Bin Huang

Back‐to‐back dimeric acceptors have attracted widespread attention for organic solar cells (OSCs) due to their exceptional stability and unique three‐dimensional (3D) charge transport channels. However, these dimers suffer from inferior intermolecular interactions and molecular packing, limiting the development of OSCs. Here, we first employed an asymmetry end‐group strategy to develop a novel asymmetry back‐to‐back dimer DQx‐FCl. Breaking structural symmetry in DQx‐FCl alters the electrostatic surface potential to strengthen intermolecular π ‐ π interactions. Meanwhile, it also reduces the overlap of electron and hole in the singlet excited state to promote charge separation. Thus, the asymmetric DQx‐FCl‐based binary device achieved a superior power conversion efficiency (PCE) of 19.11% along with improved stability, relative to its symmetric DQx‐F. More notably, DQx‐FCl‐based ternary device achieves a record PCE of 20.27% among reported back‐to‐back dimer‐based OSCs. Furthermore, the reinforced intermolecular interactions also enhance the mechanical robustness of OSCs. Flexible devices based on the PM6:L8‐BO:DQx‐FCl attain a PCE of 17.27% with a crack‐onset strain of 14.6%, while the intrinsically stretchable OSC retains 80% of its initial efficiency under a tensile strain exceeding 23%. This study demonstrates the great potential of asymmetric back‐to‐back dimeric acceptors for improving efficiency, stability, and mechanical flexibility toward high‐performance OSCs.

Back‐to‐back dimeric acceptors have attracted widespread attention for organic solar cells (OSCs) due to their exceptional stability and unique three‐dimensional (3D) charge transport channels. However, these dimers suffer from inferior intermolecular interactions and molecular packing, limiting the development of OSCs. Here, we first employed an asymmetry end‐group strategy to develop a novel asymmetry back‐to‐back dimer DQx‐FCl. Breaking structural symmetry in DQx‐FCl alters the electrostatic surface potential to strengthen intermolecular π ‐ π interactions. Meanwhile, it also reduces the overlap of electron and hole in the singlet excited state to promote charge separation. Thus, the asymmetric DQx‐FCl‐based binary device achieved a superior power conversion efficiency (PCE) of 19.11% along with improved stability, relative to its symmetric DQx‐F. More notably, DQx‐FCl‐based ternary device achieves a record PCE of 20.27% among reported back‐to‐back dimer‐based OSCs. Furthermore, the reinforced intermolecular interactions also enhance the mechanical robustness of OSCs. Flexible devices based on the PM6:L8‐BO:DQx‐FCl attain a PCE of 17.27% with a crack‐onset strain of 14.6%, while the intrinsically stretchable OSC retains 80% of its initial efficiency under a tensile strain exceeding 23%. This study demonstrates the great potential of asymmetric back‐to‐back dimeric acceptors for improving efficiency, stability, and mechanical flexibility toward high‐performance OSCs.

The dielectric constant ( ε _r ) critically influences exciton generation and subsequent dissociation into free charges, playing a pivotal role in the performance of polymer solar cells (PSCs). However, the intrinsically low ε _r of conventional polymer donors leads to strong Coulombic interactions and significant energy loss ( E _loss ). Herein, we address this challenge through a dielectric engineering strategy by incorporating zinc porphyrin units into the matrix polymer donor D18, resulting in a series of terpolymers D18‐Px (x = 5, 10, 15). The introduction of the zinc‐porphyrin‐based third component in the terpolymer donors significantly enhanced ε _r and promoted favorable molecular aggregation. When blended with L8‐BO, the D18‐P5:L8‐BO blend film demonstrated improved miscibility, efficient charge extraction and transport, and critically minimized non‐radiative energy loss to 0.212 eV. Consequently, it achieved a record power conversion efficiency (PCE) of 20.27% for metalated complex‐based PSCs. This work showcases a facile and effective approach for designing high‐efficiency polymer donors by strategically increasing the dielectric constant and minimizing non‐radiative losses.

The dielectric constant ( ε _r ) critically influences exciton generation and subsequent dissociation into free charges, playing a pivotal role in the performance of polymer solar cells (PSCs). However, the intrinsically low ε _r of conventional polymer donors leads to strong Coulombic interactions and significant energy loss ( E _loss ). Herein, we address this challenge through a dielectric engineering strategy by incorporating zinc porphyrin units into the matrix polymer donor D18, resulting in a series of terpolymers D18‐Px (x = 5, 10, 15). The introduction of the zinc‐porphyrin‐based third component in the terpolymer donors significantly enhanced ε _r and promoted favorable molecular aggregation. When blended with L8‐BO, the D18‐P5:L8‐BO blend film demonstrated improved miscibility, efficient charge extraction and transport, and critically minimized non‐radiative energy loss to 0.212 eV. Consequently, it achieved a record power conversion efficiency (PCE) of 20.27% for metalated complex‐based PSCs. This work showcases a facile and effective approach for designing high‐efficiency polymer donors by strategically increasing the dielectric constant and minimizing non‐radiative losses.

Ternary strategy represents a straightforward and effective approach for enhancing the power conversion efficiency (PCE) of polymer solar cells (PSCs). However, incorporating a third component, especially polymers, leads to additional complexity in the structure and morphology. Herein, the wide bandgap polymer donor PBQ10 with a larger total average molecular surface electrostatic potential distributions (ESP) relative to the host donor, is adopted into the PM6:L8‐BO system to elucidate the underlying mechanisms and enhance photovoltaic performance. Benefiting from complementary absorption spectra, excellent compatibility with host donors, weakened ESP‐induced intermolecular interactions and low binding energy between PBQ10 and L8‐BO, an optimized multi‐scale morphology of the ternary blend is constructed. Thus, the ternary device exhibits superior exciton generation, diffusion, and dissociation process, along with higher, and more balanced charge transport capabilities. Consequently, the ternary PSCs boost the PCE up to 20.02%, surpassing the reference binary system with 19.39%. This work not only presents a practical method toward high‐performance ternary PSCs but also provides valuable insights for molecular structure selection of the third component.

To overcome the limitations of batch‐to‐batch variations and donor material robustness in polymer solar cells (PSCs), we designed quaternary (H1–H9), ternary (H10–H15), and binary (PM6, PBQ10, PBDS‐T) polymer donors via precise monomer ratio modulation. Due to the synergistic coordination among multiple components, the H4‐based blend film demonstrated enhanced intermolecular interactions and provides additional low‐energy‐barrier pathways for efficient charge carrier transport. After blending with L8‐BO, the H4‐based films displayed a more desirable morphology and effective charge carrier transport than the categories. As a result, the H4:L8‐BO‐based PSCs achieved impressive power conversion efficiency (PCE) of 19.66% for binary device and 20.34% for ternary device. Besides, the introduced functional groups disrupt the regularity of the matrix polymer main chain, leading to stable and robust film morphologies. Consequently, the H4:L8‐BO‐based blend film not only demonstrates improved mechanical robustness, with a crack onset strain (COS) of 17.8%, and maintains a PCE of 16.35% in flexible devices, but also exhibits excellent batch‐to‐batch stability with significant variations in molecular weight. This work presents a strategy to simultaneously enhance device performance, mechanical robustness, and reproducibility through quaternary copolymerization, enabling controlled crystallinity and additional multichannel charge transport.

DNA methylation, as an important epigenetic modification, is closely related to gene expression regulation and cancer development. This study developed a new electrochemical biosensor for ultrasensitive detection of DNA methylation based on the combination of Fe/metal-organic framework (MOF)/polymer polyaniline (PANI) composite materials and catalytic hairpin assembly (CHA) cascade reaction. The Fe/MOF/PANI/S1, as the signal probe, significantly improved the conductivity and stability by doping conductive PANI into Fe/MOF. The sensor used DNAzyme to catalyze methylated DNA to trigger the CHA cascade reaction, and thus several cross-shaped CHA products were achieved. The capture probe was modified on the surface of the Au electrode to hybridize with CHA products. Thus, the binding sites were exposed to enable large amounts of Fe-MOF/PANI/S1 signal probes to bind effectively, and the electrochemical signals were generated. The sensor could produce measurable electrochemical responses in the presence of methylated DNA, with the limit of detection as low as 0.58 fM. It showed excellent specificity, repeatability (RSD = 2.23%), and stability (over 90% signal retention after 20 days). In addition, it showed high recovery in human serum samples, verifying its potential for practical applications. This will pave a new way for the rapid and sensitive detection of DNA methylation.

Owing to the intramolecular push-pull electron effect between the electron donor (D) unit and electron acceptor (A) unit, the D-A type based polymer donors display outstanding device performance. However, the imperfect energy levels lead to the D-A-type-based polymer device exhibiting high voltage loss. In this study, an A1-A2-type copolymer M1 was developed with 1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)benzo[1,2-c:4,5-c’]dithiophene-4,8-dione (BDD) as the A1 unit and dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2-c][1,2,5]thiadiazole (DTBT) as the A2 unit. Compared with D-A-type-based polymer donor PM6, the A1-A2 type based M1 possesses lower energy levels, broader absorption, and stronger crystallinity. After introducing M1 to the PM6:L8-BO-based system as the guest material, the ternary blend films exhibited exceptional face-on molecular orientation and favorable active-layer morphology, which promotes exciton dissociation and suppresses charge recombination. Consequently, the PM6:M1(5%):L8-BO-based ternary device exhibited an impressive power conversion efficiency (PCE) of 19.70% with simultaneously enhanced photostability, which is superior to the PM6:L8-BO-based binary system. Our work offers an efficient approach to developing high-performance ternary devices by introducing a novel A1-A2 type polymer donors as the guest material.

A green and efficient visible-light-driven strategy for direct cyanomethylurea synthesis from α-aminoamides and isothiocyanates via intramolecular oxygen migration is reported. This method merges cyanation and ureidation in a single step, leveraging the amide oxygen as a dual synthon to forge nitrile (C≡N) and urea (C═O) bonds. Operating under metal-free, ambient conditions (room temperature, air, visible light), the protocol accommodates diverse substrates without toxic reagents. Mechanistic studies implicate light-mediated desulfurization and oxygen atom transfer, offering a sustainable strategy for one-step dual functionalization of bioactive molecules.

Intrinsically stretchable organic photovoltaics (is‐OPVs) face a critical efficiency‐stretchability trade‐off that limits wearable applications. Here, a breakthrough molecular design strategy employing side‐chain‐engineered insulating polymers—poly(methyl methacrylate) (PMMA) and poly(benzyl methacrylate) (PBMA)—as multifunctional additives to simultaneously enhance electronic and mechanical properties is presented. Through synergistic control of compatibility, chain diffusivity, and docking position with PM6/Y6 components, PMMA selectively distributes in the amorphous regions of the PM6 donor while promoting molecular packing in crystalline regions, enabling dual stress‐dissipation networks and efficient charge transport pathways. As a result, the rigid 10PMMA (with 10 wt.% PMMA) devices achieve a record 19.01% power conversion efficiency (PCE), while maintaining 18.53% PCE (only 2% loss) for the rigid 20PMMA (with 20 wt.% PMMA) devices. More remarkably, the stretchable 20PMMA devices exhibit exceptional mechanical robustness with 10.8% fracture strain (2.2‐fold improvement) and 87% PCE retention after 100 stretching cycles (10% strain), far surpassing the control devices (50% retention). The work establishes fundamental design principles for insulating polymer additives in is‐OPVs, demonstrating how molecular control over micro‐/nanoscale distribution can simultaneously optimize electronic and mechanical properties. These findings provide a universal materials platform for high‐performance stretchable electronics, particularly for next‐generation wearable energy technologies where both efficiency and durability are paramount.