Advances of Strategies to Increase the Surface Charge Density of Triboelectric Nanogenerators: A Review.

Triboelectric nanogenerators (TENGs) have manifested a remarkable potential for harvesting environmental energy and have the prospects to be utilized for various uses, for instance, self-powered sensing devices, flexible wearables, and marine corrosion protection. However, the potential for further development of TENGs is restricted on account of their low output power that in turn is determined by their surface charge density. The current review majorly focuses on the selection and optimization of triboelectric materials. Subsequently, various methods capable of enhancing the surface charge density of TENGs, including environmental regulation, charge excitation, charge pumping, electrostatic breakdown, charge trapping, and liquid-solid structure are comprehensively reviewed. Lastly, the review is concluded by highlighting the existing challenges in enhancing the surface charge density of TENGs and exploring potential opportunities for future research endeavors in this area.

MXene-based Materials for Water Splitting: Synthesis and Modification.

With abundant metal site and tunable electronic structure, MXene is considered as a promising electrocatalyst for the conversion of energy molecules. In this review, the latest research progress on inexpensive MXene-based catalysts for water electrolysis is summarized. Typical preparation and modification methods and their advantages and disadvantages are briefly discussed, with a focus on the regulation and design of the surface interface electronic states, which improve the electrocatalytic performance of MXene-based materials. The main strategies for the electronic state modification include end-group modification, heteroatom doping, and heterostructure construction. Some limitations of MXene-based materials, which should be considered in the rational design of advanced MXene-based electrocatalyst, are also discussed. Finally, prospects for the rational design of Mxene-based electrocatalysts is proposed.

Rational Design of Daunorubicin C-14 Hydroxylase Based on the Understanding of Its Substrate-Binding Mechanism.

Doxorubicin is one of the most widely used antitumor drugs and is currently produced via the chemical conversion method, which suffers from high production costs, complex product separation processes, and serious environmental pollution. Biocatalysis is considered a more efficient and environment-friendly method for drug production. The cytochrome daunorubicin C-14 hydroxylase (DoxA) is the essential enzyme catalyzing the conversion of daunorubicin to doxorubicin. Herein, the DoxA from Streptomyces peucetius subsp. caesius ATCC 27952 was expressed in Escherichia coli, and the rational design strategy was further applied to improve the enzyme activity. Eight amino acid residues were identified as the key sites via molecular docking. Using a constructed screening library, we obtained the mutant DoxA(P88Y) with a more rational protein conformation, and a 56% increase in bioconversion efficiency was achieved by the mutant compared to the wild-type DoxA. Molecular dynamics simulation was applied to understand the relationship between the enzyme's structural property and its substrate-binding efficiency. It was demonstrated that the mutant DoxA(P88Y) formed a new hydrophobic interaction with the substrate daunorubicin, which might have enhanced the binding stability and thus improved the catalytic activity. Our work lays a foundation for further exploration of DoxA and facilitates the industrial process of bio-production of doxorubicin.

Core-shell NiS2@C encased by thin carbon layer as high-rate and durable electrode for aqueous rechargeable battery.

Nickel sulfides, as promising candidate for aqueous rechargeable battery, have aroused broad attention on account of abundant natural resources, rich phases, moderate price and high theoretical capacity. Nevertheless, tremendous volume expansion during repeated charging-discharging procedure leads to the poor rate capability and cycling stability of nickel sulfide electrodes. Therefore, in this work, core-shell NiS2@C encapsulated by thin hydrothermal carbon (HC) layer (NiS2@C/HC) has been designed and prepared without any surfactants or templates assistance, which avoid tedious process and shorten preparation cycle greatly. When matched with the treated iron powder (TIP) electrode to form NiS2@C/HC//TIP aqueous rechargeable battery, the NiS2@C/HC//TIP battery exhibits a high discharge capacity of 205.1 mAh g-1 at 1 A g-1, remarkable rate ability (176.4 mAh g-1 at 5 A g-1, about 86% capacity conversation) and superiorly durable stability (80.8 % capacity retention after 10,000 cycles at ultra-high current density of 15 A g-1). The outstanding high-rate capability and cycling stability for aqueous rechargeable battery can be ascribed to the distinct cowpea-like architecture and intrinsic properties of NiS2@C/HC. Specifically, the interior porous carbon provides a space to tolerate the volume expansion of the NiS2 nanoparticles and prevent NiS2 nanoparticles from aggregation, guaranteeing its high-rate capability. Meanwhile, the exterior HC layer is conducive to improve the electric conductivity to facilitate the electrons transfer and promote the mechanical strength of the whole active materials, ensuring its robust cycling stability.

Surface Plasmon Effect Dominated High-Performance Triboelectric Nanogenerator for Traditional Chinese Medicine Acupuncture.

Available, effectively converting low-frequency vibration into available electricity, triboelectric nanogenerator (TENG) is always research hot nowadays. However, the enhancing effect of the existing methods for the output have all sorts of drawbacks, i.e., low efficiency and unstable, and its practical applications still need to be further explored. Here, leveraging core-shell nanoparticles Ag@SiO2 doping into tribo-materials generates the surface plasmon effect to boost the output performance of the TENG. On one hand, the shell alleviated the seepage effect from conventional nanoparticles; on the other hand, the surface plasmon effect enabled the core-shell nanoparticles to further boost the output performance of TENG. We circumvent the limitations and present a TENG whose output power density can be up to 4.375 mW/cm2. Points is that this article novelty investigate the high-performance TENG applicating for traditional Chinese medicine and develop a pratical self-powered acupuncture system. This technology enables rapid, routine regulation of human health at any age, which has potential applications in nearly any setting across healthcare platforms alike.

Oxygen Plasma-Assisted Defect Engineering of Graphene Nanocomposites with Ultrasmall Co3O4 Nanocrystals for Monitoring Toxic Nitrogen Dioxide at Room Temperature.

Functional adjustment of graphene with metal oxide can in fact progress the affectability of graphene-based gas sensors. However, it could be a huge challenge to upgrade the detecting execution of nitrogen dioxide (NO2) sensors at room temperature. The ultrasmall size of nanocrystals (NCs) and copious defects are two key variables for moving forward gas detecting execution. Herein, we provide an effective strategy that the hydrothermal reaction is combined with room-temperature oxygen plasma treatment to prepare Co3O4 NCs and reduced graphene oxide (RGO) nanohybrids (Co3O4-RGO). Among all of Co3O4-RGO nanohybrids, Co3O4-RGO-60 W exhibits the most superior NO2 sensing properties and achieves the low-concentration detection of NO2. The sensitivity of Co3O4-RGO-60 W to 20 ppm NO2 at room temperature is the highest (72.36%). The excellent sensing properties can mainly depend on the change in the microstructure of Co3O4-RGO. Compared with Co3O4-RGO, Co3O4-RGO-60 W with oxygen plasma treatment shows more favorable properties for NO2 adsorption, including the smaller size of Co3O4 NCs, larger specific surface area, pore size, and more oxygen vacancies (OVs). Especially, OVs make the surface of NCs have a unique chemical state, which can increase active sites and improve the adsorption property of NO2. Besides, the agreeable impact of the p-p heterojunction (Co3O4 and RGO) and the doping of N molecule contribute to the improved NO2 detecting properties. It is demonstrated that the Co3O4-RGO-60 W sensor is expected to monitor NO2 at room temperature sensitively.

An Energy Harvester Coupled with a Triboelectric Mechanism and Electrostatic Mechanism for Biomechanical Energy Harvesting.

Energy-harvesting devices based on a single energy conversion mechanism generally have a low output and low conversion efficiency. To solve this problem, an energy harvester coupled with a triboelectric mechanism and electrostatic mechanism for biomechanical energy harvesting is presented. The output performances of the device coupled with a triboelectric mechanism and electrostatic mechanism were systematically studied through principle analysis, simulation, and experimental demonstration. Experiments showed that the output performance of the device was greatly improved by coupling the electrostatic induction mechanisms, and a sustainable and enhanced peak power of approximately 289 µW was produced when the external impedance was 100 MΩ, which gave over a 46-fold enhancement to the conventional single triboelectric conversion mechanism. Moreover, it showed higher resolution for motion states compared with the conventional triboelectric nanogenerator, and can precisely and constantly monitor and distinguish various motion states, including stepping, walking, running, and jumping. Furthermore, it can charge a capacitor of 10 µF to 3 V within 2 min and light up 16 LEDs. On this basis, a self-powered access control system, based on gait recognition, was successfully demonstrated. This work proposes a novel and cost-effective method for biomechanical energy harvesting, which provides a more convenient choice for human motion status monitoring and can be widely used in personnel identification systems.

Boosting Output Performance of Triboelectric Nanogenerator via Mutual Coupling Effects Enabled Photon-Carriers and Plasmon.

Boosting the output performance of triboelectric nanogenerators via some unique methods is always a meaningful way to speed up their commercialization. However, the available approach to boost performance is mainly restricted to one physics effect based and the basic research of boosting performance via mutual coupling effects is little research. Herein, a new strategy is creatively proposed based on charge traps from mutual coupling effects, generated from g-C3 N4 /MXene-Au composites, to further promote the output performance of triboelectric nanogenerator. It is found that photon-generated carriers coupling surface plasmon effect enables composites filled into tribo-material with visible light is an excellent value in boosting performance. The charge traps from mutual coupling effects for boosting performance are analyzed theoretically and verified by experiments. The output power of boosting-triboelectric nanogenerator (TENG) achieves a sixfold enhancement (20 mW) of normal TENG with polydimethylsiloxane (PDMS) in ambient conditions. This work provides a profound understanding of the working mechanism of mutual coupling effects boosting the performance of TENG and an effective way for promoting TENG output.

Er81 Transcription Factor Fine-Tunes Striatal Cholinergic Interneuron Activity and Drives Habit Formation.

The molecular mechanisms tuning cholinergic interneuron (CIN) activity, although crucial for striatal function and behavior, remain largely unexplored. Previous studies report that the Etv1/Er81 transcription factor is vital for regulating neuronal maturation and activity. While Er81 is known to be expressed in the striatum during development, its specific role in defining CIN properties and the resulting consequences on striatal function is unknown. We report here that Er81 is expressed in CINs and its specific ablation leads to prominent changes in their molecular, morphologic, and electrophysiological features. In particular, the lack of Er81 amplifies intrinsic delayed-rectifier and hyperpolarization-activated currents, which subsequently alters the tonic and phasic activity of CINs. We further reveal that Er81 expression is required for normal CIN pause and time-locked responses to sensorimotor inputs in awake mice. Overall, this study uncovers a new cell type-specific control of CIN function in the striatum which drives habit formation in adult male mice.SIGNIFICANCE STATEMENT Although previous studies have shown that cholinergic interneurons drive striatal activity and habit formation, the underlying molecular mechanisms controlling their function are unknown. Here we reveal that key cholinergic interneuron physiological properties are controlled by Er81, a transcription factor regulating neuronal activity and development in a cell-specific manner. Moreover, our findings uncover a link between the Er81-dependent molecular control of cholinergic interneuron function and habit formation in mice. These insights will contribute to the future enhancement of our understanding of disorders that involve behavioral inflexibility, such as autism and addiction.

A Nonresonant Hybridized Electromagnetic-Triboelectric Nanogenerator for Irregular and Ultralow Frequency Blue Energy Harvesting.

As a promising renewable energy source, it is a challenging task to obtain blue energy, which is irregular and has an ultralow frequency, due to the limitation of technology. Herein, a nonresonant hybridized electromagnetic-triboelectric nanogenerator was presented to efficiently obtain the ultralow frequency energy. The instrument adopted the flexible pendulum structure with a precise design and combined the working principle of electromagnetism and triboelectricity to realize the all-directional vibration energy acquisition successfully. The results confirmed that the triboelectric nanogenerator (TENG) had the potential to deliver the maximum power point of about 470 µW while the electromagnetic nanogenerator (EMG) can provide 523 mW at most. The conversion efficiency of energy of the system reached 48.48%, which exhibited a remarkable improvement by about 2.96 times, due to the elastic buffering effect of the TENG with the double helix structure. Furthermore, its ability to collect low frequency wave energy was successfully proven by a buoy in Jialing River. This woke provides an effective candidate to harvest irregular and ultralow frequency blue energy on a large scale.

Light-Assisted Enhancement of Gas Sensing Property for Micro-Nanostructure Electronic Device: A Mini Review.

In recent years, gas sensing electronic devices have always attracted wide attention in the field of environment, industry, aviation and others. In order to improve the gas sensing properties, many micro- and nano-fabrication technologies have been proposed and investigated to develop high-performance gas sensing devices. It is worth noting that light irradiation is an effective strategy to enhance gas sensitivity, shorten the response and recovery time, reduce operating temperature. In this review, firstly, the latest research advances of gas sensors based on different micro-nanostructure materials under UV light and visible light activation is introduced. Then, the gas sensing mechanism of light-assisted gas sensor is discussed in detail. Finally, this review describes the present application of gas sensors with improved properties under light activation assisted conditions and the perspective of their applications.

Metal-Organic Framework-Surface-Enhanced Infrared Absorption Platform Enables Simultaneous On-Chip Sensing of Greenhouse Gases.

Simultaneous on-chip sensing of multiple greenhouse gases in a complex gas environment is highly desirable in industry, agriculture, and meteorology, but remains challenging due to their ultralow concentrations and mutual interference. Porous microstructure and extremely high surface areas in metal-organic frameworks (MOFs) provide both excellent adsorption selectivity and high gases affinity for multigas sensing. Herein, it is described that integrating MOFs into a multiresonant surface-enhanced infrared absorption (SEIRA) platform can overcome the shortcomings of poor selectivity in multigas sensing and enable simultaneous on-chip sensing of greenhouse gases with ultralow concentrations. The strategy leverages the near-field intensity enhancement (over 1500-fold) of multiresonant SEIRA technique and the outstanding gas selectivity and affinity of MOFs. It is experimentally demonstrated that the MOF-SEIRA platform achieves simultaneous on-chip sensing of CO2 and CH4 with fast response time (<60 s), high accuracy (CO2: 1.1%, CH4: 0.4%), small footprint (100 × 100 µm2), and excellent linearity in wide concentration range (0-2.5 × 104 ppm). Additionally, the excellent scalability to detect more gases is explored. This work opens up exciting possibilities for the implementation of all-in-one, real-time, and on-chip multigas detection as well as provides a valuable toolkit for greenhouse gas sensing applications.

A double-helix-structured triboelectric nanogenerator enhanced with positive charge traps for self-powered temperature sensing and smart-home control systems.

Triboelectric nanogenerators (TENGs) have been in spotlight for their excellent capability to drive miniature electronics. Herein, we report a sophisticated double-helix-structured triboelectric nanogenerator (DHS-TENG) enhanced with positive charge traps for self-powered temperature sensing and smart-home control system. The DHS-TENG increases the charge density on the contact surfaces by taking advantage of the ferroelectric characteristics of polyvinylidene fluoride (PVDF). In addition, the flexible double-helix-structure endows DHS-TENG with excellent elastic property as it has no external supporting materials. The reported DHS-TENG, with the dimensions of 3 cm × 3 cm × 5 cm and a light weight of 10 g, can deliver a peak output power of 9.03 mW under a loading resistance of 4 MΩ. It also delivers an enhanced output performance of 460 V, 140 µA and 400 nC under a constant contact force of 40 N. Furthermore, the DHS-TENG is capable of powering 120 green LEDs and enabling a temperature sensor to work properly. In particular, the DHS-TENG demonstrates the capability of successful remote data transmission for application in smart-home control systems within 10 meters.

[The design and experiment of complementary S coding matrix based on digital micromirror spectrometer].

The template selection is essential in the application of digital micromirror spectrometer. The best theoretical coding H-matrix is not widely used due to acyclic, complex coding and difficult achievement. The noise ratio of best practical S-matrix for improvement is slightly inferior to matrix H. So we designed a new type complementary S-matrix. Through studying its noise improvement theory, the algorithm is proved to have the advantages of both H-matrix and S-matrix. The experiments proved that the SNR can be increased 2.05 times than S-template.