towards business manufacturing. The brand new SAM additionally improves long-term stability as a result of the densely packed molecules defend the delicate interface area from chemical and structural injury over time.
The staff now plans to topic the tandem cells to accelerated ageing protocols to probe their conduct beneath situations that simulate long-term out of doors publicity. “As the subsequent step, we wish to present that our tandem cells can show their price not simply within the lab, but additionally in accelerated ageing exams, which provides perception about actual environmental situation conduct,” says Aydin. In parallel, the researchers are evaluating how the know-how might be tailored to be used in house, with a concentrate on satellites in low Earth orbit the place low mass, radiation tolerance, and excessive energy output are important.
Analysis Report:Enhanced charge extraction in textured perovskite-silicon tandem solar cells via molecular contact functionalization
Associated Hyperlinks
Ludwig-Maximilians-Universitat Munchen
All About Solar Energy at SolarDaily.com
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