Investigation of the topography-dependent current in conductive AFM and the calibration method

The topography and the electrical properties of materials are two crucial characteristics in determining their functionalities. Conductive atomic force microscopy (CAFM) is widely recognized for its ability to independently measure the topology and conductivity of the sample surface. The increasing trend towards miniaturization in electrical devices and sensors has led to an urgent demand for enhancing the accuracy of CAFM characterization. However, the sample's topography may affect the current measured by CAFM, leading to an inaccurate estimation of the sample's conductivity. Herein, we investigated the existence of topography-dependent current that originates from changes in capacitance between the probe and sample in CAFM testing. A linear correlation between the current and topography has been established using both experimental and theoretical methods. A calibration method based on this linear correlation has been proposed to eliminate the current error induced by the uneven surface of both insulators and conductors. This work will yield substantial advantages for research requiring high-precision CAFM testing.Comment: Corrected typo

A Health Monitoring System Based on Flexible Triboelectric Sensors for Intelligence Medical Internet of Things and its Applications in Virtual Reality

The Internet of Medical Things (IoMT) is a platform that combines Internet of Things (IoT) technology with medical applications, enabling the realization of precision medicine, intelligent healthcare, and telemedicine in the era of digitalization and intelligence. However, the IoMT faces various challenges, including sustainable power supply, human adaptability of sensors and the intelligence of sensors. In this study, we designed a robust and intelligent IoMT system through the synergistic integration of flexible wearable triboelectric sensors and deep learning-assisted data analytics. We embedded four triboelectric sensors into a wristband to detect and analyze limb movements in patients suffering from Parkinson's Disease (PD). By further integrating deep learning-assisted data analytics, we actualized an intelligent healthcare monitoring system for the surveillance and interaction of PD patients, which includes location/trajectory tracking, heart monitoring and identity recognition. This innovative approach enabled us to accurately capture and scrutinize the subtle movements and fine motor of PD patients, thus providing insightful feedback and comprehensive assessment of the patients conditions. This monitoring system is cost-effective, easily fabricated, highly sensitive, and intelligent, consequently underscores the immense potential of human body sensing technology in a Health 4.0 society

Polyimides Crosslinked by Aromatic Molecules and Nanocomposites for High Temperature Capacitive Energy Storage

High temperature polymer-based dielectric capacitors are crucial for application in electronic power systems. However, the storage performance of conventional dielectrics polymer dramatically deteriorates due to the thermal breakdown under concurrent high temperatures and electric fields, and there are hardly reports on the causes of thermal breakdown from the aspects of the high temperature conduction loss and Joule heat dissipation. Herein, a combined strategy of crosslinking and compositing for polyimide-based nanocomposites is proposed, which minimizes the thermal breakdown by significantly inhibiting the high-temperature conduction loss and enhancing the high thermal conductivity. Furthermore, the rationale of the strategy was theoretically and experimentally verified from multiple perspectives. The charge-trapping effect is directly observed and quantitatively probed by Kelvin probe force microscopy with nano level resolution, indicating that the crosslinking network introduces local deep traps and effectively suppresses the charge transport. The thermal conductivity of the nanocomposites inhibits the high temperature thermal breakdown, which is confirmed by phase field simulations. Consequently, the optimized nanocomposites possess an ultra high discharge energy density(Ud) of 5.45 J/cm3 and 3.54 J/cm3 with a charge discharge efficiency, respectively, which outperforms the reported polyimide based dielectric nanocomposites. This work provides a scalable direction for high temperature polymer based capacitors with excellent performance

Identification of resection plane for anatomical liver resection using ultrasonography-guided needle insertion

PurposesTo set up an easy-handled and precise delineation of resection plane for hepatic anatomical resection (AR).MethodsCases of AR using ultrasonography-guided needle insertion to trace the target hepatic vein for delineation of resection planes [new technique (NT) group, n = 22] were retrospectively compared with those without implementation of this surgical technique [traditional technique (TT) group, n = 29] in terms of perioperative courses and surgical outcomes.ResultsThe target hepatic vein was successfully exposed in all patients of the NT group, compared with a success rate of 79.3% in the TT group (P < 0.05). The average operation time and intraoperative blood loss were 280 ± 32 min and 550 ± 65 ml, respectively, in the NT group. No blood transfusion was required in either group. The postoperative morbidities (bile leakage and peritoneal effusion) were similar between groups. No mortality within 90 days was observed.ConclusionsUltrasonography-guided needle insertion is a convenient, safe and efficient surgical approach to define a resection plane for conducting AR

Improvement in the photoelectric conversion efficiency for the flexible fibrous dye-sensitized solar cells

Abstract A dye-sensitized and flexible TiO2 fiber with multilayer structure was prepared by using brush method as the photoanode in the efficient flexible fibrous dye-sensitized solar cells (FFDSSCs) to avoid electronic recombination and improve the electronic capture efficiency. The composite Pt counter electrode, preparation from the surface modification of the electrodeposited Pt wire by using a simple one-step thermal decomposition approach of H2PtCl6 isopropanol and n-butyl alcohol (volume ratio = 1:1) solution, provided a significant improvement in electrocatalytic activity, which was confirmed by extensive electrochemical tests. The FFDSSC assembled with the fiber-shaped TiO2 photoanode and the composite Pt counter electrode achieves an enhanced photoelectric conversion efficiency of 6.35%, higher than that of the FFDSSC with monolayer fibrous TiO2 photoanode and electrodeposited Pt wire counter electrode. More importantly, the photoelectric conversion efficiency of 6.35% is comparable to that of the FFDSSC based on the pure Pt wire counter electrode (6.32%). The FFDSSC with high elasticity, flexibility, and stretchability can adapt to complex mechanical deformations, which is of great significance for the development of wearable electronics in the future

Preparation and Characterization of Solution-Processed Nanocrystalline p-Type CuAlO2 Thin-Film Transistors

Abstract The development of p-type metal oxide thin-film transistors (TFTs) is far behind the n-type counterparts. Here, p-type CuAlO2 thin films were deposited by spin coating and annealed in nitrogen atmosphere at different temperature. The effect of post-annealing temperature on the microstructure, chemical compositions, morphology, and optical properties of the thin films was investigated systematically. The phase conversion from a mixture of CuAl2O4 and CuO to nanocrystalline CuAlO2 was achieved when annealing temperature was higher than 900 °C, as well as the transmittance, optical energy band gap, grain size, and surface roughness of the films increase with the increase of annealing temperature. Next, bottom-gate p-type TFTs with CuAlO2 channel layer were fabricated on SiO2/Si substrate. It was found that the TFT performance was strongly dependent on the physical properties and the chemical composition of channel layer. The optimized nanocrystalline CuAlO2 TFT exhibits a threshold voltage of − 1.3 V, a mobility of ~ 0.1 cm2 V−1 s−1, and a current on/off ratio of ~ 103. This report on solution-processed p-type CuAlO2 TFTs represents a significant progress towards low-cost complementary metal oxide semiconductor logic circuits

The triboelectricity of the human body

Triboelectrification (contact electrification) as a physical phenomenon appeared for the first time in a dialogue by Plato around 400 B.C. The phenomenon described in the dialogue is about amber that people wear attracting dry hair. The description also indicated that triboelectrification was first discovered on the human body. However, the studies that have been carried out on triboelectrification were mostly based on other materials, such as polymers, rather than on the human body. The invention of triboelectric nanogenerators (TENGs) has recently opened a door for both fundamental and applied research and brought triboelectrification into real applications. The human body's triboelectricity, as a vital part of studies, has also attracted much interest in the past ten years. Research and review articles were published during this period. However, few articles included the biological fundamentals of the triboelectrification of the human body. Moreover, most of the review articles missed two important parts: the electrostatic discharge (ESD) of the human body, which has been widely studied in electronics, and the cosmetics that reduce the triboelectrification of hair. A systematic review including the fundamentals and the applications could help readers understand the human body's triboelectricity. Given this, we proposed this review article on the human body's triboelectricity. The paper will cover a brief history and a brief mechanism summary of triboelectrification; the epidermis structure of the human hair and skin, including how the chemicals on the epidermal layer contribute to the skin's triboelectricity; fundamental studies of the human body's triboelectricity; and applications that utilize the human body's triboelectricity. Perspectives for future studies and conclusions will be given at the end of the review.

Comprehensive Insights into Charge Dynamics and Improved Photoelectric Properties of Well-Designed Solar Cells

Here, Zn₂SnO₄ nanorods/Cu₄Bi₄S₉ (ZTO/CBS) and ZTO nanorods/CBS-graphene nanosheets (ZTO/CBS-GNs), as well as two types of bulk heterojunction (BHJ) solar cells with high flexibility were fabricated on stainless steel meshes (SSMs). The excellent photovoltaic responses of CBS-GNs and ZTO/CBS-GNs with incorporation of GNs were determined using surface photovoltage spectroscopy (SPS). The signals of time-resolved fluorescence response (TFR) and transient surface photovoltage (TPV) can provide more detailed information for transition, separation, and transport of photoinduced carriers. Besides, the ZTO nanorods/CBS-GNs cell exhibits the superior performance and the highest efficiency is 11.2%. The multichannel separation process from the TPVs indicates that the macro-photoelectric signals can be attributed to the photogenerated charges separated at the interface of CBS/GNs, rather than CBS/ZTO. The multi-interfacial recombination is the major carrier loss with electrical impedance spectroscopy (EIS) and the hole selective NiO can efficiently accelerate the charge extraction to the external circuit. The comprehensive signals of SPS, EIS, TFR, and TPV provide insights into transition, separation, recombination and shifting of carriers. Importantly, the BHJ flexible solar cells with high efficiency and facile, scalable production present a potential for application