Researchers from UNIST (Ulsan National Institute of Science and Technology), KAUST (King Abdullah University of Science and Technology), the Chinese University of Hong Kong (Shenzhen) and Forschungszentrum Jülich have developed a process-tolerant interfacial engineering strategy that enables high-efficiency perovskite and perovskite/silicon tandem solar cells to be fabricated under ambient conditions, overcoming a known bottleneck in scalable manufacturing. Self-assembled monolayers (SAMs) are widely used as hole-selective contacts in high-performance perovskite solar cells (PSCs) due to their excellent transparency and low parasitic absorption. However, conventional phosphonic-acid SAMs are highly sensitive to moisture, leading to poor surface coverage, inhomogeneity, and partial exposure of the transparent conductive oxide when processed in air. As a result, high-efficiency devices typically require fabrication in inert atmospheres, limiting throughput and increasing production cost. To address this limitation, the researchers designed a ternary self-assembled molecular contact that incorporates glycerol dimethacrylate (GDMA) and 1-acetylguanidine (AG) into the SAM system. GDMA plays a dual role: it acts as a co-solvent during deposition to improve wetting and film uniformity, and upon mild thermal curing, it forms a hydrophilic binary network that anchors the SAM robustly to the substrate. This network suppresses disruption of the monolayer during subsequent perovskite deposition. Meanwhile, AG is introduced to passivate interfacial defects, further improving charge selectivity and reducing recombination losses.
Ambient-fabricated perovskite/silicon tandems reach 31.72% efficiency using engineered SAM interface
