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The gas-sensing performance of PbSnS2 monolayer to sulfur hexafluoride (SF6) decompositions (SO2, H2S, HF, SOF2, and SO2F2) has been systematically studied by density functional theory and nonequilibrium Green’s function calculations. The most stable adsorption configurations, adsorption energies, charge transfer, electron localization function (ELF), density of states (DOS), and ${I}$ – ${V}$ curves of gas molecules on PbSnS2 are calculated and discussed. SO2 exhibits the largest adsorption energy of −0.74 eV with the charge transfer of −0.39 e and HF possesses the biggest charge transfer of −0.66 e with the adsorption energy of −0.46 eV. The results of ELF and DOS show that the interaction between SO2 and PbSnS2 may be stronger than those of other gases. Moreover, ${I}$ – ${V}$ curves show that the responses of PbSnS2 to SO2 is up to 65.5% at the bias of 2.2 V. Therefore, PbSnS2 monolayer may be a qualified material for detecting SF6 decompositions.

Sintered Cu is considered as the most promising strategy in die-attachment, since its capacities of low-temperature bonding and high-temperature working. Many studies have reported the excellent properties of sintered Cu, but there is still some room for improvement. Here, strong Cu–Cu joints and insulated-gate bipolar transistor (IGBT) devices are achieved by sintering Cu paste and three composite pastes, and the mechanical, electrical, and microstructure properties of joints are investigated. The shear strength of pure Cu bonded joint is 23.4 MPa, which is improved to 26.64 MPa by introducing 0.6 wt% N-doped multi-walled carbon nanotubes (N-doped MWCNTs) into Cu paste. Excellent electrical properties are achieved as the resistivities of sintered Cu/N-doped MWCNTs layer and Cu/carboxylated WMCNTs are 2.252 and 2.551 μ Ω·cm, respectively, which are lower than the sintered pure Cu layer (3.473 μ Ω·cm). In addition, the functionalized MWCNTs are found exerted positive effects on the joint reliability. The enhancements on the joint qualities are attributed to that the functionalized MWCNTs improve the affinity of the Cu and CNTs and increase the density of bonding layer. This article provides an effective way to improve the sintered Cu joints sintering qualities, which is suitable for the attachment of next-generation devices and substrates.

In this work, recovery performance of a novel sort of form stable phase change materials (FSPCMs) with simultaneously shape memory properties was investigated systematically. The FSPCMs comprising hexadecane as latent heat storage material and olefin block copolymer (OBC) as supporting material were prepared by simple swelling preparation method. This kind of difunctional materials exhibits fantastic shape memory properties with mass fraction of hexadecane reaching 70 wt%, which indicates excellent energy storage ability as well. It is found that the recovery performance under 50% strain is obviously better than that under higher strains for all the specimens investigated, while surprisingly, the composite with 70 wt% hexadecane exhibits better recovery performance than pure OBC as well as the composite with 30 wt% hexadecane at strains of 100 and 200%. The structural change brought by incorporation of hexadecane was explored with in situ two-dimensional X-ray scattering measurements. According to experiment results, we find that the recovery performance is closely correlated to change of long period, indicating the irreversible deformation of the difunctional materials may originate from lamellar fragmentation of OBC, while addition of massive hexadecane is beneficial to restrain lamellar fragmentation and thus improves the recovery performance. We believe this exploration may shed light on comprehending the relationship between structural change and shape memory performance, thus contributing to adjusting the properties of the difunctional materials and expanding their potential applications.