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This review highlights the advances in Schottky sensors based on 2D TMDs. The preparation methods of 2D TMDs and the vital Schottky sensors such as photodetectors, gas sensors, strain sensors, and biosensors are summarized and discussed.

Schottky-contacted sensors have been demonstrated to show high sensitivity and fast response time in various sensing systems. In order to improve their sensing performance, the Schottky barriers height (SBH) at the interface of semiconductor and metal electrode should be adjusted to appropriate range to avoid low output or low sensitivity, which was induced by excessively high or low SBH, respectively. In this work, a simple and effective SBH tuning method by triboelectric generator (TENG) is proposed, the SBH can be effectively lowered by voltage pulses generated by TENG and gradually recover over time after withdrawing the TENG. Through combining the TENG treatment with piezotronic effect, a synergistic effect on lowering SBH was achieved. The change of SBH is increased by 3.8 to 12.8 times, compared with dependent TENG treatment and piezotronic effect, respectively. Furthermore, the recovery time of the TENG-lowered SBH can be greatly shortened from 1.5 h to 40 s by piezotronic effect. This work demonstrated a flexible and feasible SBH tuning method, which can be used to effectively improve the sensitivity of Schottky-contact sensor and sensing system. Our study also shows great potential in broadening the application scenarios of Schottky-contacted electronic devices.

Tuning Schottky barrier height is crucial to optimize the performance of Schottky junction devices. Here, we demonstrate that the Schottky barrier height can be tuned with the voltage from a triboelectric nanogenerator (TENG). Schottky barrier heights at both ends are increased after the treatment with the voltage generated by the TENG. The electric field generated by the impulse voltage of the TENG drives the diffusion of the ionized oxygen vacancy in a CuO nanowire, which induces the nonuniform distribution of the ionized oxygen vacancy. The positively charged oxygen vacancy accumulates at the contacted interface of Pt and the CuO nanowire, and it impels the conduction and valence bands to bend downwards. The Schottky barrier height is raised. A theoretical model based on the energy band diagram is proposed to explain this phenomenon. This method offers a simple and effective avenue to tune the Schottky barrier height. It opens up the possibility to develop a high-performance Schottky sensor by tuning the Schottky barrier height.

Highly sensitive ethanol sensors are important for environmental and industrial monitoring. In our work, we demonstrate a method to enhance the response of a Schottky sensor based on a ZnO nano/microwire (NMW) by triboelectric nanogenerator (TENG). Via lowering the Schottky barrier height (SBH) via the high voltage from TENG, the response of the sensor is enhanced by 139% for 100 ppm ethanol. This method accelerates the recovery process. The high voltage from TENG produces a high intensity electric field to drive diffusion of the oxygen vacancies in ZnO NMW toward to the junction area around the interface. It is equivalent to applying the reverse voltage on the Schottky junction, which leads to the increase of depletion width. More chemisorbed oxygen on the depletion region is consumed once the ethanol gas is injected into the chamber, which improves the response of the ethanol sensor. This study provides a new, simple, and effective method to improve the sensor response.

Monitoring various medical information distributed throughout the body is of great importance in early clinic diagnosis and treatment of disease. To discover abnormal medical signals and find their causes in good time, the human body should be monitored continuously and accurately. To meet the requirements, various battery‐less and self‐powered information acquisition techniques are invented. In this review, the recent advances in self‐powered medical information sensors (SMIS) with different functions, structure design, and electric performance are summarized and discussed. The SMIS mainly involves triboelectric nanogenerator (TENG), piezoelectric nanogenerator (PENG), pyroelectric nanogenerator (PyNG)/ thermoelectric generator (TEG) and solar cell. Additionally, this review also analyzed the remaining challenges and prospected the development direction of SMIS in future.

In recent years, considerable attention has been devoted to the exploration of novel synthetic methods for fluoro-lactams due to their significant biological and pharmaceutical activities. This review summarizes recently established strategies for synthesizing fluorine-substituted lactams, including fluoro-β-lactams, fluoro-γ-lactams, and fluoro-δ-lactams. Additionally, the reaction scopes, limitations, and mechanisms are discussed.

The human body has an abundance of available energy from the mechanical movements of walking, jumping, and running. Many devices such as electromagnetic, piezoelectric, and triboelectric energy harvesting devices have been demonstrated to convert body mechanical energy into electricity, which can be used to power various wearable and implantable electronics. However, the complicated structure, high cost of production/maintenance, and limitation of wearing and implantation sites restrict the development and commercialization of the body energy harvesters. Here, we present a body-integrated self-powered system (BISS) that is a succinct, highly efficient, and cost-effective method to scavenge energy from human motions. The biomechanical energy of the moving human body can be harvested through a piece of electrode attached to skin. The basic principle of the BISS is inspired by the comprehensive effect of triboelectrification between soles and floor and electrification of the human body. We have proven the feasibility of powering electronics using the BISS in vitro and in vivo. Our investigation of the BISS exhibits an extraordinarily simple, economical, and applicable strategy to harvest energy from human body movements, which has great potential for practical applications of self-powered wearable and implantable electronics in the future.

In order to further improve the mechanical properties of CrN films, the influence of substrate bias current on the microstructure and properties of the CrNx films deposited by plasma enhanced magnetron sputtering was studied by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, 3D profiler, nano indenter, and ball-on-disk tribometer. With the increase of substrate bias current, the microstructure of the films is transformed from a dendritic structure into a super dense columnar structure, and the phase composition is evolved from Cr → Cr + Cr2N → pure Cr2N. When the substrate bias current is >1.5 A, the preferred orientation is transformed from Cr2N(111) to Cr2N(300) with increasing substrate bias current. The surface roughness of the films is decreased from 27.3 to 18.7 nm as the substrate bias current is increased from 0.1 to 1.5 A, but the surface roughness remains nearly unchanged when the substrate bias current exceeds 1.5 A. The hardness and effective Young's modulus of the films are obviously increased with increasing the substrate bias current from 0.1 to 3.0 A, while they are almost independent of the substrate bias current when the substrate bias current is no less than 3.0 A. The lowest friction coefficient of 0.43 is obtained when the substrate bias current is 4.5 A. When the substrate bias current is increased, the wear rate of CrN-coated samples is first increased and then decreased, and the lowest wear rates is 4.6 × 10−16 m3/(N·m) when the substrate bias current is 6.0 A.

In this work, we investigate the non-physical velocity-slip at a solid wall associated with lattice Boltzmann simulations using the bounce-back boundary scheme. By comparing the analytical solutions for the force-driven Poiseuille flow problem of two lattice models involving four and nine discrete velocities respectively, we found that the bounce-back scheme fails to define the behavior of certain discrete velocities and gives room for other factors to generate the commonly observed non-physical velocity-slip. To eliminate this deficiency, it is necessary to supplement the missing definition. For a lid-driven cavity flow, this is shown to be very simple although further study is necessary for more complex geometries.

Solar selective absorbing coatings play a valuable role in photo-thermal conversion for high efficiency concentrating solar power systems (CSP). In this paper, a novel Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coating was successfully deposited by ion beam assisted deposition. The optical properties, microstructure and element distribution in depth were investigated by spectroscopic ellipsometry, UV-vis-NIR spectrophotometer, transmission electron microscope (TEM) and Auger electron spectroscopy (AES), respectively. A high absorptance of 0.953 and a low thermal emittance of 0.079 at 400 °C are obtained by the integral computation according to the whole reflectance from 300 nm to 28,800 nm. After annealing treatment at 400 °C (in vacuum) for 192 h, the deposited coating exhibits the high thermal stability. Whereas, the photothermal conversion efficiency decreases from 12.10 to 6.86 due to the emittance increase after annealing at 600 °C for 192 h. Meanwhile, the nitrogen atom in the Zr0.3Al0.7N sub-layer diffuses toward the adjacent sub-layer due to the spinodal decomposition of metastable c-ZrAlN and the phase transition from c-AlN to h-AlN, which leads to the composition of the Zr0.3Al0.7N sub-layer deviates the initial design. This phenomenon has a guide effect for the thermal-stability improvement of cermet coatings. Additionally, a serious diffusion between copper and silicon substrate also contributes to the emittance increase.

The Zr 1-x Al x N films have been deposited on Si (111) and glass (soda lime glass) substrates by ion beam assisted deposition. The microstructure, morphology, electrical resistivity and optical properties of the Zr 1-x Al x N films were investigated by XRD, TEM, four-probe method and spectroscopic ellipsometry. In the Al composition range 0.32 ≤ x ≤ 0.7, the Zr 1-x Al x N films contain crystallized ZrAlN (NaCl type). The deposited Zr 0.2 Al 0.8 N film is amorphous. The aluminum content increase in the Zr 1-x Al x N films induces the film structure tends to amorphization. The refractive index of the Zr 1-x Al x N films increases with Al content increase, whereas, a continuous decrease of the extinction coefficient was noticed. As the Al content increase, the electrical resistivity of films increases. The addition of Al into ZrN-based films leads to the loss of the metallic character.

A novel metal–dielectric stacks coating of Cu/Zr0.2Al0.8N/ZrN/AlN/ZrN/AlN/Al34O62N4 as the solar selective absorbing coating was designed. Thin films of Zr0.2AlN0.8, ZrN, AlN and Al34O62N4 deposited by the dual ion beam assisted deposition (DIBAD) were investigated by X-ray diffraction and spectroscopic ellipsometry. XRD results indicate the deposited films of Zr0.2Al0.8N, AlN, and Al34O62N4 are poorly crystallized, whereas, the ZrN film is polycrystalline. The Drude-type dispersion model and Tauc–Lorentz dispersion model are used for determining the complex refractive indices of ZrN and Zr0.2Al0.8N, respectively. For Al34O62N4 and AlN films, Cauchy’s dispersion formula is employed to determine their optical constants. A seven-layer stack with alternating ZrN and AlN layers is optimized by optical simulation programme of TFCalc. The optimized coating obtains the solar absorptance of 0.942 and the emittance of 0.12 at 100 °C.

A force scheme of second-order accuracy in both time and space has been introduced into the lattice Boltzmann model for shallow water equations. The scheme is tested within the single relaxation framework by using a one-dimensional steady flow over a bump, two one-dimensional dam-break flows and a two-dimensional unsteady dam-break flow. It is found that this second-order force scheme can improve the computational accuracy in time compared with the previous force treatment in the lattice Boltzmann model for shallow water. Moreover, the scheme can be also incorporated in the multiple-relaxation-time models.

In this work, we derive a lattice Boltzmann model for fluid-particle interaction by considering the system as a two-phase mixture. A partially saturated type scheme is achieved rigorously without any viscosity-dependent weight parameter. The scheme is of second-order accuracy in both space and time including the body-force term. Moreover, we devise a scheme suitable for the scenario where two or more particles intersect a single computational cell, typically occurring for particles in contact or close to contact. Good performance is found when the present scheme is validated against three classic problems, namely the flow past a stationary cylinder, a cylindrical particle settling in a channel under gravity, and the flow around two impacting cylinders.

Many novel, efficient solar absorber coatings are developed in recent decades. However, the methods of qualification tests, such as test of thermal stability, corrosion resistance and prediction of service life that have important engineering significance for solar absorbers to be large-scale applications, are still lacking. Currently, European standard (EN 12975-3-1) and International standard (ISO/CD 12592, 2) are usually applied in conventional situations, such as low- to mid- temperature, slight moisture and sulphur dioxide. However, many other developing industrial countries may face a tougher circumstance, for instance, acid rain, salt mist, sandstorm, smog etc. Therefore, resulting in more complicated ageing mechanisms that the European standard and International standard are no longer well suited. As for the current thermal stability test methods. The customized test method are usually adopted to evaluate the coatings durability during research stage. And the standard test method mainly used to predict the service lifetime for low- to mid- temperature applications. The current problem is how to make up the scarcity of standard test procedure for performance evaluation of high-temperature solar absorber coatings. As for the ageing mechanisms, the most common ageing mechanisms under high temperature are diffusion and oxidation of elements. But, more details on the thermal stability and micro behaviours including element diffusion and distribution, chemical interaction, crystal transition, the surface and cross section ageing morphology of different solar absorber coatings, are still worthy of in-depth study. This paper reviews various solar absorber coatings and thermal stability test methods, evaluates the temperature induced ageing mechanisms, and discusses several commercial applications and challenges in protect the solar absorber coatings. The purpose of this review is to discuss the thermal stability and underlying ageing process of some popular coatings, and the scope for performance improvement. In addition, this paper addresses the new concept of graphene solar absorber coatings.

Highly corrosion resistant, layer-by-layer nanostructured Si3N4/Cr-CrNx/Si3N4 coatings were deposited on aluminum substrate by DC/RF magnetron sputtering. Corrosion resistance experiments were performed in 0.5, 1.0, 3.0, and 5.0 wt % NaCl salt spray at 35 °C for 168 h. Properties of the coatings were comprehensively investigated in terms of optical property, surface morphology, microstructure, elemental valence state, element distribution, and potentiodynamic polarization. UV–vis–near-IR spectrophotometer and FTIR measurements show that the change process in optical properties of Si3N4/Cr-CrNx/Si3N4/Al coatings can be divided into three stages: a rapid active degradation stage, a steady passivation stage, and a transpassivation degradation stage. With the increase in the concentration of NaCl salt spray, solar absorptance and thermal emittance experienced a slight degradation. SEM images reveal that there is an increase in surface defects, such as microcracks and holes and -cracks. XRD and TEM measurement...

Ultraviolet (UV) detection is of important significance in protecting environment, human health and related scenarios. Schottky barrier height (SBH) plays a key role in determining the performance of UV sensors. Herein, triboelectric voltage was proposed to lower the SBH of zinc oxide nano/micro wire and silver paste (ZnO//Ag) UV sensor. SBH was flexibly lowered by different times of triboelectric voltage treatment. Greatly improved UV response was achieved based on Schottky-to-Schottky contact after lowering its SBH, its photoresponse rates were enhanced by 645 % at raising edge from 6.77 s to 1.05 s, and 716 % at falling edge from 2.72 s to 0.38 s. The on/off ratio was greatly increased from 590 to 10400. Based on these results, the triboelectric technology may provide new views for tuning performance of Schottky-junction-based sensors. The developed tunable ZnO//Ag sensor combined with triboelectric voltage opens up possibility for future high sensitive UV sensing systems.

The progress of the Internet-of-Things in the past few years has necessitated the support of high-performance sensors. Schottky-contacted nanowire sensors have attracted considerable attention owing to their high sensitivity and fast response time. Their progress is reviewed here, based on several kinds of important nanowires, for applications such as bio/chemical sensors, gas sensors, photodetectors, and strain sensors. Although Schottky-contacted nanowire sensors deliver excellent performance in these fields, they can be further improved by various methods, including defect engineering, surface modification, the piezotronic effect, and the piezophototronic effect, all of which are discussed here. With regard to practical applications, further efforts are required to address challenges such as the stability, selectivity, ultrafast response, multifunctionality, flexibility, distributed energy supply, and sustainability of Schottky-contacted nanowire sensors. Finally, future perspectives and solutions are discussed.

Implantable medical electronic devices are usually powered by batteries or capacitors, which have to be removed from the body after completing their function due to their non‐biodegradable property. Here, a fully bioabsorbable capacitor (BC) is developed for life‐time implantation. The BC has a symmetrical layer‐by‐layer structure, including polylactic acid (PLA) supporting substrate, PLA nanopillar arrays, self‐assembled zinc oxide nanoporous layer, and polyvinyl alcohol/phosphate buffer solution (PVA/PBS) hydrogel. The as‐fabricated BC can not only work normally in air but also in a liquid environment, including PBS and the animal body. Long‐term normal work time is achieved to 30 days in PBS and 50 days in Sprague–Dawley (SD) rats. The work time of BC in the liquid environment is tunable from days to weeks by adopting different encapsulations along BC edges. Capacitance retention of 70% is achieved after 3000 cycles. Three BCs in series can light up 15 green light‐emitting diodes (LEDs) in vivo. Additionally, after completing its mission, the BC can be fully degraded in vivo and reabsorbed by a SD rat. Considering its performance, the developed BC has a great potential as a fully bioabsorbable power source for transient electronics and implantable medical devices.

The thermal stability of AlN films deposited by ion beam assisted deposition was performed at 600 °C for 192 h under air ambient. The composition, morphology and optical properties were studied by X-ray photoelectron spectrometer, transmission electron microscopy, scanning electron microscopy, spectroscopic ellipsometry and UV–vis spectroscopy. The results show that the deposited film is polycrystalline, smooth, dense and homogenous. The oxidation of grain boundary takes place due to the element diffusion in the polycrystalline material. Oxidation produces amorphous oxide layers on the surface of film. As annealing time increases, surface roughness and diffuse reflection increase. Annealing has little influence on refractive index and extinction coefficient.

The influence of ion–atom arrival ratio on composition, micro-structure and optical properties of ZrN x films prepared by ion beam assisted deposition was studied by using XPS, XRD, and spectroscopic ellipsometry. The stoichiometric ZrN is prepared at ion–atom arrival ratio of 1.5. For ZrN x films deposited at ion–atom arrival ratio of 2.4 and 5.0, a strong (220) texture is formed in the ZrN x film. The refractive index of ZrN x films increased with the increase of ion–atom arrival ratio; whereas, a continuous decrease of the extinction coefficient was noticed.

In order to improve the optical properties of AlN films, the influence of the ion/atom arrival ratio on the structure and optical characteristics of AlN films deposited by dual ion beam sputtering was studied by using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, spectroscopic ellipsometry and UV–vis spectroscopy. The films prepared at the ion/atom arrival ratio of 1.4 are amorphous while the crystalline quality is improved with the increase of the ion/atom arrival ratio. The films deposited at the ion/atom arrival ratio of no less than 1.8 have an approximately stoichiometric ratio and mainly consist of aluminum nitride with little aluminum oxynitride, while metallic aluminum component appears in the films deposited at the ion/atom arrival ratio of 1.4. When the ion/atom arrival ratio is not less than 1.8, films are smooth, high transmitting and dense. The films prepared with high ion/atom arrival ratio (≥1.8) display the characteristic of a dielectric. The films deposited at the ion/atom arrival ratio of 1.4 are coarse, opaque and show characteristic of cermet.

For lattice Boltzmann (LB) models, their particle feature is ensured by the streaming-collision mechanism. However, this mechanism is often discarded for high-order LB models due to multi-speed lattices. Here, we propose a new way of implementing the diffuse reflection boundary condition that can maintain the characteristic streaming-collision mechanism for high-order models. It is then tested on four lattice models, namely D2Q16, D2Q17, D2Q37 and D3Q121 for isothermal and thermal Couette flows and lid-driven cavity flows. Our implementation is shown to be able to achieve second-order accuracy globally.