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Piezoelectric sensors are excellent damage detectors that can be applied to structural health monitoring (SHM). SHM for complex structures of aerospace vehicles working in harsh conditions is frequently required, posing challenging requirements for a sensor’s flexibility, radiation hardness, and high-temperature tolerance. Here, we fabricate a flexible and lightweight Pb(Zr0.53Ti0.47)O3piezoelectric film on flexible KMg3(AlSi3O10)F2substrate via van der Waals (vdW) heteroepitaxy, endowing it with robust ferroelectric and piezoelectric properties under low energy-high flux protons (LE-HFPs) radiation (1015p/cm2). More importantly, the Pb(Zr0.53Ti0.47)O3film sensor maintains highly stable damage monitoring sensitivity on an aluminum plate under harsh conditions of LE-HFPs radiation (1015p/cm2, flat structure), high temperature (175 °C, flat structure), and mechanical fatigue (bending 105cycles under a radius of 5 mm, curved structure). All these superior qualities are suggested to result from the outstanding film crystal quality due to vdW epitaxy. The flexible and lightweight Pb(Zr0.53Ti0.47)O3film sensor demonstrated in this work provides an ideal candidate for real-timeSHM of aerospace vehicles with flat and complex curve-like structures working in harsh aerospace environments.

Heterostructures composed of superconductor and ferroelectrics (SC/FE) are very important for manipulating the superconducting property and applications. However, growth of high-quality superconducting iron chalcogenide films is challenging because of their volatility and FE substrate with rough surface and large lattice mismatch. Here, we report a two-step growth approach to get high-quality FeSe0.5Te0.5(FST) films on FE Pb(Mg1/3Nb2/3)0.7Ti0.3O3with large lattice mismatch, which show superconductivity at only around 10 nm. Through a systematic study of structural and electric transport properties of samples with different thicknesses, a mechanism to grow high-quality FST is discovered. Moreover, electric-field-induced remarkable change of Tc(superconducting transition temperature) is demonstrated in a 20 nm FST film. This work paves the way to grow high-quality films which contain volatile element and have large lattice mismatch with the substrate. It is also helpful for manipulating the superconducting property in SC/FE heterostructures.

Quadruply bonded dimolybdenum complexes with a σ2π4δ2electronic configuration for the ground state have rich metal-centered photochemistry. An earlier study showed that stoichiometric or less amount of molecular hydrogen was produced upon irradiation by ultraviolet light (λ = 254 nm) of K4Mo2(SO4)4in sulfuric acid solution, which was attributed to the reductive capability of the ππ* excited state. To make use of the δ electrons for visible-light-induced photocatalytic hydrogen evolution, a multicomponent heterogeneous photocatalytic system containing K4Mo2(SO4)4photosensitizer, TiO2electron relay, and MoS2cocatalyst is designed and tested. With ascorbic acid added as a sacrificial reagent, irradiation by artificial sunlight (AM 1.5) on the reaction in 5 M H2SO4has produced 13 400 μmol g–1of molecular hydrogen (based on the Mo2complex), which is 30 times higher than the hydrogen yield obtained from the reaction of bare K4Mo2(SO4)4with H2SO4under ultraviolet light irradiation. Further improvement of hydrogen evolution is achieved by addition of oxalic acid, along with an electron donor, which gives an additional 50% increase in H2yield. Spectroscopic analyses indicate that, in this case, a junction between the Mo2complex and TiO2is built by the oxalate bridging ligand, which facilitates charge injection and separation from the Mo2core. This Mo2–TiO2–MoS2system has achieved a high hydrogen evolution rate up to 4570 μmol g–1h–1. The efficiency of K4Mo2(SO4)4as a metal-centered photosensitizer is also proved by parallel experiments with a dye chromophore, fluorescein, which presents comparable H2yields and hydrogen evolution rates. Most importantly, in this study, detailed analyses illustrate that the photocatalytic cycle with hydrogen gas as an outcome of the reaction is established by involvement of the δδ* excited state generated by visible light irradiation. Therefore, this work shows the potential of quadruply bonded Mo2complexes as photosensitizers for photocatalytic hydrogen evolution.