The effects from the molecular configuration of diammonium spacer cations on 2D/3D perovskite properties are still unclear.H ere,w ei nvestigated systematically the mechanism of molecular configuration-induced regulation of crystallization kinetic and carrier dynamics by employing various diammonium molecules to construct Dion-Jacobson (DJ)-type 2D/3D perovskites to further facilitating the photovoltaic performance.T he minimum average Pb-I-Pb angle leads to the smallest octahedral tilting of [PbX 6 ] 4À lattice in optimal diammonium molecule-incorporated DJ-type 2D/3D perovskite,w hich enables suitable binding energy and hydrogen-bonding between spacer cations and inorganic [PbX 6 ] 4À cages,t hus contributing to the formation of high-quality perovskite film with vertical crystal orientation, mitigatory lattice distortion and efficient carrier transportation. As aconsequence,adramatically improved device efficiency of 22.68 % is achieved with excellent moisture stability.

make it one of the most promising photovoltaic technologies. [1,2] Although such solar cells have been demonstrated with a certified power conversion efficiency (PCE) reaching 25.5% for laboratory scale devices, [3] successful commercialization of PVSCs still lacks mature large-area manufacturing technology and reliable long-term stability. [4] With the continuous improvement of printing technology, the fabrication of large-area perovskite photovoltaic devices has become possible and is expected to be compatible with industrial-level manufacturing in the coming future. [5,6] However, the intrinsic and extrinsic instabilities of PVSCs remain the tremendous hurdles on the road to commercialization.The photovoltaic performance of perovskite materials is vulnerable to operating environment. In general, the main degradation pathways of perovskite can be classified as two broad categories: one is susceptible to irreversible degradation under external environment stimulants (moisture, oxygen, heat, UV light, etc.) [7] and the other arises due to intrinsic defects caused by ion migration and organic cations or halide ions losses. [8] Generally speaking, aging degradation caused by hydration and oxidation (with assistance of external stress of moisture, oxygen, etc.) can be addressed with advanced encapsulation techniques. [9] However, numerous theoretical calculations and experimental observations document that the intrinsic ion migration phenomenon of hybrid perovskite materials cannot be avoided by encapsulation. [10,11] Thus far, almost all reported high-efficiency PVSCs are based on solution-prepared ionic polycrystalline perovskite absorbers, whose ionic characteristics make them prone to phase segregation, chemical degradation, and current-voltage hysteresis of devices, especially when suffering from illumination, heat, or external electric field. [12][13][14] Ironically, although the migratory ions can passivate the interface to promote carrier transport and collection in some special cases, it brings more serious hysteresis effects and stability issues in perovskite photovoltaic devices. [15,16] The problematics of the ion migration in perovskite can be ascribed to the lower activation energies (0.2-0.8 eV) of the organic and halide ions (e.g., MA + or I − ), which makes the ions

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