This paper presents the anti-corrosion application of polyvinylbutyral/tin sulfide (PVB/SnS) composites for the first time, where the liquid-phase exfoliated (LPE) SnS nanosheets are uniformly embedded in the PVB matrix. The measurement results of the potentiodynamic polarization, the electrochemical impedance spectroscopy (EIS) and the scanning electronic microscopy (SEM) show that PVB/SnS composite coatings show the excellent corrosion protection behavior for copper under 3.0% NaCl solution. Besides, we investigated the anti-corrosion performance with different contents of SnS nanosheets. The results show that embedding 0.1 wt% SnS nanosheets in the PVB matrix can greatly improve the anti-corrosion properties of the coating due to the enhanced "Labyrinth effect" of the coatings. In addition, the results of the molecular dynamic analysis further show the high interaction energy between PVB/SnS composites and copper, which is attributed to the high aspect-ratio of LPE-SnS nanosheets. Moreover, the scratch tests reveal that the PVB/SnS composite coatings exhibit weak corrosion-promotion activity, indicating a promising potential application in the corrosion protection of the metal surface for ocean engineering. The methods for enhancing the inhibited corrosion-promotion activity of the semiconductor material SnS-based composite coatings could be expanded to other n-type and p-type semiconductors.

In this work, a thin-film transistor gas sensor based on the p-N heterojunction is fabricated by stacking chemical vapor deposition-grown tungsten disulfide (WS₂) with a sputtered indium-gallium-zinc-oxide (IGZO) film. To the best of our knowledge, the present device has the best NO₂ gas sensor response compared to all the gas sensors based on transition-metal dichalcogenide materials. The gas-sensing response is investigated under different NO₂ concentrations, adopting heterojunction device mode and transistor mode. High sensing response is obtained of p-N diode in the range of 1-300 ppm with values of 230% for 5 ppm and 18 170% for 300 ppm. On the transistor mode, the gas-sensing response can be modulated by the gate bias, and the transistor shows an ultrahigh response after exposure to NO₂, with sensitivity values of 6820% for 5 ppm and 499 400% for 300 ppm. Interestingly, the transistor has a typical ambipolar behavior under dry air, while the transistor becomes p-type as the amount of NO₂ increases. The assembly of these results demonstrates that the WS₂/IGZO device is a promising platform for the NO₂-gas detection, and its gas-modulated transistor properties show a potential application in tunable engineering for two-dimensional material heterojunction-based transistor device.

In this study, the structural, electronic and optical properties of a tungsten disulfide (WS₂) hybrid with indium-gallium-zinc-oxide (IGZO) heterostructures were investigated based on density functional theory (DFT) calculations. According to the results of binding energy, charge density difference and electron localization function of heterostructures, we found that the WS₂ and IGZO monolayers were bound to each other via non-covalent interactions with large binding energy. The calculated results illustrate that the AAii stacking pattern has an indirect band gap of 1.643 eV, while AAi and AB stacking patterns have maximum direct-gaps of 1.102 eV and 1.234 eV, respectively. Under an external E-field and mechanical strain, the response of the energy gap of the WS₂/IGZO heterostructure monotonically decreased over a wide range, even with a semiconductor-metal transition. In addition, we investigated the optical properties of the heterostructure and found that it exhibits a much broad spectral responsivity (from visible light to deep UV light) and a more pronounced optical absorption than WS₂ and IGZO monolayers. Moreover, the tensile strain could weaken the photoresponse of the heterostructure to the UV light and enhance the response for the visible light; under compressive strain, the heterostructure showed a strong absorption peak in the UV light. Meanwhile, a red-shift was observed under an external strain. All these unique and tunable properties indicate that the WS₂/IGZO heterostructure is a good candidate for nanoelectronic and photoelectronic devices, such as field-effect transistors, flexible sensors, photodetectors and photonic devices.

In this paper, four composite coatings of nano-SnS/polyvinylbutyral (PVB), nano-MoS₂/PVB, nano-SnS-Zn/PVB, and nano-MoS₂-Zn/PVB were prepared, and their anti-corrosion mechanism was analyzed by experimental and theoretical calculations. The results of the electrochemical experiments show that the effect of nano-MoS₂ on the corrosion protection performance of PVB coating is better than that of nano-SnS in 3% NaCl solution, and that the addition of Zn further enhances this effect, which is consistent with the results of weight loss measurements. Furthermore, the observation of the corrosion matrix by the field emission scanning electron microscope (FESEM) further confirmed the above conclusion. At last, the molecular dynamics (MD) simulation were carried out to investigate the anti-corrosion mechanism of the nanofillers/PVB composites for the copper surface. The results show that both nano-SnS and nano-MoS₂ are adsorbed strongly on the copper surface, and the binding energy of nano-MoS₂ is larger than that of nano-SnS.

SnS monolayer has sparked intensive attention due to its unique electronic and optical properties. We systemically investigate the electronic properties of SnS by first-principles calculation. Our results show that the monolayer possesses indirect bandgap. We further perform mechanical strain to adjust the electronic structure of SnS, corresponding results display an indirect-direct transition of band gap when subjected to proper external strain. Interestingly, the bandgap can be linearly increase under tensile strain from 0% to 7%, while the bandgap reduced under compressive strain. For biaxial strain, the band gap changes more remarkable compared with that under uniaxial strain (zigzag x or armchair y direction). Furthermore, we demonstrate that the gas molecules (CO₂, H₂S, C₂H₄ and NO₂) adsorption property on SnS monolayer can be modulated through biaxial strain. Especially, the NO₂ adsorption is further enhanced on the SnS monolayer under biaxial tensile strain. These results may provide guidance for fabricating SnS-based strained gas sensor.

In this work, the structural, electronic and optical properties of germanene and ZnSe substrate nanocomposites have been investigated using first-principles calculations. We found that the large direct-gap ZnSe semiconductors and zero-gap germanene form a typical orbital hybridization heterostructure with a strong binding energy, which shows a moderate direct band gap of 0.503 eV in the most stable pattern. Furthermore, the heterostructure undergoes semiconductor-to-metal band gap transition when subjected to external out-of-plane electric field. We also found that applying external strain and compressing the interlayer distance are two simple ways of tuning the electronic structure. An unexpected indirect-direct band gap transition is also observed in the AAII pattern via adjusting the interlayer distance. Quite interestingly, the calculated results exhibit that the germanene/ZnSe heterobilayer structure has perfect optical absorption in the solar spectrum as well as the infrared and UV light zones, which is superior to that of the individual ZnSe substrate and germanene. The staggered interfacial gap and tunability of the energy band structure via interlayer distance and external electric field and strain thus make the germanene/ZnSe heterostructure a promising candidate for field effect transistors (FETs) and nanoelectronic applications.

In this paper, the heat transfer performance of the multi-chip (MC) LED module is investigated numerically by using a general analytical solution. The configuration of the module is optimized with genetic algorithm (GA) combined with a response surface methodology. The space between chips, the thickness of the metal core printed circuit board (MCPCB), and the thickness of the base plate are considered as three optimal parameters, while the total thermal resistance (R_tot) is considered as a single objective function. After optimizing objectives with GA, the optimal design parameters of three types of MC LED modules are determined. The results show that the thickness of MCPCB has a stronger influence on the total thermal resistance than other parameters. In addition, the sensitivity analysis is performed based on the optimum data. It reveals thatR_tot increases with the increased thickness of MCPCB, and reduces as the space between chips increases. The effect of the thickness of base plate is far less than that of the thickness of MCPCB. After optimization, three types of MC LED modules obtain lower T_j andR_tot. Moreover, the optimized modules can emit large luminous energy under high-power input conditions. Therefore, the optimization results are of great significance in the selection of configuration parameters to improve the performance of the MC LED module.

Heat transfer across thermal interface material, such as graphene-polymer composite, is a critical issue for microelectronics thermal management. To improve its thermal performance, we use chemical functionalization on the graphene with hydrocarbon chains in this work. Molecular dynamics simulations are used to identify the thermal conductivity of monolayer graphene and graphene-polymer nanocomposites with and without grafted hydrocarbon chain. The influence of functionalization with hydrocarbon chains on the interfacial thermal conductance of graphene-polyethylene nanocomposites was investigated using a non-equilibrium molecular dynamics (NEMD) simulation. We also study the effects of the graft density (number of hydrocarbon chain) on the thermal conductivity of graphene and the nanocomposite.

The sensing behavior of monolayer tin sulfide (SnS) for four gas molecules (NH₃, NO₂, CO, and H₂O) are studied by the first-principle calculation based on density-functional theory. We calculate adsorption energy, adsorption distance, and Hirshfeld charge to estimate the adsorption ability of monolayer SnS for these gas molecules. The results demonstrate that all the gas molecules show physisorption nature. We further calculate the current-voltage (I -V ) curves using the nonequilibrium Green's function formalism for evaluating the NO₂ gas sensing properties. The monolayer SnS is found to be strongly sensitive to NO₂ molecule dependent on moderate adsorption energy, excellent charge transfer, and significant change of I -V property before and after gas adsorption. Therefore, we suggest that monolayer SnS can be a prominent candidate for application as NO₂ gas sensor.