Jing Zhang

This study demonstrates a versatile nanopattern fabrication method by directly immersing substrate-deposited block copolymer surface micelles in specific solvents. The morphology transformation of surface micelles results in diverse nanostructures, which are influenced by various experimental parameters. Based on these findings, a full library of unique nanopatterns is constructed, which is further employed to realize metal nanopatterns utilizing the corresponding block copolymer nanopatterns as templates.

Abstract

This study establishes a comprehensive library of nanopatterns achievable by a single block copolymer (BCP), ranging from spheres to complex structures like split micelles, flower-like clusters, toroids, disordered micelle arrays, and unspecified unique shapes. The ordinary nanostructures of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) surface micelles deposited on a SiO_x surface undergo a unique morphology transformation when immersed directly in solvents. Investigating parameters such as immersion solvents, BCP molecular weight, substrate interactions, and temperature, this work reveals the influence of these parameters on the thermodynamics and kinetics governing the morphology transformation. Additionally, the practical application of BCP nanopattern templates for fabricating metal nanostructures through direct solvent immersion of surface micelles is demonstrated. This approach offers an efficient and effective method for producing diverse nanostructures, with the potential to be employed in nanolithography, catalysts, electronics, membranes, plasmonics, and photonics.

Work cycle of an azobenzene molecule in photoisomerization, with maximum optomechanical efficiency.

Abstract

Photochromic molecular motors hold promise for a multitude of potential applications in fields ranging from medicine to communications and structural repair. Yet, it is still a challenge to predict their mechanical efficiency. Here, azobenzene is explored as a representative light-driven nanomotor and estimate its quantum yield of photoisomerization and maximum mechanical efficiency. This is based on first-principles mapping of the 3D potential energy surfaces for the ground and excited states of the trans and cis configurations and identifying the minimum energy pathway for isomerization. A work cycle is devised and identifies force constant as the parameter that resembles temperature in the Carnot heat engine, but with very different efficiencies. The results show that the optomechanical efficiency of azobenzene at constant load is about 5% albeit under ideal conditions. To test the hypothesis, the study also explores the optomechanical efficiency of stilbene and 2-butene and shows that their efficiency does not exceed 5%.

Nature Communications, Published online: 11 August 2024; doi:10.1038/s41467-024-50382-1

This study analyzes a global dataset of soil metagenomes to explore environmental drivers of growth potential, a fundamental aspect of bacterial life history. The authors show that growth potential, estimated from codon usage statistics, was highest in forested biomes and lowest in arid latitudes, which indicates that bacterial productivity generally reflects ecosystem productivity globally.

Nature, Published online: 06 August 2024; doi:10.1038/d41586-024-02368-8

Device allowing the user to control a computer cursor using their thoughts has been adjusted in a bid to prevent glitches with the first implant.

Nature, Published online: 07 August 2024; doi:10.1038/s41586-024-07786-2

By using intercalative oxidation techniques, stable, stoichiometric and atomically thin single-crystalline Al2O3 films can be produced, which can be effectively used as a dielectric in top-gated field-effect transistors based on two-dimensional materials.

Nature Electronics, Published online: 05 August 2024; doi:10.1038/s41928-024-01216-x

A biodegradable electronic tent electrode array that can be inserted into the brain cortex using a syringe, where it then expands to 200 times its original size, can be used for electrocorticography monitoring.

This study investigates the effects of various aptamer functionalization approaches on plasmonic metasurface biosensing and reveals the near-field enhancing mechanism for improving detection sensitivity of exosomes. Based on the exploration of fundamental biophysics, an optimal type of aptamer-based plasmonic metasurface biosensor is developed, which efficiently detects clinical serum exosomes for breast cancer diagnosis and classification.

Abstract

Exosomes are critical tumor biomarkers, which can be detected by label-free sensing of plasmonic metasurfaces with expensive antibody functionalization. Due to their low cost and small size, aptamers should be promising to replace antibodies in plasmonic metasensing of exosomes. However, research on aptamer-based plasmonic metasensing of exosomes is still unexplored. Here, the optical near-field sensing mechanism of aptamer-based plasmonic metasurface (APM) is investigated. Based on the study of the evanescent field of APM, using thiol-modified aptamer boosts the utilization rate of resonance wavelength shift from 27.5% to 83.3% compared to biotinylated aptamers, attributed to a significant reduction in the near-field occupation of the biofunction layer. Moreover, APM biosensors effectively detect clinical serum exosomes for breast cancer (BC) diagnosis and classification. The receiver operating characteristic analysis shows an area under the curve of 99.3% for APM diagnosis, surpassing the 79.1% for hematological tests of the conventional BC biomarker CA153. The results also indicate that APM biosensors can be a noninvasive tool for molecular classification of BC with great distinguishment of P < 0.0001. The research demonstrates that APM biosensors are enabling a reliable and convenient platform to facilitate clinical hematological tests of exosomes for auxiliary diagnosis of cancer.

This study demonstrates heterogeneous silicon-on-silicon carbide (SiSiC) as a high-performance, scalable photonic platform that overcomes several challenges associated with silicon carbide microfabrication. Ring resonators patterned into the silicon device layer support quality factors exceeding 10⁵ corresponding to propagation loss of 5.7 dB cm⁻¹, and numerical simulations show SiSiC's potential for nonlinear and quantum applications.

Abstract

Silicon carbide (SiC)'s nonlinear optical properties and applications to quantum information have recently brought attention to its potential as an integrated photonics platform. However, despite its many excellent material properties, such as large thermal conductivity, wide transparency window, and strong optical nonlinearities, it is generally a difficult material for microfabrication. Here, it is shown that directly bonded silicon-on-silicon carbide can be a high-performing hybrid photonics platform that does not require the need to form SiC membranes or directly pattern in SiC. The optimized bonding method yields defect-free, uniform films with minimal oxide at the silicon–silicon–carbide interface. Ring resonators are patterned into the silicon layer with standard, complimentary metal–oxide–semiconductor (CMOS) compatible (Si) fabrication and measure room-temperature, near-infrared quality factors exceeding 10⁵. The corresponding propagation loss is 5.7 dB cm⁻¹. The process offers a wafer-scalable pathway to the integration of SiC photonics into CMOS devices.

In this study, magneto-optical and spintronic garnets that can be crystallized using a micro-heater built into a Si substrate are developed and the local crystallization of the garnets using the heater is demonstrated. Electron backscatter diffraction from a scanning electron microscope shows that the garnet on the heater is a polycrystalline film.

Abstract

Ferrimagnetic iron garnets enable magnetic and magneto-optical functionality in silicon photonics and electronics. However, garnets require high-temperature processing for crystallization which can degrade other devices on the wafer. Here bismuth-substituted yttrium and terbium iron garnet (Bi-YIG and Bi-TbIG) films are demonstrated with good magneto-optical performance and perpendicular magnetic anisotropy (PMA) crystallized by a microheater built on a Si chip or by rapid thermal annealing. The Bi-TbIG film crystallizes on Si at 873 K without a seed layer and exhibits good magneto-optical properties with Faraday rotation (FR) of −1700 deg cm⁻¹. The Bi-YIG film also crystallizes on Si and fused SiO₂ at 873 K without a seed layer. Rapidly cooled films exhibit PMA due to the tensile stress caused by the thermal expansion mismatch with the substrates, increasing the magnetoelastic anisotropy by 4 kJ m⁻³ versus slow-cooled films. Annealing in the air for 15 s using the microheater yields fully crystallized Bi-TbIG on the Si chip.

A novel YNbO₄:Pr³⁺ phosphor with adjustable photoluminescence and red persistent luminescence for dual-wavelength excited thermometry and dynamic anti-counterfeiting is proposed. The maximum S _r value reaches 2.58% K⁻¹ upon 261 nm excitation, while that is 1.01% K⁻¹ under 300 nm excitation. Besides, the dynamic multicolor luminescence can be realized by adjusting ion doping concentration, temperature, and observation time.

Abstract

Phosphors with multifunctional applications have attracted extensive research, especially in thermometer and anti-counterfeiting fields. Herein, a series of Pr³⁺-doped YNbO₄ (YNO) phosphors with adjustable photoluminescence and red persistent luminescence (PersL) performances are developed. YNO host exhibits the blue self-activated luminescence, and the different Pr³⁺ emission peaks possess various thermal stability properties due to the thermal quenching channel generated by the intervalence charge transfer state between Pr³⁺ and Nb⁵⁺ ions. Two kinds of fluorescence intensity ratio models with high absolute and relative sensitivities are realized to measure the temperature under dual-wavelength excitation. Moreover, YNO:Pr³⁺ exhibits the red PersL with a duration of about 120 s upon ceasing the UV excitation light source. The fabricated YNO:Pr³⁺-polydimethylsiloxane films display different luminescence patterns with the passage of time after turning off UV light, which can cleverly achieve dynamic conversion. These results demonstrate that YNO:Pr³⁺ phosphor has potential applications in dual-wavelength excited thermometry and dynamic anti-counterfeiting fields.

A facile pre-nucleation strategy is developed to generate crystal seeds for further triggering the room-temperature growth of high-quality perovskite single crystal emissive layers, enabling the fabrication of highly-efficient and stable perovskite single crystal-based light-emitting diodes. This pre-nucleation strategy shows excellent universality and can be used for the room-temperature growth of hybrid perovskite and all-inorganic perovskite single crystals.

Abstract

Metal lead perovskite (MHP) single crystals (SCs) with extraordinary optical properties are promising candidates for high-performance SC-based perovskite light-emitting diodes (SC-PeLEDs). However, the heating process involved in traditional methods to initiate crystal nucleation and growth inevitably induces massive defects in MHP SCs, leading to inferior electroluminescence performance and poor operational stability of the SC-PeLEDs. Preparation of low-defect thin MHP SCs for high-performance SC-PeLEDs remains a formidable challenge. Here, a facile pre-nucleation strategy is developed to enable room-temperature (RT) growth of high-quality MAPbBr₃ (MA⁺ = CH₃NH₃ ⁺) SCs. By avoiding the detrimental effect of high growth temperature, the MAPbBr₃ SCs prepared at RT show improved crystallinity with lower trap-state density, giving rise to higher photoluminescence quantum yield and uniform fluorescence. Consequently, the MAPbBr₃-based SC-PeLEDs achieve a high external quantum efficiency up to 9.7%, along with an ultrahigh luminance of 126 800 cd m⁻², which is among the highest for MAPbBr₃-based SC-PeLEDs. Moreover, the SC-PeLEDs demonstrate remarkably high operational stability with half-lifetimes as long as 594 min and 33.2 min at initial luminances of ≈1000 cd m⁻² and ≈10 000 cd m⁻², respectively. The work has excellent universality and paves the way toward the fabrication of high-performance SC-PeLEDs for future lighting, display, and laser applications.

A novel mechanism is proposed, involving rare earth (RE) elements 4f orbitals hybridization with Mo-4d orbitals to electronic displacement induce polarization loss. Experimental demonstration by using liquid plasma preparation RE-decorated 1T-MoS₂ showcases its superior performance. The Pr15-D7 sample achieves an RL_min of −50.60 dB and effective absorption bandwidth (EAB) of 7.19 GHz, advancing the development of transition metal dichalcogenides (TMDs)-based EMW absorbing materials.

Abstract

The incorporation of large-sized rare earth (RE) elements with high coordination characteristics into transition metal dichalcogenide (TMD) absorbers while preserving a high 1T phase content during post-processing poses a significant challenge. To address this, a novel strategy involving the confinement of RE elements within the 1T-MoS₂ lattice via liquid plasma assistance, is proposed. This approach effectively mitigates the environmental impact on the 1T phase of MoS₂, yielding a remarkable 1T phase content of 82.69% for Ce20-D7 (20 wt.% Cerium trinitrate and 7 kV applied voltage). Combining experimental and theoretical investigations reveals that the multi-orbital characteristics of RE elements facilitate hybridization between the RE-4f and Mo-4d orbitals on the MoS₂ surface, leading to the occupation of weakly bound electrons in bonding orbitals with short-distance motion, enhanced inter-orbital electron-electron interactions, and induced polarization loss. Notably, the results demonstrate that the Pr15-D7 sample (15 wt.% praseodymium nitrate and 7 kV applied voltage) exhibits an effective absorption bandwidth (EAB) of 7.12 GHz at 2.6 mm, with a minimum reflection loss of -52.02 dB while the Ce20-D7 sample achieves an EAB of 6.96 GHz at 2.7 mm. These findings provide valuable insights for the rational design and development of high-performance TMD absorbers leveraging RE-modified materials.

A novel single-component Sb/Ho: Cs₂Na_0.9Ag_0.1(In/Bi)Cl₆ white phosphor with a high photoluminescence quantum yield of 93% is reported, which originated from triple synergistic emissions of Sb³⁺: sp→s², Ho³⁺: 4f→4f and STE recombination. The fabricated white light-emitting diode can produce full-spectrum white light with a record color rendering index of 97.4.

Abstract

The study on phosphors-converted white light-emitting diodes (pc-WLEDs) using lead-free double perovskites (DPs) as single-component white phosphors is widely concerned. However, the photoluminescence quantum yields (PLQY) of white luminescence and color rendering index (CRI) of WLED are not satisfactory. Herein, a new Sb/Ho: Cs₂Na_0.9Ag_0.1(In/Bi)Cl₆ single-component white phosphor with the highest PLQY of 93% and a record CRI of 97.4 is reported. Experimental data and theoretical calculations evidence that in addition to broadband yellow emission of the self-trapped exciton (STE) recombination, the material also exhibits blue emission from Sb³⁺: ³P₁→¹S₀ transition and red one assigned to Ho³⁺: ⁵F₅→⁵I₈ transition. Steady-state and time-resolved PL spectra verify the existence of two energy transfer channels from both Sb³⁺ and STE to Ho³⁺ dopants. As a demo, Sb/Ho: Cs₂Na_0.9Ag_0.1(In/Bi) Cl6-based WLED is constructed, showing excellent comprehensive optical performance with specially improved saturation red index R9 and blue one R12. This work provides a novel single-component rare-earth doped DP white phosphor for high CRI full-spectrum solid-state lighting.

A self-encapsulated n-type semiconducting photoresist (SPr) with process stability is developed. By resisting chemical erosion and air doping, SPr largely remains electrical properties by ≈90% after long-term exposure to chemical reagents and atmospheric conditions, while fabrication of OFET arrays as high as 9 × 10⁵ units cm⁻¹ is realized. This work paves the way for scale-up manufacturing of integrated organic electronics.

Abstract

Semiconducting photoresists hold great promise for scale-up manufacturing of organic field-effect transistors (OFETs) for integrated organic electronics. While photolithographic p-type OFETs have achieved a considerable balance among patterning precision, electrical properties and process stability, it remains challenging for n-type OFETs due to the inherent limited mobility and ambient instability. Herein, a n-type semiconducting photoresist (SPr) is developed that is compatible with photolithography procedures. By utilizing the solvent-driven force, a self-encapsulated blend film with gradient semiconductor phase is prepared, where the underneath transistor active layer is protected by the upper cross-linked network, avoiding solvent erosion and air doping. As such, a mobility up to 1.1 cm² V⁻¹ s⁻¹ that is comparable with amorphous Si is achieved, with remained mobility by ≈90% after long-term exposure to developer and stripper or atmospheric conditions. The sub-micrometer patterning accuracy of SPr enables the fabrication of organic transistor arrays with a density of 9 × 10⁵ units cm⁻¹, which is comparable to other state-of-the-art devices fabricated by the printing or photolithography, demonstrating immense potential in integrated organic electronics.

Aqueous-based red emissive perovskite nanocrystals (r-PNCs) are developed by phase transition route and anion-exchange reaction. Moreover, with the passivation of SCN⁻ ions, the r-PNCs display high photoluminescence quantum yields (75.3%), extended PL lifetime (423.38 ns), and excellent water stability. Therefore, by combining aqueous r-PNCs and portable smartphones, a sensing platform for sensitive detection of aqueous SCN⁻ is constructed.

Abstract

Recently emerging perovskite nanocrystals (PNCs) have drawn considerable attention due to the superior optoelectronic performances. However, the terrible stability of red emissive PNCs (r-PNCs) limits their broader application in aqueous media. Despite various encapsulation methods are proposed, the preparation of aqueous r-PNCs with facile operation and excellent durability is still challenging. Herein, aqueous green emissive PNCs (g-PNCs) by employing water as an external stimulus to treat oleyamine-capped CsPbBr₃ PNCs are synthesized initially, and then aqueous-stable pure red emissive PNCs by anion-exchange reaction and subsequently thiocyanate (SCN^-) passivation treatment (SCN-r-PNCs) are prepared. The obtained aqueous-stable SCN-r-PNCs display high brightness, outstanding stability, and extended photoluminescence lifetime. Moreover, by combining aqueous r-PNCs and portable smartphones, a fluorescence chemosensor for the detection of aqueous SCN⁻ ions is constructed, which exhibits simple operation, high sensitivity, high selectivity, low detection limit, and visualized sensing. This work not only provides a new and facile strategy to prepare aqueous-stable red emissive PNCs, but also further extends the application of red emissive PNCs in aqueous-based fields.

Non-destructive in situ scanning transmission electron microscopy reveals a novel atomic fracture behavior in suspended monolayer MoS₂ and MoSe₂, featured by single chalcogen atoms (S or Se) on both crack edges. The out-of-plane deformation, arising from the ultrathin nature of these suspended monolayer films, plays a central role in this fracture process.

Abstract

A comprehensive understanding of atomic fracture mechanisms in 2D materials is essential for their practical applications, yet this knowledge is currently limited. To address this gap, an aberration-corrected scanning transmission electron microscope (STEM) to induce new cracks in suspended monolayer transition metal dichalcogenides (TMDs) using broad electron beam illumination, is employed. During characterization, a low-dose electron beam to avoid irradiation damage, allowing to observe the atomic fracture behavior in these materials, is utilized. The STEM experiments reveal a novel atomic fracture pattern along the zigzag direction, resulting in a distribution where half of the chalcogen atoms (S or Se) adhered to the molybdenum-terminated (Mo-T) edge and the other half to the chalcogen-terminated (S-T or Se-T) edge. Density functional theory (DFT) calculations suggest that this fracture mode produces a pair of edges with the lowest formation energy. Additionally, molecular dynamics (MD) simulations support the observed fracture behavior under a mixed mechanical loading mode of “I+III” with both in-plane and out-of-plane stress, originating from the ultrathin nature and nonplanar deformation in suspended 2D materials. This research offers new insights for the development of 2D fracture mechanics and is pivotal for designing devices incorporating 2D materials.

The proposed bioinspired nanocomposite adhesive structure, with a “suction cup-shaped” tip and the ability to regulate the structural modulus, enables strong and contamination-free adhesion (>350 kPa) with high adhesive efficiency (up to 77.7) in a wide temperature range (from room temperature to high temperatures (>200 °C)), opening an avenue for the development of devices and systems based on dry adhesives.

Abstract

Bioinspired structural adhesives have shown great potential in the field of industrial manipulation and locomotion. However, such adhesives usually perform great adhesion performance at room temperature, reliable adhesion under high-temperature conditions remains a major challenge and is rarely investigated, which severely limits the applications of current bioinspired adhesives. Here, a bioinspired adhesive structure based on fluororubber (FKM) and nanofillers is proposed. The adhesive structure has a “suction cup-shaped” tip that mimics the special structural configuration of the adhesive setae of Dytiscus lapponicus, and the ability to regulate the structural modulus by adjusting the content of nanofillers, as well as exhibiting strong and contamination-free adhesion (>350 kPa) with high adhesive efficiency (up to 77.7) in a wide temperature range (from room temperature to high temperatures (>200 °C)). Moreover, the adhesion performance can be enhanced by precisely regulating the structural modulus, and the enhancement mechanism is demonstrated based on the cohesive zone theory. The proposed adhesion strategy expands the application areas of dry adhesives from room- to high-temperature conditions, especially for the pick-up and transfer of thin and fragile materials that require high-temperature operation, opening an avenue for the development of devices and systems based on dry adhesives.

A near-field microscopy technique is introduced that resolves and quantifies quasi-bound state in the continuum modes in dielectric metasurfaces. The technique is employed for analyzing metasurface properties such as the finite array size effect, directional coupling, edge effects and defects on the single resonator level promising advancements in metasurface based catalysis and biospectroscopy by optimizing spatial footprint and active area.

Abstract

Photonic metasurfaces offer exceptional control over light at the nanoscale, facilitating applications spanning from biosensing, and nonlinear optics to photocatalysis. Many metasurfaces, especially resonant ones, rely on periodicity for the collective mode to form, which makes them subject to the influences of finite size effects, defects, and edge effects, which have considerable negative impact at the application level. These aspects are especially important for quasi-bound state in the continuum (BIC) metasurfaces, for which the collective mode is highly sensitive to perturbations due to high-quality factors and strong near-field enhancement. Here, the mode formation in quasi-BIC metasurfaces on the individual resonator level using scattering scanning near-field optical microscopy (s-SNOM) in combination with a new image processing technique, is quantitatively investigated. It is found that the quasi-BIC mode is formed at a minimum size of 10 × 10-unit cells much smaller than expected from far-field measurements. Furthermore, it is shown that the coupling direction of the resonators, defects and edge states have pronounced influence on the quasi-BIC mode. This study serves as a link between the far-field and near-field responses of metasurfaces, offering crucial insights for optimizing spatial footprint and active area, holding promise for augmenting applications such as catalysis and biospectroscopy.

In this work, muscle-inspired, formable wood-based phase change materials (PCMs) are fabricated by leveraging the aligned structure of delignified wood and supramolecular networks of polyvinyl alcohol (PVA)/wood composites. The biodegradable PVA/wood composite with solvent-responsive characteristics between wood fibers and PVA chains enables the development of wood-based PCMs with switchable stiffness, making them formable and sustainable for versatile thermal management applications.

Abstract

Phase change materials (PCMs) are crucial for sustainable thermal management in energy-efficient construction and cold chain logistics, as they can store and release renewable thermal energy. However, traditional PCMs suffer from leakage and a loss of formability above their phase change temperatures, limiting their shape stability and versatility. Inspired by the muscle structure, formable PCMs with a hierarchical structure and solvent-responsive supramolecular networks based on polyvinyl alcohol (PVA)/wood composites are developed. The material, in its hydrated state, demonstrates low stiffness and pliability due to the weak hydrogen bonding between aligned wood fibers and PVA molecules. Through treatment of poly(ethylene glycol) (PEG) into the PVA/wood PEG gel (PEG/PVA/W) with strengthened hydrogen bonds, the resulting wood-based PCMs in the hard and melting states elevate the tensile stress from 10.14 to 80.86 MPa and the stiffness from 420 MPa to 4.8 GPa, making it 530 times stiffer than the PEG/PVA counterpart. Capable of morphing in response to solvent changes, these formable PCMs enable intricate designs for thermal management. Furthermore, supported by a comprehensive life cycle assessment, these shape-adaptable, recyclable, and biodegradable PCMs with lower environmental footprint present a sustainable alternative to conventional plastics and thermal management materials.

The rising demand for transformative optical devices derives the importance of optical Fourier surfaces (OFSs) minimizing optical loss of diffraction. To address the current challenges of OFSs regarding scalability and full-color diffraction, an integrative manufacturing strategy is presented for the first realization of scalable and fully transparent OFSs reaching the fundamental diffraction limits at the full-visible regimes.

Abstract

Optical Fourier surfaces (OFSs), characterized by sinusoidally profiled diffractive optical elements, can outperform traditional binary-type counterparts by minimizing optical noise through selectively driving diffraction at desired frequencies. While scanning probe lithography (SPL), gray-scale electron beam lithography (EBL), and holographic inscriptions are effective for fabricating OFSs, achieving full-color diffractions at fundamental efficiency limits is challenging. Here, an integrated manufacturing process is presented, validated theoretically and experimentally, for fully transparent OFSs reaching the fundamental limit of diffraction efficiency. Leveraging holographic inscriptions and soft nanoimprinting, this approach effectively addresses challenges in conventional OFS manufacturing, enabling scalable production of noise-free and maximally efficient OFSs with record-high throughput (10¹⁰–10¹² µm² h⁻¹), surpassing SPL and EBL by 10¹⁰ times. Toward this end, a wafer-scale OFSs array is demonstrated consisting of full-color diffractive gratings, color graphics, and microlenses by the one-step nanoimprinting, which is readily compatible with rapid prototyping of OFSs even on curved panels, demanding for transformative optical devices such as augmented and virtual reality displays.

This study explores the synthesis of Tellurium sulfur oxide (TeSO_x) and Tellurium selenium oxide (TeSeO_x) nanomaterials via vapor deposition, highlighting their unique photo-synaptic responses to different optical stimulations. Further, TeSeO_x multiropes demonstrate their potential in optical neuromorphic computing through enhanced electrical performance and high responsivity achieved with low voltage and light intensity.

Abstract

Nanomaterials like graphene and transition metal dichalcogenides are being explored for developing artificial photosensory synapses with low-power optical plasticity and high retention time for practical nervous system implementation. However, few studies are conducted on Tellurium (Te)-based nanomaterials due to their direct and small bandgaps. This paper reports the superior photo-synaptic properties of covalently bonded Tellurium sulfur oxide (TeSO_x) and Tellurium selenium oxide (TeSeO_x)nanomaterials, which are fabricated by incorporating S and Se atoms on the surface of Te multiropes using vapor deposition. Unlike pure Te multiropes, the TeSO_x and TeSeO_x multiropes exhibit controllable temporal dynamics under optical stimulation. For example, the TeSO_x multirope-based transistor displays a photosensory synaptic response to UV light (λ = 365 nm). Furthermore, the TeSeO_x multirope-based transistor exhibits photosensory synaptic responses to UV–vis light (λ = 365, 565, and 660 nm), reliable electrical performance, and a combination of both photodetector and optical artificial synaptic properties with a maximum responsivity of 1500 AW⁻¹ to 365 nm UV light. This result is among the highest reported for Te-heterostructure-based devices, enabling optical artificial synaptic applications with low voltage spikes (1 V) and low light intensity (21 µW cm⁻²), potentially useful for optical neuromorphic computing.

A bismuth-based ultrathin nanosheet with massive oxygen vacancies is exploited for highly efficient tumor radiotherapy. The exposure of almost all atoms to environmental factors and the nature of oxycarbonates makes the nanosheet easily degrade into biocompatible species without causing any damage to the liver or kidney.

Abstract

Nanomaterials doped with high atom number elements can improve the efficacy of cancer radiotherapy, but their clinical application faces obstacles, such as being difficult to degrade in vivo, or still requiring relatively high radiation dose. In this work, a bismuth oxycarbonate-based ultrathin nanosheet with the thickness of 2.8 nm for safe and efficient tumor radiotherapy under low dose of X-ray irradiation is proposed. The high oxygen content (62.5% at%) and selective exposure of the facets of ultrathin 2D nanostrusctures facilitate the escape of large amounts of oxygen atoms on bismuth nanosheets from surface, forming massive oxygen vacancies and generating reactive oxygen species that explode under the action of X-rays. Moreover, the exposure of almost all atoms to environmental factors and the nature of oxycarbonates makes the nanosheets easily degrade into biocompatible species. In vivo studies demonstrate that nanosheets could induce apoptosis in cancer cells after low dose of X-ray irradiation without causing any damage to the liver or kidney. The tumor growth inhibition effect of radiotherapy increases from 49.88% to 90.76% with the help of bismuth oxycarbonate nanosheets. This work offers a promising future for nanosheet-based clinical radiotherapies of malignant cancers.

Nature Photonics, Published online: 02 August 2024; doi:10.1038/s41566-024-01481-4

The integration of a single-photon detector array and imaging scanning microscopy in a confocal scanning microscope enables doubling the resolution of single-molecule localization microscopy.

Tools for single-cell manipulation provide the approach to fabricate biological structures with single-cell and heterogeneous features and have advanced new capabilities in both biofabrication and biological applications. This review presents a comprehensive overview of these single-cell technologies with principles and advancements, biological structures through manipulating single cells, and enabled applications with these bioconstructs.

Abstract

Artificial biological structures hold the promise for modeling cellular assembly in vitro and have advanced considerable studies in cell biology, disease modeling, drug testing, and regenerative medicine. Biological functions are derived from micro- and macroscale interactions of various cell types, and a structural property matching the tissue in vivo is required to enable precision biological function. Despite various types of tissues and organs are successfully constructed by conventional biofabrication technologies, they mostly only show a small fraction of structural features found in real tissues. Tools for single-cell manipulation provide the approach to fabricate artificial tissues cell-by-cell, and have enabled the construction of biological structures with single-cell and heterogeneous features, recapitulating the complexity in vivo. This review presents a comprehensive overview of the construction of biological structures through manipulating single cells, covering single-cell technologies with operation principles and main advances, biological structures associated with informative explanations of single-cell manipulation during construction, and representative applications mainly focusing on analysis and modeling. Current challenges and future perspectives in this field are also discussed.

This study visualizes light-induced ferroelectric polarization in an α-In₂Se₃/Te heterojunction using photocurrent mapping. The device shows nonvolatile photoresponsivity with photocurrent enhancement up to 1000 times after polarization saturation. These findings demonstrate the potential of 2D ferroelectric materials for advanced photodetectors and optical information storage applications.

Abstract

Light-induced ferroelectric polarization in 2D layered ferroelectric materials holds promise in photodetectors with multilevel current and reconfigurable capabilities. However, translating this potential into practical applications for high-density optoelectronic information storage remains challenging. In this work, an α-In₂Se₃/Te heterojunction design that demonstrates spatially resolved, multilevel, nonvolatile photoresponsivity is presented. Using photocurrent mapping, the spatially localized light-induced poling state (LIPS) is visualized in the junction region. This localized ferroelectric polarization induced by illumination enables the heterojunction to exhibit enhanced photoresponsivity. Unlike previous reports that observe multilevel polarization enhancement in electrical resistance, the device shows nonvolatile photoresponsivity enhancement under illumination. After polarization saturation, the photocurrent increases up to 1000 times, from 10⁻¹² to 10⁻⁹ A under the irradiation of a 520 nm laser with a power of 1.69 nW, compared to the initial state in a self-driven mode. The photodetector exhibits high detectivity of 4.6×10¹⁰ Jones, with a rise time of 27 µs and a fall time of 28 µs. Furthermore, the device's localized poling characteristics and multilevel photoresponse enable spatially multiplexed optical information storage. These results advance the understanding of LIPS in 2D ferroelectric materials, paving the way for optoelectronic information storage technologies.

Nature Communications, Published online: 01 August 2024; doi:10.1038/s41467-024-50845-5

Author Correction: Engineering programmable material-to-cell pathways via synthetic notch receptors to spatially control differentiation in multicellular constructs