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Tandem solar cells can boost efficiency by using a wider range of the solar spectrum. The bandgap of organic semiconductors can be tuned over a wide range, but, for a two-terminal device that directly connects the cells, the currents produced must be nearly equal. Meng et al. used a semiempirical analysis to choose well-matched top- and bottom-cell active layers. They used solution processing to fabricate an inverted tandem device that has a power conversion efficiency as high as 17.4%. Science , this issue p. 1094 A semi-empirical analysis helped to optimize materials for a tandem organic solar cell with high power conversion efficiency. Although organic photovoltaic (OPV) cells have many advantages, their performance still lags far behind that of other photovoltaic platforms. A fundamental reason for their low performance is the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption. In this work, guided by a semi-empirical model analysis and using the tandem cell strategy to overcome such issues, and taking advantage of the high diversity and easily tunable band structure of organic materials, a record and certified 17.29% power conversion efficiency for a two-terminal monolithic solution-processed tandem OPV is achieved.

HighlightsVarious morphological structures in pressure sensors with the resulting advanced sensing properties are reviewed comprehensively.Relevant manufacturing techniques and intelligent applications of pressure sensors are summarized in a complete and interesting way.Future challenges and perspectives of flexible pressure sensors are critically discussed.As an indispensable branch of wearable electronics, flexible pressure sensors are gaining tremendous attention due to their extensive applications in health monitoring, human –machine interaction, artificial intelligence, the internet of things, and other fields. In recent years, highly flexible and wearable pressure sensors have been developed using various materials/structures and transduction mechanisms. Morphological engineering of sensing materials at the nanometer and micrometer scales is crucial to obtaining superior sensor performance. This review focuses on the rapid development of morphological engineering technologies for flexible pressure sensors. We discuss different architectures and morphological designs of sensing materials to achieve high performance, including high sensitivity, broad working range, stable sensing, low hysteresis, high transparency, and directional or selective sensing. Additionally, the general fabrication techniques are summarized, including self-assembly, patterning, and auxiliary synthesis methods. Furthermore, we present the emerging applications of high-performing microengineered pressure sensors in healthcare, smart homes, digital sports, security monitoring, and machine learning-enabled computational sensing platform. Finally, the potential challenges and prospects for the future developments of pressure sensors are discussed comprehensively.

A key feature of organic electronic devices is their mechanical flexibility. However, the performance of flexible organic optoelectronic devices still lags behind the performance of devices on rigid substrates. This is due, in particular, to the lack of flexible transparent electrodes that simultaneously offer low resistance, high transparency and a smooth surface. Here, we report flexible transparent electrodes created using water-processed silver nanowires and a polyelectrolyte. Due to ionic electrostatic charge repulsion, the nanowires form grid-like structures in a single step, leading to smooth, flexible electrodes that have a sheet resistance of around 10 Ω □ −1 and a transmittance of around 92% (excluding the substrate). To illustrate the potential of the approach in organic electronics, we use the flexible electrodes to create organic photovoltaic devices. The devices are tested with different types of donors and acceptors, and exhibit performance comparable to devices based on commercial rigid electrodes. Furthermore, flexible single-junction and tandem devices achieve power conversion efficiencies of 13.1% and 16.5%, respectively. Flexible transparent electrodes made from silver nanowires that form grid-like structures due to ionic electrostatic charge repulsion can be used to create flexible single-junction and tandem organic photovoltaic devices with power conversion efficiencies of 13.1% and 16.5%, respectively.

Three-dimensional (3D) bioprinting has emerged as a promising scaffold fabrication strategy for tissue engineering with excellent control over scaffold geometry and microstructure. Nanobiomaterials as bioinks play a key role in manipulating the cellular microenvironment to alter its growth and development. This review first introduces the commonly used nanomaterials in tissue engineering scaffolds, including natural polymers, synthetic polymers, and polymer derivatives, and reveals the improvement of nanomaterials on scaffold performance. Second, the 3D bioprinting technologies of inkjet-based bioprinting, extrusion-based bioprinting, laser-assisted bioprinting, and stereolithography bioprinting are comprehensively itemized, and the advantages and underlying mechanisms are revealed. Then the convergence of 3D bioprinting and nanotechnology applications in tissue engineering scaffolds, such as bone, nerve, blood vessel, tendon, and internal organs, are discussed. Finally, the challenges and perspectives of convergence of 3D bioprinting and nanotechnology are proposed. This review will provide scientific guidance to develop 3D bioprinting tissue engineering scaffolds by nanotechnology.

In organic solar cells (OSCs), which represent a quintessential application system for organic conjugated films, the intrinsic light reflection of these films significantly influences the optical performance of the devices through the Fabry–Pérot micro-cavity effect. However, this phenomenon has not been comprehensively investigated. This study demonstrates that the film’s intrinsic reflection arises from the light-matter interaction, which is mainly governed by the polarizability of delocalized electron cloud and the orientation of the conjugated backbone. Furthermore, the multi-level interference within the OSC micro-cavity leads to a dependence of both the reflection properties and the short-circuit current density ( J SC ) on the active layer thickness. Based on these insights, a strategy for synergistic optimization of device performance through precise tailoring of optical constants and the micro-cavity structure is proposed. By systematically analyzing the intrinsic reflection behavior of organic conjugated films, this study enhances the understanding of the role reflection plays in the performance of photovoltaic devices and provides theoretical support for further optical optimization of organic photovoltaics. The intrinsic light reflection of organic conjugated films significantly influences the optical performance of devices through Fabry–Pérot micro-cavity effect. Here, authors modulate cell micro cavity via tuning materials’ refractive index to improve photovoltaic performance of organic solar cells.

More recently, soft actuators have evoked great interest in the next generation of soft robots. Despite significant progress, the majority of current soft actuators suffer from the lack of real‐time sensory feedback and self‐control functions, prohibiting their effective sensing and multitasking functions. Therefore, in this work, a near‐infrared‐driven bimorph membrane, with self‐sensing and feedback loop control functions, is produced by layer by layer (LBL) assembling MXene/PDDA (PM) onto liquid crystal elastomer (LCE) film. The versatile integration strategy successfully prevents the separation issues that arise from moduli mismatch between the sensing and the actuating layers, ultimately resulting in a stable and tightly bonded interface adhesion. As a result, the resultant membrane exhibited excellent mechanical toughness (tensile strengths equal to 16.3 MPa (||)), strong actuation properties (actuation stress equal to 1.56 MPa), and stable self‐sensing (gauge factor equal to 4.72) capabilities. When applying the near‐infrared (NIR) laser control, the system can perform grasping, traction, and crawling movements. Furthermore, the wing actuation and the closed‐loop controlled motion are demonstrated in combination with the insect microcontroller unit (MCU) models. The remote precision control and the self‐sensing capabilities of the soft actuator pave a way for complex and precise task modulation in the future. A light‐driven and self‐sensing intelligent bilayer soft actuator, the PM‐liquid crystal elastomer (LCE), built with LCE, MXene, and Poly(dimethyldiallylammonium chloride) (PDDA) is prepared through the layer‐by‐layer self‐assembly strategy; moreover, the high‐precision, self‐sensing and feedback loop control functions are realized. Furthermore, a PM‐LCE‐based closed‐loop control system is also demonstrated.

As the main component of wearable electronic equipment, flexible pressure sensors have attracted wide attention due to their excellent sensitivity and their promise with respect to applications in health monitoring, electronic skin, and human–computer interactions. However, it remains a significant challenge to achieve epidermal sensing over a wide sensing range, with short response/recovery time and featuring seamless conformability to the skin simultaneously. This is critical since the capture of minute electrophysiological signals is important for health care applications. In this paper, we report the preparation of a nacre-like MXene/sodium carboxymethyl cellulose (CMC) nanocomposite film with a “brick-and-mortar” interior structure using a vacuum-induced self-assembly strategy. The synergistic behavior of the MXene “brick” and flexible CMC “mortar” contributes to attenuating interlamellar self-stacking and creates numerous variable conductive pathways on the sensing film. This resulted in a high sensitivity over a broad pressure range (i.e., 0.03–22.37 kPa: 162.13 kPa −1 ; 22.37–135.71 kPa: 127.88 kPa −1 ; 135.71–286.49 kPa: 100.58 kPa −1 ). This sensor also has a low detection limit (0.85 Pa), short response/recovery time (8.58 ms/34.34 ms), and good stability (2000 cycles). Furthermore, we deployed pressure sensors to distinguish among tiny particles, various physiological signals of the human body, space arrays, robot motion monitoring, and other related applications to demonstrate their feasibility for a variety of health and motion monitoring use cases. Graphic abstract

In consideration of that the correlation between any two assets of the asset pool is always stochastic in the actual market and that collateralized debt obligation (CDO) pricing models under nonhomogeneous assumptions have no semianalytic solutions, we designed a numerical algorithm based on randomized quasi-Monte Carlo (RQMC) simulation method for CDO pricing with stochastic correlations under nonhomogeneous assumptions and took Gaussian factor copula model as an example to conduct experiments. The simulation results of RQMC and Monte Carlo (MC) method were compared from the perspective of variance changes. The results showed that this numerical algorithm was feasible, efficient, and stable for CDO pricing with stochastic correlation under nonhomogeneous assumptions. This numerical algorithm is expected to be extended to other factor Copula models for CDO pricing with stochastic correlations under nonhomogeneous assumptions.

Although nonalcoholic fatty liver disease (NAFLD) is associated with obstructive sleep apnea syndrome (OSAS), studies on the direct relationship between NAFLD and snoring, an early symptom of OSAS, are limited. We evaluated whether snorers had higher risk of developing NAFLD. The study was performed using data of the Tongmei study (cross-sectional survey, 2,153 adults) and Kailuan study (ongoing prospective cohort, 19,587 adults). In both studies, NAFLD was diagnosed using ultrasound; snoring frequency was determined at baseline and classified as none, occasional (1 or 2 times/week), or habitual (≥3 times/week). Odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals were estimated using logistic and Cox models, respectively. During 10 years’ follow-up in Kailuan, 4,576 individuals with new-onset NAFLD were identified at least twice. After adjusting confounders including physical activity, perceived salt intake, body mass index (BMI), and metabolic syndrome (MetS), multivariate-adjusted ORs and HRs for NAFLD comparing habitual snorers to non-snorers were 1.72 (1.25–2.37) and 1.29 (1.16–1.43), respectively. These associations were greater among lean participants (BMI < 24) and similar across other subgroups (sex, age, MetS, hypertension). Snoring was independently and positively associated with higher prevalence and incidence of NAFLD, indicating that habitual snoring is a useful predictor of NAFLD, particularly in lean individuals.

The cyano group is extensively employed in the molecular engineering of high‐performance small‐molecule acceptors (SMAs) for organic solar cells (OSCs) to fine‐tune energy levels and optimize molecular packing. To date, the application of cyano group has predominantly been confined to end‐group modification in SMAs, with limited investigation in central unit engineering. Herein, in this work, the role of cyano substitution is systematically investigated in the central unit of SMAs and design a novel cyano‐functionalized wide‐bandgap acceptor UF‐BCN. The introduction of the cyano group significantly enhances the surface energy of the molecule and substantially deepens the highest occupied molecular orbital (HOMO) energy level due to its strong electron‐withdrawing capability, then leading to a blue‐shifted absorption. When introduced as the third component in the D18:BTP‐eC9, UF‐BCN demonstrates complementary light absorption, strong intermolecular interactions, and excellent compatibility with BTP‐eC9 to form a mixed acceptor phase, enabling it to function as an effective morphological modulator within the ternary system. Consequently, the ternary OSC based on D18:BTP‐eC9:UF‐BCN achieves an impressive power conversion efficiency (PCE) of 19.34%. This study underscores the effectiveness of cyano substitution in central unit engineering and highlights its potential for optimizing active layer morphology and enhancing the performance of ternary OSCs. A novel wide‐bandgap acceptor, UF‐BCN, is designed where cyano substitution significantly enhances surface energy and HOMO levels. When incorporated into a ternary system with D18:BTP‐eC9, UF‐BCN achieves a high‐power conversion efficiency of 19.34% by forming a mixed acceptor phase with strong intermolecular interactions, highlighting the role of the cyano group in central unit engineering of small‐molecule acceptors.