Weifei Fu

π-Backbone isomerism regulates the aggregation and surface coverage of carbazole self-assembled monolayers on nickel oxide. The bent isomer forms a dense and robust buried contact, improving perovskite solar cell efficiency and stability.

Fluorination is widely used to regulate the molecular electrostatic potential (ESP) and packing of nonfullerene acceptors (NFAs) in organic solar cells (OSCs). Current strategies mainly involve direct fluorination or trifluoromethylation, but high-performance NFAs still suffer from large exciton binding energy (Eb) and nonradiative energy loss (ΔE3). Herein, we introduce a novel fluorinated group, trifluoromethylthio (SCF3), into the quinoxaline core of an A-DA′D-A-type NFA, combined with alkyl side-chain engineering, to construct three new acceptors, ZY-SCF3-EH, ZY-SCF3-BO, and ZY-SCF3-HD. Theoretical calculations reveal that SCF3 possesses moderate electron-withdrawing ability, affording a favorable ESP to balance exciton dissociation and ΔE3 suppression. Besides, SCF3-based acceptors exhibit smaller hole–electron overlap, larger centroid distances, and lower Eb, which are beneficial for further suppressing energy loss. Experimentally, the high lipophilicity of SCF3 enhances solubility and solution processability, while multiple noncovalent interactions induce a three-dimensional honeycomb-like packing network that improves charge mobility. Consequently, the side-chain-optimized acceptor ZY-SCF3-HD delivers a superior power conversion efficiency (PCE) of 19.4%, with simultaneously improved open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF), alongside a low ΔE3 of 0.23 eV. A ternary blend further boosts the efficiency to 20.1%. Notably, a 20.25 cm2 module fabricated at room temperature achieves an impressive efficiency of 16.4%, ranking among the highest values reported to date. This work illustrates SCF3 as an effective fluorinated unit for constructing high-performance NFAs, providing a new strategy to simultaneously achieve high VOC, JSC, FF, and low ΔE3, and offering new design insights for next-generation high-efficiency OSCs.

Carbazole phosphonic acid (PACz) molecular contacts are widely used in inverted perovskite solar cells (PSCs), yet they often suffer from limited interfacial dipoles, insufficient robustness, and a trade‐off between intermolecular packing and coating uniformity under realistic solution processing. Here, we introduce a substituent‐asymmetric strategy by acetylating MeO‐4PACz to afford AcMeO‐4PACz, enabling simultaneous regulation of interfacial energetics, wetting, uniformity, and contact robustness. AcMeO‐4PACz exhibits a substantially enhanced surface‐normal dipole component (0.36 to 2.68 D) and downshifted frontier energy levels, thereby improving energetic alignment at the buried interface. The carbonyl motif mediates intermolecular hydrogen bonding, which fine‐tunes intermolecular interactions and yields a more homogeneous and solvent‐resilient molecular contact. The acetyl substitution also increases surface polarity, leading to improved precursor wetting and higher quality buried interface formation during blade coating. Consequently, blade‐coated inverted PSCs achieve a champion power conversion efficiency (PCE) of 25.57% and exhibit excellent stability under ISOS protocols (ISOS‐D‐1: 98.7% retention after 1920 h; ISOS‐D‐2: 88.0% retention after 1000 h at 65°C; ISOS‐L‐1: 99.0% retention after 1000 h under 1‐sun maximum power point tracking). This work establishes substituent asymmetry, together with carbonyl‐mediated intermolecular modulation, as an effective design strategy for processing‐resilient molecular contacts in scalable inverted PSCs.

Amplifying the quadrupole moment of non‐fullerene acceptors (NFAs) is key to facilitating exciton dissociation and suppressing recombination in organic solar cells (OSCs), yet current molecular design strategies predominantly enhance quadrupole moments by strengthening the electron‐withdrawing character of acceptor end groups, inevitably deepening frontier energy levels, and penalizing open‐circuit voltage ( V _OC ). Here, we introduce chlorine positional isomerization to amplify the molecular quadrupole moment without altering frontier orbital energies. By relocating a chlorine atom between asymmetric end groups, we improve the quadrupole moment from 154.5 to 176.0 Debye·Å, without altering the frontier energy level. This electrostatic reconfiguration accelerates exciton dissociation under minimal energetic offsets, as evidenced by ultrafast transient absorption spectroscopy. As a result, the optimized binary device achieves a power conversion efficiency of 19.0%, combining enhanced short‐circuit current and fill factor with low voltage loss. When incorporated as a guest acceptor in a ternary blend, this strategy further enables a promising efficiency of 20.3%, together with exceptional thickness tolerance (410 nm) and a scalable module (20.25 cm ² ), with maximum efficiencies exceeding 16.5%. This work establishes positional isomerization as a general electrostatic design handle to decouple quadrupole‐moment enhancement from energy‐level deepening, offering a transferable pathway to overcome exciton dissociation limits in OSCs.

Dielectric elastomer actuators (DEAs) are promising artificial muscles featuring large actuation strains, high energy densities, and fast response speeds. However, their reliance on kilovolt-level driving voltages remains a substantial barrier to their application in untethered systems. Here, low-voltage and high-output DEAs (LVHO-DEAs) were developed by synthesizing an elastomer material—high–dielectric constant processable high-performance dielectric elastomer, with optimized stress-strain behavior and an improved dielectric constant—and by multilayering its thin films through a scalable dry-stacking process. The developed LVHO-DEAs achieved an energy density of 38.4 joules per kilogram and a power density of 452 watts per kilogram at a nominal electric field of 20 volts per micrometer without any prestretching or high-frequency resonance. Driven by LVHO-DEAs, untethered wearable devices and soft robots with different actuation mechanisms were fabricated, demonstrating effective operation at 200 volts. These findings bridge the gap between the theoretical promise of DEAs and their practical application in untethered soft systems by enabling them to serve as high-performance actuators at low driving voltages.

Turning off 3D to 2D reconstruction with sulfone-modified passivation delivers 25.21% efficiency and durable inverted perovskite solar cells.

The α‐phase formamidinium lead iodide (α‐FAPbI ₃ ) perovskite has a near‐ideal bandgap approaching the Shockley–Queisser limit, yet its full potential remains underexploited in inverted perovskite solar cells (PSCs), particularly those fabricated by scalable blade‐coating methods. One of the key reasons is that the hole transport layer (HTL) cannot yet fully match the requirements of blade‐coated α‐FAPbI ₃ . Herein, an approach of mixing amino acid derivatives with traditional self‐assembled molecules (SAM) to form mixed‐SAMs is applied to enable full blade‐coating of high‐quality HTLs and α‐FAPbI ₃ films, and to realize a “four‐in‐one effect,” encompassing enhanced anchoring, improved film formation, defect passivation, and optimized energy level alignment. Devices incorporating 1‐Guanidineacetic acid as the co‐assembled SAM component exhibit power conversion efficiencies (PCEs) of 25.43% (3.5 mm ² ) and 22.94% (6.25 cm ² mini‐modules), respectively. The unencapsulated device retained 90.4% of its initial PCE after 3048 h of thermal aging at 85 ± 2 °C in N ₂ atmosphere. This work provides a feasible approach toward scalable solution‐processed α‐FAPbI ₃ ‐based PSCs with high performance.

Thermal annealing is essential for optimizing the bulk‐heterojunction (BHJ) morphology of organic solar cells (OSCs), yet traditional thermal annealing (TA) under ambient air suffers from film degradation and nonuniform heating. Here, a novel post‐treatment, solvent bath thermal annealing (STA), enabling effective TA of large‐area OSC active layers under ambient conditions, is introduced. In STA, the BHJ film is immersed in a perfluorodecalin (PFD) bath during heating, ensuring uniform thermal distribution and protection against oxygen and moisture. STA‐treated films thus exhibit optimized vertical component distribution, enhanced crystallinity, and improved molecular packing with higher structural order, leading to efficient charge transport and suppressed nonradiative recombination regardless of the annealing atmosphere. As a result, STA‐treated OSCs based on PM6/L8‐BO blend deliver outstanding performance: small‐area cells achieve a power conversion efficiency (PCE) of 19.05%, while large‐area (20.25 cm ² ) modules attain a PCE of 17.37% (certified 16.75%), among the highest PCEs for large‐area organic solar modules. It also successfully bridges the performance gap between inert and ambient processing conditions. Moreover, STA‐treated devices show excellent operational stability under continuous illumination and thermal stress. This ambient‐compatible annealing strategy thus provides a scalable route toward high‐efficiency and stable organic solar modules for practical large‐area manufacturing.

The self‐assembled monolayer (SAM) molecules on ITO or metal oxide transporting layers tend to desorb during perovskite film processing and device operation, leading to reduced power conversion efficiency (PCE) and device degradation. Developing effective strategies to stabilize SAMs at interfaces is therefore crucial for further improving the performance and stability of SAM‐based perovskite solar cells (PVSCs). Here, a facile method is developed to construct robust self‐assembled bilayers (SABs) by depositing cross‐linkable organosilanes, n ‐propyltrimethoxysilane (PTMS) and (3‐mercaptopropyl)trimethoxysilane (MPTMS), onto the widely used Me‐4PACz SAM for NiO _x modification. Me‐4PACz enables excellent hole extraction, suppresses interfacial reactions and recombination, while the cross‐linked organosilane network forms a robust protective layer that prevents the solvent‐induced SAM desorption and fills molecular voids, yielding a more compact and stable interface. In addition, the thiol group in MPTMS can strongly interact with the undercoordinated Pb ²⁺ at the buried interface of perovskite, further mitigating interfacial defects. Consequently, NiO _x /Me‐4PACz/MPTMS based PVSCs achieve a high PCE of 24.9% with a T ₈₀ lifetime of 475 h under continuous 1 sun equivalent illumination in air, compared to 23.3% and tens of hours for NiO _x /Me‐4PACz‐based control device. This work provides important insights into designing robust interfaces for high‐performance and highly stable PVSCs.

A bimolecular amine vapor passivation (BAVP) strategy enables 25.2% efficient blade-coated FAPbI ₃ solar cells with outstanding thermal stability.