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Electrochemiluminescence (ECL) is a luminescence production technique triggered by electrochemistry, which has emerged as a powerful analytical technique in bioanalysis and clinical diagnosis. During ECL, charge transfer (CT) is an important process between electrochemical excitation and luminescent emission, and dramatically affects the efficiency of exciton generation, playing a pivotal role in the light-emitting properties of nanomaterials. Reticular framework materials with intramolecular/intermolecular interactions offer a promising platform for regulating CT pathways and enhancing luminescence efficiency. Deciphering the role of intramolecular/intermolecular CT processes in reticular framework materials allows for the targeted design and synthesis of emitters with precisely controlled CT properties. This sheds light on the microscopic mechanisms of electro-optical conversion in ECL, propelling advancements in their efficiency and breakthrough applications. This mini-review focuses on recent advancements in engineering CT within reticular frameworks to boost ECL efficiency. We summarized strategies including intra-reticular charge transfer, CT between the metal and ligands, and CT between guest molecules and frameworks within reticular frameworks, which holds promise for developing next-generation ECL devices with enhanced sensitivity and light emission. [ABSTRACT FROM AUTHOR]

Chiral two-dimensional (2D) perovskites offer numerous attractive features for optoelectronics owing to their soft, deformable lattices and a high degree of chemical tunability. While tremendous advances have been made in perovskite-based direct circularly polarized light (CPL) detection, the low circular polarization anisotropy factor and sensitivity of those photodetectors arising from large lattice distortion still limit practical applications. Herein, chiral 2D perovskite-based single-crystalline microwire arrays with enhanced circular dichroism (CD) absorption are fabricated with the synergy of the capillary-bridge-confined assembly method and chlorine-substituted phenethylamine (Cl-MBA). Compared with phenethylamine (MBA)-inserted perovskites, the smaller lattice distortion and increased halogen–halogen interaction within Cl–MBA-inserted perovskites strengthen lattice rigidity and weaken electron-phonon coupling to improve carrier transport and thermal stability, resulting in high-performance CPL photodetectors with an anisotropy factor of 0.25, responsivity exceeding 95.7±9.3 A W−1 and detectivity exceeding (3.05±0.30)×1013 Jones. This work opens a new perspective to modulate circular polarization sensitivity and will be helpful to realize promising implementations in quantum computation and communication. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the influence of the neurotoxicity of nanoalumina on primarily cultured neurons. Normal control, particle size control, aluminum, micron-alumina, and nanoalumina at 50-nm and 13-nm particle sizes were included as subjects to evaluate the level of apoptosis, necrosis, and autophagy in primarily cultured neurons and further explore the mitophagy induced by nanoalumina. The results demonstrated that nanoalumina could induce neuronal cell apoptosis, necrosis, and autophagy, among which autophagy was the most notable. When the autophagy inhibitor was added to the nanoalumina-treated group, it significantly downregulated the protein expression levels of Beclin-1 and LC3II/LC3. Observation under a transmission electron microscope and a fluorescence microscope revealed mitophagy characteristics induced by nanoalumina. Additionally, the neurotoxicological effects induced by nanoalumina were more significant than those induced by aluminum and in a particle size–dependent manner. [ABSTRACT FROM AUTHOR]

Understanding the atomic structure and structural instability of organic-inorganic hybrid perovskites is the key to appreciate their remarkable photoelectric properties and understand failure mechanism. Here, using low-dose imaging technique by direct-detection electron-counting camera in a transmission electron microscope, we investigate the atomic structure and decomposition pathway of CH3NH3PbI3 (MAPbI3) at the atomic scale. We successfully image the atomic structure of perovskite in real space under ultra-low electron dose condition, and observe a two-step decomposition process, i.e., initial loss of MA+ followed by the collapse of perovskite structure into 6H-PbI2 with their critical threshold doses also determined. Interestingly, an intermediate phase (MA0.5PbI3) with locally ordered vacancies can robustly exist before perovskite collapses, enlightening strategies for prevention and recovery of perovskite structure during the degradation. Associated with the structure evolution, the bandgap gradually increases from ~1.6 eV to ~2.1 eV. In addition, it is found that C-N bonds can be readily destroyed under irradiation, releasing NH3 and HI and leaving hydrocarbons. These findings enhance our understanding of the photoelectric properties and failure mechanism of MAPbI3, providing potential strategies into material optimization. The knowledge of atomic structure and structural instability of hybrid perovskites is crucial to understand their photoelectric properties and failure mechanism. Here, the authors utilise low-dose TEM imaging technique to investigate the atomic structure and decomposition pathway of MAPbI3 at the atomic scale. [ABSTRACT FROM AUTHOR]

Interfaces in heterostructures have been a key point of interest in condensed-matter physics for decades owing to a plethora of distinctive phenomena—such as rectification1, the photovoltaic effect2, the quantum Hall effect3 and high-temperature superconductivity4—and their critical roles in present-day technical devices. However, the symmetry modulation at interfaces and the resultant effects have been largely overlooked. Here we show that a built-in electric field that originates from band bending at heterostructure interfaces induces polar symmetry therein that results in emergent functionalities, including piezoelectricity and pyroelectricity, even though the component materials are centrosymmetric. We study classic interfaces—namely, Schottky junctions—formed by noble metal and centrosymmetric semiconductors, including niobium-doped strontium titanium oxide crystals, niobium-doped titanium dioxide crystals, niobium-doped barium strontium titanium oxide ceramics, and silicon. The built-in electric field in the depletion region induces polar structures in the semiconductors and generates substantial piezoelectric and pyroelectric effects. In particular, the pyroelectric coefficient and figure of merit of the interface are over one order of magnitude larger than those of conventional bulk polar materials. Our study enriches the functionalities of heterostructure interfaces, offering a distinctive approach to realizing energy transduction beyond the conventional limitation imposed by intrinsic symmetry. A built-in electric field at the interface of metals and centrosymmetric semiconductors is shown to induce polar structures in the semiconductors and generate substantial piezoelectric and pyroelectric effects. [ABSTRACT FROM AUTHOR]

We estimate the effects of the Chinese water sector's privatization reforms based on firm-level panel data from 1999 to 2006. By applying a translog stochastic frontier production function and a Parametric Generalized Malmquist Productivity Index, we find that the privatization reforms and the participation of multinational water firms contributed to the performance improvement of the Chinese water sector. The foreign-owned water firms stood at the sector's productivity frontier and the domestic privately-owned water firms were close to the frontier. However, state-owned water firms had the lowest technical efficiency scores, though they improved modestly over time. [ABSTRACT FROM AUTHOR]

The continuous titanium-doped ZrO mesoporous fibers with a large surface area (190 m g, TZ50-400) have been prepared by the sol-gel method coupled with the chemical template route. In the formation process, the self-induced acid environment of ZrOCl·8HO in ethanol solution was utilized to avoid a rapid hydrolysis process and the viscous sol precursors were successfully obtained for spinning fibers. X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectra were used to study the chemical environment of surface Ti(IV) and Zr((IV)) ions. The findings disclose that the partial Ti atoms (less than 30 %) enter into the ZrO lattice and occupy the positions of Zr atoms, while the excess Ti atoms construct the linear Ti-O-Ti chains inside the extra framework, being favorable to prevent the collapse of meso structure. [ABSTRACT FROM AUTHOR]

Craters, one of the most significant features of the lunar surface, have been widely researched because they offer us the relative age of the surface unit as well as crucial geological information. Research on crater detection algorithms (CDAs) of the Moon and other planetary bodies has concentrated on detecting them from imagery data, but the computational cost of detecting large craters using images makes these CDAs impractical. This paper presents a new approach to crater detection that utilizes a digital elevation model instead of images; this enables fully automatic global detection of large craters. Craters were delineated by terrain attributes, and then thresholding maps of terrain attributes were used to transform topographic data into a binary image, finally craters were detected by using the Hough Transform from the binary image. By using the proposed algorithm, we produced a catalog of all craters ⩾10 km in diameter on the lunar surface and analyzed their distribution and population characteristics. [ABSTRACT FROM AUTHOR]

The separation on microchip provides the advantages including high efficiency, increased throughput, reduced quantities of hazardous materials, cost saving, relatively facile instrumentation, improved portability, etc. A technique of micellar electrokinetic chromatography (MEKC) coupled with amperometric detection has been actualized on a polydimethylsiloxane microchip for the rapid separation and determination of three phenolic xenoestrogens as octylphenol (OP), 4-nonylphenol (4-NP), and bisphenol A (BPA). The baseline separation of these phenolic xenoestrogens is successfully obtained within 55 s under the optimized MEKC conditions with borate running buffer of pH 8.0 containing sodium dodecyl sulfate and β-cyclodextrin. The linear range for OP, 4-NP, and BPA are 20-1,000, 15-1,000, and 20-1,000 μg/L with the detection limit of 5.0, 4.0, and 3.0 μg/L, respectively. The present method is successfully applied for the determination of these phenolic xenoestrogens in some industrial wastewater samples from mainland of China with the recoveries ranged from 90.2 to 109.4 %. [ABSTRACT FROM AUTHOR]

Photovoltaic conversion efficiency (PCE) of halide perovskite solar cells has risen spectacularly, yet the very crystalline structure of CH3NH3PbI3 remains ambiguous after extensive researches, and its polar nature remains hotly debated. Here we present compelling evidences that CH3NH3PbI3 crystals self-grown on FTO/TiO2 substrate consist of ferroic domains with alternating polar and nonpolar orders, in contrast to previous experimental and theoretical expectations, and polar domains possess reduced photocurrent. It is found that polar and nonpolar orders of CH3NH3PbI3 can be distinguished from their distinct lateral piezoresponse, energy dissipation, first and second harmonic electromechanical couplings, and temperature variation, even though their difference in crystalline lattice is very subtle, and they possess two-way memory effect through cubic-tetragonal phase transition. We hope these findings resolve key questions regarding polar nature of CH3NH3PbI3 and its implication on photovoltaics, reconcile contradictory data widely reported, and point a direction toward engineering ferroic domains for enhanced PCE. Perovskite solar cells: Polar ordering The crystalline structure and polar nature of a hybrid organic−inorganic perovskite widely used in solar cells — CH3NH3PbI3 — is still a matter of debate. Now, an international team of researchers led by Jiangyu Li and Jinjin Zhao used a combination of experimental methods, including scanning probe and transmission electron microscopy, to show that CH3NH3PbI3 crystals grown on a FTO/TiO2 substrate exhibit ferroic domains with alternating polar and nonpolar order. The structural differences between the polar and nonpolar phase are very subtle, and scanning probe techniques are well suited to resolve their functional responses with high resolution. The polar domains were observed to have a lower photocurrent than that expected from theoretical predictions. Building on these results, it should be possible to engineer ferroic domains to enhance the efficiency of halide perovskite solar cells. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid perovskites are promising candidates for the next-generation solar cells. Many efforts have been made to study their structures in the search for a better mechanistic understanding to guide the materials optimization. Here, we investigate the structure instability of the single-crystalline CH3NH3PbI3 (MAPbI3) film by using transmission electron microscopy. We find that MAPbI3 is very sensitive to the electron beam illumination and rapidly decomposes into the hexagonal PbI2. We propose a decomposition pathway, initiated with the loss of iodine ions, resulting in eventual collapse of perovskite structure and its decomposition into PbI2. These findings impose important question on the interpretation of experimental data based on electron diffraction and highlight the need to circumvent material decomposition in future electron microscopy studies. The structural evolution during decomposition process also sheds light on the structure instability of organic-inorganic hybrid perovskites in solar cell applications. [ABSTRACT FROM AUTHOR]