Solution-processed triple-cation perovskite solar cells (PSCs) rely on complex compositional engineering or delicate interfacial passivation to balance the trade-off between cell efficiency and long-term stability. Herein, the facile fabrication of highly efficient, stable, and hysteresis-free tin oxide (SnO 2 )based PSCs is demonstrated with a champion cell efficiency of 20.06% using a green, halogen-free antisolvent. The antisolvent, composed of ethyl acetate (EA) solvent and hexane (Hex) in different proportions, works exquisitely in regulating perovskite crystal growth and passivating grain boundaries, leading to the formation of a crack-free perovskite film with enlarged grain size. The high quality perovskite film inhibits carrier recombination and substantially improves the cell efficiency, without requiring an additional enhancer/passivation layer. Furthermore, these PSCs also demonstrate remarkable long-term stability, whereby unencapsulated cells exhibit a power conversion efficiency (PCE) retention of ≈71% after >1500 hours of storage under ambient condition. For encapsulated cells, an astounding PCE retention of >98% is recorded after >3000 hours of storage in air. Overall, this work realizes the fabrication of SnO 2 -based PSCs with a performance greater or comparable to the state-of-the-art PSCs produced with halogenated antisolvents. Evidently, EA-Hex antisolvent can be an extraordinary halogenfree alternative in maximizing the performance of PSCs.

The performance and scalability of perovskite solar cells (PSCs) is highly dependent on the morphology and charge selectivity of the electron transport layer (ETL). This work demonstrates a high‐speed (1800 mm min−1), room‐temperature (25 °C–30 °C) deposition of large‐area (62.5 cm2) tin oxide films using a multi‐pass spray deposition technique. The spray‐deposited SnO2 (spray‐SnO2) films exhibit a controllable thickness, a unique granulate morphology and high transmittance (≈85% at 550 nm). The performance of the PSC based on spray‐SnO2 ETL and formamidinium lead iodide (FAPbI3)‐based perovskite is highly consistent and reproducible, achieving a maximum efficiency of ≈20.1% at an active area (A) of 0.096 cm2. Characterization results reveal that the efficiency improvement originates from the granular morphology of spray‐SnO2 and high conversion rate of PbI2 in the perovskite. More importantly, spray‐SnO2 films are highly scalable and able to reduce the efficiency roll‐off that comes with the increase in contact‐area between SnO2 and perovskite film. Based on the spray‐SnO2 ETL, large‐area PSC (A = 1.0 cm2) achieves an efficiency of ≈18.9%. Furthermore, spray‐SnO2 ETL based PSCs also exhibit higher storage stability compared to the spin‐SnO2 based PSCs.

of a lightweight, flexible, self-charging device with stable and sustainable power output. To tackle this issue, researchers are committed to assembling a flexible, uninterruptible, self-charging system by integrating various flexible energy-harvesting and energy-storage devices, giving rise to novel photocapacitor-integrated devices. Individually, the device application of flexible, fabric/stripe-type photovoltaic (PV) cells and supercapacitors in futuristic textile circuits has been extensively explored. These fiber/stripe-based devices can be easily integrated and woven together into garments with orderly patterns, such as stripes or mosaics, without compromising the wearing comfort and aesthetic design of the garment itself. [5-7] For flexible energy-harvesting devices, researchers have developed highly efficient and flexible PV cells, such as dyesensitized, [5] organic, [8] and perovskite [9] solar cells, which are environmentally benign. Compared to dye-sensitized and perovskite solar cells, organic solar cells (OSCs) exhibit superior device flexibility and higher power conversion efficiency (PCE) retention under extreme mechanical deformation/ distortion. They have these benefits because they are based on organic polymers, which are non-brittle in nature. Additionally, OSCs are low-cost, printable, reproducible, and lightweight, rendering them compatible with futuristic wearable textile applications. [1,3,5,10-13] However, conventional film-based OSCs exhibit flexibility only in a direction perpendicular to the film and are not compatible with the weaving process for wearable electronic applications. By virtue of their diverse fabrication techniques and structural designs, the dimensions of flexible OSC devices can be tuned from 2D (film) to 1D (fibers/stripes) by further scaling down the y-axis of the conventional film-based device. 1D fiber/ stripe-shaped devices that are fully compatible with the weaving process can then be obtained. Stripe-shaped OSCs have inherent advantages over planar OSCs, such as incredibly high mechanical flexibility, which means they can conform to arbitrary shapes like the human body. [14] Furthermore, after the weaving process, the relative shadowed active area is less for stripe-shaped device structures as compared with fiber-shaped geometries. On another note, flexible supercapacitors (F-SCs) have been used as energy storage systems in futuristic smart electronics The popularity of wearable smart electronic gadgets, such as smartphones, smartwatches, and medical sensors, is inhibited by their limited operation lifetime due to the lack of a sustainable self-charging power supply. This constraint can be overcome by developing a flexible, self-charging photocapacitor that can synchronously harvest and store energy. Here, ultrathin, all-printed, and metal-embedded transparent conducting electrodes (ME-TCEs) are designed for the fabrication of large-area, flexible organic solar cells (F-OSCs) and flexible supercapacitors (F-SCs). Stripe-shaped F-OSCs (SF-OSCs) and F-SCs (SF-SCs) ...

State‐of‐the‐art perovskite solar cells (PSCs) based on three‐dimensional (3D) films have achieved high power conversion efficiencies (PCEs), but are relatively fragile in high‐temperature and humid environments. This shortcoming must be addressed before PSCs can be fully commercialized. Herein, the use of a fluorinated aromatic organic spacer cation, 4‐fluoro‐phenethylammonium iodide (FPEAI), to fine‐tune the dimensionality and surface morphology of perovskite films is demonstrated. Surface treatment with FPEAI can lead to in situ formation of a two‐dimensional (2D) (FPEA)2PbI4 perovskite capping layer atop a 3D perovskite film, producing novel 3D/2D interface in perovskite films. Simultaneously, FPEAI treatment can induce a novel grain‐boundary passivation effect on the film surface, which helps to suppress undesirable charge recombination. After FPEAI treatment, standard (0.09 cm2) and large‐area (2.00 cm2) PSCs achieve PCEs of 20.53% and 16.82%, respectively. The FPEAI‐treated PSCs also demonstrate superior air‐ and photo‐stability due to the hydrophobic (FPEA)2PbI4 capping layer that reduces moisture ingress into perovskite structures. Furthermore, a 11.2 cm2 large FPEAI‐treated PSC module with a PCE of 13.66% are successfully fabricated. FPEAI passivation is a facile strategy to produce 3D/2D multi‐dimensional PSCs with superior performance and stability.

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