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Halide perovskites are potential next‐generation optoelectronic devices. However, the film quality of this charming material fabricated by the conventional spin‐coating method is far from satisfactory, significantly affecting the optoelectronic devices' performance. Here, one facile slow‐evaporating solvent (SE) method is demonstrated to synthesize high‐quality organic–inorganic halide perovskite films. Compared with the conventional spin coating method, the films fabricated by this SE method show much higher crystallinity, oriented lattice, smoother surface morphology, and lower trap density. Besides, the photodetector manufactured by the SE method‐based film also performs much better than the ones by the spin‐coating method. Importantly, this universal method can be applied to different organic–inorganic halide perovskites, such as Dion–Jacobson (DJ) type and Ruddlesden–Popper type 2D halide perovskites and conventional 3D halide perovskites. This work gives an effective solution to improve the quality of the DJ‐type halide perovskites, which endows the halide perovskites with a more practical chance to be commercialized cosmically. [ABSTRACT FROM AUTHOR]

Epitaxial γ′-Fe4N films with different thicknesses were fabricated on Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) substrates by facing-target reactive sputtering. The magnetoelectric coupling (MEC) in the samples was systematically investigated. Firstly, the magnetization along different in-plane directions is tunable by the electric field. It was found that MEC in the films on PMN-PT(011) is stronger than that on PMN-PT(001) due to the different in-plane magnetic anisotropy. Moreover, the magnetoelectric coupling is strongly related to the γ′-Fe4N film thickness, which can be ascribed to the competition between the strain and spin-dependent screening effect induced MEC. Additionally, the electric-field tailored remanent magnetization of the samples gradually increases with temperature due to the thermal agitation. Besides, the electric-field effect on the out-of-plane magnetic hysteresis loops is consistent with the in-plane cases. The results are of benefit to the development of the electric-field controlled spintronic devices. [ABSTRACT FROM AUTHOR]

The visual system, one of the most crucial units of the human perception system, combines the functions of multi‐wavelength signal detection and data processing. Herein, the large‐scale artificial synaptic device arrays based on the organic molecule‐nanowire heterojunctions with tunable photoconductivity are proposed and demonstrated. The organic thin films of p‐type 2,7‐dioctyl[1]benzothieno[3,2‐b][1] benzothiophene (C8‐BTBT) or n‐type phenyl‐C61‐butyric acid methyl ester (PC61BM) are used to wrap the InGaAs nanowire parallel arrays to configure two different type‐I heterojunctions, respectively. Due to the difference in carrier injection, persistent negative photoconductivity (NPC) or positive photoconductivity (PPC) are achieved in these heterojunctions. The irradiation with different wavelengths (solar‐blind to visible ranges) can stimulate the heterojunction devices, effectively mimicking the synaptic behaviors with two different photoconductivities. The long‐term and multi‐state light memory are also realized through synergistic photoelectric modulation. Notably, the arrays with different photoconductivities are adopted to build the hardware kernel for the visual system. Due to the tunable photoconductivity and response to multiple wavelengths, the recognition rate of neural networks can reach 100% with lower complexity and power consumption. Evidently, these photosynaptic devices are illustrated with retina‐like behaviors and capabilities for large‐area integration, which reveals their promising potential for artificial visual systems. [ABSTRACT FROM AUTHOR]

Controllable self‐catalyzed growth of semiconductor nanowires (NWs) is of great importance, particularly to avoid impurities coming from foreign catalysts to deteriorate the NW properties. Although this catalyst‐free NW growth has many obvious advantages, there are very limited works focused on all‐inorganic CsPbBr3 perovskite NWs, which is one of the recent champion materials for electronics and optoelectronics. Here, a direct self‐catalyzed synthesis of freestanding CsPbBr3 NWs via vapor–liquid–solid growth mechanism by chemical vapor deposition is developed. Notably, mainipulation of the substrate surface roughness is the key enabling parameter for the self‐catalyzed NW growth here. It is revealed that the surface energy of substrates, modulated by its surface roughness, is found to effectively mediate the self‐catalytic growth of CsPbBr3 NWs. When configured into photodetectors, the intrinsic p‐type CsPbBr3 NWs exhibit good optoelectronic performance with a photoresponivity of ≈2000 A W−1, a detectivity of ≈2.57 × 1012 Jones, and a fast response down to 362 µs. All these results evidently indicate the technological potential of this self‐catalyzed synthesizing route for other high‐quality all‐inorganic perovskite NWs. [ABSTRACT FROM AUTHOR]

Continuous miniaturization of semiconductor devices is the key to boosting modern electronics development. However, this downscaling strategy has been rarely utilized in photoelectronics and photovoltaics. Here, in this work, a full‐van der Waals (vdWs) 1D p‐Te/2D n‐Bi2O2Se heterodiode with a rationally designed nanoscale ultra‐photosensitive channel is reported. Enabled by the dangling bond‐free mixed‐dimensional vdWs integration, the Te/Bi2O2Se type‐II diodes show a high rectification ratio of 3.6 × 104. Operating with 100 mV reverse bias or in a self‐power mode, the photodiodes demonstrate excellent photodetection performances, including high responsivities of 130 A W−1 (100 mV bias) and 768.8 mA W−1 (self‐power mode), surpassing most of the reports of other heterostructures. More importantly, a superlinear photoelectric conversion phenomenon is uncovered in these nanoscale full‐vdWs photodiodes, in which a model based on the in‐gap trap‐assisted recombination is proposed for this superlinearity. All these results provide valuable insights in light–matter interactions for further performance enhancement of photoelectronic devices. [ABSTRACT FROM AUTHOR]

CsPb2Br5/CsPbBr3 composite systems have received considerable attention among numerous lead halide perovskite materials due to their significantly enhanced photoluminescence intensity and stability against moisture. However, the luminescence mechanism of CsPb2Br5 based materials remains controversial, which significantly hinders the further material design and utilization for optoelectronic devices. In this work, to deconvolute their luminescent mechanisms, high-quality CsPb2Br5 crystals without any undesired by-products and impurities have been first prepared by a microwave-assisted synthesis method. The luminescence-inactive characteristics of the material are then confirmed by the steady-state absorption, photoluminescence, transient absorption spectra, and time-resolved terahertz spectroscopy. The prepared CsPb2Br5 crystals exhibit excellent crystallinity and enhanced thermal stability, particularly that they can maintain their crystalline structures in polar organic solvents. By simply manipulating the ratios of different precursor materials, it is witnessed that the green emission comes from the CsPbBr3 adhered, nucleated, and grown on the CsPb2Br5 crystals. Ultrafast transient absorption measurements in visible and terahertz spectral regions reveal that with the help of phonon scattering-assisted hopping at interfacial states, intersystem crossing dominates the electron transfer process in the composite crystals. As a result, the CsPb2Br5 and CsPbBr3 interact extensively with each other. Meanwhile, the Auger recombination rate and the defect-related non-radiative process are suppressed in the composite crystals, thereby enhancing the fluorescence of composite crystals. This work has not only deconvoluted the controversial and unclear luminescent mechanisms of CsPb2Br5 materials but also established a pathway to design and enhance the fluorescence of materials for technological applications. [ABSTRACT FROM AUTHOR]