[en] While analyzing energy spectrum of nuclear species with linear fit method, standard deviation σ is an important parameter. The authors introduced a method of selecting, and explained it's compensation effect for the error resulted from peak drift

[en] Highlights: • The flexible chemiresistive pH sensor based on two-terminal microsensors eliminating the need for a reference electrode, is simple in structure and can be fabricated on a variety of substrates such as PET, PI and PVC. • SWNTs as an ideal one dimensional material are carboxyl-functionalized to make the pH sensor show high sensitivity and outstanding flexibility for practical applications. • DEP technique is used to manipulate and position SWNTs into appropriate locations and desired formations to improve the metal-nanotube interface and highly rapid detection of pH value, resulting in better overall device performance. • Mechanical bendability of the pH sensor, which arises from the combination of flexible PET substrates and SWNTs, offer a significant improvement for applications that are difficult or impossible to achieve with traditional sensors on rigid substrates. - Abstract: The detection and control of the pH is very important in many biomedical and chemical reaction processes. A miniaturized flexible pH sensor that is light weight, robust, and conformable is very important in many applications, such as multifunctional lab-on-a-chip systems or wearable biomedical devices. In this work, we demonstrate a flexible chemiresistive pH sensor based on dielectrophoresis (DEP) aligned carboxyl-functionalized single-walled carbon nanotubes (SWNTs). Decorated carboxyl groups can react with hydrogen (H"+) and hydroxide (OH"−) ions, enabling the sensor to be capable of sensing the pH. DEP is used to deposit well-organized and highly aligned SWNTs in desired locations, which improves the metal-nanotube interface and highly rapid detection of the pH, resulting in better overall device performance. When pH buffer solutions are dropped onto such SWNTs, the H"+ and OH"− ions caninteract with the carboxyl groups and affect the generation of holes and electrons in the SWNTs, leading to resistance variations in the SWNTs. The results shows that the relative resistance variations of the sensor increases linearly with increasing the pH values in the range from 5 to 9 and the response time ranges from 0.2 s to 22.6 s. The pH sensor also shows high performance in mechanical bendability, which benefited from the combination of flexible PET substrates and SWNTs. The SWNT-based flexible pH sensor demonstrates great potential in a wide range of areas due to its simple structure, excellent performance, low power consumption, and compatibility with integrated circuits.

[en] It is proposed that double acceptor-level vacancies are responsible for arsenic diffusion in silicon. The diffusion equation is solved using the Crank-Nicolson differential method. A computer program is used to calculate diffusion coefficient and diffusion distribution of arsenic implanted into silicon. The results on diffusion distribution and junction depth are compared with the SRP measured profiles and the SUPREM-II simulation. A good agreement with the measured values has been observed

[en] Highlights: • Conductive island shape influences the dynamic process occurring in DEP assembly of 10 nm gold nanoparticles in a conductive-island-based microelectrode system. • The DEP-assembled nanoparticle wires form a straighter conduction path with the increase in the geometric angle of conductive island tip. • The different island shapes distort the DEP force distribution and increase the local electrothermally induced fluid flow to different extents, which is important for the morphology and electrical conductance quality of the DEP-assembled metal nanoparticle chains. - Abstract: The electrical conduction quality of an electric circuit connection formed by dielectrophoretic (DEP)-assembled metal nanoparticle wires between small conductive elements plays a significant role in electronic devices. One of the major challenges for improving the electrical conductance of nanowires is optimizing their geometric morphology. So far, the electrical conduction quality has been enhanced by optimizing the AC frequency and conductivity of nanoparticle suspensions. Herein, the effect of the conductive island shapes on the dynamic process occurring in a DEP assembly of 10 nm gold nanoparticles was investigated in a conductive-island-based microelectrode system. The nanoparticle wires between the microelectrodes were assembled in situ from colloidal suspensions. The wires were grown in a much straighter route by increasing the geometric angle of the conductive-island tip. To validate the experiments, the effects of mutual DEP interactions and electrothermally induced fluid flow on the dynamic behavior of particle motion for different island geometric configurations in the conductive-island-based microelectrode system were determined by numerical simulations. The simulation results are consistent with those of experiments. This indicates that different conductive island shapes change the distribution of DEP force and increase the electrothermally induced fluid flow to different extents in the vicinity, leading to different morphologies of DEP-assembled nanoparticle wires

[en] We propose a novel method for fabricating high-aspect-ratio micro-/nano-structures by dielectrophoresis-electrocapillary force (DEP-ECF)-driven UV-imprinting. The force of DEP-ECF, acting on an air–liquid interface and an air–liquid–solid three-phase contact line, is generated by applying voltage between an electrically conductive mold and a substrate, and tends to pull the dielectric liquid (a UV-curable pre-polymer) into the mold micro-cavities. The existence of DEP-ECF is explained theoretically and demonstrated experimentally by the electrically induced reduction of the contact angle. Furthermore, DEP-ECF is proven to play a critical role in forcing the polymer to fill into the mold cavities by the real-time observation of the dynamic filling process. Using the DEP-ECF-driven UV-imprinting process, high-aspect-ratio polymer micro-/nano-structures (more than 10:1) are fabricated with high consistency. This patterning method can overcome the drawbacks of the mechanically induced mold deformation and position shift in conventional imprinting lithography and maximize the pattern uniformity which is usually poor in capillary force lithography

[en] A stable and uniform electric field is to be generated even though a large mechanical deformation is the primary criterion for a transparent conductive film. This study proposes a protective integrated transparent conductive film (PITCF) including indium tin oxide (ITO), a silver nanowire (Ag NW) network, and a protective polydimethylsiloxane (PDMS) layer. A firmly bonding process of ITO/Ag NW/PDMS is established to avoid the failure of Ag NW to be oxidized by interlayer residual air or wrapped by liquid PDMS. Besides the good optical transparency, haze, and electrical conductivity as the only ITO film, the developed PITCF exhibits excellent bending resistance and mechanical stability. The ITO rupture fragments after bending deformation are firmly interconnected by the constrained Ag NWs. Even though the PITCF is bended more than 1000 cycles at a 6.5 mm bending distance, the changes in electrical resistance of PITCF are below 9.7%. Finally, an electroluminescent device with high bending resistance and uniform and high luminance is developed based on the designed PITCF. (paper)

[en] Flexible tactile sensors with high sensitivity, good flexibility and the capability of measuring multidirectional forces are urgently required in modern robot technology and flexible electronic applications. Here, we present a flexible three-axial tactile sensor using piezoelectricity enhanced P(VDF-TrFE) micropillars. For achieving three-axis force measurement, the vertical aligned P(VDF-TrFE) micropillars are sandwiched between four square bottom electrodes and a common top electrode to form four symmetrically arranged piezoelectric sensing units. An elastomeric PDMS bump is fixed on the common top electrode surface to effectively transfer the contact force to the four sensing units. Taking advantage of the high sensitivity and good flexibility of the imprinted P(VDF-TrFE) micropillars, the resultant four distributed piezoelectric units are highly sensitive to the strain and can generate related signals corresponding to the compressive and tensile stress, from which the direction and the amplitude of the applied force can be deduced. The structural design, manufacturing technique，the three-axial force measuring principle, and sensing performance characterization of the proposed tactile sensor are presented in this paper. The sensitivities for X-, Y-, and Z-axis force components are calibrated as 0.3738 V N⁻¹, 0.4146 V N⁻¹, and 0.3443 V N⁻¹ in experimental study. Furthermore, the proposed tactile sensor array is successfully integrated with a magnetic bar consist of NdFeB/PDMS composites to construct a magnetic actuator with sensing ability. These results give the flexible three-axial tactile sensor high potential for use in advanced robots, wearable electronics and a variety of human-machine interface implementations. (paper)

[en] Here we demonstrate a novel magnetic functional material composed of montmorillonite (Mt) with superparamagnetic coating Fe₃O₄ dispersed in the aqueous solution. Colloidal stability can be obtained through keeping 2 < pH < 3. After applying an external magnetic field, Mt@Fe₃O₄ exhibits long-range order and liquid crystalline phase. The transmittance of the liquid crystal is dependent on the solid content of Mt@Fe₃O₄, magnetic field strength and magnetic field direction. We also observe reflective phenomena when we modulate the magnetic field. The photonic bandgap can be tuned by changing the angle between incident light and magnetic field. The varying observation points also make a difference to the reflection. This facile approach for fabricating Mt@Fe₃O₄ with ordered periodic structures and optically tunable property is of interest for a variety of advanced optics applications with low cost and environment-friendly.

[en] Highlights: • The uprightness of commonly used microstructures has limited the triboelectrification effects. • Bendabe and slidable fish-scale-like microstructures are proposed to improve the triboelectrification effects. • The performances of the TENGs or self-powered pressure sensors are significantly improved. Improving the triboelectrification effect between tribo-materials is fundamentally important for advancing the booming community of triboelectric nanogenerators (TENGs) and self-powered sensors. Microstructures played key roles in improving the triboelectrification effect, however, the uprightness of commonly used microstructures always limited the triboelectrification to interfaces between the tops of microstructures and opposite tribo-films during vertical contact/separation processes. In this study, bendable and slidable fish-scale-like microstructures were developed to surpass the limitations by extending the triboelectric interfaces from their tops to their sidewalls, taking the advantages of bending and sliding movements. Based on the fish-scale-like microstructures, the as-prepared TENGs delivered open-circuit voltages reaching up to 470 V and a short-circuit current density of 45 μA/cm². These values were two-fold higher than those obtained with vertical microstructures under the same testing conditions. The as-assembled self-powered pressure sensors based on fish-scale-like microstructures delivered linear measurement ranges reaching up to 42 kPa, low detection limit of 10 mPa, high sensitivity of 1.03 mV/Pa, and ultrafast response of 0.1 ms. These features were significantly enhanced when compared to those of vertical microstructures. More importantly, we also developed a straightforward and low-cost duplication method for fabricating the fish-scale-like microstructures, which are easily achievable for fabricating the high-performance TENGs or self-powered pressure sensors.

[en] Polarized radiative luminous semiconductor chips have huge application potential in many highly value-added fields. The integration of a subwavelength grating is recognized to be the most promising method for the development of polarized chips, but still faces the challenge of low polarized radiative performance. This paper describes a proposal for, and the development of, a scattering-induced enhanced-polarization light-emitting diode chip by directly nanoimprinting a metal-containing nanoparticle-doped grating onto the top surface of a common flip chip. The rate at which quantum-well light emission is used by the developed polarized chip is improved by more than 30%. More attractively, the doped scattering nanoparticles function as a scattering-induced polarization state converter that is sandwiched in between the top aluminum grating and the bottom silver reflector of the chips. The originally non-radiated light, with an electric-field vector parallel to the grating lines, is reflected back and forth inside the sandwich until it changes to the perpendicular vibration mode and is radiated outside the chip. Therefore, the polarization extinction ratio is greatly improved, compared to undoped samples. (paper)