Tin‐based halide perovskites attract incremental attention due to the favorable optoelectronic properties and ideal bandgaps. However, the poor crystalline quality is still the biggest challenge for further progress in tin‐based perovskite solar cells (PVSCs) due to the unfavorable defects and uncontrollable crystallization kinetics. Here, acetic acid (HAc) is first introduced to reduce the supersaturated concentration of the precursor solution to preferentially form pre‐nucleation clusters, thus inducing rapid nucleation for effective regulation of crystallization kinetics. In particular, the hydrogen ion and acetate ion contained in HAc can effectively inhibit the oxidation of Sn2+, and the hydrogen bonding interaction between HAc and iodide ion (I‐) greatly reduces the loss of I‐, which guarantees the I‐/Sn2+ stoichiometric ratio of the corresponding perovskite film close to theoretical value, thus effectively reducing the defect density and maintaining the perfect crystal lattice. Consequently, the HAc‐assisted tin‐based PVSCs achieve a champion power conversion efficiency of 12.26% with superior open‐circuit voltage up to 0.75 V. Moreover, the unencapsulated device maintains nearly 90% of the initial PCE even after 3000 h storage in nitrogen atmosphere. This demonstrated strategy enables to prepare high‐quality tin‐based perovskite film with lower defect density and lattice distortion.

and modifying the charge transporting layers (CTLs), yet the interfacial mismatch between perovskite and CTLs is a non-negligible issue that dominates the efficiency and stability of corresponding devices. [7][8][9][10][11] Nickel oxide (NiO x ) nanocrystals as a promising stable hole transporting layer (HTL) in inverted p-i-n PVSCs are less prone to hysteresis and work well with flexible or tandem architectures. [12] Nevertheless, the PCE of NiO x -based inverted devices are usual inferior to the organic regular counterparts owing to the several interfacial issues: i) abundant surface traps and mismatch energy level restrict the charge carrier extraction, causing large energy offset; [13] ii) the redox reaction between Ni 3+ and A-site cation salts form a PbI 2 -rich hole extraction barrier, leading to severe interfacial destruction; [14] iii) inconsistent thermal expansion of lattice units in NiO x and perovskite results in tensile strain, prejudicing the microstructure and accelerating the degradation of perovskite. [15][16][17] Therefore, it is urge to solve these issues for performance enhancement and commercialization application of NiO x -based PVSCs.Recently, a great deal of molecular interlayers have been applied to passivate or adjust the energy level of NiO x /perovskite interface for strengthen the efficiency and stability in p-i-n devices, such as inorganic salts, [18][19][20] acids, [21] fullerene derivatives [22] and polymers buffer layer. [23][24][25] Nevertheless, most of the buffer layers are nonconductive and accompanied with the uncontrollable thickness and uniformity, which undoubtedly affect the optimization of charge transfer and perovskite crystal growth. Relatively speaking, the self-assembled small-molecule (SASM) can form thermodynamically favored ordered self-assembled layer that has been extensively proved as effective modifier to modulate the energy level and surface chemical state, as well as enhance the affinities of the deposition layer and substrate. [26] For instance, Fang et al. has reported that a polar chlorine-terminated SASM can modulate the energy-level alignment by forming a dipole moment at the interface. [27] Chen et al. has regulated the crystalline process and optimized the morphology of perovskite film by using 3-aminopropanioc acid SASM modified titanium oxide. [28] Other SASMs with different chemical terminations (such as amines, [29] carboxylates, [30] thiols, [31] and phosphonic acid [32] ) are also demonstrated to dramatically modify the electron Interfacial lattice mismatch and adverse reaction are the key issues hindering the development of nickel oxide (NiO x )-based inverted perovskite solar cells (PVSCs). Herein, a p-chlorobenzenesulfonic acid (CBSA) self-assembled small-molecule (SASM) is adopted to anchor NiO x and perovskite crystals to endow dual-passivation. The chlorine terminal of SASMs can provide growth sites for perovskite, leading to interfacial strain release. Meanwhile, the sulfonic acid group from SASMs can passivate surface defects of NiO x ,...

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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.

Tin-based perovskite solar cells (Sn-PSCs) have emerged as promising environmentally viable photovoltaic technologies, but still suffer from severe non-radiative recombination loss due to the presence of abundant deep-level defects in the perovskite film and under-optimized carrier dynamics throughout the device. Herein, we healed the structural imperfections of Sn perovskites in an "inside-out" manner by incorporating a new class of biocompatible chelating agent with multidentate claws, namely, 2-Guanidinoacetic acid (GAA), which passivated a variety of deep-level Snrelated and I-related defects, cooperatively reinforced the passivation efficacy, released the lattice strain, improved the structural toughness, and promoted the carrier transport of Sn perovskites. Encouragingly, an efficiency of 13.7 % with a small voltage deficit of � 0.47 V has been achieved for the GAA-modified Sn-PSCs. GAA modification also extended the lifespan of Sn-PSCs over 1200 hours.