Perovskite solar cells (PSCs) have reached an impressive efficiency over 23%. One of its promising characteristics is the low-cost solution printability, especially for flexible solar cells. However, printing large area uniform electron transport layers on rough and soft plastic substrates without hysteresis is still a great challenge. Herein, we demonstrate slot-die printed high quality tin oxide films for high efficiency flexible PSCs. The inherent hysteresis induced by the tin oxide layer is suppressed using a universal potassium interfacial passivation strategy regardless of fabricating methods. Results show that the potassium cations, not the anions, facilitate the growth of perovskite grains, passivate the interface, and contribute to the enhanced efficiency and stability. The small size flexible PSCs achieve a high efficiency of 17.18% and large size (5 × 6 cm2) flexible modules obtain an efficiency over 15%. This passivation strategy has shown great promise for pursuing high performance large area flexible PSCs.

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Perovskite solar cells represent a promising photovoltaic technology, which achieves record power conversion efficiencies over 24%. However, a problem on the commercial processing is the unavoidable efficiency loss during the scalable fabrication of perovskite solar module. The efficient and reliable fabrications of high‐quality large‐area perovskite films guarantee commercialized up‐scaling of perovskite solar cells with high efficiency. Herein, a simple dynamic antisolvent quenching (DAS) process is presented to understand large‐area uniform perovskite films to obtain an efficient perovskite solar module. This method provides a facile and universal approach to fabricate cracks‐free and uniform large‐area mixed‐cation perovskite films. A champion module device (10 × 10 cm2) with efficiency of 17.82% (another module with certified efficiency of 17.4%) is obtained using DAS process.

We report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors.

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Hybrid perovskite solar cells (PSC) have gained stupendous achievement in single/tandem solar cell, semitransparent solar cell and flexible devices. Aiming for potential commercialization of perovskite photovoltaic technology, up scalable processing is crucial for all function layers in PSC. Herein we present a study on room temperature magnetron sputtering of tin oxide electron transporting layer (ETL) and apply it in a large area PSC for low cost and continues manufacturing. The SnO2 sputtering targets with varied oxygen and deposition models are used. Specifically, the working gas ratio of Ar/O2 during the radio frequency sputtering process plays a crucial role to obtain optimized SnO2 film. The sputtered SnO2 films demonstrate similar morphological and crystalline properties, but significant varied defect states and carrier transportation roles in the PSC devices. With further modification of thickness of SnO2, the PSCs based on sputtered SnO2 ETL shows a champion efficiency of 18.20% in small area and an efficiency of 14.71% in sub-module with an aperture area of 16.07 cm 2 , which is the highest efficiency of perovskite sub module with sputtered ETLs.

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Inverted perovskite solar cells (PSCs) with a p-i-n structure have attracted great attention. Normally, inorganic p-type metal oxides or polymers are used as the hole-transport material (HTM), a vital component in the inverted PSCs. However, this type of HTM often requires high processing temperatures and/or high costs. On the other hand, a commonly used organic HTM, poly(3,4-ethylenedioxythiophene polystyrene sulfonate (PEDOT:PSS), is sensitive to humidity and thus affects the stability of the PSCs. Herein, we employ a small molecule, 4,4',4''-tris(N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) to replace PEDOT:PSS as a new HTM for inverted PSCs. Compared to a PEDOT:PSS-based device, m-MTDATA-based PSCs exhibit enhanced performance. The highest power conversion efficiency (PCE) was notably improved from 13.44 % (PEDOT:PSS) to 18.12 % (m-MTDATA), suggesting that m-MTDATA could be an efficient HTM to achieve high performance inverted PSCs. Furthermore, the m-MTDATA-based device demonstrated improved stability (retaining 90 % PCE) under ambient conditions over 1000 h compared with the PEDOT:PSS-based devices (retaining 40 % PCE).