Inhibiting the Growth of 1D Intermediates in Quasi-2D Ruddlesden?Popper Perovskites

摘要

Quasi-2D perovskite solar cells have recently emerged as a highly prospectiveand inexpensive solution for sustainable energy due to their intrinsicoptoelectronic properties and stability. The qualities of these promisingquasi-2D perovskite cells are generally affected by different intermediatesderived from the precursor solution during film fabrication processing. However,efficient solutions to inhibit intermediates remain insufficient to date.Here, an effective strategy is prsented to inhibit the growth of 1D solvateintermediate during the fabricating process of quasi-2D perovskite filmsby introducing a guanidinium thiocyanate (GUASCN) inhibitor. Theoreticalcalculations reveal that the SCN? anions spontaneously replace the iodideions in the inorganic framework PbI_6~(3?) and induce the decomposition of thesolvate intermediate. The resulted perovskite solar cells exhibit a significantimprovement in power conversion efficiency (PCE), benefiting from thereduced trap-state density and enhanced carrier mobilities. The unencapsulateddevices retain 91 and 95 of the original PCEs under 45 ± 10humidity in air or under continuous light irradiation at 100 mW cm~(?2) and45 ℃ in a nitrogen atmosphere for 1000 h. Particularly, devices withoutelectron-transporting layers maintain 85 of the peak PCE under maximumpower point tracking at 45 ℃ for 1000 h.