NEATmap: a high-efficiency deep learning approach for whole mouse brain neuronal activity trace mapping.

Quantitative analysis of activated neurons in mouse brains by a specific stimulation is usually a primary step to locate the responsive neurons throughout the brain. However, it is challenging to comprehensively and consistently analyze the neuronal activity trace in whole brains of a large cohort of mice from many terabytes of volumetric imaging data. Here, we introduce NEATmap, a deep learning-based high-efficiency, high-precision and user-friendly software for whole-brain neuronal activity trace mapping by automated segmentation and quantitative analysis of immunofluorescence labeled c-Fos+ neurons. We applied NEATmap to study the brain-wide differentiated neuronal activation in response to physical and psychological stressors in cohorts of mice.

Multifunctional MOF@COF Nanoparticles Mediated Perovskite Films Management Toward Sustainable Perovskite Solar Cells.

Although covalent organic frameworks (COFs) with high π-conjugation have recently exhibited great prospects in perovskite solar cells (PSCs), their further application in PSCs is still hindered by face-to-face stacking and aggregation issues. Herein, metal-organic framework (MOF-808) is selected as an ideal platform for the in situ homogeneous growth of a COF to construct a core-shell MOF@COF nanoparticle, which could effectively inhibit COF stacking and aggregation. The synergistic intrinsic mechanisms induced by the MOF@COF nanoparticles for reinforcing intrinsic stability and mitigating lead leakage in PSCs have been explored. The complementary utilization of π-conjugated skeletons and nanopores could optimize the crystallization of large-grained perovskite films and eliminate defects. The resulting PSCs achieve an impressive power conversion efficiency of 23.61% with superior open circuit voltage (1.20 V) and maintained approximately 90% of the original power conversion efficiency after 2000 h (30-50% RH and 25-30 °C). Benefiting from the synergistic effects of the in situ chemical fixation and adsorption abilities of the MOF@COF nanoparticles, the amount of lead leakage from unpackaged PSCs soaked in water (< 5 ppm) satisfies the laboratory assessment required for the Resource Conservation and Recovery Act Regulation.

Molecular near-infrared triplet-triplet annihilation upconversion with eigen oxygen immunity.

Molecular triplet-triplet annihilation upconversion often experiences drastic luminescence quenching in the presence of oxygen molecules, posing a significant constraint on practical use in aerated conditions. We present an oxygen-immune near-infrared triplet-triplet annihilation upconversion system utilizing non-organometallic cyanine sensitizers (λex = 808 nm) and chemically synthesized benzo[4,5]thieno[2,3-b][1,2,5]thiadiazolo[3,4-g]quinoxaline dyes with a defined dimer structure as annihilators (λem = 650 nm). This system exhibits ultrastable upconversion under continuous laser irradiance (>480 mins) or extended storage (>7 days) in aerated solutions. Mechanistic investigations reveal rapid triplet-triplet energy transfer from sensitizer to annihilators, accompanied by remarkably low triplet oxygen quenching efficiencies ( η O 2 < 13% for the sensitizer, <3.7% for the annihilator), endowing the bicomponent triplet-triplet annihilation system with inherent oxygen immunity. Our findings unlock the direct and potent utilization of triplet-triplet annihilation upconversion systems in real-world applications, demonstrated by the extended and sensitive nanosensing of peroxynitrite radicals in the liver under in vivo nitrosative stress.

Lanthanide 3D Supramolecular Framework Boosts Stable Perovskite Solar Cells with High UV Utilization.

In this work, the ligand-to-metal charge transition and Förster resonance energy transfer process is exploited to derive lanthanide-organic framework (Tb-cpon) modified perovskite solar cells (PSCs) with enhanced performance under UV irradiation. Tb-cpon-modified PSCs exhibit rapid response and reduced degradation due to energy downconversion facilitated by effective coupling of UV-sensitive chromophores to lanthanide luminescent centers, enhancing the spectral response range of the composite films. Furthermore, the characteristic changes of precursor particle sizes suggest formation of Tb-cpon adducts as intermediate products, leading to enhanced crystallinity and reduced defect concentrations in the Tb-cpon-perovskite hybrid film. Accordingly, the Tb-cpon-modified PSC devices obtain a champion efficiency up to 23.72% as well as a sensitive photovoltaic conversion even under pure UV irradiation. Moreover, the unencapsulated devices maintain more than 80% of the initial efficiency after continuous irradiation under a 310 nm UV lamp for 24 h (from the Au electrode side), compared to 21% for the control devices.

High precision vibration sectioning for 3D imaging of the whole central nervous system.

BACKGROUND: Imaging and reconstruction of the morphology of neurons within the entire central nervous system (CNS) is important for deciphering the neural circuitry and related brain functions. With combination of tissue clearing and light sheet microscopy, previous studies have imaged the mouse CNS at cellular resolution, while remaining single axons unresolvable due to the tradeoff between sample size and imaging resolution. This could be improved by sectioning the sample into thick slices and imaged with high resolution light sheet microscopy as described in our previous study. However, the achievable quality for 3D imaging of serial thick slices is often hindered by surface undulation and other artifacts introduced by sectioning and handling limitations. NEW METHODS: In order to improve the imaging quality for mouse CNS, we develop a high-performance vibratome system for sample sectioning and handling automation. The sectioning mechanism of the system was modeled theoretically and verified experimentally. The effects of process parameters and sample properties on sectioning accuracy were studied to optimize the sectioning outcome. The resultant imaging outcome was demonstrated on mouse samples. RESULTS: Our theoretical model of vibratome effectively depicts the relationship between the sample surface undulation errors and the sectioning parameters. With the guidance of the theoretical model, the vibratome is able to achieve a local surface undulation error of ±0.5 µm and a surface arithmetic mean deviation (Sa) of 220 nm for 300-µm-thick tissue slices. Imaging results of mouse CNS show the continuous sectioning capability of the vibratome. COMPARISON WITH EXISTING METHOD: Our automatic sectioning and handling system is able to process serial thick slices for 3D imaging of the whole CNS at a single-axon resolution, superior to the commercially available vibratome devices. CONCLUSION: Our automatic sectioning and handling system can be optimized to prepare thick sample slices with minimal surface undulation and manual manipulation in support of 3D brain mapping with high-throughput and high-accuracy.

Multilateral Passivation Strategy in Post-Synthetic Flexible Metal-Organic Frameworks for Enhancing Perovskite Solar Cells.

The photovoltaic performance of perovskite solar cells is severely limited by the innate defects of perovskite films. Metal-organic framework (MOF)-based additives with luxuriant skeleton structures and tailored functional groups show a huge potential to solve these problems. Here, a multilateral passivation strategy is performed by introducing two alkyl-sulfonic acid functionalized MOFs, MIL-88B-1,3-SO3H and MIL-88B-1,4-SO3H, respectively, obtained from MIL-88B-NH2 through a post-synthetic process, for coordinating the lead defects and inhibiting non-radiative recombination. The flexible MIL-88B-type frameworks endow both functionalized MOFs with excellent electrical conductivity and preferable carrier transport in the hole-transport materials. Compared with the original MIL-88B-NH2 and MIL-88B-1,4-SO3H, MIL-88B-1,3-SO3H exhibits optimal steric hindrance and multiple passivation groups (-NH2, -NH-, and -SO3H), achieving the champion doped device with an enhanced power conversion efficiency (PCE) of 22.44% and excellent stability, which maintains 92.8% of the original PCE under ambient conditions (40% humidity and 25 °C) for 1200 h.

Synthesis and properties of novel type I photosensitizer polycyclic amide.

Herein, we have designed and synthesized a novel type-I photosensitizer (PhPA) via Rh-catalyzed oxidative cyclization of diacetoxyterephthalamide with alkynes. The photoelectric properties, photosensitivity and photodegradation process of PhPA have been systematically investigated. The remarkable fluorescence quenching effect (ΦPL < 0.01) of PhPA suggests that the intersystem crossing from the singlet excited state to the reactive triplet state is enhanced by the enlarged conjugated backbone. Additionally, the ability of superoxide radical (O2-˙) generation was confirmed by electron paramagnetic resonance spectroscopy. Finally, the mechanism of PhPA photo-oxidative degradation via the structure of two metabolites is proposed.

Regulating Crystallization and Lead Leakage of Perovskite Solar Cell Via Novel Polyoxometalate-Based Metal-Organic Framework.

Despite the unprecedented progress in lead-based perovskite solar cells (PSCs), the toxicity and leakage of lead from degraded PSCs triggered by deep-level defects and poor crystallization quality increase environmental risk and become a critical challenge for eco-friendly PSCs. Here, a novel 2D polyoxometalate (POM)-based metal-organic framework (MOF) (C5 NH5 )4 (C3 N2 H5 )2 Zn3 (H8 P4 Mo6 O31 )2 ·2H2 O (POMOF) is ingeniously devised to address these issues. Note that the integration of POM endows POMOF with great advantages of electrical conductivity and charge mobility. Ordered POMOF induces the crystallization of high-quality perovskite film and eliminates lead-based defects to improve internal stability. The resultant PSCs achieve a superior power conversion efficiency (23.3%) accompanied by improved stability that maintains ≈90% of its original efficiency after 1600 h. Meanwhile, POMOF with phosphate groups effectively prevents lead leakage through in situ chemical anchoring and adsorption methods to reduce environmental risk. This work provides an effective strategy to minimize lead-based defects and leakage in sustainable PSCs through multi-functional POM-based MOF material.

Construction of Ag nanocluster-modified Ag3PO4 containing silver vacancies via in-situ reduction: With enhancing the photocatalytic degradation activity of sulfamethoxazole.

Photocatalytic removal of sulfonamide antibiotics is an effective strategy to solve environmental pollution. Ag3PO4 is a promising anode material for photocatalytic material with photocatalytic degradation ability under ultraviolet light or natural light. Unfortunately, due to its instability, Ag+ could be reduced to Ag0 which loaded onto the surface of Ag3PO4 during the photocatalytic process, causing self-photocorrosion and resulting in the reduction of photocatalytic activity and stability. Herein, Ag3PO4 nanoparticles loaded with Ag nanoclusters containing Ag vacancies (Ag/Ag3PO4-VAg) were constructed by an in-situ reduction strategy to achieve effectively photocatalytic degradation behavior. The Ag nanoclusters loaded on the surface of Ag3PO4 can not only effectively inhibit the self-photocorrosion but also affords a localized surface plasmon resonance (LSPR) effect in the photocatalytic process, thus leading to the efficient generation and rapid transfer of photogenerated carriers behavior. In addition, the Ag vacancies in Ag3PO4 are crucial to increasing the adsorption energy of H2O for further enhancing the capture and accumulation of electrons. In detail, according to Zeta potential analysis, the strong adsorption sites of sulfamethoxazole (SMX) molecules are generated at the interface of Ag and Ag3PO4, which promote the activation of SMX molecules. A 100 ml of 20 mg/L SMX could be completely degraded within 15 min with an apparent rate constant (Kapp) of 0.306 min-1, which far exceeds the activity of most of the photocatalysts. This work may provide an attractive strategy to address the activity, stability of Ag3PO4 and and realizing the green remediation of SMX wastewater.

{Mo126 W30 }: Polyoxometalate Cages Shaped by π-π Interactions.

Here we report the formation of giant {Mo126 W30 } polyoxometalate cages templated by π-conjugated planar ligands. Their inorganic shells incorporate arrays of 18 stacked aromatic carboxylates, such as 1,3,5-benzenetricarboxylate or 5-nitroisophthalate, and the assembly is stabilized by multiple π-π interactions. NMR data confirmed that the cages are stable in solution and the inner aromatic templates can be postsynthetically replaced by selected aliphatic dicarboxylates, paving the way for endo-functionalization and exploration of the reactivities within the cage cavities.

Timing matters: pre-assembly versus post-assembly functionalization of a polyoxovanadate-organic cuboid.

The pre-assembly and post-assembly approaches in the functionalization of a polyoxovanadate-organic cuboid, [{V6S}8(QPTC)8{V3}2]10-, are discussed. We have shown that the two pathways have led to distinctly different systems, with either an expanded or contracted interior void space, when phenylphosphonate is introduced at different stages of the self-assembly. One leaves the cuboid framework largely intact, whereas the other results in a compact, twisted cuboid. Kinetic factors will have to be considered in the equilibrium of these complex processes. Furthermore, the exceptional stability of these polyoxometalate-organic systems facilitates mass spectrometric characterization, which confirms the composition of the complexes and also indicates that the methoxide groups on the vanadium cluster nodes are labile. The results will help deepen the mechanistic understanding of the formation mechanisms of polyoxovanadate-based metal-organic cages and other functionalized polyoxovanadate clusters in general.

The Evolution of Classical Spiro-OMeTAD: Synthesis of Arylamine Endcapped Indenone Spirofluorene.

Spiro-OMeTAD is the well-known hole transporting material (HTM) in perovskite solar cells. In this work, its derivatives, namely four D-A shaped triphenylamine or biphenylamine endcapped indenone spirofluorene (SFD-TPA, SFD-OMeTPA, SFD-TAD, and SFD-OMeTAD), were designed and synthesized. With the introduction of electron-donating moieties and the extension of conjugation length, a series of changes in photophysical and electrochemical properties could be detected. Notably, in comparison with the optical gap (2.96 eV) of the reported spiro-OMeTAD, SFD-OMeTAD presents an optical gap as low as 1.87 eV. Moreover, density functional theory simulations were employed to further investigate their geometric and electronic structures. Finally, steady-state photoluminescence measurements proved the efficient charge separation and collection processes at the perovskite/HTM interface. It can be predicted that all four compounds with enhanced sunlight absorption capability and suitable frontier energy levels can be used as hole-transporting materials for perovskite solar cells.

Investigation on the Mechanism of Radical Intermediate Formation and Moderate Oxidation of Spiro-OMeTAD by the Synergistic Effect of Multisubstituted Polyoxometalates in Perovskite Solar Cells.

Conventional oxidation of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) by air would bring various drawbacks for perovskite solar cells (PSCs), such as low power conversion efficiency (PCE) and poor stability. Here, a series of heteroatom-substituted Keggin-type polyoxometalates (POMs), H4PMo11VO40 (PMo11V), H5PMo10V2O40 (PMo10V2), and H6PMo9V3O40 (PMo9V3) are prepared and applied as p-type dopants to realize quantitative and controllable oxidation of Spiro-OMeTAD under an inert condition. The possible mechanism and electron donor regions in the oxidation of Spiro-OMeTAD are investigated using two-dimensional nuclear magnetic resonance (NMR) spectra and the relationship between POM structures and the oxidation degree of Spiro-OMeTAD is proposed. In addition, the synergistic effect of heteroatoms makes V2-substituted PMo10V2 exhibit appropriate oxidation of Spiro-OMeTAD and promoted the highest efficient hole extraction as well as the decreased charge recombination. Therefore, the champion device doped with PMo10V2 shows a PCE of 20.41% and a superior open circuit voltage (Voc) of 1.133 V, surpassing that of the pristine device (18.61%). This work presents a fresh perspective to the controllable oxidation of Spiro-OMeTAD employing economical inorganic POM dopants, which would promote the commercialization of PSCs.

Weakly supervised learning analysis of Aß plaque distribution in the whole rat brain.

Alzheimer's disease (AD) is a great challenge for the world and hardly to be cured, partly because of the lack of animal models that fully mimic pathological progress. Recently, a rat model exhibiting the most pathological symptoms of AD has been reported. However, high-resolution imaging and accurate quantification of beta-amyloid (Aß) plaques in the whole rat brain have not been fulfilled due to substantial technical challenges. In this paper, a high-efficiency data analysis pipeline is proposed to quantify Aß plaques in whole rat brain through several terabytes of image data acquired by a high-speed volumetric imaging approach we have developed previously. A novel segmentation framework applying a high-performance weakly supervised learning method which can dramatically reduce the human labeling consumption is described in this study. The effectiveness of our segmentation framework is validated with different metrics. The segmented Aß plaques were mapped to a standard rat brain atlas for quantitative analysis of the Aß distribution in each brain area. This pipeline may also be applied to the segmentation and accurate quantification of other non-specific morphology objects.

New Insight into the Lewis Basic Sites in Metal-Organic Framework-Doped Hole Transport Materials for Efficient and Stable Perovskite Solar Cells.

Currently, Spiro-OMeTAD is the most widely used hole transport material (HTM) in the best-performing perovskite solar cells (PSCs), resulting from its suitable energy level and facile processing. However, the intrinsic properties of organic molecules, such as low conductivity and a nonpolar contact interface, will limit the power conversion efficiency (PCE) and stability of Spiro-OMeTAD-based PSCs. Chemical doping could be an effective strategy to ameliorate the performance of Spiro-OMeTAD, and most of the dopants are designed for controllably oxidizing Spiro-OMeTAD. In this work, a highly stable metal-organic framework {[Zn(Hcbob)]·(solvent)}n (Zn-CBOB) with rod topology and Lewis basic sites is assembled and employed as a dopant for the hole transport layer. It is found that Zn-CBOB not only controllably oxidizes Spiro-OMeTAD and improves the conductivity of the HTM but also passivates the surface traps of the perovskite film by coordinating with Pb2+. The Zn-CBOB-doped PSCs achieved a remarkable PCE of 20.64%. In addition, the hydrophobicity of Zn-CBOB can prevent water from destroying the perovskite layer, which helps elevate the stability of PSCs.

Rigidly Fused Spiro-Conjugated π-Systems.

Spiro-fused π-systems have gained considerable attention for their application as semiconductors in molecular electronics. Here, a synopsis regarding recent breakthroughs in ladderized spirobifluorenes and indeno-spirobifluorenes, along with further spiro-condensed heteroatomic hydrocarbons with donor-acceptor moieties, is provided. Additionally, an extended range of rigid spirobifluorene polymers and specific doubly linked spiro-systems with partial chiral character is discussed. The diverse applications of the aforementioned structures are thoroughly evaluated.

Chemical doping engineering by utilizing trilacunary Keggin polyoxometalates as a dopant for high performance perovskite solar cells.

Chemical doping engineering is an effective strategy to modify the hole transport layer (HTL) and achieve high-efficiency perovskite solar cells (PSCs). In this work, we synthesize an infrequent trilacunary Keggin type polyoxometalate Na10[Zn2(H2O)6(WO2)2(BiW9O33)2] (BiW9-Zn) and apply it as an additive to enhance the hole mobility and electrical conductivity of Spiro-OMeTAD based HTLs. Thanks to the strong electron-accepting properties of polyoxometalate molecules, the as-synthesized BiW9-Zn can directly oxidize Spiro-OMeTAD under an inert atmosphere and avoid the tedious long-term oxidation process. Therefore, the power conversion efficiency (PCE) of optimal PSCs with BiW9-Zn doping is enhanced from 17.58% (without doping) to 19.56% with a significantly improved fill factor and open-circuit voltage. In addition, the assembly repeatability and long-term stability of PSCs are also improved. This work demonstrates the potential of using polyoxometalates (POMs) as low-cost, efficient and highly flexible chemical dopants for HTLs, and more importantly paves a new route to enhance the performance of PSCs.

Insights into the Mechanism of Solid-State Metal Organic Complexes as Controllable and Stable p-Type Dopants in Efficient Planar Perovskite Solar Cells.

Perovskite solar cells (PSCs) based on spiro-OMeTAD have achieved efficiencies greater than 20% in recent years; however, poorly designed dopants and ambiguous working mechanisms are still obstacles that restrict the process of commercialization. Various dopants have been introduced to modulate the electrical properties of spiro-OMeTAD, often accompanying some negative problems, such as complex synthetic routes and accelerated degradation of perovskite. Here, two novel metal organic complexes (Cu-2Cl and Cu-4Cl) with similar molecular fragments are designed and synthesized to investigate the effects on the chemical p-doping of spiro-OMeTAD. The unique coordination environment of copper ions and harmless oxidation byproducts make Cu-2Cl superior for oxidation of spiro-OMeTAD, and the possible synergetic mechanism of the heterogeneous reactions with Li-TFSI is also proposed. Utilizing Cu-2Cl-doped hole transport materials to fabricate PSCs will facilitate hole transport, reduce interfacial charge recombination, and passivate the trap states of perovskite, resulting in a champion efficiency of 20.97%. In addition, the intrinsic solid-state hydrophobic characteristics of Cu-2Cl nanoparticles well dispersed in the hole transport layer successfully suppress the invasion of water vapor, and the corresponding device retains 84% of its original efficiency after being stored for 720 h in ambient air condition.

Self-Assembly of Hybrid Oxidant POM@Cu-BTC for Enhanced Efficiency and Long-Term Stability of Perovskite Solar Cells.

The controllable oxidation of spiro-OMeTAD and improving the stability of hole-transport materials (HTMs) layer are crucial for good performance and stability of perovskite solar cells (PSCs). Herein, we report an efficient hybrid polyoxometalate@metal-organic framework (POM@MOF) material, [Cu2 (BTC)4/3 (H2 O)2 ]6 [H3 PMo12 O40 ]2 or POM@Cu-BTC, for the oxidation of spiro-OMeTAD with Li-TFSI and TBP. When POM@Cu-BTC is introduced to the HTM layer as a dopant, the PSCs achieve a superior fill factor of 0.80 and enhanced power conversion efficiency 21.44 %, as well as improved long-term stability in an ambient atmosphere without encapsulation. The enhanced performance is attributed to the oxidation activity of POM anions and solid-state nanoparticles. Therefore, this research presents a facile way by using hybrid porous materials to accelerate oxidation of spiro-OMeTAD, further improving the efficiency and stability of PSCs.

Sulfur-Containing Bent N-Heteroacenes.

A series of novel sulfur-containing bent N-heteroacenes were constructed and characterized by NMR and UV/Vis spectroscopy, cyclic voltammetry, and single-crystal X-ray diffraction. By introducing sulfur-containing groups (thio, sulfinyl, and sulfonyl) into bent azaacenes, their electronic delocalization was improved and frontier energy levels were modulated. The target products displayed tunable optical and electronic properties through altering the valence of sulfur and fused length of the azaacenes. For the first time, typical products were utilized as organic field effect transistor materials, affording promising results.