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Zero-dimensional metal halide perovskite quantum dots (PQDs) display distinct chemical, physical, electrical, and optical properties compared to their bulk counterparts. These unique characteristics make PQDs highly promising materials for a broad range of applications spanning solar cells and light-emitting diodes (LEDs), to lasers and quantum technologies. Despite the recent advances, the translations of PQDs into commercially viable materials are hindered by several drawbacks; for example, an unclear understanding of their formation mechanism(s), the complex chemistry and dynamic instabilities at the PQDs surface, and the inefficient or unbalanced charge transportation in PQDs-based devices. In this review, we present an in-depth analysis of the current progress and challenges in the field of PQDs and their applications. Additionally, we offer insights into potential future research directions in this exciting area of study.

Ligands as a part of perovskite quantum dots (QDs) play an important role in determining their optoelectronic properties and stability. This review presents a critical overview focusing on the ligand engineering of perovskite QDs for efficient and stable solar cells.

Semi-transparent perovskite solar cells (ST-PSCs) featuring high performance and light transmittance are highly desirable for building integrated photovoltaic (BIPV) applications. However, it is challenging to balance the device efficiency and transmittance due to the trade-off between light-harvesting capability and transparency of the perovskite active layer. Herein, we demonstrate a simple solvent- and bandgap-engineering strategy to effectively enhance film transparency of (FAPbI3)0.85(MAPbBr3)0.15perovskite while simultaneously preserving its decent light-harvesting capability. N-methyl-2-pyrrolidone (NMP) as the solvent of the perovskite precursor effectively confines the growth of perovskite grains, leading to reduced light-scattering and enhanced average visible transparency (AVT) of the perovskite layer (over 28 %). Meanwhile, the NMP solvent promotes the growth of highly crystalline perovskite films with excellent light-harvesting capability, largely benefiting from stable intermediate adducts due to its intrinsic nature as a coordinative Lewis base. Further bandgap engineering of the perovskite light adsorber (1.6 eV) leads to the design of highly efficient bifacial ST-PSCs, achieving a power conversion efficiency of 15.58 % when illuminated from the conductive glass side and 9.67 % from the top electrode side, both under 1 sun illumination. The best-performing devices also show great promise for indoor applications with an efficiency of 25 % under 1000 lux indoor light illumination.

Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency. In light of the rapid development of perovskite materials and devices, a systematic survey on the latest advancements covering a broad range of related work is urgently needed. This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective. The discussed topics include the devices based on different type of perovskites (organic-inorganic hybrid, all-inorganic, and lead-free perovskite and perovskite quantum dots), the properties of perovskite defects, different type of charge transport materials (organic, polymeric, and inorganic hole transport materials and inorganic and organic electron transport materials), counter electrodes, and interfacial materials used to improve the efficiency and stability of devices. Most discussions focus on the key progresses reported within the recent five years. Meanwhile, the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.

Lead (Pb) halide perovskites have witnessed highly promising achievements for high-efficiency solar cells, light-emitting diodes (LEDs), and photo/radiation detectors due to their exceptional optoelectronic properties. However, compound stability and Pb toxicity are still two main obstacles towards the commercialization of halide perovskite-based devices. Therefore, it is of substantial interest to search for non-toxic candidates with comparable photophysical characteristics. Metal-halide double perovskites (MHDPs), A2BBʹX6, are recently booming as promising alternatives for Pb-based halide-perovskites for their non-toxicity and significantly enhanced chemical and thermodynamic stability. Moreover, this family exhibits rich combinatorial chemistry with tuneable optoelectronic properties and thus a great potential for a broad range of optoelectronic/electronic applications. Herein, we present a comprehensive review of the MHDPs synthesized so far, and classified by their optical and electronic properties. We systematically generalize their electronic structure by both theoretical and experimental efforts to prospect the relevant optoelectronic properties required by different applications. The progress of the materials in various applications is explicated in view of the material structure-function relationship. Finally, a perspective outlook to improve the physical and optoelectronic properties of the materials is proposed aiming at fostering their future development and applications.

Cyberspace is a new spatial realm of activities involving both humans and data, and it has become a cornerstone of the national security of every country. A scientific understanding of cyberspace is essential for analyzing cyberspace incidents, governing cyberspace and ensuring cybersecurity. Accordingly, cyberspace has become a new field of geographic research in the Information Age. Against the backdrop of fierce international competition over cyberspace, there has been an urgent need to strengthen research between the fields of geography and cybersecurity, leading to theoretical and methodological innovations that have created the sub-discipline of cyberspace geography. Cyberspace geography (CG) extends geographical research from real spaces to virtual spaces, and its theoretical basis is the evolution of the traditional geographic human-land relationship theory into a human-land-network relationship theory. CG research includes constructing mapping rela-tionships between cyberspace and real space, redefining the traditional geographic concepts of distance and regions for cyberspace, creating a language, models and methodologies for visually representing cyberspace, drawing maps of cyberspace, and researching the principles governing the evolution of cyberspace structures and behaviors. The technical methods of CG include collecting and integrating data on elements of cyberspace, visually representing cyberspace and conducting cyberspace situational and behavioral intelligence awareness. Intelligence awareness covers cyberspace situational status assessments, network hotspot event dissemination and traceability analysis, and network event situational simulations and risk predictions. CG offers new perspectives on the scientific understanding of cyberspace, the development of disciplines such as geography and cybersecurity, and the creation of national cybersecurity prevention and control mechanisms as well as a community of common future in cyberspace.

A series of Ce-SBA-15 mesoporous materials were synthesized through a direct hydrothermal method and further impregnated with different amounts of Cs. The catalysts were characterized by XRD, XPS, SEM, NH3-TPD, CO2-TPD, FT-IR and N2adsorption–desorption isotherm analyses. The XRD and N2adsorption–desorption isotherm results showed that the Ce successfully incorporated into the framework of SBA-15, which was favorable for the generation of mesoporous materials with high specific surface areas, large pore volumes and narrow pore size distribution. The incorporation of Ce changed the acid–base properties of the support and promoted the dispersion of Cs species. NH3–CO2TPD results indicated that a number of medium-strong acid and base sites existed in the 10Cs/Ce-SBA-15(10) catalyst, which made it suitable as a catalyst for the aldol condensation of methyl acetate with formaldehyde to prepare methyl acrylate.

CuSbS2 nanocrystals, synthesized via hot-injection method using oleylamine (OLA) as solvent, exhibited brick-like shape and were recognized as chalcostibite, verified by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. A high-performance photodetector based on a hybrid film of CuSbS2 nanocrystals and poly (3-hexylthiophene) was constructed. The device showed distinct "ON" and "OFF" states with a ratio of >5 in photocurrents responding to illumination. The high sensitivity and stability of the hybrid device reveals a broad prospect for use of the hybrid material in light detection and signal magnification. In industry, the hybrid material would be a good choice for large-area, low-cost, lightweight, and foldable products.

In this paper, we provided a manufacturing method for low-sintering-temperature radio frequency (RF) devices by stereolithographic (SLA) printing. The effect of ceramic powder percentage on rheological properties, curing behavior, sintering properties, microstructure, and dielectric properties was discussed. With the proportion of ceramic powder ranging from 60wt.% to 75wt.%, the viscosity of slurries declined, the sintering shrinkage rate varied from 21.61% to 15.83%, the dielectric constant raised from 5.22 to 6.64, and the dielectric loss initially reached the optimum value of 0.0024 and then deteriorated to 0.0035. The maximum solid content of slurries was 75wt.%, and the printable viscosity should be below 7.33Pa·s. At the mass ratio of 65:35, the samples sintered at 850 °C showed good properties: a density of 3.0135g·cm−3, a dielectric constant of 5.56, a low dielectric loss of 2.4 × 10−3, and τf= −32.76 ppm/°C. The printed Luneburg lens showed a gain enhancement of over 5dB, by using a 10 dBi standard gain horn antenna as a feed source. Thus, this research established a foundation for the fabrication of ceramic RF devices with high-performance, complex structures, and low sintering temperature via SLA printing.

Perovskite solar cells (PSCs) have demonstrated high power conversion efficiencies (PCEs) but poor stability against ultraviolet (UV) irradiation. Here, we report a one-pot synthesized luminescent europium-doped titania (Eu-TiO2) via chemical-bath deposition at low-temperature (70 °C) for planar PSCs, which enables simultaneous efficiency and UV-stability enhancement. We show that the Eu-TiO2could effectively convert damaging UV photons into useful visible luminescence for additional light harvesting. A more optimal energy band alignment at the Eu-TiO2/perovskite interface leads to facilitated charge extraction and suppressed non-radiative recombination. The use of Eu-TiO2in PSCs results in increased photocurrent and open-circuit voltage, yielding an enhanced PCE of 21.40% with relative to pristine TiO2device (19.22%). More importantly, the Eu-TiO2devices exhibit remarkably improved UV stability, retaining 75% of the initial PCE after exposing to UV illumination for 500 h, while the devices with pristine TiO2lost the majority of their original PCEs in 150 h. As a proof-of-concept, we further demonstrate the scalability of our method by fabricating a large-area Eu-TiO2film of 64 cm2showing excellent uniformity.

CuSbS2nanocrystals, synthesized via hot-injection method using oleylamine (OLA) as solvent, exhibited brick-like shape and were recognized as chalcostibite, verified by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. A high-performance photodetector based on a hybrid film of CuSbS2nanocrystals and poly (3-hexylthiophene) was constructed. The device showed distinct “ON” and “OFF” states with a ratio of >5 in photocurrents responding to illumination. The high sensitivity and stability of the hybrid device reveals a broad prospect for use of the hybrid material in light detection and signal magnification. In industry, the hybrid material would be a good choice for large-area, low-cost, lightweight, and foldable products.