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Lead halide perovskites have attracted extensive attention in recent years because of their excellent photoelectronic properties, such as high absorption coefficients, carrier mobilities, defect tolerances, and photoluminescence efficiencies. However, a key issue hindering their commercial application is the toxicity of lead. Replacing lead with other nontoxic elements is a promising solution to this problem. Considering their atomic radii, relative atomic masses, and electron arrangements, perovskites based on Sn, Bi, Sb, and other elements instead of Pb have been widely synthesized. Here, we summarized the growth methods, photoelectric properties, and device applications of these lead-free perovskites. First, we introduced several common growth methods for lead-free perovskites, including solution methods, solid-state reaction, and chemical vapor deposition methods. Second, we discussed the photoelectric properties and methods for optimizing these properties of lead-free perovskites with different structure dimensions. Finally, the applications of lead-free perovskites in solar cells, light-emitting diodes, and X-ray detectors were examined. This review also provides suggestions for future research on lead-free perovskites.

Mass production of semiconductor quantum dots (QDs) from bulk materials is highly desired but far from being satisfactory. Herein, we report a general strategy to mechanically tailor semiconductor bulk materials into QDs. Semiconductor bulk materials are routinely available via simple chemical precipitation. From their bulk materials, a variety of semiconductor (e.g., lead sulfide (PbS), cadmium sulfide (CdS), copper sulfide (CuS), ferrous sulfide (FeS), and zinc sulfide (ZnS)) QDs are successfully produced in high yields (>15 wt%). This is achieved by a combination of silica-assisted ball-milling and sonication-assisted solvent treatment. The as-produced QDs show intrinsic characteristics and outstanding water solubility (up to 5 mg mL-1), facilitating their practical applications. The QD dispersions present remarkable photoluminescence (PL) with exciton-dependence and nanosecond (ns)-scale lifetimes. The QDs-poly(methyl methacrylate) (PMMA) hybrid thin films demonstrate exciting solid-state fluorescence and exceptional nonlinear saturation absorption (NSA). Absolute modulation depths of up to 58% and saturation intensities down to 0.40 MW cm-2 were obtained. Our strategy could be applied to any semiconductor bulk materials and therefore paves the way for the construction of the complete library of semiconductor QDs.

Perovskite materials, especially metal halide perovskites, exhibit excellent properties, such as large optical coefficients, high carrier mobilities, long carrier lifetimes, tunable resistivities, large X-ray attenuation coefficients, and simple processing techniques. In recent decades, perovskites have attracted significant attention in the photoelectric field due to their versatile utility in solar cells, light-emitting diodes, photodetectors, X/γ-ray detectors, and lasing. However, the wide applicability of perovskites highly depends on the quality of perovskite crystals and films. Thus far, several perovskite growth technologies and methods have emerged. Therefore, this review classified and summarized the main methods that have been employed to achieve perovskite growth in recent years, including the solution temperature-lowering (STL) method, inverse temperature crystallization (ITC), anti-solvent vapor-assisted crystallization (AVC), spin coating, and chemical vapor deposition (CVD). Through analysis and summary, it has been determined that the STL, ITC, and AVC methods are mainly used to grow high-quality perovskite single crystals. While the spin-coating method has a significant advantage in the preparation of perovskite films, the CVD method is propitious in the fabrication of a variety of morphologies of micro/nano perovskite materials. We hope that this review can be a comprehensive reference for scientific researchers to prepare perovskite-related materials.

A series of mesoporous materials of SBA-16 were in situ incorporated into ZSM-5 crystallites via a two-step self-assemble method, and hydrodesulfurization (HDS) catalysts were prepared on the corresponding ZSM-5/SBA-16 (ZS) composites. The characterization results indicated that ZSM-5 nanoseeds were fabricated into the silica framework of the ZS composites, and the three-dimensional Im3m cubic structure of SBA-16 was retained simultaneously. In addition, the ZS series materials possessed open pores and large surfaces, which would facilitate the diffusion of reactants in the mesoporous channels. Moreover, the introduction of ZSM-5 seeds into composites could enhance the acidities of supports. As a result, the NiMo/ZS series catalysts exhibited high activities for DBT HDS processes. The NiMo/ZS-160 catalyst exhibited the highest catalytic efficiency (96.5%), which was apparently attributed to the synergistic contributions of the physicochemical properties of ZS supports and the dispersion states of active metals. Correspondingly, DBT HDS reactions over the NiMo/ZS series catalysts mainly proceeded via a hydrogenation desulfurization route that benefitted from the enhanced acidities especially the total Brønsted acid.

Low-cost pure aluminum-based Al-TUD-1 mesoporous materials (AT) were successfully synthesized and the corresponding NiMo/AT catalysts were modified with Citric acid (CA), which were utilized for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) reactions. CA could effectively modulate the acidity and metal-support-interaction (MSI) of NiMoCA(x)/AT catalysts, which were in favor of generating more MoS2 active species with higher sulfurization degree and higher dispersion degree. The morphology of the MoS2 active phase of NiMoCA(x)/AT catalysts was changed after the addition of CA. The NiMoCA(2)/AT catalyst showed the higher B/L ratio and higher S-edge/M-edge ratio, which was conducive to the isomerization (ISO) route selectivity (81%) of 4,6-DMDBT HDS, thus resulting the improvement of HDS activity of the NiMoCA(2)/AT catalyst. The NiMoCA(2)/AT exhibited the maximal DBT and 4,6-DMDBT HDS efficiency of 99.0% and 95.5% as well as maximal kHDS and TOF values of 4,6-DMDBT HDS (13.4 × 10−4 mol⋅g−1⋅h−1, 4.7 h−1) among other series NiMoCA(x)/AT catalysts and reference commercial NiMo/Al2O3 catalyst at the Weight hour space velocity (WHSV) of 10 h−1.