ACS Applied Materials & Interfaces最新文献

Hybrid organic–inorganic heterojunctions have attracted considerable interest in optoelectronic applications, as they combine the excellent electronic transport of inorganic semiconductors with the ease of processing and tunability of organic conductors. While the performance of such heterojunctions is strongly governed by their built-in electric field and interfacial band alignment, strategies for actively tuning these parameters in printed bulk heterojunctions have remained largely unexplored. In this regard, here we show an inkjet-printed bulk heterojunction diode with semiconducting amorphous indium gallium oxide (a-IGO) and conducting poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), whose interfacial barrier can be dynamically modulated by a solvent (dimethyl sulfoxide, DMSO) or a composite solid polymer electrolyte (CSPE). Systematic studies of pristine, DMSO-treated, and CSPE-treated devices reveal that DMSO enhances charge transport in PEDOT:PSS, while mobile ions of CSPE penetrate the polymer matrix and accumulate at the heterojunction interface. Capacitance–voltage measurements show that ionic screening increases the built-in potential from 0.36 to 0.70 eV by inducing additional band bending within a-IGO. Consequently, the off-current decreases by more than two orders of magnitude, accompanied by a substantial enhancement in rectification ratio. The strengthened junction field promotes efficient separation of photogenerated carriers under ultraviolet illumination, increasing the photosensitivity from 10³ to beyond 10⁶ while achieving a responsivity of 80 A/W, a specific detectivity of 0.25 × 10¹² Jones, and an external quantum efficiency of 27200%. This elevated built-in potential further enables zero-biased ultraviolet photodetection with a photosensitivity of ∼10⁴ and a responsivity of 45 mA/W. Furthermore, a three-terminal electrolyte-gated device can demonstrate ion-induced modulation of the interfacial barrier, enabling a transition from rectifying to near-Ohmic behavior and thereby realizing a tuneable diode. This electrolyte-assisted ionic-modulation strategy enables reconfigurable hybrid heterojunctions for next-generation, energy-efficient sensing and multifunctional optoelectronic applications.

Barium titanate (BaTiO₃, BTO) is an archetypal ferroelectric of broad technological relevance. Molecular beam epitaxy (MBE) offers compelling advantages for BTO thin film growth, such as superior crystalline quality and epitaxial integration with semiconductor substrates. However, the low oxygen partial pressures inherent to MBE environments, together with the challenges associated with precise stoichiometry control when using elemental sources, promote composition imbalances and oxygen vacancy formation and make MBE-grown BTO films significantly less documented than their pulsed laser deposition (PLD) or sputtered counterparts. Here, we present a detailed study of the ferroelectric response of an epitaxial MBE-grown BTO thin film, combining synchrotron-based X-ray diffraction with temperature- and frequency-dependent electrical characterizations, including the first Rayleigh analysis reported for an MBE-grown BTO layer and only the third direct demonstration of ferroelectricity in such films based on macroscopic P(E) and ε(E) loops. The film exhibits a soft ferroelectric response—low coercive field (12 kV/cm), high tunability (≃65%), and a large Rayleigh coefficient reflecting significant irreversible domain wall motion. We show that this response is governed by a landscape of weak oxygen vacancy pinning centers, whose effect is amplified by the high structural quality, full plastic relaxation, and pure c-oriented single-domain state of the film. These results provide a physically grounded picture of the ferroelectric response of MBE-grown BTO thin films, offering a solid basis for device optimization.

Calcium overload therapy represents a highly promising therapeutic strategy and has attracted extensive attention in the field of tumor treatment. Nevertheless, the challenge of achieving high-concentration and precise enrichment of calcium ions inside tumors seriously hinders the clinical translation of this therapy. Moreover, monotherapy fails to deliver superior anti-tumor efficacy. To address such issues, a tumor microenvironment (TME)-triggered calcium ion and hydroxyl radical amplifier with near-infrared absorption (CuMPB@CaCO₃@HA) is presented to process calcium overload-synergized multimodal combination therapy. It can bind to the CD44 receptor on the surface of cancer cells, thereby accumulating in tumor tissues, where it is decomposed by the TME to release Ca²⁺ and copper-doped mesoporous Prussian blue (CuMPB). The released Ca²⁺ triggers intracellular calcium overload. The released CuMPB has a characteristic absorption peak in the range of 650–900 nm, which enables photoacoustic (PA) imaging and photothermal therapy of the tumor. In addition, Cu²⁺ in CuMPB undergoes a cascade reaction with highly abundant glutathione and H₂O₂ in the TME, producing hydroxyl radicals (·OH); additionally, the Fe²⁺ ion in MPB also undergoes a Fenton reaction with H₂O₂ to generate ·OH, achieving highly efficient chemodynamic therapy (CDT). Moreover, laser irradiation promotes the generation of ·OH, thereby further enhancing CDT. Both in vitro and in vivo experiments verified that CuMPB@CaCO₃@HA enables in situ PA diagnosis of tumors to visualize tumor accumulation and optimize the treatment window and enables PA imaging-guided synergistic calcium overload-chemodynamic-photothermal antitumor therapy based on TME characteristics, thus providing a new strategy for the development of tumor-targeted nanotheranostic agents, highlighting the untapped potential of nanoassembly.

Supramolecular materials are traditionally designed by strengthening noncovalent interactions or increasing the number of binding motifs. Here, we demonstrate a fundamentally different strategy: using macromolecular architecture to amplify weak molecular interactions into robust material functions. Bottlebrush poly(ethylene glycol) (PEG) polymers, consisting of a linear backbone densely grafted with short side chains, transform tetrazine π–π interactions that are insufficient to gel linear polymers into stable supramolecular hydrogels without covalent crosslinking. The resulting networks remain stable up to ∼65 °C, undergo shear-reversible solid–liquid transitions, and disassemble upon tetrazine deactivation. Density functional theory calculations reveal unusually strong antiparallel tetrazine–tetrazine interactions (∼17 k_BT at room temperature), supporting the hypothesis that the bottlebrush architecture promotes molecular alignment and cooperative association. By varying polymer concentration and tetrazine grafting ratio, we uncover a universal scaling relationship between hydrogel stiffness and the distance from the percolation threshold, with two distinct regimes that deviate from classical percolation theory. The hydrogels are cytocompatible and, unlike linear PEG hydrogels, exhibit minimal fibrotic encapsulation following implantation in immunocompetent mice. These findings establish molecular architecture as a design principle for supramolecular assembly, demonstrating that robust material function can emerge from the architectural amplification of weak interactions and enabling a class of injectable antifibrotic biomaterials.

Confining the redox activity of perylenetetracarboxylic diimide (PTCDI) to the single-electron neutral/radical-anion couple enables ultrafast, durable aqueous sodium-ion storage. Differential electrochemical mass spectrometry and comparative OCP measurements identify hydrogen evolution and oxygen-associated reoxidation as self-discharge pathways of the dianion, motivating operation within a restricted potential window. XPS and EDX measurements support Na-ion coordination to reduced carbonyls as the principal charge-compensation mechanism. In a symmetric PTCDI cell, the selected redox couple retains 88% of its capacity after more than 19,000 cycles with near-unity coulombic efficiency. At nominal charge times of 60 and 2 s, the electrode retains 86 and 41% of its theoretical capacity, respectively, demonstrating ultrafast kinetics without sacrificing durability. These results establish redox-selective control as a design strategy for aqueous carbonyl electrodes whose deeper reduction approaches the stability limit of water.

Precious metal recovery from secondary resources is increasingly important for securing a sustainable supply of critical materials, yet conventional adsorption–reduction systems remain constrained by the finite electron-donating capacity of redox-active adsorbents. Electron-sustained adsorption–reduction (ESAR) overcomes this limitation by continuously supplying electrons through light-driven, electrically driven, or self-powered processes, thereby sustaining interfacial reduction and enabling cumulative recovery beyond conventional adsorption limits. This perspective examines redox-active adsorption interfaces, external electron supply, and electron utilization in ESAR systems. It further explains how ESAR shifts the design focus from maximizing adsorption capacity to regulating interfacial electron supply, transport, and consumption. We highlight improving electron-use efficiency, regenerating active sites, enabling continuous metal release, and directing metal nucleation and growth as key priorities for advancing ESAR into a scalable platform for precious metal recovery and functional materials synthesis.

Musculoskeletal defects remain difficult to treat because current grafts often have limited supply, donor-site morbidity, risk of immune reaction, or insufficient local biological stimulation. To address this problem, this study developed 3D-printed β-tricalcium phosphate (TCP) scaffolds loaded with quercetin-loaded nanostructured lipid carriers (Que-NLCs) to combine an osteoconductive ceramic structure with local delivery of a natural osteogenic and anti-resorptive compound. Que-NLCs provided controlled release for up to 21 days and reduced the initial burst release compared with free Que at both pH 5.0 and 7.4. At pH 5.0, release was ∼40% for Que and ∼33% for Que-NLCs, while at pH 7.4, release was ∼32% for Que and ∼26% for Que-NLCs. In vitro studies showed that Que-NLC-loaded scaffolds increased osteoblast viability by ∼28.6%, increased alkaline phosphatase activity by 33% by day 11, and reduced osteoclastic activity by 56% by day 21. RT-qPCR further showed up to 4-fold increases in osteogenic markers and up to 60% reduction in osteoclastogenesis-related genes. In a 6-week rat distal femur model, Que-NLC scaffolds increased new bone formation by ∼1.9-fold compared with TCP. These results show that Que-NLC-TCP scaffolds provide a localized, controlled drug-delivery platform to improve bone regeneration in non-load-bearing defects.

The development of high-performance energetic fuel components with rapid ignition characteristics is crucial for next-generation ammonium perchlorate (AP)-based composite propellants. Herein, we report a series of pyrimidine- and pyrazine-substituted azetidine nitrate esters (3, 6, and 9) and systematically investigate their structural, thermal, energetic, and combustion properties. Notably, compound 3 crystallized in two polymorphic forms (3 and 3′), revealing how crystal packing influences intermolecular interactions, density, and energetic performance despite identical molecular composition. All compounds exhibit favorable thermal stability, with decomposition temperatures ranging from 161 to 179 °C, high densities of 1.68–1.75 g cm^–3, and moderate impact sensitivities (<2.5 J). Among them, compound 9 shows the highest energetic performance, with a detonation velocity of 7740 m s^–1. To evaluate their potential as energetic fuel components, binary AP/fuel formulations with varying oxidizer-to-fuel ratios were prepared and assessed using combustion and hot-needle ignition tests. All formulations displayed rapid flame propagation and ignition delay times below 10 ms, while the formulation containing 5 wt % of AP with compound 3 achieved an exceptional short ignition delay of 1 ms. These findings demonstrate that nitrate-functionalized azetidines not only possess attractive intrinsic energetic properties but also exhibit remarkable fuel-oxidizer synergy with AP, enabling rapid ignition and efficient combustion. This work establishes pyrimidine and pyrazine-substituted azetidine nitrate esters as promising energetic fuel components for next-generation AP-based composite propellant formulations.

Although O3-type layered oxides featuring an open framework demonstrate potential as high-capacity cathode materials for sodium-ion batteries, such cathode materials are confronted with commercial limitations, including intricate phase transition mechanisms, structural degradation, and sluggish sodium ion diffusion kinetics, culminating in rapid capacity fading and severe performance deterioration. Cationic high-entropy doping was adopted to fabricate the O3-Na_0.95Mg_0.045Ni_0.22Fe_0.045Cu_0.08Co_0.08Ti_0.08Mn_0.45O₂ (HE-NNMO) cathode. The HE-NNMO cathode manifests acceptable Na storage capability, rapid electron transmission, apparent pseudocapacitance effect, and preferable structural integrity. HE-NNMO achieved an initial discharge specific capacity of 142.2 mAh g⁻¹ at a current density of 50 mA g⁻¹ and maintained a capacity retention rate of 93.0% after 100 cycles at a current density of 500 mA g⁻¹. Additionally, it achieved an ultrahigh specific energy of 431.8 Wh kg⁻¹ (based on the cathode active material) at a current density of 0.05 A g⁻¹, and the Coulombic efficiency reached 89%. Notably, in the full cell, HE-NNMO//H`C maintained capacity retention rates of 78.8% and 65.7% after 200 and 1200 cycles at current densities of 200 mA g⁻¹ and 1 A g⁻¹, respectively, demonstrating its practical applicability. This study provides insights for the high-entropy design of O3-type layered oxides in sodium-ion batteries.