Search

Using low-energy electron microscopy,we find that the mechanisms of graphene growth on Ir(111) depend sensitivelyon island orientation with respect to Ir. In the temperature rangeof 750–900 °C, we observe that growing rotated islandsare more faceted than islands aligned with the substrate. Further,the growth velocity of rotated islands depends not only on the C adatomsupersaturation but also on the geometry of the island edge. We deducethat the growth of rotated islands is kink-nucleation-limited, whereasaligned islands are kink-advancement-limited. These different growthmechanisms are attributed to differences in the graphene edge bindingstrength to the substrate. [ABSTRACT FROM AUTHOR]

With the increasing global focus on sustainable materials, paper is favored for its biodegradability and low cost. Their integration with triboelectric nanogenerators (TENGs) establishes broad prospects for self-powered, paper-based triboelectric materials. However, these materials inherently lack efficient charge storage structures, leading to rapid charge dissipation. This study introduced a paper-based triboelectric material with efficient charge storage using deep traps assembled by a hydrogen bonds strategy. Compared to pure paper, the material increased the deep trap density by ∼54 times, with an ∼10 times higher dielectric constant at high frequency. TENG based on the material had a peak output power density ∼45 times higher than paper-based TENG and maintained a stable voltage after 20,000 cycles. It also shows exceptional environmental stability and practicality with minimal voltage reduction in heat environments. This offers a practical and effective solution for powering and sustaining small electronic devices under extreme conditions.

Aerogels are widely applied for construction, aerospace, military, and energy owing to their lightweight, high specific surface area, and high porosity. The high porosity of aerogels often leads to a lack of mechanical strength, which limits their applications. Here, this study reports a mechanically robust MXene/cellulose nanocrystal composite aerogel enabled by inducing dense bridging through salting-out. First, MXene sheets are bridged with cellulose molecular chains via hydrogen bonds, and further dense bridging is constructed by promoting hydrogen bond formation through salting-out. By enhancing hydrogen bonding, the interlayer spacing of MXene sheets is reduced and their orientation is improved, effectively increasing the energy dissipation capacity of the porous structure. The aerogel exhibits a Young's modulus of 72.4 MPa, a specific modulus of 342.0 kN m/kg. An aerogel is used as a triboelectric material to construct a highly robust triboelectric nanogenerator. This study provides an effective strategy for the preparation of the mechanically robust aerogels.

Driven by the "Internet of Everything" (IoE) vision, the demand for smart materials is growing. Wood, one of the most abundant and renewable resources, has long been a staple in construction and furnishing applications. To further expand its application range, this study developed a high-strength, stable wood-based triboelectric material through a synergistic biphasic mechanism. The in situ growth of flame retardants and the formation of a dense char layer significantly enhanced the fire resistance of the wood-based triboelectric material, reducing the heat release rate (HRR) by 95.4% and total heat release (THR) by 94.2%. The dense laminate structure provided an excellent impact toughness (126 kJ m -2 ). As a smart sensor, the wood-based triboelectric material demonstrated the ability to recognize human motion states and trajectories, exhibiting great potential for applications in smart homes. This study provides valuable insights for exploring the potential applications of wood as a smart material.

Emulating biological perception mechanisms to construct intelligent sensing devices and systems represents a paradigm for promoting human-computer interaction in the Internet of Everything era. Nonetheless, developing highly sensitive, real-time sensing and rapidly integrated intelligent interaction units remains a challenging and time-consuming endeavor. This study employs a low-temperature glow discharge technique to rapidly fabricate graded nanotexturing architectural triboelectric nanopaper, upon which wearable triboelectric sensors for real-time tactile detection are designed. The structure enhances the contact area under an external force. Additionally, the Z-stacking structure design enables the sensor to achieve a remarkable sensitivity of 10.3 kPa -1 and a rapid response time of 52 ms. Furthermore, a tactile sensor array was designed to demonstrate the triboelectric sensor's ability to recognize characteristic pressures. With programmable machine learning techniques, the object recognition rate reached 97%. This study supports material structural design across disciplines, laying a solid foundation for the rapid fabrication and integration of transient wearable electronics.

Biomimetic engineering surfaces featuring heterogeneous wettability are vital for atmospheric water harvesting applications. Existing research predominantly focuses on the coordinated regulation of surface wettability through structural and chemical modifications, often overlooking the prevalent triboelectric charge effect at the liquid-solid interface. In this work, we designed a heterogeneous wettability surface by strategic masking and activated its latent triboelectric charge using triboelectric brushes, thereby enhancing the removal and renewal of surface droplets. By examining the dynamic evolution of droplets, the mechanism of triboelectric enhancement in the water collection efficiency is elucidated. Leveraging this inherent triboelectric charge interaction, fog collection capacity can be augmented by 29% by activating the system for 5 s every 60 s. Consequently, the advancement of triboelectric charge-enhanced fog collection technology holds both theoretical and practical significance for overcoming the limitations of traditional surface wettability regulation.

Noncontact sensing technology serves as a pivotal medium for seamless data acquisition and intelligent perception in the era of the Internet of Things (IoT), bringing innovative interactive experiences to wearable human-machine interaction perception networks. However, the pervasive limitations of current noncontact sensing devices posed by harsh environmental conditions hinder the precision and stability of signals. In this study, the triboelectric nanopaper prepared by a phase-directed assembly strategy is presented, which possesses low charge transfer mobility (1618 cm 2 V -1 s -1 ) and exceptional high-temperature stability. Wearable self-powered noncontact sensors constructed from triboelectric nanopaper operate stably under high temperatures (200 °C). Furthermore, a temperature warning system for workers in hazardous environments is demonstrated, capable of nonintrusively identifying harmful thermal stimuli and detecting motion status. This research not only establishes a technological foundation for accurate and stable noncontact sensing under high temperatures but also promotes the sustainable intelligent development of wearable IoT devices under extreme environments.

Wearable sensors are experiencing vibrant growth in the fields of health monitoring systems and human motion detection, with comfort becoming a significant research direction for wearable sensing devices. However, the weak moisture-wicking capability of sensor materials leads to liquid retention, severely restricting the comfort of the wearable sensors. This study employs a pattern-guided alignment strategy to construct microhill arrays, endowing triboelectric materials with directional moisture-wicking capability. Within 2.25 s, triboelectric materials can quickly and directionally remove the droplets, driven by the Laplace pressure differences and the wettability gradient. The directional moisture-wicking triboelectric materials exhibit excellent pressure sensing performance, enabling rapid response/recovery (29.1/37.0 ms), thereby achieving real-time online monitoring of human respiration and movement states. This work addresses the long-standing challenge of insufficient moisture-wicking driving force in flexible electronic sensing materials, holding significant implications for enhancing the comfort and application potential of electronic skin and wearable electronic devices.

Lightweight, easily processed, and durable polymeric materials play a crucial role in wearable sensor devices. However, achieving simultaneously high strength and toughness remains a challenge. This study addresses this by utilizing an ion-specific effect to control crystalline domains, enabling the fabrication of a polymeric triboelectric material with tunable mechanical properties. The dense crystal-domain cross-linking enhances energy dissipation, resulting in a material boasting both high tensile strength (58.0 MPa) and toughness (198.8 MJ m -3 ), alongside a remarkable 416.7% fracture elongation and 545.0 MPa modulus. Leveraging these properties, the material is successfully integrated into wearable self-powered devices, enabling real-time feedback on human joint movement. This work presents a valuable strategy for overcoming the strength-toughness trade-off in polymeric materials, paving the way for their enhanced applicability and broader use in diverse sensing applications.

As intelligent technology surges forward, wearable electronics have emerged as versatile tools for monitoring health and sensing our surroundings. Among these advancements, porous triboelectric materials have garnered significant attention for their lightness. However, these materials face the challenge of improving structural stability to further enhance the sensing accuracy of triboelectric sensors. In this study, a lightweight and strong porous cellulosic triboelectric material is designed by cell wall nanoengineering. By tailoring of the cell wall structure, the material shows a high mechanical strength of 51.8 MPa. The self-powered sensor constructed by this material has a high sensitivity of 33.61 kPa -1 , a fast response time of 36 ms, and excellent pressure detection durability. Notably, the sensor still enables a high sensing performance after the porous cellulosic triboelectric material exposure to 200 °C and achieves real-time feedback of human motion, thereby demonstrating great potential in the field of wearable electronic devices.

Here we report the growth of phase-pure InAs nanowires on Si (111) substrates by molecular-beam epitaxy using Ag catalysts. A conventional one-step catalyst annealing process is found to give rise to InAs nanowires with diameters ranging from 4.5 to 81 nm due to the varying sizes of the Ag droplets, which reveal strong diameter dependence of the crystal structure. In contrast, a novel two-step catalyst annealing procedure yields vertical growth of highly uniform InAs nanowires ∼10 nm in diameter. Significantly, these ultrathin nanowires exhibit a perfect wurtzite crystal structure, free of stacking faults and twin defects. Using these high-quality ultrathin InAs nanowires as the channel material of metal-oxide-semiconductor field-effect transistor, we have obtained a high ION/IOFF ratio of ∼10(6), which shows great potential for application in future nanodevices with low power dissipation.

We have observed the growth of monolayer graphene on Cu foils using low-energy electron microscopy. On the (100)-textured surface of the foils, four-lobed, 4-fold-symmetric islands nucleate and grow. The graphene in each of the four lobes has a different crystallographic alignment with respect to the underlying Cu substrate. These "polycrystalline" islands arise from complex heterogeneous nucleation events at surface imperfections. The shape evolution of the lobes is well explained by an angularly dependent growth velocity. Well-ordered graphene forms only above ∼790 °C. Sublimation-induced motion of Cu steps during growth at this temperature creates a rough surface, where large Cu mounds form under the graphene islands. Strategies for improving the quality of monolayer graphene grown on Cu foils must address these fundamental defect-generating processes.