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The power conversion efficiencies (PCEs) of the solar cells containing metal halide perovskites (MHPs) have rapidly increased and exceeded 25% during the past decade. The photovoltaic properties of these devices are extensively investigated in terms of their microstructures, environmental characteristics, and carrier dynamics, and the MHP structural evolution under high pressure is evaluated. In addition, the energy level structure, electron/hole dynamics, and optical/electronic properties of MHPs with anisotropic crystal structures are examined. However, the correlation between the structural anisotropy and material properties of these perovskites is rarely considered in the literature studies on their high‐pressure behavior. In this progress report, the optical/electronic properties of MHPs with anisotropic structures under thermal, mechanically imposed, and in‐service strains/stresses that have been previously neglected by researchers are summarized.

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Perovskite resistive random-access memory (RRAM) is a promising candidate for next-generation logic, adaptive and nonvolatile memory devices, because of its high ON/OFF ratio, low-cost fabrication, and good photoelectric regulation performance. In this work, a flexible transparent CsPbBr 3 quantum dots (QDs) mixed in graphene oxide (GO) RRAM device is introduced, which is controllable by both an electric field and illumination. Under illumination, the ON/OFF ratio of the Ag/CsPbBr 3 QDs:GO/ITO device is ≈1.4 × 10 7 , which is 1077 times larger than that in the dark condition (1.3 × 10 4 ). The SET/RESET voltages are +2.28/−2.04 V and +1.68/−1.08 V under the dark and illumination conditions, respectively. As a flexible memory device, the resistances are little affected by the bending curvatures and load-cycling. Before and after 10 4 bending cycles with a radius of 5 mm under illumination, the ON/OFF ratios keep in the same order, which are 2.5 × 10 7 and 2.3 × 10 7 , respectively. The ratio values are 8.8 × 10 4 and 2.9 × 10 4 under the dark condition, respectively. This innovative resistive memory based on the CsPbBr 3 QDs:GO hybrid film supports a huge space for the development of photoelectrical dual-controlled flexible RRAM devices.

Methylammonium lead triiodide (MAPbI 3 ) perovskite has attracted broad interest for solar cells, light-emitting diodes, and so forth. Experiments have captured that the alternative coexistence of polar and nonpolar domains in MAPbI 3 can be switched by photons and phonons. Therefore, it is urgent to clarify the interplay among the crystal space group, polarity, ferroic properties, and switching mechanisms for MAPbI 3 . Herein, we perform a statistical synthesis on ferroelectric and anti-ferroelectric features for tetragonal MAPbI 3 perovskite. The polar and nonpolar domains are ferroelectric with the I4cm space group and anti-ferroelectric with the I4/mcm space group, respectively.The domain wall (DW) separating nonpolar and polar regions is charged. Combining the effects of the electric properties of ferroic domains and the charged DWs, novel switching mechanisms are proposed in which photons and phonons drive alternations between ferroelectric and anti-ferroelectric domains, which provide a reasonable approach to clarify the ambiguous understanding of ferroic behavior for MAPbI 3 perovskite.

Existing strategies for reconfigurable three-dimensional (3D) electronics are greatly constrained by either the complicated driven mechanisms or harsh demands for conductive materials. Developing a simple and robust strategy for 3D electronics reconstruction and function extension remains a challenge. Here, we propose a solvent-driven bistable actuator, which acts as a substrate to reconstruct the combined 3D electronic device. Extraction of silicon oil from a hybrid poly(dimethylsiloxane) (PDMS) circle sheet buckles the dish to a bistable structure. The ultraviolet (UV)/ozone treatment on one surface of the PDMS structure introduces an oxidized layer, yielding a bilayered, solvent-driven bistable smart actuator. The snap-back stimulus to the oxidized layer differs from the snap-through stimulus. Experimental and numerical studies reveal the fundamental regulations for buckling configurations and the bistable behavior of the actuator. The prepared bistable actuator drives the bonded kirigami polyimide (PI) sheets to diverse 3D structures from the original bending configuration, reversibly. A frequencyreconfigurable electrically small monopole antenna is presented as a demonstration, which paves a way for the applications of this actuator in the field of reconfigurable 3D electronics.

This paper presents an experimental study on the spalling characteristics, mass loss ratio, ultrasonic pulse velocity, compressive strength and flexural strength of self-compacting lightweight concrete (SCLC) at elevated temperature.Four types of SCLC specimens with and without polypropylene fibres (PPFs) and one type of normal concrete (NC) specimens were cast and tested. Based on the experimental observations and results, it was found that, compared with NC, SCLC spalls at a lower temperature but maintains a higher residual strength. For all the concretes the peak mass loss ratio increased but the relative ultrasonic pulse velocity decreased with the rise of temperature. At a given elevated temperature, the relative compressive strength and flexural strength of SCLC was larger than those of NC.The addition of PPFs greatly reduced the risk of spalling of SCLC. The thermal damage and the loss in residual mechanical properties of SCLC with PPFs were smaller compared with that without PPFs.

In this work, a thermally induced bistable plate made of functionally graded carbon nanotubereinforced composite (FG-CNTRC) with integrated piezoelectric patches is proposed for broadband energy harvesting. Single-walled carbon nanotubes (SWCNTs) in this nanocomposite are assumed to have two kinds of functionally graded distributions in the thickness direction. Based on Hamilton's principle and the first-order shear deformation theory of laminates with considering von Kármán geometrical nonlinearity, a finite element (FE) model is developed to predict the energy harvesting performance of the proposed bistable plate. By applying thermal field and harmonic excitation to the plate, the cooling-down process and nonlinear dynamic response are analyzed for the bistable behavior of the plate, respectively. The simulation results are validated through comparing with the results obtained from the commercial FE software package ABAQUS. The developed FE model is then used to predict the open-circuit voltages for the proposed bistable energy harvester under different excitation levels. Frequency response diagrams of the root mean square (rms) voltage for the plates with and without bistability are simulated and compared. It is found that bistable FG-CNTRC plates can operate over a wide range of frequencies with delivering higher power than their linear counterparts. Effects of volume fractions and distribution types of SWCNTs on the dynamic behaviors of FG-CNTRC plate are also discussed. It is demonstrated that FG-CNTRC plates show different dynamic characteristics when changing CNTs volume fractions and distributions in it.