Jing Zhang

The retainable enhancement of upconversion (UC) emission is achieved in the erbium oxyfluoride by local symmetry breaking with the pressure engineering. The integral intensity of UC emission of pressure-treated sample increases to more than twice the intensity of its pristine state, and further to 5.1-fold enhancement by defects relieving through heating at low temperature.

Abstract

Pressure-induced performance enhancement of a given material is an emerging phenomenon, however, among the various known examples very few enhanced properties can retain to ambient conditions. Both new structural mechanism and new material systems are the key challenge to achieve recoverable properties via pressure treatment. Herein, an “Er-rich” erbium oxyfluoride ErOF is reported with retainable enhanced upconversion (UC) emission by high pressure treatment. The UC emission increases to more than twice the intensity of its pristine state, and followed by additional improvement to 5.1-fold increase by heat treatment at 100 °C. The site symmetry breaking of Er³⁺ ions along with the crystal phase transition from R3¯$\bar{3}$m to Pnma, revealed by X-ray diffraction, is believed to be the underlying reasons for the enhanced UC emission after release. Further, high-resolution transmission electron microscopy (HRTEM) study reveals that the defects relieved with heat treatment might account for the UC emission enhancement in the released sample. Time-resolved spectra and I-P curves are measured comparatively to further illustrate the intrinsic mechanism of UC processes. The findings open up a window to advance UC performance through structure optimization by pressure engineering, thus facilitating its potential applications under ambient conditions.

In-plane selective area epitaxy is a promising technique for achieving large-scale nanowire photodetectors. Here it is experimentally demonstrated that the high-performance InAsSb nanowire network photodetectors have a low dark current density (≤2 mA cm⁻²) and a wide spectral response (1200–1650 nm) at room temperature. The stable and rapid photoresponse (75.3 µs) shows their potential for applications in Si photonics.

Abstract

CMOS-compatible III–V semiconductor nanowire infrared photodetectors have attracted extensive research interest in various fields such as Si photonics and gas sensors. However, the traditional vertical configuration of nanowires limits their applications at the circuit level. Here, an in-plane selective area epitaxy route is developed to grow large-scale InAsSb nanowire networks on patterned Si substrates. By precisely tuning the growth parameters, the well-aligned InAsSb nanowire networks with good selectivity are successfully achieved. Detailed structural studies confirm that there is a sharp interface between the InAsSb nanowire and the substrate. On the basis of optoelectronic measurements, it is confirmed that the fabricated InAsSb nanowire network photodetectors exhibit a low dark current density (≤2 mA cm⁻²) and a wide spectral response (1200–1650 nm) at room temperature, covering the important telecommunication bands. Moreover, these devices present a high on-off ratio, large responsivity, high detectivity, and rapid response speed at zero bias voltage. At the illumination wavelength of 1200 nm, the on-off ratio, responsivity, detectivity, and response time of a double nanowire networks photodetector can reach 2680, 286.9 mA W⁻¹, 1.4 × 10¹⁰ Jones and 75.3 µs, respectively. This work offers a straightforward approach to in situ fabricating high-performance scalable nanowire photodetectors.

An exchange bias effect at an all-antiferromagnetic polycrystalline heterointerface is observed. The chiral antiferromagnet Mn₃Sn works as the active layer, replacing conventional ferromagnets. The unidirectional magnetic anisotropy can be determined omnidirectionally due to the absence of the shape anisotropy. These findings are significant for developing various antiferromagnetic spintronic devices, including antiferromagnetic tunnel junctions, essential for ultrafast and ultra-power-efficient computing.

Abstract

Due to promising functionalities that may dramatically enhance spintronics performance, antiferromagnets are the subject of intensive research for developing the next-generation active elements to replace ferromagnets. In particular, the recent experimental demonstration of tunneling magnetoresistance and electrical switching using chiral antiferromagnets has sparked expectations for the practical integration of antiferromagnetic materials into device architectures. To further develop the technology to manipulate the magnetic anisotropies in all-antiferromagnetic devices, it is essential to realize exchange bias through the interface between antiferromagnetic multilayers. Here, the first observation on the omnidirectional exchange bias at an all-antiferromagnetic polycrystalline heterointerface is reported. This experiment demonstrates that the interfacial energy causing the exchange bias between the chiral-antiferromagnet Mn₃Sn/collinear-antiferromagnet MnN layers is comparable to those found at the conventional ferromagnet/antiferromagnet interface at room temperature. In sharp contrast with previous reports using ferromagnets, the magnetic field control of the unidirectional anisotropy is found to be omnidirectional due to the absence of the shape anisotropy in the antiferromagnetic multilayer. The realization of the omnidirectional exchange bias at the interface between polycrystalline antiferromagnets on amorphous templates, highly compatible with existing Si-based devices, paves the way for developing ultra-low power and ultra-high speed memory devices based on antiferromagnets.

A high-quality gate stack (native HfO₂ on 2D HfSe₂) is proposed for future low-power computing applications. The proposed gate stack exhibits atomically sharp interface with suppressed gate leakage ensuring ideal operation (subthreshold slope (SS) ≈ 60 mV dec⁻¹). Furthermore, steep-switching operation (SS ≈ 3.43 mV dec⁻¹) overcoming the fundamental Boltzmann limit is demonstrated at room temperature with gated-region-controlled structure.

Abstract

Herein, a high-quality gate stack (native HfO₂ formed on 2D HfSe₂) fabricated via plasma oxidation is reported, realizing an atomically sharp interface with a suppressed interface trap density (D _it ≈ 5 × 10¹⁰ cm⁻² eV⁻¹). The chemically converted HfO₂ exhibits dielectric constant, κ ≈ 23, resulting in low gate leakage current (≈10⁻³ A cm⁻²) at equivalent oxide thickness ≈0.5 nm. Density functional calculations indicate that the atomistic mechanism for achieving a high-quality interface is the possibility of O atoms replacing the Se atoms of the interfacial HfSe₂ layer without a substitution energy barrier, allowing layer-by-layer oxidation to proceed. The field-effect-transistor-fabricated HfO₂/HfSe₂ gate stack demonstrates an almost ideal subthreshold slope (SS) of ≈61 mV dec⁻¹ (over four orders of I _DS) at room temperature (300 K), along with a high I _on/I _off ratio of ≈10⁸ and a small hysteresis of ≈10 mV. Furthermore, by utilizing a device architecture with separately controlled HfO₂/HfSe₂ gate stack and channel structures, an impact ionization field-effect transistor is fabricated that exhibits n-type steep-switching characteristics with a SS value of 3.43 mV dec⁻¹ at room temperature, overcoming the Boltzmann limit. These results provide a significant step toward the realization of post-Si semiconducting devices for future energy-efficient data-centric computing electronics.

Subnano-scale TiO₂-DNA (SNTD) can be applied as a new DNA-based sub-nanomedicine for anti-inflammation and accelerating infected wound healing with high efficiency, biostability, and biosafety. SNTD can positively recruit H₂O₂ owing to its subnano-scale thickness, and further enhance the ROS-scavenging efficiency of DNA.

Abstract

Oxidative stress (OS) resulting from excessive reactive oxygen species (ROS) is the initial pathogenesis of many diseases, thus various pharmaceutical materials are explored to scavenge ROS. However, the medical applications of most ROS-scavenging materials are limited due to side effects and low bio-stability. DNA has emerged as a promising ROS-scavenging material with excellent biosafety and programmability, but the efficiency needs to be improved by developing new fabrication methods. Here, a sub-nanoscale TiO₂ composite modified with DNA with excellent biostability, biocompatibility, and enhanced ROS-scavenging efficiency for medical applications is presented. The sub-nanoscale TiO₂-DNA (SNTD) composite exhibits higher scavenging capacities for multiple ROS including ·OH, H₂O₂, and O₂ ^•−. Additionally, it can regulate macrophages from pro-inflammatory to anti-inflammatory phenotype. In vivo experiments show that the nanocomposites reduce ROS concentration, decrease inflammatory cell infiltration, accelerate re-epithelization, and promote collagen regeneration, thereby enhancing the healing of infected skin wounds.

A series of Rh-lanthanides intermetallics (Rh₃Ln IMs) is synthesized using the sodium vapor reduction method. Benefiting from the upshift of the d-band center and electron transfer from Ln to Rh introduced by alloying, the adsorption and dissociation of H₂O molecules are optimized, and Rh₃Tb IM exhibits outstanding hydrogen evolution reaction activity in both alkaline environments and seawater.

Abstract

Design of highly efficient electrocatalysts for alkaline hydrogen evolution reaction (HER) is of paramount importance for water electrolysis, but still a considerable challenge because of the slow HER kinetics in alkaline environments. Alloying is recognized as an effective strategy to enhance the catalytic properties. Lanthanides (Ln) are recognized as an electronic and structural regulator, attributed to their unique 4f electron behavior and the phenomenon known as lanthanide contraction. Here, a new class of Rh₃Ln intermetallics (IMs) are synthesized using the sodium vapor reduction method. The alloying process induced an upshift of the d-band center and electron transfer from Ln to Rh, resulting in optimized adsorption and dissociation energies for H₂O molecules. Consequently, Rh₃Tb IMs exhibited outstanding HER activity in both alkaline environments and seawater, displaying an overpotential of only 19 mV at 10 mA cm⁻² and a Tafel slope of 22.2 mV dec⁻¹. Remarkably, the current density of Rh₃Tb IMs at 100 mV overpotential is 8.6 and 5.7 times higher than that of Rh/C and commercial Pt/C, respectively. This work introduces a novel approach to the rational design of HER electrocatalysis and sheds light on the role of lanthanides in electrocatalyst systems.

InP/ZnS quantum dots (QDs) can be relevant for in vivo platelet imaging. It shows that careful selection of QD phase transfer agent is critical to maintaining platelet function. These results indicate that platelet-QD interaction can occur across a wide range of concentrations. It can image the platelet-QD interaction via FLIM, and use platelet functional assays to monitor platelet activation.

Abstract

InP/ZnS quantum dots (QDs) have received a large focus in recent years as a safer alternative to heavy metal-based QDs. Given their intrinsic fluorescent imaging capabilities, these QDs can be potentially relevant for in vivo platelet imaging. The InP/ZnS QDs are synthesized and their biocompatibility investigated through the use of different phase transfer agents. Analysis of platelet function indicates that platelet-QD interaction can occur at all concentrations and for all QD permutations tested. However, as the QD concentration increases, platelet aggregation is induced by QDs alone independent of natural platelet agonists. This study helps to define a range of concentrations and coatings (thioglycolic acid and penicillamine) that are biocompatible with platelet function. With this information, the platelet-QD interaction can be identified using multiple methods. Fluorescent lifetime imaging microscopy (FLIM) and confocal studies have shown QDs localize on the surface of the platelet toward the center while showing evidence of energy transfer within the QD population. It is believed that these findings are an important stepping point for the development of fluorescent probes for platelet imaging.

Upon heating, symmetry reduction around Eu³⁺ site caused by anisotropic contraction of MIL-68-In framework and Boltzmann population between ⁷F₀ and ⁷F₁ levels of Eu³⁺, together lead to thermally enhanced luminescence. Further modulation of Eu³⁺ concentration in MIL-68-In/Eu allows modulation of thermal-responsive emissions toward advanced information encryption.

Abstract

Applications of luminescence at high temperature such as high-power lighting, lasing, thermophotovoltaics, and photonic coding, are severely prevented due to the notorious thermal quenching (TQ). Although anti-TQ luminescence (anti-TQL) is reported using highly oxygen-coordinated solid-state oxide as host in virtue of the rigid skeleton that resists lattice vibration at elevated temperatures, it is meaningful to extend anti-TQL to other hosts. Herein, taking advantage of the ligand-metal antenna effect and the negative thermal expansion feature of Eu³⁺ doped MIL-68-In (MIL-68-In/xEu), adjustable anti-TQL is realized for the first time, that is, anti-TQ, zero-TQ, and TQ at x = 5%, 10%, and 50%, respectively. Therefore, except for added novel mechanisms, this work has also expanded the hosts available for high-temperature luminescence and enabled advanced photonic coding in terms of facial synthesis, rich information, and visual changes of emission intensity instead of device-dependent analogous.

This work unveils SPLASH, a cutting-edge Spectrally Programmable Liquid-State Active System facilitating White Light Fluorescence, White Light Hybrid-Emission, and multicolor tunability. With its remarkable phase separation, compact design, and precise spectral control, SPLASH promises revolutionary advancements in the fluidlike environment for lighting technology and the Li-Fi concept. This study underscores the potential of color adjustment, wireless communication, and laser displays.

Abstract

The development of a Spectrally Programmable Liquid-State Active System for High-performance (SPLASH) is introduced, which allows for multicolor lasing and White Emission. This completely liquid, three-phase device showcases exceptional tunability within a singular Liquid Crystal Cell (LCC). Components include a Coumarin 540 (CM540)-doped liquid crystal (LC) mesophase, an ionic liquid (RTIL) richly endowed with Rhodamine 6G (R6G) dye, and a Stilbene 420 (SB420)-infused water-based solution. This device displays significant accomplishments in multicolor tunability through the use of both lasing and fluorescence mechanisms. As a result, White Light Fluorescence (WFluo) and White Light Hybrid-Emission (WHE) are showed, which consist of two lasing bands and one fluorescence. This is achieved in a liquid-state environment characterized by phase separation and careful device management. Additionally, due to its fluid-like nature and compact design, the device inherently offers considerable scalability — since its components can be easily adjusted and rearranged. This approach promises ground-breaking advancements in high-impact applications such as the Li-Fi concept. Therefore, SPLASH stands out as an innovative platform for White Light Fluorescence (WFluo) and Multicolor Lasing (ML) within liquid-state active systems.

The pioneering approach in the multi-layered epitaxial growth of perovskite oxides culminates in the advanced double-level double-gate FETs (DL DG-FETs), which exhibit enhanced electrical performance over bottom-gate FETs. This innovation not only showcases the versatility of perovskite oxides but also broadens the potential for integration with other perovskite materials, promising more sophisticated electronic functionalities.

Abstract

Perovskite oxide semiconductor is unique for its capability to form epitaxial heterostructures with both dielectric and metallic perovskite oxides. The study underscores the potential of perovskite oxides for multi-layer stacking, a key aspect in advancing semiconductor technology as silicon-based devices evolve toward 3D stacked structures. Fabrication of the first double-level double-gate field-effect transistors (DL DG-FETs) is demonstrated, where each layer is epitaxially grown using all-perovskite oxides. This resulted in improvements in subthreshold swing, current drivability, and field effect mobility. This innovation not only highlights the distinctive potential of perovskite oxides but also provides new avenues for integration with other perovskite oxides on Si for more advanced electronic functions.

A highly flexible and adaptive triboelectric vibration sensor with conductive sponge-silicone is proposed. It can work even when the detection point of the mechanical equipment is curved and can transmit vibration signal to mobile phone application for real-time monitoring, which will greatly accelerate the development of wireless sensor networks and provide sustainable energy solutions for smart sensing systems.

Abstract

Vibration sensors for continuous and reliable condition monitoring of mechanical equipment, especially detection points of curved surfaces, remain a great challenge and are highly desired. Herein, a highly flexible and adaptive triboelectric vibration sensor for high-fidelity and continuous monitoring of mechanical vibration conditions is proposed. The sensor is entirely composed of flexible materials. It consists of a conductive sponge-silicone layer and a fluorinated ethylene propylene film. It can detect vibration acceleration of 5 to 50 m s⁻² and vibration frequency of 10 to 100 Hz. It has strong robustness and stability, and the output performance barely changes after the durability test of 168 000 working cycles. Additionally, the flexible sensor can work even when the detection point of the mechanical equipment is curved, and the linear fit of the output voltage and acceleration is very close to that when the detection point is flat. Finally, it can be applied to monitoring the working condition of blower and vehicle engine, and can transmit vibration signal to mobile phone application through Wi-Fi module for real-time monitoring. The flexible triboelectric vibration sensor is expected to provide a practical paradigm for smart, green, and sustainable wireless sensor system in the era of Internet of Things.

Nature Materials, Published online: 21 March 2024; doi:10.1038/s41563-024-01831-1

Electrocaloric effects are large in a limited set of materials that display hysteretic first-order phase transitions. Here epitaxial SrTiO3 thin films are strain engineered to achieve anhysteretic second-order phase transitions, with electrocaloric effects enhanced by one order of magnitude over bulk.

Self-Sustained Programmable Hygroelectronic Interfaces

In article number 2208081, Yaoxin Zhang, John Wang, Swee Ching Tan, and co-workers report an intelligent and programmable moisture-driven energy generating platform for humidity-regulated information encryption and display. This is enabled by asymmetric coating of ionic hygroscopic hydrogels on a carbon black nano-surface. Further tuning the hydrogel's deliquescence to relative humidity, the device is able to conceal and reveal information hierarchically in various relative humidity ranges.

Using a polyoxometalate-encapsulated hydrophilic multichannel lanthanide-based nanoprobe, the depth of a tumor can be evaluated through fluorescence imaging. The probe enables tunable release of a heat shock protein inhibitor to enhance thermal sensitivity of tumors for customized photothermal therapy. An optimized nonuniform light field enables efficient ablation of tumors at different subcutaneous depths while minimizing injury to surrounding tissues.

Abstract

The photothermal therapeutic effect on tumors located at different subcutaneous depths varies due to the attenuation of light by tissue. Here, based on the wavelength-dependent optical attenuation properties of tissues, the tumor depth is assessed using a multichannel lanthanide nanocomposite. A zeolitic imidazolate framework (ZIF-8)-coated nanocomposite is able to deliver high amounts of the hydrophilic heat shock protein 90 inhibitor epigallocatechin gallate through a hydrogen-bonding network formed by the encapsulated highly polarized polyoxometalate guest. It is superior to both bare and PEGylated ZIF-8 for drug delivery. With the assessment of tumor depth and accumulated amount of nanocomposite by fluorescence, an irradiation prescription can be customized to release sufficient HSP90 inhibitor and generate heat for sensitized photothermal treatment of tumors, which not only ensured therapeutic efficacy but also minimized damage to the surrounding tissues.

Nature, Published online: 20 March 2024; doi:10.1038/s41586-024-07097-6

A local driving mechanism for solitons that accelerates both solitons and antisolitons in the same direction, called non-reciprocal driving, is introduced, showing a subtle interplay between non-reciprocity and topological solitons and providing waveguiding and wave-processing possibilities for other fields.

Nature, Published online: 20 March 2024; doi:10.1038/s41586-024-07214-5

Transport evidence of a fractional quantum spin Hall insulator is reported in 2.1°-twisted bilayer MoTe2, which supports spin-Sz conservation and flat spin-contrasting Chern bands.

Nature, Published online: 20 March 2024; doi:10.1038/s41586-024-07131-7

Wafer-scale realization of a nanoscale magnetic tunnel junction hosting a single, ambient skyrmion enables its large readout, efficient switching, and compatibility with lateral manipulation, and thereby provides the backbone for all-electrical skyrmionic device architectures.

Nature Electronics, Published online: 20 March 2024; doi:10.1038/s41928-024-01145-9

Interface electronics using 28-nm node CMOS

The polymer optical fiber based on the temperature-dependent fluorescence of NaLaTi₂O₆:Yb/Er phosphors is inserted into a pouch-type battery, and the continuous temperature variations are instantly obtained to deduce the immediate internal circumstances. The real-time and in situ thermal evolution inside the battery can be stably transmitted by the optical fiber without hindering the normal operation.

Abstract

Thermal characteristics are essential for improving the performance and monitoring the status of Li-ion batteries (LIBs). However, it is a challenge to design efficient and facile sensing materials for the detection of the in situ temperature of a working LIB. Herein, a ratiometric fluorescence optical fiber is developed and real-time temperature monitoring is performed with a measurement accuracy of 0.12 °C, and the feasibility based on this polymer optical fiber composed of NaLaTi₂O₆:Yb/Er phosphors is verified in a pouch-type battery. During the charging and discharging cycles, the in situ temperature is instantaneously conveyed, revealing the internal situation of LIBs. This article further dwells on the thermal characteristics in constant current (CC)/constant voltage charging and CC discharging processes at different C-rates and the battery failure when operated at low temperatures (0 °C). This work demonstrates an innovative strategy for operando solitary temperature monitoring conducted by ratiometric fluorescence optical fiber.

The method of salt-assisted vapor–liquid–solid (VLS) growth is introduced to synthesize 1D nanostructures of trichalcogenide van der Waals (vdW) materials, exemplified by niobium trisulfide (NbS₃). The method uses a unique catalyst consisting of an alloy of Au and an alkali metal halide (NaCl) to enable rapid and directional growth.

Abstract

The method of salt-assisted vapor–liquid–solid (VLS) growth is introduced to synthesize 1D nanostructures of trichalcogenide van der Waals (vdW) materials, exemplified by niobium trisulfide (NbS₃). The method uses a unique catalyst consisting of an alloy of Au and an alkali metal halide (NaCl) to enable rapid and directional growth. High yields of two types of NbS₃ 1D nanostructures, nanowires and nanoribbons, each with sub-ten nanometer diameter, tens of micrometers length, and distinct 1D morphology and growth orientation are demonstrated. Strategies to control the location, size, and morphology of growth, and extend the growth method to synthesize other transition metal trichalcogenides, NbSe₃ and TiS₃, as nanowires are demonstrated. Finally, the role of the Au–NaCl alloy catalyst in guiding VLS synthesis is described and the growth mechanism based on the relationships measured between structure (growth orientation, morphology, and dimensions) and growth conditions (catalyst volume and growth time) is discussed. These results introduce opportunities to expand the library of emerging 1D vdW materials to make use of their unique properties through controlled growth at nanoscale dimensions.

Non-volatile floating-gate memory devices with all functional layers made of 2D materials with atomically sharp interface, including MoS₂ channel layer, hBN tunnel layer, multilayer graphene (MLG) floating-gate layer, hBN block layer and MLG control gate layer, can be ultrafastly programmed/erased in ≈20 ns with high extinction ratios (up to 10⁸) and long-term retention characteristics.

Abstract

The explosive growth of massive-data storage and the demand for ultrafast data processing require innovative memory devices with exceptional performance. 2D materials and their van der Waal heterostructures with atomically sharp interfaces hold great promise for innovations in memory devices. Here, this work presents non-volatile, floating-gate memory devices with all functional layers made of 2D materials, achieving ultrafast programming/erasing speeds (20 ns), high extinction ratios (up to 10⁸), and multi-bit storage capability. These devices also exhibit long-term data retention exceeding 10 years, facilitated by a high gate-coupling ratio (GCR) and atomically sharp interfaces between functional layers. Additionally, this work demonstrates the realization of an “OR” logic gate on a single-device unit by synergistic electrical and optical operations. The present results provide a solid foundation for next-generation ultrahigh-speed, ultralong lifespan, non-volatile memory devices, with a potential for scale-up manufacturing and flexible electronics applications.

The successful synthesis of highly crystalline 2D FeCr₂S₄ in 2D form with pure cubic spinel structure, which exhibits perpendicular magnetic anisotropy, thickness independent of T _C and excellent air stability. The work promotes further exploration of the fundamental aspects of 2D magnets, and paves the way for the application of the 2D robust ferrimagnetic material in multiferroic and spintronic devices.

Abstract

The discovery of intrinsic 2D magnetic materials has opened up new opportunities for exploring magnetic properties at atomic layer thicknesses, presenting potential applications in spintronic devices. Here a new 2D ferrimagnetic crystal of nonlayered FeCr₂S₄ is synthesized with high phase purity using chemical vapor deposition. The obtained 2D FeCr₂S₄ exhibits perpendicular magnetic anisotropy, as evidenced by the out-of-plane/in-plane Hall effect and anisotropic magnetoresistance. Theoretical calculations further elucidate that the observed magnetic anisotropy can be attributed to its surface termination structure. By combining temperature-dependent magneto-transport and polarized Raman spectroscopy characterizations, it is discovered that both the measured Curie temperature and the critical temperature at which a low energy magnon peak disappeared remains constant, regardless of its thickness. Magnetic force microscopy measurements show the flipping process of magnetic domains. The exceptional air-stability of the 2D FeCr₂S₄ is also confirmed via Raman spectroscopy and Hall hysteresis loops. The robust anisotropic ferrimagnetism, the thickness-independent of Curie temperature, coupled with excellent air-stability, make 2D FeCr₂S₄ crystals highly attractive for future spintronic devices.

Protein nanostructures, spanning zero to three dimensions, are effectively engineered utilizing fundamental strategies such as computational design, self-assembly induction, template introduction, complexation induction, chemical modification, and in vivo assembly. Exploiting the flexibility of nanoarchitecture along with the unique biological attributes of proteins, these nanostructures showcase considerable potential for a plethora of applications.

Abstract

Controllable protein nanoarchitectonics refers to the process of manipulating and controlling the assembly of proteins at the nanoscale to achieve domain-limited and accurate spatial arrangement. In nature, many proteins undergo precise self-assembly with other structural domains to engage in synergistic physiological activities. Protein nanomaterials prepared through protein nanosizing have received considerable attention due to their excellent biocompatibility, low toxicity, modifiability, and versatility. This review focuses on the fundamental strategies used for controllable protein nanoarchitectinics, which include computational design, self-assembly induction, template introduction, complexation induction, chemical modification, and in vivo assembly. Precise controlling of the nanosizing process has enabled the creation of protein nanostructures with different dimensions, including 0D spherical oligomers, 1D nanowires, nanorings, and nanotubes, as well as 2D nanofilms, and 3D protein nanocages. The unique biological properties of proteins hold promise for diverse applications of these protein nanomaterials, including in biomedicine, the food industry, agriculture, biosensing, environmental protection, biocatalysis, and artificial light harvesting. Protein nanosizing is a powerful tool for developing biomaterials with advanced structures and functions.

This review systematically summarized the state of the art of 2D transition metal dichalcogenides (TMDCs) in photovoltaic solar cell. The energy diagram, 2D TMDCs-based homojunction, heterojunction and Schottky-junction as well as their multi-field tunability are systematically summarized and discussed. The role of 2D TMDCs layer as functional layer in silicon-, perovskite- and organic-based photovoltaic solar cells is summarized. Finally, the current challenges and future perspectives are presented.

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have gained much attention due to their excellent electronic and optoelectronic properties. The reasonable band gap, higher light-matter interaction, hundreds of categories as well as wafer-scale growth and Si-compatible fabrication etc. proof their immense potential for next-generation solar cells. Over the past years, a variety of specific device structure are investigated including multi-field tunable 2D TMDCs-based photovoltaic solar cell since its electronic structure is easily tunable. Their work function distributes in a wide range which facilitate interfacial modulation and optimize the electron/hole transfer layer in perovskite-/organic-based photovoltaic solar cell. In this review, the recent developments of TMDCs in photovoltaic solar cell are comprehensively described. First, the energy diagram of traditional semiconductor and 2D TDMCs are discussed. Then, 2D TMDCs-based photovoltaic solar cell is introduced considering the homojunction, heterojunction and Schottky-junction as well as their multi-field tunability. Third, the role of 2D TMDCs layer as photosensitive layer and modifying layer in silicon-based solar cells, as well as their applications in perovskite-/organic-based solar cells are summarized considering their role of electron/hole transfer layer or active layer. Lastly, the prospect for future materials, device and process trends and practical applications of TMDCs-based photovoltaic solar cell are presented.

A gradient-strained van der Waals (vdWs) heterojunction based on ZnO/WSe₂/graphene is constructed by controlling the height of ZnO nanorods. Impressively, as the strain increases by 2.7%, the external quantum efficiency of the heterojunction triples. This confirms that strain can effectively modulate the behavior of carriers, which provides a new direction for the design of next-generation vdWs heterojunction photodetectors.

Abstract

Maximizing light-to-electricity conversion efficiency is a crucial challenge for the practical applications of 2D material photodetectors. However, due to the lack of stable and precise electronic structure control methods for 2D materials, the driving force of photogenerated carriers is insufficient that severely hinders the efficiency of separation and transport. Herein, a gradient-modulated, stable and precise strain applied strategy for 2D materials is designed and constructed, which results in a significant improvement in the detect efficiency of ZnO/WSe₂/graphene van der Waals heterojunction photodetectors. Different from the overall strain of all-component materials in typical photodetectors, biaxial tensile strain is applied to WSe₂ that can be precisely modulated by controlling the height of ZnO nanorods, while the strain is nearly unaffected to ZnO. As the strain modulation increases from 1.3% to 4.0%, the external quantum efficiency (EQE) of the heterojunction increases from 11.4% to 35.3%, representing a threefold increase. Furthermore, with increasing strain, the EQE can reach higher levels. Moreover, the strain-enhanced conversion efficiency mechanism is elucidated that results from the synergistic effect of the strain-induced WSe₂ exciton convergence and the strain-increased ZnO/WSe₂ interface barrier, which enhances the carrier interface separation efficiency.

The fast interface charge transfer and the extension of the π-conjugated electron cloud are utilized to significantly enhance the electrical conductivity and the nonlinear optical properties of the 2D conjugated Ni₃(HITP)₂ metal-organic framework (MOF) and graphene π–π stacked vertical heterostructures. Furthermore, the potential of Ni₃(HITP)₂/graphene vertical heterostructures for generating diverse mode-locked fiber laser pulse output has been investigated.

Abstract

2D conjugated metal-organic frameworks (MOFs) with high in-plane-π-conjugation are attracting significant attention in various fields owing to their outstanding electrical transport property, substantial specific surface areas, and tunable structures. However, their potential in ultrafast photonics has not been extensively explored. Herein, 2D conjugated Ni₃(HITP)₂ metal-organic framework (MOF) and graphene (GR) π–π stacked vertical heterostructures (NG-VHS) are synthesized using an ultrasound-assisted method. Based on theoretical simulations and characterization analyses, the results suggest that the fast interface charge transfer and the extension of the π-conjugated electron cloud will significantly enhance the electrical conductivity and the nonlinear optical properties, which is attributed to the π–π stacking interactions between Ni₃(HITP)₂ and GR. The charge transfer rate of NG-VHS is given by 6.9 × 10¹¹ s⁻¹. Noticeably, NG-VHS can serve as an excellent saturable absorber (SA) that can achieve fundamental mode-locking with a pulse width of 451 fs, harmonic mode-locking with repetition frequencies up to 1.205 GHz, and tunable dual-wavelength mode-locking. These results indicate the potential of NG-VHS as a promising nonlinear optical material for ultrafast optical applications and a new platform for the design of advanced optoelectronic devices based on 2D conjugated MOFs.

High-performance n-type PbSe thermoelectrics is obtained by stepwise strategy. Pb self-compensation plains the lattice and improves carrier mobility, making the thermoelectric performance enhance near room temperature. Then the introduction of mobile Cu ions inhibits phonon transport and optimizes lattice thermal conductivity, achieving high ZT values at wide-range temperatures. Eventually, a peak ZT of ≈1.8 at 773 K is realized.

Abstract

The coupling relationship between electrical and thermal transports makes it rather challenging to enhance thermoelectric performance. Here, electrical and thermal transports are successfully decoupled to realize high performance in n-type PbSe by utilizing a stepwise strategy. First, the PbSe lattice is plained with extra Pb to compensate for the intrinsic Pb vacancies, which can weaken defect scattering and improve carrier mobility to ≈1230 cm² V⁻¹ s⁻¹. The room-temperature power factor triples and reaches ≈32 µW cm⁻¹ K⁻², and ZT is significantly enhanced to ≈0.6 in Pb_1.006Se. Subsequently, liquid-like interstitial Cu ions are introduced to inhibit heat conduction without damaging electrical transport. While maintaining a high power factor of ≈25 µW cm⁻¹ K⁻², Cu ions strongly suppress phonon transport at high temperature, leading to an ultralow lattice thermal conductivity of ≈0.28 W m⁻¹ K⁻¹ in Pb_1.006Cu_0.006Se, only 30% of the Cu-free PbSe. Eventually, a remarkable peak ZT of ≈1.8 at 773 K is achieved along with a high average ZT of ≈1.1 from 300 to 823 K in Pb_1.006Cu_0.006Se. An outstanding experimental conversion efficiency of ≈7.1% is obtained in the single-leg device, demonstrating great potential for PbSe as low- to mid-temperature thermoelectrics.