Abstract Precise control of heterogeneous nucleation at inorganic interfaces is essential for constructing uniform multicomponent nanostructures but remains challenging because nucleation is highly sensitive to local surface chemistry. Here, we demonstrate a ligand-programmed interfacial nucleation strategy for controlling ferrite-gold growth through regulation of surface citrate coverage. Using gold magnetic nanoparticles (GMNPs) composed of Fe3O4 and Au as a model system, we show that surface-bound citrate modulates gold precursor adsorption and the heterogeneous nucleation landscape, enabling interlayer-free aqueous synthesis of highly uniform nanostructures with tunable sizes. Notably, citrate transforms iterative gold deposition from a heterogeneity-amplifying process into a self-homogenizing process by suppressing secondary nucleation and excessive growth of pre-existing particles while promoting utilization of residual ferrite nanoparticles. Surface citrate quantification and density functional theory calculations reveal that increasing citrate coverage strengthens interfacial Au-O electronic coupling, charge redistribution, and gold precursor adsorption, providing a molecular basis for the observed growth behavior. The strategy is further validated in Co0.5Fe2.5O4@Au and Mn0.5Fe2.5O4@Au systems. The resulting GMNPs enable a 10-fold sensitivity enhancement over conventional AuNPs-based lateral flow immunoassays following magnetic enrichment. These findings establish surface ligand coverage as a molecular parameter for programming heterogeneous growth at ferrite-gold interfaces.
Abstract Simultaneous electrochemical detection of dopamine (DA) and hydroquinone (HQ) is clinically significant but challenging because overlapping redox signals obscure detection on conventional sensing materials. Single-atom catalysts (SACs) offer promising adsorption and electron-transfer capabilities; however, limited synthetic control, poor cycling durability, and inevitable signal interference in complex multi-analyte matrices hamper their application. Herein, we report a nickel single-atom catalyst embedded in nitrogen-doped carbon (Ni SA/NC) with a unique electronic structure that enables simultaneous detection of DA and HQ. Benefiting from the unique Ni–N4 moieties, the oxidation peaks for DA and HQ are well resolved, enabling simultaneous quantification. Notably, the Ni SA/NC achieves ultra-low detection limits (0.0018 μM for DA and 0.0017 μM for HQ), wide segmented linear response windows, and high anti-interference selectivity toward typical coexisting contaminants. Additionally, the Ni SA/NC exhibits outstanding measurement reproducibility, as evidenced by ultra-low relative standard deviations, alongside favorable storage stability. DFT calculations reveal that the Ni–N4 configuration modulates the Ni d-band center to afford moderate *OH adsorption strength, thereby lowering the electro-oxidation barriers. Overall, this work establishes a rational design paradigm for SAC-based electrochemical sensing materials, offering potential for practical implementations in early disease diagnosis.
Abstract Despite the promise of Te as a p-type channel material, realizing Te-based thin-film transistors (TFTs) with low off-state current and high on/off ratio is challenging due to its small bandgap and high background carrier density. Se-alloying offers a potential solution to mitigate these limitations, yet the device performance has remained suboptimal. In this work, through the synergy of stoichiometric control and thickness engineering, we achieve an optimal trade-off between charge transport and switching characteristics in Te1-xSex TFTs. The resulting devices exhibit an average field-effect mobility of 16.8 cm2 V-1 s-1, Ion/Ioff ratio of 1.3×105 and an ultralow off-state current of 10 pA μm-1. The fabrication process is fully compatible with established low-temperature TFT technologies, enabling high-yield production of transistor arrays with favorable electrical uniformity. Notably, the devices demonstrate exceptional environmental stability, retaining critical performance metrics after six months of storage without encapsulation. Complementary logic gates (NOT, NAND, and NOR) are fabricated by integrating p-Te0.63Se0.37 and n-IGZO TFTs. The inverter achieves a high voltage gain of 28, a noise margin of 92.3%, and a low static power consumption of 420 pW at 3 V supply voltage. This study highlights the potential of Te1-xSex as a scalable p-type channel material, advancing the development of TFT-based logic circuits.
Abstract The practical performance of proton exchange membrane fuel cells (PEMFCs) is critically hampered by the disordered distribution of ionomers within the catalyst layer, which causes severe sulfonate‑induced poisoning of Pt active sites, discontinuous proton conduction, and restricted oxygen transport to catalytic centers. However, addressing these interrelated limitations simultaneously remains a formidable challenge, as most existing strategies tackle only one aspect at the expense of others. In this study, we report a catalyst layer architecture based on a one-dimensional proton conductor (1D Proton Conductor) that addresses the coupled limitations of random ionomer distribution, Pt site poisoning, and inefficient transport in PEMFCs. This design encapsulates ionomers uniformly on carbon nanotubes to create linear and continuous proton pathways, while spatially separating sulfonate groups from Pt surfaces and preserving open pore structures. The 1D Proton Conductor reduces sulfonate coverage on Pt from 31.7% to 14.9%, and decreases proton conduction and oxygen transport resistances by 34% and 40%, respectively. As a result, the mass activity of Pt doubles and the cell achieves a peak power density of 0.73 W cm-2 under 30% relative humidity, twice that of conventional electrodes. This work demonstrates that simultaneous regulation of ionomer distribution, surface chemistry, and transport properties offers a viable route to high-performance PEMFCs, particularly under low-humidity conditions. This study provides a feasible strategy for designing high-performance catalyst layer for PEMFCs.
Abstract Various structural phases in two-dimensional (2D) crystal polytypes provide distinct material properties including electronic band structure, conductivity, optical properties, ferromagnetic and ferroelectric properties. However, the impact of phase on mechanical properties remains largely unexplored. Here, we quantitatively resolve the Young’s modulus of MoSe2 polytypes with different structural phases by leveraging the dynamic response of MoSe2 nanomechanical resonators. Through experimentally elucidating resonant behavior of MoSe2 drumheads with varying diameters and thicknesses, and developing theoretical models linking resonance behavior to phase-dependent mechanical properties, we determine the Young’s modulus for 2H (131 ± 10 GPa), 3R (77 ± 8 GPa), and 2H-3R mixed-phase (95 ± 5 GPa) MoSe2. We further show that structural phase can modulate the Young’s modulus by up to ~70%, which is effective for tuning device frequency and nonlinearity. Our findings establish phase as a powerful degree of freedom for tailoring mechanical properties of 2D polytypes and for exploiting polymorphism in designing strain-engineered multifunctional nanoelectromechanical devices.
