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A long‐lasting challenge in ultraviolet (UV) nonlinear optical (NLO) materials design is to combine conflicting and harsh properties into one structure, including wide UV transparency, strong NLO efficiency, and moderate birefringence to realize phase‐matching at short wavelength. A fluorine‐directed material design strategy is adopted to accelerate the process of finding NLO materials with optimal performances. In this work, taking LiB3O5 (LBO) as a maternal structure, one O atom with two F atoms is substituted and LiNaB6O9F2 which possesses novel double interpenetrating 3[B6O9F2]∞ networks and fluorine‐directed optimal performances including enhanced birefringence and phase‐matching capacity is successfully obtained. The perfect balance among deep‐UV cutoff edge, large second‐harmonic generation (SHG) response (1.1 × KDP), and moderate birefringence (0.067 at 1064 nm) of LiNaB6O9F2 makes it a promising UV NLO crystal. [ABSTRACT FROM AUTHOR]

Mass spectrometry imaging (MSI) has made the spatio-chemical characterization of a broad range of small-molecule metabolites within biological tissues possible. However, available matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) suffers from severe background interferences in low-mass ranges and inhomogeneous matrix deposition. Thus, surface-assisted LDI-MS (SALDI-MS) has been an attractive alternative for high-sensitivity detection and imaging of small biomolecules. In this study, we construct a new composite substrate, hydrophobic polydopamine (hPDA)-modified TiO2 nanotube (TDNT) coated with plasmonic gold nanoparticle (AuNP-hPDA-TDNT), as a dual-polarity SALDI substrate using an easy and cost-effective fabrication approach. Benefitting from the synergistic effects of TDNT semiconductor and plasmonic PDA modification, this SALDI substrate exhibits superior performance for dual-polarity detection of a vast diversity of small molecules. Highly reduced background interferences, lower detection limits, and spot-to-spot repeatability can be achieved using AuNP-hPDA-TDNT substrates. Due to its unique imprinting performance, various metabolites and lipids can be visualized within jatropha integerrima petals, ginkgo leaves, strawberry fruits, and latent fingerprints. More valuably, the universality of this matrix-free substrate is demonstrated for mapping spatial distribution of lipids within mouse brain tissue sections. Considered together, this AuNP-hPDA-TDNT material is expected to be a promising SALDI substrate in various fields, especially in nanomaterial development and life sciences. [ABSTRACT FROM AUTHOR]

The spectral purity of an oscillator is central to many applications, such as detecting gravity waves (1), defining the second (2,3), ground-state cooling and quantum manipulation of nanomechanical objects (4), [...]

The fluorooxoborate A2B6O9F2 family (A = alkali metal) has attracted much attention because of its diverse structures and properties. Herein, two new members of this family, (NH4)2B6O9F2 and K2B6O9F2, have been synthesized which exhibit different two-dimensional [B6O9F2]∞ layered structures. Millimeter-sized crystals of (NH4)2B6O9F2 have been grown with NH4F as the flux. The transmittance spectrum indicates that it has a wide UV transparency window with a cutoff edge lower than 180 nm. First-principles calculations show that both (NH4)2B6O9F2 and K2B6O9F2 have deep-UV cutoff edges and moderate birefringence. The contributions of the constituent structural groups to the optical properties are discussed. [ABSTRACT FROM AUTHOR]

The large‐scale conversion of natural mangroves to aquaculture reduces species richness and diversity. Large areas of abandoned aquaculture ponds in areas where mangroves formerly predominated in China and southeast Asia represent important potential effective targets for mangrove restoration. Here, we empirically assessed the α‐diversity (species richness) and β‐diversity (variation in community composition) of mangrove, macrobenthos, fish and waterbird in a tropical mangrove bay on Hainan Island, China. We compared sites subjected to different pond‐to‐mangrove restoration programs more than 20 years ago (passive restoration without planting and active restoration with planting) to nearby reference site with natural mangrove forests and mudflats. To better understand how β‐diversity responds to restoration, we also distinguished between β‐diversity turnover and nestedness (richness difference). In general, α‐diversity values for both fish and waterbird communities and β‐diversity values for the mangrove, macrobenthos and waterbird communities were lower at the restoration sites than at the reference site, suggesting that the strong homogenizing effects of anthropogenic habitat alternation were still apparent after more than 20 years since aquaculture ceased. In addition, spatial turnover, not nestedness, dominated total β‐diversity both across the whole study area and at individual sites, suggesting that multiple processes, such as environmental filtering, helped to shape multi‐taxa community structures. Moreover, we found no evidence that planting in the abandoned ponds, in addition to standard hydrological restoration, supported greater species diversity of taxa like macrobenthos and waterbird than the naturally regenerated site after more than 20 years' recovery. Our results underline the importance of avoiding the conversion of natural mangrove stands to aquaculture wherever possible and the urgent need to design effective mangrove restoration techniques in tropical Asia. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) nonlinear optical (NLO) crystals which can produce short‐wavelength lasers via a direct second harmonic generation (SHG) process are of great importance in modern laser technology. Currently, the exploration of UV NLO crystals in borosulfates is nearly stagnant since the non‐phase matching (PM) property lies on the small birefringence induced by the intrinsically small optical anisotropy of the tetrahedral groups. Herein, for the first time, the planar [BO3] units were introduced into borosulfates leading to a boron‐rich borosulfate (NH4)2B4SO10 with unprecedented [B4SO10]∞ layers and evidently enhanced birefringence. To the best of our knowledge, it achieves the shortest SHG PM wavelength of 252 nm in all reported borosulfates with deep UV cutoff edge (184 nm), large SHG response (1.1×KDP at 1064 nm and 0.15×β‐BBO at 532 nm) and large birefringence (0.053 at 1064 nm) and is easy to grow single crystals via simple chemical vapor deposition method. These results confirm the feasibility of utilizing planar [BO3] units to optimize birefringence of borosulfates, and also open up broad prospects for UV NLO crystals in boron‐rich borosulfates. [ABSTRACT FROM AUTHOR]

A new alkaline-earth metal borate, Sr3B14O24, was successfully synthesized by a high-temperature solution method. It crystallizes in the monoclinic space group P21/c (no. 14) and features a fundamental building block (FBB) [B14O30] which is composed of eight [BO3] and six [BO4] units. The FBBs further condense to form an unwonted infinite 2D double layer extended in the bc plane. The UV-Vis-NIR diffuse reflectance spectrum shows that the cutoff edge of Sr3B14O24 is less than 200 nm, which indicates its potential use in the deep UV region. In addition, the first principles theoretical study was carried out to better understand the relationship between the structure and performance. [ABSTRACT FROM AUTHOR]

Interfacial properties of a hole‐transport material (HTM) and a perovskite layer are of high importance, which can influence the interfacial charge transfer dynamics as well as the growth of perovskite bulk crystals particularly in inverted structure. The halogen bonding (XB) has been recognized as a powerful functional group to be integrated with new small molecule HTMs. Herein, a carbazole‐based halo (iodine)‐functional HTM (O1), is synthesized for the first time, demonstrating a high hole mobility and suitable energy levels that align well with those of perovskites. The strong interaction between O1 and perovskite, i.e., I···I−, induces the formation of an ordered interlayer, which are verified by both theoretical and experimental studies. Compared to the reference HTM (O2) without any halo‐function, the XB‐induced interlayer effectively enhances the interfacial charge extraction efficiency, while significantly hindering the non‐radiative charge recombination by reducing the surface traps upon the strong passivation effect. This is reflected as a big increase in the open‐circuit voltage by up to 114 mV in the fabrication of inverted devices with the highest power conversion efficiency of 22.34%. Moreover, the ordered XB‐driven interlayer at the interface of O1 and perovskite is mainly responsible for the extended lifespan under the operational conditions. [ABSTRACT FROM AUTHOR]