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The buried interface has important effect on carrier extraction and nonradiative recombination of perovksite solar cells (PSCs). Herein, to inactivate the buried interfacial defects of perovskite and boost the crystallization quality of perovskite film, 3‐amino‐1‐adamantanol (AAD) serves as a pre‐buried interface modifier on nickel oxide (NiOx) surface to regulate the nucleation and crystallization process of perovskite precursor. The amino and hydroxyl groups in AAD molecule can synchronously coordinate with nickel ion (Ni3+) in NiOx and lead ion in perovskite, respectively. The dual action favors the ordered arrangement of AAD molecules between NiOx and perovskite, which not only enhances hole extraction in hole transport layer, but also provides active sites for homogeneous nucleation. Furthermore, AAD modifier blocks the unfavorable reaction between Ni3+ and perovskite, and effectively passivates the buried interfacial defects. The optimal inverted PSCs achieve a champion power conversion efficiency of 22.21% with negligible hysteresis, favorable thermal, optical, and long‐term stability. Thus, this strategy of modulating perovskite nucleation and crystallization by pre‐buried modifier is feasible for achieving efficient and stable inverted perovskite solar cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interfacial redox reaction between NiO x and perovskite is obstructed. • SaC-100 is developed as a modifier layer in NiO x -based perovskite solar cells. • SaC-100 can efficiently reduce the open-circuit voltage loss of device. • SaC-100 can inhibit perovskite decomposition ascribed from interfacial reaction. In NiO x -based perovskite solar cells (PVSCs), the interfacial redox reaction between Ni3+ (on the surface of NiO x) and A-site cation salt (MAI in perovskite precursor solution) is invariably ignored. This adverse reaction will generate PbI 2 -rich hole extraction barriers at the NiO x -perovskite interface, which limits hole transmission and increases charge recombination, thus resulting in open-circuit voltage (V oc) loss. Furthermore, it will accelerate perovskite degradation by deprotonating the precursor amine and oxidizing iodide to interstitial iodine, which induces the severe instability of devices. Herein, a physical separation strategy by introducing a modifier layer to obstruct the detrimental reaction is explored. The results demonstrate that the trimethylolpropane tris(2-methyl-1-aziridinepropionate) (SaC-100) depositing onto NiO x can suppress the reaction between Ni3+ and MAI to endow the improvement of conductivity and reduction of interfacial defects, thus reducing V oc loss and enhancing device stability. Moreover, the interfacial energy level alignment and the morphology of perovskite are also optimized. As a result, the PVSCs device based on NiO x /SaC-100 presents the best power conversion efficiency (PCE) of 20.21% with a superior V oc value of 1.12 V. Furthermore, the device shows better light and thermal stability because of the hindering effect and defect passivation effect of SaC-100. [ABSTRACT FROM AUTHOR]

The elimination of methylammonium (MA) cation from mixed tin–lead (Sn–Pb) narrow‐bandgap (NBG) perovskites is an effective approach to enhance the operational stability of all‐perovskite tandem solar cells (TSCs). Unfortunately, the uncontrolled nucleation and crystallization processes of MA‐free Sn–Pb perovskites usually lead to inferior film quality and device performance. Herein, a bimolecular crystallization modulation strategy is reported by using guanidine thiocyanate (GuaSCN) and aminoacetamide hydrochloride (AHC) together as additives to improve the film quality of MA‐free Sn–Pb perovskites. It is demonstrated that the use of bimolecular additives can effectively improve the crystallinity, increase the grain size, and induce a preferred (100) orientation for the corresponding films, leading to high‐quality absorber with considerably reduced defect density and suppressed non‐radiative recombination. In addition, the bimolecular additives can reduce the self‐p‐doping hole concentration within the perovskite films and enhance the charge extraction at the perovskite/electron transport layer interface. The modified NBG perovskite solar cells deliver a power conversion efficiency (PCE) of 22.14%. Coupled with the wide‐bandgap (WBG) subcell, the all‐perovskite TSCs give a champion certified PCE of 27.15%, which is the highest certified PCE for MA‐free all‐perovskite TSCs. Encapsulated tandem devices maintain 90% of the initial PCE after 473 h operation. [ABSTRACT FROM AUTHOR]