Researchers at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), University of Macau and Celanese (China) Holding have developed a long-alkyl- chain anionic surfactant (LAS) additive that can significantly improve the long-term operational stability of perovskite/silicon tandem solar cells.
Traditional methods to improve the stability of perovskite solar cells include encapsulation, crystallization engineering, and defect passivation. Similar to “stress corrosion” in metals, glass and polymers, subcritical perovskite deterioration inevitably occurs due to tensile stress during the fabrication and operation, which degrades device performance. To suppress the “stress corrosion”, the researchers developed the novel LAS additive for the perovskite/silicon tandem solar cells.
Relying on surface segregation and micellization, the LAS additive can chemically modify the perovskite crystallization kinetics. Besides, it can physically form a glue-like scaffold to eliminate the residual stress.
Due to reduced defects, suppressed ion migration, and improved energy level alignment, the unencapsulated perovskite and perovskite/silicon tandem solar cells exhibited excellent operational stability.
Under continuous light illumination, the LAS-modified single-junction perovskite and dual-junction perovskite/silicon tandem devices can retain 85.7% and 93.6% of their original PCE after 3,000 hours and 450 hours of maximum power point tracking, respectively, which are among the best stabilities reported to date under similar conditions.
The innovative approach of this study may provide insight into the commercial production and large-scale application of highly stable perovskite/silicon tandem solar cells.