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Abstract Electroluminescence efficiencies and stabilities of quasi-two-dimensional halide perovskites are restricted by the formation of multiple-quantum-well structures with broad and uncontrollable phase distributions. Here, we report a ligand design strategy to substantially suppress diffusion-limited phase disproportionation, thereby enabling better phase control. We demonstrate that extending the π-conjugation length and increasing the cross-sectional area of the ligand enables perovskite thin films with dramatically suppressed ion transport, narrowed phase distributions, reduced defect densities, and enhanced radiative recombination efficiencies. Consequently, we achieved efficient and stable deep-red light-emitting diodes with a peak external quantum efficiency of 26.3% (average 22.9% among 70 devices and cross-checked) and a half-life of ~220 and 2.8 h under a constant current density of 0.1 and 12 mA/cm 2 , respectively. Our devices also exhibit wide wavelength tunability and improved spectral and phase stability compared with existing perovskite light-emitting diodes. These discoveries provide critical insights into the molecular design and crystallization kinetics of low-dimensional perovskite semiconductors for light-emitting devices. 

The grassland leafhopper genus Aconurella is widespread in the Old World. Species of this genus are difficult to identify by traditional morphological characters but the morphology-based species classification in this genus has not previously been tested using molecular data. This study analysed DNA sequence data from two mitochondrial genes (COI, 16S) and one nuclear gene (ITS2) to infer the phylogenetic relationships and status of five previously recognized Aconurella species and compare the performance of different molecular species-delimitation methods using single and multiple loci. The analysis divided the included haplotypes into five well-supported subclades, most corresponding to existing morphology-based species concepts. However, different molecular species delimitation methods (jMOTU, ABGD, bPTP, GMYC and BPP) yielded somewhat different results, suggesting the presence of between 4 and 8 species, sometimes lumping the haplotypes of Aconurella diplachnis and Aconurella sibirica into a single species or recognizing multiple putative species within Aconurella prolixa. Considering the different results yielded by various methods employing single loci, the BPP method, which combines data from multiple loci, may be more reliable for delimiting species of Aconurella. Our results suggest that the morphological characters previously used to identify these species are reliable and adequately reflect boundaries between genetically distinct taxa. 

A selenophene-containing conjugated organic ligand, 2-(4′-methyl-5′-(5-(3-methylthiophen-2-yl)selenophen-2-yl)-[2,2′-bithiophen]-5-yl)ethan-1-aminium (STm), was synthesized and incorporated into a Sn( ii )-based two-dimensional perovskite, (STm) 2 SnI 4 . The band offset between the perovskite and ligand can be fine-tuned by introducing the STm ligand. Both field-effect transistor and light-emitting diode devices based on (STm) 2 SnI 4 films exhibit high performance and enhanced operational stability. 

Abstract. Peatlands have often been neglected in Earth system models (ESMs).Where they are included, they are usually represented via a separate, prescribed grid cell fraction that is given the physical characteristics of a peat (highly organic) soil. However, in reality soils vary on a spectrum between purely mineral soil (no organic material) and purely organicsoil, typically with an organic layer of variable thickness overlying mineral soil below. They are also dynamic, with organic layer thickness and its properties changing over time. Neither the spectrumof soil types nor their dynamic nature can be captured by current ESMs. Here we present a new version of an ESM land surface scheme (Joint UK Land Environment Simulator, JULES) where soil organic matter accumulation – and thus peatland formation, degradation and stability – is integratedin the vertically resolved soil carbon scheme. We also introduce the capacity to track soil carbon age as a function of depth in JULES and compare this to measured peat age–depth profiles. The new scheme is tested and evaluated at northern and temperate sites. This scheme simulates dynamic feedbacks between the soil organic material and its thermal and hydraulic characteristics. We show that draining the peatlands can lead to significant carbon loss, soil compaction and changes in peat properties. However, negative feedbacks can lead to the potential for peatlands to rewet themselves following drainage.These ecohydrological feedbacks can also lead to peatlands maintaining themselves in climates where peat formation would not otherwise initiate in the model, i.e. displaying some degree of resilience. The new model produces similar results to the original model for mineral soils and realistic profiles of soil organic carbon for peatlands.We evaluate the model against typical peat profiles based on 216 northern and temperate sites from a global dataset of peat cores.The root-mean-squared error (RMSE) in the soil carbon profile is reduced by 35 %–80 % in the best-performing JULES-Peat simulationscompared with the standard JULES configuration. The RMSE in these JULES-Peat simulations is 7.7–16.7 kg C m−3 depending on climate zone, which is considerably smaller than the soil carbon itself (around 30–60 kg C m−3). The RMSE at mineral soil sites is also reducedin JULES-Peat compared with the original JULES configuration (reduced by ∼ 30 %–50 %). Thus, JULES-Peat can be used as a complete scheme that simulates both organic and mineral soils. It does not requireany additional input data and introduces minimal additional variables to the model. This provides a new approach for improving the simulation of organic and peatland soils andassociated carbon-cycle feedbacks in ESMs. 

A new genus of Deltocephalini Pascoia Duan gen. n. with P. rakitovi Duan sp. n. as type species is described and illustrated from the Andes Mountains in Peru. 

Two-dimensional (2D) organic–inorganic hybrid halide perovskites exhibit unique properties, such as long charge carrier lifetimes, high photoluminescence quantum efficiencies, and great tolerance to defects. Over the last several decades tremendous progress has occurred in the development of 2D layered halide perovskite semiconductor materials and devices. Chemical functionalization of 2D halide perovskites is an effective approach for tuning their electronic properties. A large amount of effort has been made in compositional engineering of the cations and anions in the perovskite lattice. However, few efforts have incorporated rationally designed semiconducting organic moieties into these systems to alter the overall chemical and optoelectronic properties of 2D perovskites. In fact, incorporation of large conjugated organic groups in the spatially confined inorganic perovskite matrix was found to be challenging, and this synthetic challenge hinders a deeper understanding of the materials’ structure–property relationships. Recently, exciting progress has been made regarding the molecular design, optical characterization, and device fabrication of novel 2D halide perovskite materials that incorporate functional organic semiconducting building blocks. In this article, we provide a timely review regarding this recent progress. Moreover, we discuss successes and current challenges regarding the synthesis, characterization, and device applications of such hybrid materials and provide a perspective on the true future promise of these advanced nanomaterials.