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Stretchable electrodes are critical to the development of advanced technologies such as human–machine interaction, flexible sensing, and wearable power supply, making them of significant research value. However, the current preparation methods for high‐performance stretchable electrodes are complex and inefficient, posing challenges for their large‐scale application in the realm of flexible wearables. To address this need, a straightforward and efficient embedding strategy is reported for fabricating stretchable silver nanowire/thermoplastic elastomer composite electrodes (referred to as Strem‐AT) utilizing the viscoelasticity and outstanding mechanical properties of polymer elastomers to achieve outstanding extensibility, conductivity, and a smooth surface. These electrodes exhibit excellent tensile behavior, low surface roughness, and stable electrical properties, enabling their successful integration into stretchable sensors and intrinsically stretchable organic photovoltaic cells (IS‐OPV). When applied to human skin joints for motion detection, the sensor demonstrates remarkable stretchability and stable signal output. Importantly, the all‐polymer IS‐OPV exhibits a top‐notch power conversion efficiency (PCE) of >12.5% and a PCE80% strain exceeding 50%. Furthermore, even after subjecting high‐strain stretching at 50% for 1000 cycles, the IS‐OPV can retain 76% of the initial PCE. This study presents a multifunctional stretchable electrode with high repeatability and easy‐to‐scale fabrication in wearable sensors and photovoltaics. [ABSTRACT FROM AUTHOR]

Intrinsically stretchable organic photovoltaic cells (OPVs) have garnered significant attention as crucial devices for powering next‐generation wearable electronics. Despite the rapid power conversion efficiency gains in champion OPVs, their brittle stretchability has failed to meet the demands of the Internet of Things era, severely hindering further development and practical applications. In this regard, a new dual‐donor polymer blending strategy is demonstrated for constructing intrinsically stretchable OPVs by designing a novel high‐molecular–weight conjugated polymer PM6‐HD. This PM6 derivative featuring long alkyl chains can reach a sufficiently high molecular weight and thus exhibits a high fracture strain exceeding 90%, which is ≈12 times higher than the benchmark PM6. Synergistic optimization of mechanical properties and photovoltaic performance in polymer:small molecule and all‐polymer systems constructed from the physical blends of PM6 and PM6‐HD is achieved. Crucially, the resulting intrinsically stretchable OPV demonstrates excellent stretchability and stability, with a record PCE80% strain of 50.3% and the efficiency retention of above 80% even after 1000 cycles of cyclic stretching at high strains. This work contributes to the advancement of intrinsically stretchable OPV technology and opens up new possibilities for its integration into wearable electronic devices. [ABSTRACT FROM AUTHOR]

The progress of stretchable and wearable photovoltaics relies heavily on intrinsically stretchable active layer films. Nevertheless, there is a paucity of research clarifying the connections between their microstructure, performance, and their adaptation to large strain in polymer electronic films. The current study utilizes multiple synchrotron X‐ray scattering methods to collectively examine the correlations between morphology and stretchability, as well as the microstructural evolution induced by stretching in three sample cases of highly stretchable ternary blend films. These blends contain over 30% by weight of a polymer elastomer, such as styrene‐ethylene‐butylene‐styrene block copolymer, integrated into the high‐performance polymer:nonfullerene small molecule mixture. Specifically, the real‐time microstructural changes of these durable organic photovoltaic films with elastomers are monitored when subjected to tensile stretching through in situ synchrotron X‐ray scattering. The experiments demonstrate that polymeric elastomers can effectively lower the degree of crystallinity in films and deform the crystallites of semiconductor molecules. The elastomeric component aids in stress dispersion during stretching, thereby improving the microstructural durability of blend films. This study provides new recommendations for advancing stretchable organic optoelectronic devices. [ABSTRACT FROM AUTHOR]

The power conversion efficiency of organic photovoltaics (OPVs) has witnessed continuous breakthroughs in the past few years, mostly benefiting from the extensive use of a facile ternary blending strategy by blending the host polymer donor:small molecule acceptor mixture with a second small molecule acceptor. Nevertheless, this rather general strategy used in the well‐known PM6 systems fails in constructing high‐performance P3HT‐based ternary OPVs. As a result, the efficiencies of all resulting ternary blends based on a benchmark host P3HT:ZY‐4Cl and a second acceptor are no more than 8%. Employing the mutual miscibility of the binary blends as a guide to screen the second acceptor, here we were able to break the longstanding 10%‐efficiency barrier of ternary OPVs based on P3HT and dual nonfullerene acceptors. With this rational approach, we identified a multifunctional small molecule acceptor BTP‐2Br to simultaneously improve the photovoltaic performance in both P3HT and PM6‐based ternary OPVs. Attractively, the P3HT:ZY‐4Cl:BTP‐2Br ternary blend exhibited a record‐breaking efficiency of 11.41% for P3HT‐based OPVs. This is the first‐ever report that over 11% efficiency is achieved for P3HT‐based ternary OPVs. Importantly, the study helps the community to rely less on trial‐and‐error methods for constructing ternary solar cells. [ABSTRACT FROM AUTHOR]

The emerging solution‐based solar cells and photodetectors have gained worldwide research interest over the past decades. Hole transport materials (HTMs) have greatly advanced the progress of these solution‐based electronics. Nevertheless, developing low‐cost and efficient HTMs is far from satisfactory. In this contribution, poly(3‐pentylthiophene) (P3PT) is introduced as a facile, low‐cost, and versatile dopant‐free polymer HTM for both quantum dot (QD) and perovskite electronic devices. Compared to the broadly used poly(3‐hexylthiophene), P3PT presents the reduced molecular aggregation and preferential face‐on orientation, which can markedly enhance the hole‐carrier transport in optoelectronic devices. Accordingly, P3PT can deliver the substantial improvement of photovoltaic performance from ∼8.6% to ∼9.5% for QD/polythiophene solar cells and from ∼16% to ∼18.8% for perovskite/polythiophene solar cells, which are both among the topmost values in the corresponding fields. Furthermore, P3PT HTMs can also significantly enhance the photodetection performance of QD and perovskite photodetectors by a factor of ∼3, indicating its great application potential in a variety of emerging optoelectronics. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the emergence of Y‐series small molecule acceptors, polymerizing the small molecule acceptors with aromatic linker units has attracted significant research attention, which has greatly advanced the photovoltaic performance of all‐polymer solar cells. Despite the rapid increase in efficiency, the unique characteristics (e. g., mechanical stretchability and flexibility) of all‐polymer systems were still not thoroughly explored. In this work, we demonstrate an effective approach to simultaneously improve device performance, stability, and mechanical robustness of all‐polymer solar cells by properly suppressing the aggregation and crystallization behaviors of polymerized Y‐series acceptors. Strikingly, when introducing 50 wt% PYF‐IT (a fluorinated version of PY‐IT) into the well‐known PM6:PY‐IT system, the all‐polymer devices delivered an impressive photovoltaic efficiency of 16.6%, significantly higher than that of the control binary cell (15.0%). Compared with the two binary systems, the optimal ternary blend exhibits more efficient charge separation and balanced charge transport accompanying with less recombination. Moreover, a high‐performance 1.0 cm2 large‐area device of 15% efficiency was demonstrated for the optimized ternary all‐polymer blend, which offered a desirable PCE of 14.5% on flexible substrates and improved mechanical flexibility after bending 1000 cycles. Notably, these are among the best results for 1.0 cm2 all‐polymer OPVs thus far. This work also heralds a bright future of all‐polymer systems for flexible wearable energy‐harvesting applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the emergence of Y‐series small molecule acceptors, polymerizing the small molecule acceptors with aromatic linker units has attracted significant research attention, which has greatly advanced the photovoltaic performance of all‐polymer solar cells. Despite the rapid increase in efficiency, the unique characteristics (e. g., mechanical stretchability and flexibility) of all‐polymer systems were still not thoroughly explored. In this work, we demonstrate an effective approach to simultaneously improve device performance, stability, and mechanical robustness of all‐polymer solar cells by properly suppressing the aggregation and crystallization behaviors of polymerized Y‐series acceptors. Strikingly, when introducing 50 wt% PYF‐IT (a fluorinated version of PY‐IT) into the well‐known PM6:PY‐IT system, the all‐polymer devices delivered an impressive photovoltaic efficiency of 16.6%, significantly higher than that of the control binary cell (15.0%). Compared with the two binary systems, the optimal ternary blend exhibits more efficient charge separation and balanced charge transport accompanying with less recombination. Moreover, a high‐performance 1.0 cm2 large‐area device of 15% efficiency was demonstrated for the optimized ternary all‐polymer blend, which offered a desirable PCE of 14.5% on flexible substrates and improved mechanical flexibility after bending 1000 cycles. Notably, these are among the best results for 1.0 cm2 all‐polymer OPVs thus far. This work also heralds a bright future of all‐polymer systems for flexible wearable energy‐harvesting applications. [ABSTRACT FROM AUTHOR]

All‐polymer solar cells (all‐PSCs) are one of the most promising application‐oriented organic photovoltaic technologies due to their excellent operational and mechanical stability. However, the power conversion efficiencies (PCEs) are mostly lower than 16%, restricting their core competitiveness. Furthermore, the improvement of mechanical durability is rarely paid attention to cutting‐edge all‐PSCs. This work deploys a low‐cost "technical grade" PCBM (incompletely separated but pure mixtures containing ≥90% [70]PCBM or [60]PCBM), into the efficient PM6:PY‐IT all‐polymer blend, successfully yielding a high‐performance ternary device with 16.16% PCE, among the highest PCE values for all‐PSCs. Meanwhile, an excellent mechanical property (i.e., crack onset strain = 11.1%) promoted from 9.5% for the ternary system is also demonstrated. The "technical grade" PCBM slightly disrupts the crystallization of polymers, and disperses well into the amorphous polymer regions of the all‐PSC blends, thus facilitating charge transport and improving film ductility simultaneously. All these results confirm introducing low‐cost "technical grade" PCBM with high electron mobility into all‐polymer blends can improve carrier mobility, reduce charge recombination, and optimize morphology of the amorphous polymer regions, thus yielding more efficient and mechanically durable all‐PSCs. [ABSTRACT FROM AUTHOR]

Hybrid solar cells with organic semiconductors and quantum dots (QDs) have witnessed great advance in the past few years. Nevertheless, the great majority of organic and QD hybrid solar cells generally employ halogenated solvents for the processing of organic hole‐transporting interlayers. Herein, the impact of solvents on the organic semiconductor material for hybird solar cells is systematically explored. The o‐xylene‐processed polythiophene delivers a champion photovoltaic performance of 8.7%, which is the record value for QD and poly(3‐hexylthiophene) (P3HT) hybrid solar cells. The morphology results reveal that P3HT films processed with o‐XY present the moderate morphology and characteristic length scales, enabling the high photovoltaic performance. Moreover, the relationships between solvents, molecular stacking, film morphology, and photovoltaic performance are built to offer the guideline of solvents screening for these hybrid solar cells. Moreover, the great superiority of nonhalogenated solvents in fabricating high‐performance optoelectronic devices with low hazards is demonstrated. [ABSTRACT FROM AUTHOR]

The emerging solution‐processed solar cells have attracted worldwide effort in the last decade. Developing efficient, stable, and cost‐effective solar cells is strongly desirable in countering the growing global warming. Nevertheless, the photovoltaic performance and stability of hybrid solar cells based on low‐cost polythiophenes are far from satisfactory, due to their high‐lying energy levels and excessive aggregation. Herein, it is shown that brominated polythiophene (P3HT‐Br), prepared via a facile two‐step approach can effectively facilitate charge transport and suppress recombination in quantum dot (QD)/organic heterojunctions. Accordingly, the power conversion efficiency of the optimized hybrid polythiophene/QD cell is boosted from 8.7% to 11% (a 26% increase) with markedly reduced energy loss. More strikingly, the device achieves record‐high thermal stability with a lifetime of over 400 h maintaining 80% of the initial performance. Both device efficiency and stability are the best reported for polythiophene/QD hybrid solar cells. Moving forward, brominated polythiophenes hold great application in perovskite solar cells with significantly improved performance and offer new opportunities for other emerging solar cells. [ABSTRACT FROM AUTHOR]

The rapid development of low bandgap polymer acceptors has promoted the efficiency up to ≈17% for all‐polymer solar cells (all‐PSCs). Nevertheless, the polymeric blend film, core to the photoelectric conversion of all‐PSCs, has not been thoroughly understood in terms of the influence and regulatory factors of mechanical properties, which hinders the advances in flexible and wearable applications. Herein, a range of characterization methods is combined to investigate the mechanical properties, miscibility, and film microstructure of the blends based on several representative polymer donors (PTzBI‐Si, PTVT‐T, PM6 and PTQ10) and a benchmark polymer acceptor N2200, and to further reveal the miscibility‐property relationships of the miscibility property. The results stress that fracture behaviors and elastic moduli of these blends with varied compositions show different changing trends, which are affected by molecular interactions and aggregated structure of the blends. The elastic moduli of the four all‐polymer blends can be nicely predicted by different models that are deduced from macromolecular mechanics. Most crucially, the correlations between elastic modulus, morphology, and miscibility of all‐polymer blends are elucidated for the first time. The derived relationships is validated with another high‐efficiency blend and will be the key to the successful fabrication of mechanically robust and stretchable all‐PSCs with high efficiency. [ABSTRACT FROM AUTHOR]

All‐polymer solar cells (All‐PSCs) have attracted tremendous research interest in the recent decade due to the great potentials in stretchable electronic applications in terms of long‐term stability and mechanical stretchability. Driven by the molecular design of novel polymer acceptors and morphology optimization, the power conversion efficiency (PCE) of All‐PSCs has developed rapidly and now exceeded 17%. This review outlines the promising strategies for high‐performance All‐PSCs from the aspect of morphology control with the motivation to rationally guide the optimization. In this review, we briefly discuss the thermodynamic mixing principles of all‐polymer blends and the effects of the molecular structure of conjugated polymers on thin‐film morphology in All‐PSCs. The crucial role of molecular miscibility in influencing morphological features and performance metrics was highlighted. We also expound on the effective methods of controlling film morphology through properly tuning the aggregation behavior of polymers. In particular, insightful studies on the commonly used naphthalene diimide‐based acceptor polymers and the newly emerging polymerized nonfullerene small molecule acceptors (ITIC‐series, Y6 ‐series, etc) are discussed in detail. Finally, we present an outlook on the major challenges and the new opportunities of All‐PSCs for efficiency breakthroughs targeting 20%. [ABSTRACT FROM AUTHOR]

Wearable strain sensors based on flexible conductive polymer composites (FCPCs) have attracted great attention due to their applications in the fields of human–machine interaction, disease diagnostics, human motion detection, and soft robotic skin. In recent decades, FCPC‐based strain sensors with high stretchability and sensitivity, short response time, and excellent stability have been developed, which are expected to be more versatile and intelligent. Smart strain sensors are required to provide wearable comfort, such as breathability, self‐cooling ability, and so forth. To adapt to the harsh environment, wearable strain sensors should also be highly adaptive to protect the skin and the sensor itself. In addition, portable power supply system, multisite sensing capability, and multifunctionality are crucial for the next generation of FCPC‐based strain sensor. [ABSTRACT FROM AUTHOR]

Flexible strain sensors capable of acquiring tiny mechanical signals and attaching to various irregular surfaces are becoming prevalent in physiological measurement, soft robotics, and human‐machine interaction. However, the advancement of flexible strain sensors is substantially impeded by the intrinsic compromise between sensitivity and the range of detectable signals. Inspired by the multilayer structure of nacre in nature, a carbon nanotubes (CNTs)/graphene (GR)/graphene (GR)/thermoplastic polyurethane (TPU) mat (CGGTM) is prepared by electrospinning and high‐pressure spraying technology. By designing a multilayer structure with mutually non‐interfering conductive networks, the resulting CGGTM possesses a low detection limit (0.05% strain), high sensitivity (gauge factor, GF > 152537), large detection range (up to 364% strain), fast response/recovery time (80 ms/100 ms), and excellent cyclic durability (up to 1000 cycles). Furthermore, the CGGTM also exhibits satisfactory triboelectric performances when assembled into a triboelectric nanogenerator (TENG, 3 × 3 cm2), including high triboelectric output (open‐circuit voltage Voc = 135.4 V, short‐circuit current Isc = 1.25 µA) and power density (88 mW m−2), enabling reliable power supply, self‐powered sensing, and pulse monitoring capability. Finally, CGGTM is successfully applied to the collection of biological signals and multi‐gesture motion recognition assisted by machine learning algorithms, which holds promise for intelligent interaction with gestures in the future. [ABSTRACT FROM AUTHOR]

Concurrently achieving high efficiency, mechanical robustness and thermal stability is critical for the commercialization of all‐polymer solar cells (APSCs). However, APSCs usually demonstrate complicated morphology, primarily attributed to the polymer chain entanglement which has a detrimental effect on their fill factors (FF) and morphology stability. To address these concerns, an end‐group extended polymer acceptor, PY‐NFT, was synthesized and studied. The morphology analysis showed a tightly ordered molecular packing mode and a favorable phase separation was formed. The PM6 : PY‐NFT‐based device achieved an exceptional PCE of 19.12 % (certified as 18.45 %), outperforming the control PM6 : PY‐FT devices (17.14 %). This significant improvement highlights the record‐high PCE for binary APSCs. The thermal aging study revealed that the PM6 : PY‐NFT blend exhibited excellent morphological stability, thereby achieving superior device stability, retaining 90 % of initial efficiency after enduring thermal stress (65 °C) for 1500 hours. More importantly, the PM6 : PY‐NFT blend film exhibited outstanding mechanical ductility with a crack onset strain of 24.1 %. Overall, rational chemical structure innovation, especially the conjugation extension strategy to trigger appropriate phase separation and stable morphology, is the key to achieving high efficiency, improved thermal stability and robust mechanical stability of APSCs. [ABSTRACT FROM AUTHOR]

Stretchable, flexible, and strain‐sensitive hydrogels have gained tremendous attention due to their potential application in health monitoring devices and artificial intelligence. Nevertheless, it is still a huge challenge to develop an integrated strain sensor with excellent mechanical properties, broad sensing range, high transparency, biocompatibility, and self‐recovery. Herein, a simple paradigm of stretchable strain sensor based on multifunctional hydrogels is prepared by constructing synergistic effects among polyacrylamide (PAM), biocompatible macromolecule sodium alginate (SA), and Ca ion in covalently and ionically crosslinked networks. Under large deformation, the dynamic SA‐Ca2+ bonds effectively dissipate energy, serving as sacrificial bonds, while the PAM chains bridge the crack and stabilize the network, endowing hydrogels with outstanding mechanical performances, for instance, high stretchability and compressibility, as well as excellent self‐recovery performance. The hydrogel is assembled to be a transparent and wearable strain sensor, which has good sensitivity and very wide sensing range (0–1700%), and can precisely detect dynamic strains, including both low and high strains (20–800% strain). It also exhibits fast response time (800 ms) and long‐time stability (200 cycles). The sensor can monitor and distinguish complicated human motions, opening up a new route for broad potential applications of eco‐friendly flexible strain‐sensing devices. [ABSTRACT FROM AUTHOR]