Screening Surface-Defective Graphene Quantum Dots: Promoting Plant Growth and Combating Phytovirus.

Reduced graphene quantum dots (r-GQD), graphene oxide quantum dots (GOQD), and carboxylated graphene quantum dots (C-GQD) are screened to promote tobacco growth and combat tobacco mosaic virus (TMV). First, a 21-day foliar exposure is employed to explore GQDs' impacts on N. benthamiana. Surface-defective GOQD and C-GQD are screened out to facilitate N. benthamiana uptake through leaf stomata, and to promote seedlings of differently leaf ages to various degrees at different concentrations after different durations of foliar exposure. Specially, compared to the ddH2O treatment, GOQD/C-GQD at 400 mg L-1 increase biomass by 44%/68%, increase chlorophyll content by 43%/54% and up-regulate the expression of growth-related genes NtLRX1, CycB, and NtPIP1 by more than two-fold. Second, different from the transient inhibition shown by r-GQD and the TMV enhancement shown by GOQD, C-GQD can directly inactivate TMV infection by inducing TMV aggregation and attachment outside TMV, significantly decreasing TMV replication and hindering TMV spread over 21-day. Specially, C-GQD decreases the transcript abundance of TMV RdRp and TMV CP to 0.11-fold and 0.29-fold, and down-regulates the host defensive response pathways. This work provides a comparative analysis of GQDs with different surface-functionalizations, highlighting C-GQD as a promising nanotechnology tool for promoting plant growth and inactivating phytovirus.

Copper-catalyzed C2-selective alkynylation of chromones via 1,4-conjugate addition.

Copper-catalyzed selective alkynylation with N-propargyl carboxamides as nucleophiles has been successfully developed for the synthesis of C2-functionalized chromanones. Under optimized reaction conditions, 21 examples were obtained in one-pot procedure through 1,4-conjugate addition. This protocol features readily available feedstocks, easy operations, and moderate to good yields, which provides viable access to pharmacologically active C2-functionalized chromanones.

Crystallization-Induced Dimerization and Solution-Phase Bond Dissociation of Stable Dibenzoolympicenyl Radicals.

Crystallization of organic materials can lead to different assembly structure with different reactivity, but this phenomenon is rarely observed for delocalized hydrocarbon radicals. This report introduces a crystallization-induced radical-radical coupling reaction, which employs a series of stable nonplanar organic π-radicals as reactants. Six stable radical congeners are synthesized, resulting in radical-radical coupling at the allenyl radical site during crystallization to produce close-shell dimers. This coupling reaction is absent in the solution phase, which highlights the importance of preorganization in the lattice. Remarkably, the attempts of cocrystallization of different congeners yielded homocoupling products instead of cross-coupling products. In specific cases, two distinct polymorphs are observed and their reactivity is different according to the distance of the reaction sites. Theoretical calculations indicate that the transition from a metastable preorganized monomer to a dimer is barrierless and spontaneous. The dimer could regenerate free radicals by heating or photoirradiation in the solution phase. This discovery may lead to controllable molecular switches.

Phenanthroline-Based Low-Cost and Efficient Small-Molecule Cathode Interfacial Layer Enables High-Performance Inverted Perovskite Solar Cells via Doctor-Blade Coating.

Perovskite solar cells (PSCs) have recently emerged as highly efficient and cutting-edge photovoltaic technology. In inverted PSCs, challenges are focused on the insufficient interface contact and energy level misalignment between the electron transport layer (ETL) and the metal electrode. Hence, the cathode interfacial layer (CIL) plays a crucial role in regulating energy levels and enabling charge extraction in PSCs. In this study, a low-cost phenanthroline derivative, 4,7-dimethoxy-1,10-phenanthroline (Phen-OMe), is developed as an efficient CIL between the PCBM and Ag electrodes. The incorporation of Phen-OMe not only improves the interfacial contact but also effectively reduces the work function (WF) of the Ag electrode, thus promoting charge dissociation and transport at the interface. Through utilizing a wide-band-gap perovskite with the band gap of 1.77 eV as the active layer by a simple, high-throughput, and low-cost doctor-blade coating process, the power conversion efficiency (PCE) is enhanced significantly from 16.11% of the control device to 18.61% of the device with Phen-OMe as the CIL. Interestingly, Phen-OMe shows a broad application as the CIL in PSCs and tandem solar cells (TSCs), resulting in a boosted efficiency of 22.29% in intermediate-band-gap PSCs and a PCE of 22.05% with a high open-circuit voltage (VOC) of 2.12 V in the perovskite/organic TSC. This achievement shows that Phen-OMe would be a potential candidate as low-cost and efficient CILs for PSCs.

Bulk Photovoltaic Current Mechanisms in All-Inorganic Perovskite Multiferroic Materials.

After the discovery of bulk photovoltaic effect more than half a century ago, ferro-electrical and magneto-optical experiments have provided insights into various related topics, revealing above bandgap open voltages and non-central symmetrical current mechanisms. However, the nature of the photon-generated carriers responses and their microscopic mechanisms remain unclear. Here, all-inorganic perovskite Bi0.85Gd0.15Fe1-xMnxO3 thin films were prepared by a sol-gel process and the effects of Gd and Mn co-doped bismuth ferrites on their microtopography, grain boundries, multiferroic, and optical properties were studied. We discovered a simple "proof of principle" type new method that by one-step measuring the leakage current, one can demonstrate the value of photo generated current being the sum of ballistic current and shift current, which are combined to form the so-called bulk photovoltaic current, and can be related to the prototype intrinsic properties such as magneto-optical coupling and ferroelectric polarization. This result has significant potential influence on design principles for engineering multiferroic optoelectronic devices and future photovoltaic industry development.

The application of covalent organic frameworks in Lithium-Sulfur batteries: A mini review for current research progress.

Recently, how to enhance the energy density of rechargeable batteries dramatically is becoming a driving force in the field of energy storage research. Among the current energy storage technologies, the lithium-sulfur (Li-S) batteries are one of the most promising candidates for achieving high-capacity and commercial batteries. The theoretical energy density of Li-S batteries reaches to 2,600 Wh kg-1 with the theoretical capacity of 1,675 mA h g-1. Therefore, Li-S batteries are considered as the great potential for developing future energy storage technology. However, some of problems such as Li dendrites growth, the shuttle effect of sulfides and the electronic insulation feature of sulfur, have brought obstacles to the development of Li-S batteries. The covalent organic frameworks (COFs) are a series of porous materials with different topological structures, which show the versatile characteristics of high specific surface area, permanent pores, ordered porous channels and tunable internal structure. Potentially, their ordered channels and extended conjugated frameworks could facilitate rapid Li-ion diffusion and electron transport for the remarkable rate capability. On the basis of these merits, the COFs become the potential electrode materials to solve the above serious problems of Li-S batteries. In this mini review, we summarize the research progress of COFs utilized as electrode materials in the Li-S batteries, including the cathode, separator and anode materials. Accordingly, the outlook of COFs as electrodes for future development in Li-S batteries is also given.

Morel Production Associated with Soil Nitrogen-Fixing and Nitrifying Microorganisms.

True morels (Morchella, Pezizales) cultivated in soil are subject to complex influences from soil microbial communities. To explore the characteristics of soil microbial communities on morel cultivation, and evaluate whether these microbes are related to morel production, we collected 23 soil samples from four counties in Sichuan and Yunnan Provinces, China. Based on ITS and 16S rDNA amplicon sequencing, the alpha diversity analysis indicated that the biodiversity of morel cultivation soil showed a downward trend compared with the bare soil. The results also showed that there were no significant differences in soil microbial communities between OC (bare soil) and OO (after one-year suspension of sowing). This means that, after about one year of stopping sowing, the component and structure of soil that once cultivated morel would be restored. In co-occurrence networks, some noteworthy bacterial microbes involved in nitrogen fixation and nitrification have been identified in soils with high morel yields, such as Arthrobacter, Bradyhizobium, Devosia, Pseudarthrobacter, Pseudolabrys, and Nitrospira. In contrast, in soils with low or no morel yield, some pathogenic fungi accounted for a high proportion, including Gibberella, Microidium, Penicillium, Sarocladium, Streptomyces, and Trichoderma. This study provided valuable information for the isolation and culturing of some beneficial microbes for morel cultivation in further study and, potentially, to harness the power of the microbiome to improve morel production and health.

A low-cost naphthaldiimide based organic cathode for rechargeable lithium-ion batteries.

Recently, the development of cathode materials is becoming an important issue for lithium-ion batteries (LIBs). Compared with inorganic cathodes, the organic cathodes are developing rapidly, ascribing to their distinct merits in light weight, low cost, massive organic resources and high capacity. In this paper, a cost-efficiency naphthaldiimide (NDI) based derivative, 2,7-bis(2-((2-hydroxyethyl) amino) ethyl) benzo[lmn] [3,8] phenanthroline-1,3,6,8(2H, 7H)-tetraone (NDI-NHOH), was used as organic cathode in LIBs. The NDI-NHOH was synthesized easily via one-step process, and it showed very high thermal stability. Through mixing NDI-NHOH with acetylene black and polyvinylidene fluoride (weight ratio of 6:3:1) as composite cathode in lithium-metal based LIBs, the NDI-NHOH presented versatile electrochemical properties. From cyclic voltammetry (CV) test, it exhibited two reversible peaks for oxidation and reduction in the first cycle, respectively. Notably, the oxidation and reduction peaks were located at 2.54, 3.22 and 2.14, 2.32 V vs. Li+/Li, respectively. By employing NDI-NHOH as cathode, it demonstrated a specific capacity of about 80 mAh g-1 in the range of 1.5-3.5 V, where the batteries retained a capacity retention of 50% over 20 cycles. According to the LIBs study, it suggests that the NDI-NHOH-based derivative shows a potentially promising candidate as efficient organic cathode materials for high-performance metal-ions batteries.

Monilochaetes pteridophytophila (Australiascaceae, Glomerellales), a new fungus from tree fern.

BACKGROUND: During taxonomic and phylogenetic studies of fungi on pteridophytes in Thailand, Monilochaetes pteridophytophila sp. nov. was collected from the frond stalks of a tree fern (Alsophila costularis, Cyatheaceae). The new species is introduced, based on evidence from morphology and phylogenetic analyses of a concatenated dataset of LSU, ITS, SSU and RPB2 sequences. NEW INFORMATION: Monilochaetes pteridophytophila differs from extant species of Monilochaetes in having darker conidiophores with fewer septae (1-4-septate). Monilochaetes pteridophytophila forms a distinct clade, basal from other species of Monilochaetes in Australiascaceae. A detailed description and illustrations of the new species are provided. We also provided a synopsis of accepted species of Monilochaetes.

An Electrically Modulated Single-Color/Dual-Color Imaging Photodetector.

An electrically modulated single-/dual-color imaging photodetector with fast response speed is developed based on a small molecule (COi 8DFIC)/perovskite (CH3 NH3 PbBr3 ) hybrid film. Owing to the type-I heterojunction, the device can facilely transform dual-color images to single-color images by applying a small bias voltage. The photodetector exhibits two distinct cut-off wavelengths at ≈544 nm (visible region) and ≈920 nm (near-infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W-1 at ≈525 nm and 0.041 A W-1 at ≈860 nm with a fast response speed (≈102 ns). Under 0.6 V bias, the photodetector can operate in a single-color mode with a peak responsivity of 0.09 A W-1 at ≈475 nm, showing a fast response speed (≈102 ns). A physical model based on band energy theory is developed to illustrate the origin of the tunable single-/dual-color photodetection. This work will stimulate new approaches for developing solution-processed multifunctional photodetectors for imaging photodetection in complex circumstances.

Achieving Fast Charge Separation and Low Nonradiative Recombination Loss by Rational Fluorination for High-Efficiency Polymer Solar Cells.

Four low-cost copolymer donors of poly(thiophene-quinoxaline) (PTQ) derivatives are demonstrated with different fluorine substitution forms to investigate the effect of fluorination forms on charge separation and voltage loss (Vloss ) of the polymer solar cells (PSCs) with the PTQ derivatives as donor and a A-DA'D-A-structured molecule Y6 as acceptor. The four PTQ derivatives are PTQ7 without fluorination, PTQ8 with bifluorine substituents on its thiophene D-unit, PTQ9, and PTQ10 with monofluorine and bifluorine substituents on their quinoxaline A-unit respectively. The PTQ8- based PSC demonstrates a low power conversion efficiency (PCE) of 0.90% due to the mismatch in the highest occupied molecular orbital (HOMO) energy levels alignment between the donor and acceptor. In contrast, the devices based on PTQ9 and PTQ10 show enhanced charge-separation behavior and gradually reduced Vloss , due to the gradually reduced nonradiative recombination loss in comparison with the PTQ7-based device. As a result, the PTQ10-based PSC demonstrates an impressive PCE of 16.21% with high open-circuit voltage and large short-circuit current density simultaneously, and its Vloss is reduced to 0.549 V. The results indicate that rational fluorination of the polymer donors is a feasible method to achieve fast charge separation and low Vloss simultaneously in the PSCs.

[6,6]-phenyl-C61-butyric acid 2-((2-(dimethylamino)ethyl)(methyl)amino)-ethyl ester as an acceptor and cathode interfacial material in polymer solar cells.

An amine-based, alcohol-soluble fullerene [6,6]-phenyl-C61-butyric acid 2-((2-(dimethylamino)ethyl)(methyl)amino)-ethyl ester (PCBDAN) with 4-fold electron mobility of 6,6-phenyl-C61-butyric acid methyl ester (PCBM) is applied successfully as an acceptor and cathode interfacial material in polymer solar cells ITO/P3HT:PCBDAN/MoO3/Ag, where indium tin oxide (ITO) alone is used as the cathode and poly(3-hexylthiophene) (P3HT) is used as a donor. The X-ray photoelectron spectroscopy (XPS) depth profile confirming a favorable vertical phase separation is formed where P3HT is rich at the air/active blend interface and PCBDAN is rich at the buried interface with ITO and, thus, reduces the work function of ITO for use as the cathode. A moderate power conversion efficiency (PCE) of 3.1% is achieved. The slightly low PCE could be due to unoptimized morphology and low structure ordering of P3HT in the blends. However, this result demonstrates that the amine-based fullerene could be used as the acceptor and cathode interfacial material, which eliminated the multilayer device fabrication process. Because PCBDAN has high electron mobility, it would have potential applications in nano-structured organic solar cells. In the near future, alcohol-processable, high-efficient organic/polymer solar cells can be anticipated.

Self-organization of amine-based cathode interfacial materials in inverted polymer solar cells.

We present a strategy to fabricate polymer solar cells in inverted geometry by self-organization of alcohol soluble cathode interfacial materials in donor-acceptor bulk heterojunction blends. An amine-based fullerene [6,6]-phenyl-C61-butyric acid 2-((2-(dimethylamino)-ethyl)(methyl)amino)ethyl ester (PCBDAN) is used as an additive in poly(3-hexylthiophene) (P3HT) and 6,6-phenyl C61-butyric acid methyl ester (PCBM) blend to give a power conversion efficiency of 3.7% based on devices ITO/P3HT:PCBM:PCBDAN/MoO3/Ag where the ITO alone is used as the cathode. A vertical phase separation in favor of the inverted device architecture is formed: PCBDAN is rich on buried ITO surface reducing its work function, while P3HT is rich on air interface with the hole-collecting electrode. The driving force of the vertical phase separation is ascribed to the surface energy and its components of the blend compositions and the substrates. Similar results are also found with another typical alcohol soluble cathode interfacial materials, poly[(9,9-bis(3'-(N, N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN), implying that self-organization may be a general phenomenon in ternary blends. This self-organization procedure could eliminate the fabrication of printing thin film of interlayers or printing on such thin interlayers and would have potential application for roll-to-roll processing of polymer solar cells.

N-acyldithieno[3,2-b:2',3'-d]pyrrole-based low-band-gap conjugated polymer solar cells with amine-modified [6,6]-phenyl-C61-butyric acid ester cathode interlayers.

Efficient low-band-gap polymers are one key component for constructing tandem solar cells with other higher-band-gap materials to harvest wide absorption of the solar spectrum. The N-acyldithieno[3,2-b:2',3'-d]pyrrole (DTP) building block is used for making low-band-gap polymers. It is attractive because of its strong donating ability and relatively low highest-occupied-molecular-orbital level in comparison with the N-alkyl DTP building block. However, additional solubilizing groups on the accepting units are needed for soluble donor-acceptor polymers based on the N-alkanoyl DTP building block. Combining N-benzoyl DTP with a 4,7-dithieno-2,1,3-benzothiadiazole building block, a polymer with a low band gap of 1.44 eV, delivers a high short-circuit current of 17.1 mA/cm(2) and a power conversion efficiency of 3.95%, which are the highest for the devices with DTP-containing materials. Herein, an alcohol-soluble diamine-modified fullerene cathode interfacial layer improved the device efficiency significantly more than the mono-amine analogue.

A hyperbranched conjugated polymer as the cathode interlayer for high-performance polymer solar cells.

An alcohol-soluble hyperbranched conjugated polymer HBPFN with a dimethylamino moiety is synthesized and used as a cathode interlayer. A PCE of 7.7% is obtained for PBDTTT-C-T/PC71 BM based solar cells. No obvious interfacial dipole is found at the interface between the active layer and HBPFN however, an interfacial dipole with the cathode could be one of the reasons for the enhanced performance.

Preparation and helical folding of aromatic polyamides.

Long aromatic polyamide chains are prepared from the corresponding monomers. The resultant polymer adopts a hollow helical conformation that is stabilized by intramolecular H-bonding interaction between side chains.