Methoxy SAM boosts tandem perovskite solar cell to 30.9% efficiency

Researchers have shown that self-assembled monolayers (SAMs) are effective in tuning energy alignment in wide-bandgap perovskite solar cells for tandem applications. The methoxy-substituted SAM, PyAA-MeO, has exhibited strong p-type character, which has improved hole extraction and reduced recombination losses. Devices incorporating PyAA-MeO have achieved a power conversion efficiency of 22.8%, with an open-circuit voltage of 1.24 V and a fill factor of 84.3%. When integrated into a perovskite/TOPCon tandem structure, the configuration has delivered a certified efficiency of 30.9% and a champion result of 31.1%. The SAMs were deposited on ITO substrates and have shifted energy levels without altering perovskite crystallinity or morphology. Spectroscopic and photoluminescence analyses have confirmed the inductive tuning effect. PyAA-MeO-based devices were shown to retain 99% efficiency after 400 hours at 60°C and 96% after 2400 hours of illumination.