Scalable deposition of high-efficiency perovskite solar cells (PSCs) is critical to accelerating their commercial applications. However, a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition, exhibiting much negative influence on the efficiency and stability of PSCs. Herein, 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) is incorporated as the bridging layer between the tin oxide (SnO₂) electron transport layer (ETL) and the perovskite film deposited via scalable two-step doctor blading. Both experiment and simulation results demonstrate that MESK can passivate the trap states of Sn suspension bonds, thereby enhancing the charge extraction and transport of the SnO₂ ETL. Meanwhile, the strong interaction with uncoordinated Pb ions can modulate the crystal growth and crystallographic orientation of perovskite film and passivate buried defects. With employing MESK interface bridging, PSCs fabricated via scalable doctor blading in ambient condition achieve a power conversion efficiency (PCE) of 24.67%, which is one of the highest PCEs for doctor-bladed PSCs, and PSC modules with an active area of 11.35 cm² achieve a PCE of 19.45%. Furthermore, PSCs exhibit excellent long-term stability, and the unpackaged target device with a storage of 1680 h in ambient condition (25 °C and humidity of 30% relative humidity (RH)) can maintain more than 90% of the initial PCE. The research provides a strategy for constructing a high-performance interface bridge between SnO₂ ETL and perovskite film, and achieving efficient and stable large-area PSCs and modules fabricated via scalable doctor-blading process in ambient condition.

Layer-by-layer (LbL) strategy has been developed to form bulk heterojunction (BHJ) structure for processing efficient organic solar cells (OSCs). Herein, LbL slot-die coating with twin boiling point solvents (TBPS) strategy was developed to fabricate highly efficient OSCs, which matches with large-scale, high throughput roll-to-roll (R2R) industrialized mass process. The TBPS strategy could produce high-quality thin film without any additive, leading to the optimized vertical phase separation with interpenetrating nanostructures, as well as the enhanced charge transport and extraction. Thus, the power conversion efficiency up to 14.42% was achieved for [(2, 6-(4, 8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo [1, 2-b: 4, 5-b']dithiophene))-alt-(5, 5-(1', 3'-di-2-thienyl-5', 7'- bis(2-ethylhexyl)benzo[1', 2'-c: 4', 5'-c']dithiophene-4, 8-dione)]: 2, 2'-((2Z, 2'Z)-((12, 13-bis(2-ethylhexyl)-3, 9-diundecyl-12, 13-dihydro-[1,2,5]thiadiazolo[3, 4-e]thieno[2'', 3'': 4'', 5'']thieno[2', 3': 4, 5]pyrrolo[3, 2-g]thieno[2', 3': 4, 5]thieno[3, 2-b]indole-2, 10-diyl)bis(methanylylidene)) bis(5, 6-difluoro-3-oxo-2, 3-dihydro-1H-indene-2, 1-diylidene))dimalononitrile (PM6:Y6) OSCs fabricated via sequentially LbL slot-die coating using the TBPS strategy under ambient condition. The research provides a potential route for industrialized production of high-efficiency and large-area OSC devices.

Strain sensors with good stability are vital to the development of wearable healthcare monitoring systems. However, the design of strain sensor with both duration stability and environmental stability is still a challenge. In this work, we propose an ultra-stable and washable strain sensor by embedding a coupled composite film of carbon nanotube (CNT) and Ti₃C₂T_x MXene into polydimethylsiloxane (PDMS) matrix. The composite strain sensor with embedded microstructure and uneven surface makes it conformal to skin, while the CNT/MXene sensing layer exhibits a resistance sensitive to strain. This sensor shows reliable responses at different frequencies and with long-term cycling durability (over 1,000 cycles). Meanwhile, the CNT/MXene/PDMS composite strain sensor provides the advantages of superior anti-interference to temperature change and water washing. The results demonstrate less than 10% resistance changes as the temperature rises from -20 to 80 °C or after sonication in water for 120 min, respectively. The composite sensor is applied to monitor human joint motions, such as bending of finger, wrist and elbow. Moreover, the simultaneous monitoring of the electrocardiogram (ECG) signal and joint movement while riding a sports bicycle is demonstrated, enabling the great potential of the as-fabricated sensor in real-time human healthcare monitoring.

Flexible strain sensors exhibit outstanding advantages in terms of sensitivity and stability by detecting changes in physical signals. It can be easily attached to human skin and clothed to achieve monitoring of human motion and health. However, general sensing material shows low stretchability and cannot respond to signals under large deformation. In this work, a highly stretchable polymer composite was developed by adding small amount (0.17 wt.%) of silver nanowires (AgNWs) in stretchable conductive polymer materials. The conductivity of polymer/AgNWs composite is 1.3 S/m with the stretchability up to 500%. The stretchable strain sensor based on the polymer/AgNWs composite can respond to strain signals in real time, even for 1% strain response, and shows excellent stability over 1,000 loading/unloading cycles. Moreover, the strain sensor can be attached to human skin and clothed to monitor joints, throat and pulse of the human body. The human body electrocardiogram (ECG) signal was detected successfully with the polymer/AgNWs electrode, which is comparable to the signal obtained by the commercial electrode. Overall, the sensors enable monitoring of human movement and health. These advantages make it a potential application in wearable devices and electronic skin.