The remarkable progress in PCE can be attributed to excellent photoelectric properties of perovskites, including tunable bandgaps, high absorption coefficients, low exciton binding energies, and long carrier lifetime. [2][3][4][5] To achieve highly efficient and stable PVSCs, formamidinium (FA)-based lead triiodide perovskites have been employed as the prime light absorbers, which possess a relatively narrow bandgap (E g ≈ 1.5 eV) and promising thermal stability. [6][7][8] Consequently, various approaches have been dedicated to manipulate the crystal nucleation and grain growth for achieving high-quality perovskite films. Among these, antisolvent quenching is the most popularly used method for obtaining highly crystalline perovskite films through inducing rapid and uniform nucleation of perovskites, boosting the PCE of both conventional n-i-p and inverted p-i-n PVSCs to go beyond 25%. [9][10][11] However, the device reproductivity is limited by the narrow processing window of antisolvent dripping. [12][13][14] In addition, the commonly used antisolvents (chlorobenzene, toluene, ethyl ether etc) are quite toxic, [15][16][17] which will hinder their application in upscaling production of PVSCs.As a result, there is a strong push for searching antisolvent-free techniques to facilitate swift solvent evaporation and effective tuning of crystallization dynamics of perovskites, Developing a facile method to prepare high-quality perovskite films without using the antisolvent technique is critical for upscaling production of perovskite solar cells (PVSCs). However, the as-prepared formamidinium (FA)-based perovskite films often exhibit poor film quality with high density of defects if antisolvent is not used, limiting the photovoltaic performance and long-term stability of derived PVSCs. Herein, this work adopts presynthesized 3D methylammonium lead chloride (MAPbCl 3 ) and 1D 2-aminobenzothiazole lead iodide (ABTPbI 3 ) microcrystals into self-drying perovskite precursors, which serve as seed crystals to promote nucleation and growth of FAPbI 3 -based perovskites without requiring antisolvent extraction. The combined binary microcrystals facilitate the formation of a dense and pinhole-free perovskite film with a stable perovskite lattice and defect-healed grain boundaries, enabling efficient charge carrier transfer and reduced nonradiative recombination loss. As a result, the best-performing inverted architecture device exhibits a champion power conversion efficiency of 23.27% for small-area devices (0.09 cm 2 ) and 21.52% for large-area devices (1.0 cm 2 ). These values are among the highest efficiencies reported for antisolvent-free PVSCs. Additionally, the unencapsulated device shows enhanced moisture, thermal, and operational stabilities, and maintains 92% of its initial efficiency after being held at the maximum power point for 1000 h.

Post-treatment has been recognized as one of the effective methods for passivating the underlying defects in perovskite solar cells (PSCs), but little attention has been paid to how to pick suitable passivation agents with diverse isomers for efficient PSCs, particularly for the tin−lead (Sn−Pb) mixed PSCs. Here, we introduce the dependence of the power conversion efficiency (PCE) on a dipole moment for surface passivator screening, in which we chose three trifluoromethyl-phenylethylamine hydroiodide (CF 3 -PEAI) isomers as surface-treatment materials for hole-transport-layer-free (HTL-free) Sn−Pb mixed PSCs. The different positions of the −CF 3 group for the CF 3 -PEAI isomer result in different dipole moments, which influences the interaction between CF 3 -PEAI and lead iodide. The para position CF 3 with the highest dipole moment exhibits a higher PCE than the ortho-position with a lower dipole moment, which is attributed to the large dipole moment on the surface that could tune the surface polarity from p-type to n-type, facilitating electron charge transport in the HTL-free Sn−Pb mixed PSCs. An ultrathin 2D layer is formed on the perovskite surface to passivate the surface defects, which is responsible for the enhancement of the PCE and stability of the PSCs. As a result, the open-circuit voltage (V OC ) of the device is improved from 0.775 to 0.824 V, yielding a champion PCE of 20.17%, which is one of the highest PCEs among the reported HTL-free Sn−Pb mixed PSCs. The device also shows improved stability with remaining 75% of its initial PCEs after storage in N 2 for 700 h.

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Inorganic hole transporting materials (HTMs), particularly NiOX, have shown significant promise in boosting the efficiency and stability of perovskite solar cells. However, a major challenge facing NiOX-based p-i-n perovskite solar cells (PSCs) is their direct contact with the absorber layer, which can lead to photovoltage and filling factor losses. Additionally, under-coordinated Ni cations can react with the perovskite and cause damage. In this work, we address these issues by using an ionic compound (QAPyBF4) as a perovskite additive to passivate the entire perovskite layer and interact with under-coordinated Ni cations. Our results show that the introduction of QAPyBF4 significantly enhances the performance and stability of NiOX-based PSCs. Specifically, the decorated cells achieved a power conversion efficiency (PCE) of 23.38% and a fill factor (FF) of 85.46%, with no need for complicated surface treatment or NiOX doping. The QAPyBF4 compound passivates the buried NiOX/perovskite interface, effectively reducing photovoltage and filling factor losses. Moreover, the [BF4]‒ component of the compound interacts with under-coordinated Ni cations to prevent their negative impact on the perovskite layer. Overall, our study proposes a simple and effective approach to optimize the performance and stability of NiOX-based PSCs through the use of ionic compound additives. Our findings suggest that addressing buried NiOX/perovskite interface issues and under-coordinated Ni cation considerations are critical in achieving high-performance and stable NiOX-based PSCs.