Journals
2025 EN
Newman Peter L. H. · Mirkhalaf Mohammad · Gauci Steven C.
+4 more
Abstract Fabrication methods that synthesize materials with higher precision and complexity at ever smaller scales are rapidly developing. Despite such advances, generating complex 3D materials with controlled mechanical properties at the nanoscale remains challenging. Exerting precise control over mechanical properties at the nanoscale would enable material strengths near theoretical maxima, and the replication of natural structures with hitherto unattainable strength‐to‐weight ratios. Here, a method for fabricating materials with nanovoxelated elastic moduli by employing a volume‐conserving photoresist composed of a copolymer hydrogel, along with OpenScribe, an open‐source software that enables the precise programming of material mechanics, is presented. Combining these, a material composed of periodic unit cells featuring heteromechanically tessellated soft‐stiff structures, achieving a mechanical transition over an order‐of‐magnitude change in elastic modulus within 770 nm, a 130‐fold improvement on previous reports, is demonstrated. This work critically advances material design and opens new avenues for fabricating materials with specifically tailored properties and functionalities through unparalleled control over nanoscale mechanics.
Journals
2025 EN
Đorđević Luka · Jaynes Tyler J. · Sai Hiroaki
+5 more
Abstract Mechanical expansion and contraction of pores within photosynthetic organisms regulate a series of processes that are necessary to manage light absorption, control gas exchange, and regulate water loss. These pores, known as stoma, allow the plant to maximize photosynthetic output depending on environmental conditions such as light intensity, humidity, and temperature by actively changing the size of the stomal opening. Despite advances in artificial photosynthetic systems, little is known about the effect of such mechanical actuation in synthetic materials where chemical reactions occur. It is reported here on a hybrid hydrogel that combines light‐activated supramolecular polymers for superoxide production with thermal mechanical actuation of a covalent polymer. Superoxide production is important in organic synthesis and environmental remediation, and is a potential precursor to hydrogen peroxide liquid fuel. It is shown that the closing of pores in the hybrid hydrogel results in a substantial decrease in photocatalysis, but cycles of swollen and contracted states enhance photocatalysis. The observations motivate the development of biomimetic photosynthetic materials that integrate large scale motion and chemical reactions.
Journals
2025 EN
Hennessey Seán · GonzálezGómez Roberto · Arisnabarreta Nicolás
+9 more
Abstract Covalent and metal‐organic frameworks (COFs and MOFs) have shown great promise in light‐driven processes mainly due to their ligand‐to‐metal charge‐separation properties, as well as having access to a diverse range of photoactive metalloligands and organic linkers. However, both frameworks present individual drawbacks that can potentially be avoided by combining both systems (metal and covalent) to produce metal‐covalent organic frameworks (MCOFs), exhibiting the advantages of both material types. Yet, due to their poor crystallinity, the understanding of the structure‐properties relation of MCOFs remains unclear. Herein, we report photoactive linkers in the form of a [Ru(tpy) 2 ] 2+ (tpy: 2,2′,6,2″‐terpyridine) complex which covalently binds to a luminescent pyrene core to yield a new, photoactive Schiff‐base MCOF. The structure, thermal, electronic, and optical properties of this novel material have been exhaustively characterized by a wide range of microscopy, spectroscopic, and computational methods. This combined experimental and computational work represents a significant step toward the fundamental understanding of the photoactive units within the framework, their hierarchical arrangement and interactions with substrates, which is essential for the future design of efficient photocatalytic materials.
Journals
2025 EN
Lin Haichen · Wang Zishen · Solares Oliver
+16 more
Abstract Rechargeable batteries wherein both the cathode and the anode are vanadium‐based phases are promising grid‐energy storage candidates, offering long cycle life and easy recycling. However, their system‐level energy density must be improved to lower their footprint and operating costs. In this work, an all‐vanadium sodium‐ion battery that uses a new disordered rock salt (DRS) anode, Na 3 V 2 O 5 (DRS‐NVO), is proposed. For DRS‐NVO, ≈2 Na + ions can be reversibly cycled at ≈0.7 V versus Na/Na + . Structural characterization by X‐ray diffraction and pair distribution function (PDF) analysis reveal increased local distortions during Na + insertion but the overall DRS structure is maintained. The material shows exceptional stability and rate capability, achieving 10 000 cycles in half‐cell tests at rates of up to 20 C. Molecular dynamics simulations produce voltage profiles and ion diffusivities in good agreement with experimental results. Pairing the DRS‐NVO anode with a Na 3 V 2 (PO 4 ) 3 (NVP) cathode yields a cell (NVO|NVP) voltage of 2.7 V, with symmetric voltage profiles and an energy efficiency >93%. This all‐vanadium sodium‐ion battery exhibits excellent cycling stability, retaining 80% of its capacity after 3 000 cycles. Levelized cost‐of‐storage (LCOS) evaluations based on a cell design model confirm the cost‐effectiveness, positioning NVO|NVP as a competitive grid‐scale energy storage solution.
Journals
2025 EN
Riney Logan · Bac SeulKi · Zhukovskyi Maksym
+8 more
Abstract The interface of common III‐V semiconductors InAs and GaSb can be utilized to realize a two‐dimensional (2D) topological insulator state. The 2D electronic gas at this interface can yield Hall quantization from coexisting electrons and holes. This anomaly is a determining factor in the fundamental origin of the topological state in InAs/GaSb. Here, the coexistence of electrons and holes in InAs/GaSb is tied to the chemical sharpness of the interface. Magnetotransport, in samples of Mn‐doped InAs/GaSb cleaved from wafers grown at a spatially inhomogeneous substrate temperature, is studied. It is reported that the observation of quantum oscillations and a quantized Hall effect whose behavior, exhibiting coexisting electrons and holes, is tuned by this spatial nonuniformity. Through transmission electron microscopy measurements, it is additionally found that samples that host this co‐existence exhibit a chemical intermixing between group III and group V atoms that extends over a larger thickness about the interface. The issue of intermixing at the interface is systematically overlooked in electronic transport studies of topological InAs/GaSb. These findings address this gap in knowledge and shed important light on the origin of the anomalous behavior of quantum oscillations seen in this 2D topological insulator.
Journals
2025 EN
Kim Kiyoung · Edwards Steven · Fuxa Kyle
+8 more
Abstract Monitoring the elasticity of soft biological tissues in the gastrointestinal (GI) tract with minimal invasion holds promise for early diagnosis of intestinal fibrosis, colorectal cancer, and other diseases featuring abnormal elasticity. However, existing methods of sensing tissue elasticity have drawbacks such as insufficient resolution for elastography, and discomfort or the requirement of risky anesthesia for flexible endoscopes or implantable devices. Here a wirelessly actuated palpation mechanism is presented, integrated into a swallowable capsule device, offering in situ tissue elasticity measurement with minimal invasiveness. The approach employs a magnetic soft cantilever beam actuated by external magnetic fields to gently press against soft tissues. Mechanical stress and strain are monitored by an onboard magnetic sensor and a strain gauge, allowing for an accurate assessment of tissue elasticity. Additionally, wireless modules utilizing Bluetooth Low Energy (LE) and powered by a battery facilitate real‐time communication. The device operates under external magnetic field control, which can move freely over soft tissues during examinations and palpate suspicious areas. The elasticity sensing mechanism is validated and assessed on both phantom structures and ex vivo porcine colon tissues. The capsule device holds significant promise for assessing tissue physiological conditions and facilitating early disease diagnosis in hard‐to‐reach areas of the body.
Journals
2025 EN
Zhang Anyu · Redzikultsava Katazhyna · Mamizadeh Leila
+10 more
Abstract Tubular constructs are fundamental in tissue engineering and implant applications across vascular, renal, and urethral systems. Covalent attachment of biomolecules to their internal surfaces is often needed to create biofunctional structures, yet achieving uniform biofunctionalization within these confined geometries remains challenging. Surface‐embedded radicals generated via plasma immersion ion implantation (PIII) enable single‐step, reagent‐free covalent biofunctionalization without requiring multi‐step processing. However, uniform plasma treatment of 3D tubular structures is hindered by limited plasma penetration into confined geometries. To address this, a novel tubular dielectric barrier discharge (DBD) configuration is introduced for PIII treatment to achieve uniform internal PIII surface activation and biofunctionalization. By optimizing electric field distribution, informed by numerical modeling, PIII activation is selectively confined to either inside or outside of expanded polytetrafluoroethylene (ePTFE) tubes. Electron paramagnetic resonance spectroscopy data confirmed surface radicals remained detectable after six months, far exceeding the reactivity lifespan of conventional plasma treatments. Covalent immobilization of tropoelastin and fibronectin was validated using fluorescence imaging, ELISA, and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Endothelialization studies using human coronary artery endothelial cells demonstrated enhanced cell attachment and proliferation in biofunctionalized submillimetre‐scale tubes. This industrially scalable, radical‐based, solvent‐free technology enables the fabrication of biofunctional tubular constructs, advancing tissue engineering, regenerative medicine, and beyond.
Journals
2025 EN
Popescu Cosmin Constantin · Aryana Kiumars · Mills Brian
+17 more
Abstract Chalcogenide optical phase change materials (PCMs) have garnered significant interest for their growing applications in programmable photonics, optical analog computing, active metasurfaces, and beyond. Limited endurance or cycling lifetime is however increasingly becoming a bottleneck toward their practical deployment for these applications. To address this issue, a systematic study elucidating the cycling failure mechanisms of Ge 2 Sb 2 Se 4 Te (GSST) is performed, a common optical PCM tailored for infrared photonic applications, in an electrothermal switching configuration commensurate with their applications in on‐chip photonic devices. Further a set of design rules building on insights into the failure mechanisms is proposed, and successfully implemented them to boost the endurance of the Ge 2 Sb 2 Se 4 Te (GSST) device to over 67 000 cycles.
Journals
2025 EN
Lukaskawcez Brayden · Varshney Shivasheesh · Choo Sooho
+12 more
Abstract Membranes of complex oxides like perovskite SrTiO 3 extend the multi‐functional promise of oxide electronics into the nanoscale regime of 2D materials. Here, it is demonstrated that freestanding oxide membranes supply a reconfigurable platform for nano‐photonics based on propagating surface phonon polaritons. Infrared near‐field imaging and spectroscopy enabled by a tunable ultrafast laser are applied to study pristine nano‐thick SrTiO 3 membranes prepared by hybrid molecular beam epitaxy. As predicted by coupled mode theory, it is found that strong coupling of interfacial polaritons realizes symmetric and antisymmetric hybridized modes with simultaneously tunable negative and positive group velocities. By resolving reflection of these propagating modes from membrane edges, defects, and substrate structures, their dispersion is quantified with position‐resolved nano‐spectroscopy. Remarkably, polariton negative dispersion is found to be both robust and tunable through choice of membrane dielectric environment and thickness, and proposes a novel design for in‐plane Veselago lensing harnessing this control. This work lays the foundation for tunable transformation optics at the nanoscale using polaritons in a wide range of freestanding complex oxide membranes.
Journals
2025 EN
Maharjan Samjhana · Dakoju Ravi Kishore · Albano Bella
+7 more
Abstract Photochemical C−C coupling reactions can be tailored to industrial chemical processes and preparations of pharmaceuticals. Recent approaches in this area are limited to using precious transition metal coordination complexes that facilitate light absorption and redox processes with benchtop chemicals. Herein, we propose a paradigm that involves all‐in‐one organo‐photo‐auxiliaries, thio ‐heteroarenes, which exhibit unique photophysical properties. These thio ‐heteroarenes were employed to prepare several all‐in‐one ionic photo‐salts from commercially available alkyl/benzyl and heterocyclic halides via aromaticity‐mediated nucleophilic substitution reactions. From the library of >30 salts, we performed on‐demand photochemical C−C coupling reactions to isolate numerous symmetrical and unsymmetrical diary/alkyl‐ethanes with yields up to 84% and mass balance as high as 96%. We also investigated the influence of structural features/properties on the outcomes of the photochemical C−C coupling reactions. The current photochemical C−C method was successful in the isolation of >30 photoproducts, including the natural product Brittonin A, a precursor of Imipramine, and derivatives of the bioactive Honokiol Analogues. Furthermore, transient absorption spectroscopy and time‐dependent density functional theory calculations were used to decipher the nature of light‐promoted electronic transitions.