en.Wedoany.com Reported - Researchers from multiple institutions across mainland China and Hong Kong have reported a dual-molecule interfacial engineering strategy for inverted (p–i–n) perovskite solar cells, achieving a certified efficiency of 27.31%. This approach combines the phosphonic acid-based self-assembled monolayer Me-4PACz with a synergistic modifier, 9H-carbazol-2-yl trifluoromethanesulfonate (CzOTf), to form a hybrid and interface-locked molecular layer at the NiOx/perovskite interface. CzOTf is designed to stabilize charge extraction, passivate buried Pb-related defects, and alleviate tensile stress that can deteriorate perovskite crystallization and interfacial degradation, while suppressing Ni3+-induced redox loss pathways.

The optimized devices achieved a certified efficiency of 27.31% (best device: 27.32%), with an open-circuit voltage of 1.185 V, a short-circuit current density of 26.30 mA/cm², and a fill factor of 87.64%. Reference devices without CzOTf exhibited an efficiency of 26.20%. The strategy was extended to perovskite/silicon HJT tandem cells (32.84%) and large-area 766 cm² modules (21.54%). In terms of stability, the devices retained 92% of their initial efficiency after 2000 hours of continuous illumination, and the modules operated stably outdoors for 35 days.

Me-4PACz, a phosphonic acid-based molecule, anchors onto the NiOx surface via phosphonate groups to form a dense monolayer interfacial layer, resisting desorption and locking the interfacial chemistry. Its carbazole-based functional electron/charge interaction sites passivate electroactive NiOx-perovskite interface traps, reducing non-radiative recombination. This interfacial monolayer also improves the wettability and contact at the NiOx/perovskite interface, promoting more uniform perovskite nucleation. The coordination effect of Me-4PACz suppresses the formation of undercoordinated lead and other deep-level defects near the surface, reducing trap-assisted recombination pathways. CzOTf complements Me-4PACz by pairing with the interfacial chemical environment through its sulfonate anion-related functionality and carbazole moiety, further stabilizing near-surface defect states in the perovskite and helping neutralize buried charge imbalance sites formed during operation. The dual-molecule layer improves charge extraction by modulating interfacial energy levels, alleviates mechanical mismatch at the NiOx/perovskite interface, and acts as a barrier to ion migration, thereby reducing redox-driven degradation at the junction. The resulting NiOx/perovskite contact maintains crystal quality and mitigates interfacial degradation under continuous illumination and outdoor conditions.