Interactions between nonfullerene acceptors lead to unstable ternary organic photovoltaic cells.

For organic photovoltaic (OPV) devices to achieve consistent performance and long operational lifetimes, organic semiconductors must be processed with precise control over their purity, composition, and structure. This is particularly important for high volume solar cell manufacturing where control of materials quality has a direct impact on yield and cost. Ternary-blend OPVs containing two acceptor-donor-acceptor (A-D-A)-type nonfullerene acceptors (NFAs) and a donor have proven to be an effective strategy to improve solar spectral coverage and reduce energy losses beyond that of binary-blend OPVs. Here, we show that the purity of such a ternary is compromised during blending to form a homogeneously mixed bulk heterojunction thin film. We find that the impurities originate from end-capping C=C/C=C exchange reactions of A-D-A-type NFAs, and that their presence influences both device reproducibility and long-term reliability. The end-capping exchange results in generation of up to four impurity constituents with strong dipolar character that interfere with the photoinduced charge transfer process, leading to reduced charge generation efficiency, morphological instabilities, and an increased vulnerability to photodegradation. As a consequence, the OPV efficiency falls to less than 65% of its initial value within 265 h when exposed to up to 10 suns intensity illumination. We propose potential molecular design strategies critical to enhancing the reproducibility as well as reliability of ternary OPVs by avoiding end-capping reactions.

The transcription factor ThDOF8 binds to a novel cis-element and mediates molecular responses to salt stress in Tamarix hispida.

Salt stress is a common abiotic factor that restricts plant growth and development. As a halophyte, Tamarix hispida is a good model plant for exploring salt-tolerance genes and regulatory mechanisms. DNA-binding with one finger (DOF) is an important transcription factor (TF) that influences and controls various signaling substances involved in diverse biological processes related to plant growth and development, but the regulatory mechanisms of DOF TFs in response to salt stress are largely unknown in T. hispida. In the present study, a newly identified Dof gene, ThDOF8, was cloned from T. hispida, and its expression was found to be induced by salt stress. Transient overexpression of ThDOF8 enhanced T. hispida salt tolerance by enhancing proline levels, and increasing the activities of the antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). These results were also verified in stably transformed Arabidopsis. Results from TF-centered yeast one-hybrid (Y1H) assays and EMSAs showed that ThDOF8 binds to a newly identified cis-element (TGCG). Expression profiling by gene chip analysis identified four potential direct targets of ThDOF8, namely the cysteine-rich receptor-like kinases genes, CRK10 and CRK26, and two glutamate decarboxylase genes, GAD41, and GAD42, and these were further verified by ChIP-quantitative-PCR, EMSAs, Y1H assays, and ß-glucuronidase enzyme activity assays. ThDOF8 can bind to the TGCG element in the promoter regions of its target genes, and transient overexpression of ThCRK10 also enhanced T. hispida salt tolerance. On the basis of our results, we propose a new regulatory mechanism model, in which ThDOF8 binds to the TGCG cis-element in the promoter of the target gene CRK10 to regulate its expression and improve salt tolerance in T. hispida. This study provides a basis for furthering our understanding the role of DOF TFs and identifying other downstream candidate genes that have the potential for improving plant salt tolerance via molecular breeding.

Color-neutral, semitransparent organic photovoltaics for power window applications.

Semitransparent organic photovoltaic cells (ST-OPVs) are emerging as a solution for solar energy harvesting on building facades, rooftops, and windows. However, the trade-off between power-conversion efficiency (PCE) and the average photopic transmission (APT) in color-neutral devices limits their utility as attractive, power-generating windows. A color-neutral ST-OPV is demonstrated by using a transparent indium tin oxide (ITO) anode along with a narrow energy gap nonfullerene acceptor near-infrared (NIR) absorbing cell and outcoupling (OC) coatings on the exit surface. The device exhibits PCE = 8.1 ± 0.3% and APT = 43.3 ± 1.2% that combine to achieve a light-utilization efficiency of LUE = 3.5 ± 0.1%. Commission Internationale d'eclairage chromaticity coordinates of (0.38, 0.39), a color-rendering index of 86, and a correlated color temperature of 4,143 K are obtained for simulated AM1.5 illumination transmitted through the cell. Using an ultrathin metal anode in place of ITO, we demonstrate a slightly green-tinted ST-OPV with PCE = 10.8 ± 0.5% and APT = 45.7 ± 2.1% yielding LUE = 5.0 ± 0.3% These results indicate that ST-OPVs can combine both efficiency and color neutrality in a single device.

Vector magnetic field sensor based on U-bent single-mode fiber and magnetic fluid.

A novel, compact, and easy fabrication vector magnetic field sensor has been proposed and investigated. The proposed sensor consists of a U-bent single-mode fiber fixed in a magnetic-fluid-filled vessel. Neither mechanical modification nor additional fiber grating is needed during the sensor fabrication. The results show that the response of magnetic fluid to magnetic field can be used to measure the direction and intensity of magnetic field via whispering gallery modes supported by the U-bent fiber structure with suitable bending radius. The sensitivity of direction is 0.251 nm/°, and the maximum magnetic field intensity sensitivity is 0.517 nm/mT. Besides, the results of this work prove the feasibility for realizing vector magnetic sensors based on other bending structures (such as bending multimode interference, bending SPR structure) in the future.

Vacuum-Deposited Biternary Organic Photovoltaics.

Ternary blend organic photovoltaics (OPVs) have been introduced to improve solar spectral absorption and reduce energy losses beyond that of binary blend OPVs, but the difficulties in simultaneously optimizing the morphology of three molecular components result in devices that have generally exhibited performance inferior to that of analogous binary OPVs. Here, we introduce a small molecule-based biternary OPV comprising two individual, vacuum-deposited binary bulk heterojunctions fused at a planar junction without component intermixing. In contrast to previous reports where the open circuit voltage (VOC) of a conventional, blended ternary cell lies between those of the individual binaries, the VOC of the biternary OPV corresponds to one of the constituent binaries, depending on the order in which they are stacked relative to the anode. Additionally, dipole-induced energy-level realignment between the two binary segments necessary to achieve maximum efficiency is observed only when using donor-acceptor-acceptor' dipolar donors in the photoactive heterojunctions. The optimized biternary OPV shows improved performance as compared to its two constituent binary OPVs, achieving a power conversion efficiency of 10.6 ± 0.3% under AM 1.5G 1 sun (100 mW/cm2) simulated illumination with VOC = 0.94 ± 0.01 V, a short circuit current density of 16.0 ± 0.5 mA cm-2, and a fill factor of 0.70 ± 0.01.

All-fiber-optic vector magnetic field sensor based on side-polished fiber and magnetic fluid.

A kind of compact all-fiber-optic vector magnetic sensor is proposed and demonstrated. The sensor consists of a side-polished-fiber (SPF)-integrated with singlemode-no core-singlemode (SNS) fiber structure. A section of side-polished fiber breaks the axially symmetry of the composite structure. The as-fabricated sensor supports vector sensing and has a magnetic field strength sensitivity of up to -2370 pm/mT over 2-6 mT range. The physical mechanism is that the modal interference is strongly influenced by the refractive index (RI) near the side-polished surface. The advantages of the proposed sensor lie in low cost, simple structure and easy manufacture, which make it attractive in the field of magnetic field vector sensing.

MiR-744-3p regulates keratinocyte proliferation and differentiation via targeting KLLN in psoriasis.

Psoriasis is a chronic inflammatory disease, and microRNAs have been reported to regulate the pathogenesis of psoriasis. Up-regulated miR-744-3p level was identified to associate with psoriasis while the precise functions of miR-744-3p in psoriasis were not well-elucidated. We first confirmed the up-regulation of miR-744-3p in psoriasis by measuring its expression level in psoriatic samples. We explored the roles of miR-744-3p on keratinocytes proliferation and differentiation. We searched the targets of miR-744-3p and evaluated the roles of one target, KLLN on keratinocytes proliferation and differentiation. We confirmed the up-regulation of miR-744-3p in psoriatic samples. MiR-744-3p promoted keratinocytes proliferation while inhibited differentiation. MiR-744-3p targeted KLLN and overexpression of miR-744-3p resulted in decreased expression of KLLN. Overexpression of KLLN prevented the effects of miR-744-3p on keratinocytes proliferation and differentiation. MiR-744-3p regulated the proliferation and differentiation of keratinocytes through targeting KLLN in psoriasis.

Verbascoside Alleviates Atopic Dermatitis-Like Symptoms in Mice via Its Potent Anti-Inflammatory Effect.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by the interplay between multiple genetic and environmental factors. The pathogenesis of AD remains incompletely understood. Treatment with topical steroids for chronic AD symptoms has severe side effects and so a new treatment is required. Verbascoside is a hydrophilic phenylethanoid glycoside with antioxidant, anti-inflammatory properties. METHODS: Verbascoside was evaluated in AD-like lesions induced by the repetitive and alternative application of 2,4-dinitrochlorobenzene (DNCB) in BALB/c mice. Overall symptomatic score and serological and molecular changes of the skin lesions were investigated. RESULTS: Verbascoside relieved the overall AD-like symptoms such as scratching behavior and skin lesion severity. At whole-body level, verbascoside significantly reduced DNCB-induced IgE and Th2 cytokines in the peripheral blood. At the skin lesion site, verbascoside also inhibited DNCB-induced production of proinflammatory cytokine TNF-α, IL-6, and IL-4 mRNA. In a human monocyte THP-1 model, verbascoside could suppress DNCB-induced upregulation of CD86 and CD54 at the cell surface, the secretion of the proinflammatory cytokines TNF-α and IL-6, and the activation of NFκB signaling in a dose-dependent manner. CONCLUSION: Our results demonstrate that verbascoside could be a potential therapeutic agent for the treatment of AD.

High Efficiency Near-Infrared and Semitransparent Non-Fullerene Acceptor Organic Photovoltaic Cells.

The absence of near-infrared (NIR) solar cells with high open circuit voltage (Voc) and external quantum efficiency (EQE) has impeded progress toward achieving organic photovoltaic (OPV) power conversion efficiency PCE > 15%. Here we report a small energy gap (1.3 eV), chlorinated nonfullerene acceptor-based solar cell with PCE = 11.2 ± 0.4%, short circuit current of 22.5 ± 0.6 mA cm-2, Voc = 0.70 ± 0.01 V and fill factor of 0.71 ± 0.02, which is the highest performance reported to date for NIR single junction OPVs. Importantly, the EQE of this NIR solar cell reaches 75%, between 650 and 850 nm while leaving a transparency window between 400 and 600 nm. The semitransparent OPV using an ultrathin (10 nm) Ag cathode shows PCE = 7.1 ± 0.1%, with an average visible transmittance of 43 ± 2%, Commission d'Eclairage chromaticity coordinates of (0.29, 0.32) and a color rendering index of 91 for simulated AM1.5 illumination transmitted through the cell.

An Imide-Based Pentacyclic Building Block for n-Type Organic Semiconductors.

A new electron-deficient unit with a fused 5-membered heterocyclic ring was developed by replacing a cyclopenta-1,3-diene from electron-rich donor indacenodithiophene (IDT) with a cyclohepta-4,6-diene-1,3-diimde unit. The imide bridge endows dithienylbenzenebisimide (BBI) with a fixed planar configuration and low energy levels for both the highest occupied molecular orbital (HOMO; -6.24 eV) and the lowest unoccupied molecular orbit (LUMO; -2.57 eV). Organic field-effect transistors (OFETs) based on BBI polymers exhibit electron mobility up to 0.34 cm2 V-1 s-1 , which indicates that the BBI is a promising n-type building block for optoelectronics.

Pharmacokinetics and pharmacodynamics of single and multiple doses of the glucagon receptor antagonist LGD-6972 in healthy subjects and subjects with type 2 diabetes mellitus.

AIM: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple doses of a novel, oral glucagon receptor antagonist, LGD-6972, in healthy subjects and subjects with type 2 diabetes (T2DM). METHODS: In the single ascending dose study, LGD-6972 (2-480 mg) was administered to healthy subjects (n = 48) and T2DM subjects (n = 8). In the multiple ascending dose study, healthy subjects (n = 12) received a dose of 15 mg LGD-6972 and T2DM subjects (n = 36) received doses of 5, 10 or 15 mg of LGD-6972 daily for 14 days. RESULTS: LGD-6972 had linear plasma pharmacokinetics consistent with once-daily dosing that was comparable in healthy and T2DM subjects. Dose-dependent decreases in fasting plasma glucose were observed in all groups with a maximum of 3.15 mmol/L (56.8 mg/dL) on day 14 in T2DM subjects. LGD-6972 also reduced plasma glucose in the postprandial state. Dose-dependent increases in fasting plasma glucagon were observed, but glucagon levels decreased and insulin levels increased after an oral glucose load in T2DM subjects. LGD-6972 was well tolerated at the doses tested without dose-related or clinically meaningful changes in clinical laboratory parameters. No subject experienced hypoglycaemia. CONCLUSION: Inhibition of glucagon action by LGD-6972 was associated with decreases in glucose in both healthy and T2DM subjects, the magnitude of which was sufficient to predict improvement in glycaemic control with longer treatment duration in T2DM patients. The safety and pharmacological profile of LGD-6972 after 14 days of dosing supports continued clinical development.

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis.

Carotenoids are crucial for plant growth and human health. The finding of ORANGE (OR) protein as a pivotal regulator of carotenogenesis offers a unique opportunity to comprehensively understand the regulatory mechanisms of carotenoid accumulation and develop crops with enhanced nutritional quality. Here, we demonstrated that alteration of a single amino acid in a wild-type OR greatly enhanced its ability to promote carotenoid accumulation. Whereas overexpression of OR from Arabidopsis (Arabidopsis thaliana; AtOR) or from the agronomically important crop sorghum (Sorghum bicolor; SbOR) increased carotenoid levels up to 2-fold, expression of AtOR(His) (R90H) or SbOR(His) (R104H) variants dramatically enhanced carotenoid accumulation by up to 7-fold in the Arabidopsis calli. Moreover, we found that AtOR(Ala) (R90A) functioned similarly to AtOR(His) to promote carotenoid overproduction. Neither AtOR nor AtOR(His) greatly affected carotenogenic gene expression. AtOR(His) exhibited similar interactions with phytoene synthase (PSY) as AtOR in posttranscriptionally regulating PSY protein abundance. AtOR(His) triggered biogenesis of membranous chromoplasts in the Arabidopsis calli, which shared structures similar to chromoplasts found in the curd of the orange cauliflower (Brassica oleracea) mutant. By contrast, AtOR did not cause plastid-type changes in comparison with the controls, but produced plastids containing larger and electron-dense plastoglobuli. The unique ability of AtOR(His) in mediating chromoplast biogenesis is responsible for its induced carotenoid overproduction. Our study demonstrates OR(His/Ala) as powerful tools for carotenoid enrichment in plants, and provides insights into the mechanisms underlying OR(His)-regulated carotenoid accumulation.

The Control of Conjugation Lengths and Steric Hindrance to Modulate Aggregation-Induced Emission with High Electroluminescence Properties and Interesting Optical Properties.

A series of novel AIE-active (aggregation-induced emission) molecules, named SAF-2-TriPE, SAF-3-TriPE, and SAF-4-TriPE, were designed and synthesized through facile reaction procedures. We found that incorporation of the spiro-acridine-fluorene (SAF) group, which is famous for its excellent hole-transporting ability and rigid structure, at different substitution positions on the phenyl ring affected the conjugation lengths of these compounds. Consequently, we have obtained molecules with different emission colors and properties without sacrificing good EL (electroluminescence) characteristics. Accordingly, a device that was based on compound SAF-2-TriPE displayed superior EL characteristics: it emitted green light with ηc, max =10.5 cd A(-1) and ηext, max =4.22 %, whereas a device that was based on compound SAF-3-TriPE emitted blue-green light with ηc, max =3.9 cd A(-1) and ηext, max = 1.71 %. These compounds also displayed different AIE performances: when the fraction of water in the THF solutions of these compounds was increased, we observed a significant improvement in the ΦF of compounds SAF-2-TriPE and SAF-3-TriPE; in contrast, compound SAF-4-TriPE showed an abnormal phenomenon, in that it emitted a strong fluorescence in both pure THF solution and in the aggregated state without a significant change in ΦF . Overall, this systematic study confirmed a relationship between the regioisomerism of the luminophore structure and its AIE activity and the resulting electroluminescent performance in non-doped devices.

Acid-Catalyzed Highly Enantioselective Synthesis of α-Amino Acid Derivatives from Sulfinamides and Alkynes.

An enantioselective difunctionalization of activated alkynes using chiral sulfinamide reagents is developed. It is an atom and chirality transfer process that allows for the modular synthesis of optically active α-amino acid derivatives under mild conditions. The reaction proceeds through an acid-catalyzed [2,3]-sigmatropic rearrangement mechanism with predictable stereochemistry and a broad scope.

Self-assembled π-extended condensed benzothiophene nanoribbons for field-effect transistors.

Nanostructures: A new air-stable π-extended condensed benzothiophene was prepared by starting from 4,8-dioctyl-oxybenzo[1,2-b:4,5-b']dithiophene in about 54 % overall yield. Highly ordered 1D organic nanoribbons of the resultant compound were formed by molecular self-assembly. An individual nanoribbon-based organic field-effect transistor (see figure) exhibited an average mobility of 0.05 cm(2) V(-1) s(-1).

Control of Host-Matrix Morphology Enables Efficient Deep-Blue Organic Light-Emitting Devices.

Mixing a sterically bulky, electron-transporting host material into a conventional single host-guest emissive layer is demonstrated to suppress phase separation of the host matrix while increasing the efficiency and operational lifetime of deep-blue phosphorescent organic light-emitting diodes (PHOLEDs) with chromaticity coordinates of (0.14, 0.15). The bulky host enables homogenous mixing of the molecules comprising the emissive layer while suppressing single host aggregation; a significant loss channel of nonradiative recombination. By controlling the amorphous phase of the host-matrix morphology, the mixed-host device achieves a significant reduction in nonradiative exciton decay, resulting in 120 ± 6% increase in external quantum efficiency relative to an analogous, single-host device. In contrast to single host PHOLEDs where electrons are transported by the host and holes by the dopants, both charge carriers are conducted by the mixed host, reducing the probability of exciton annihilation, thereby doubling of the deep-blue PHOLED operational lifetime. These findings demonstrate that the host matrix morphology affects almost every aspect of PHOLED performance.

Characterizing and Improving the Thermal Stability of Organic Photovoltaics Based on Halogen-Rich Non-Fullerene Acceptors.

The thermal stability of inverted, halogen-rich non-fullerene acceptor (NFA)-based organic photovoltaics with MoOx as the hole transporting layer is studied at temperatures up to 80 °C. Over time, the power conversion efficiency shows a "check-mark" shaped thermal aging pattern, featuring an early decrease, followed by a long-term recovery. A high Cl concentration at the bulk heterojunction (BHJ)/MoOx interface in the thermally aged device is found using energy dispersive X-ray spectroscopy. X-ray photoelectron spectroscopy shows that the MoOx is chlorinated after thermal aging. With bulk quantum efficiency analysis, we propose an explanation to the check-mark shaped pattern. Inserting a thin C70 layer between the BHJ and MoOx suppresses the thermal degradation mechanisms, resulting in three orders of magnitude increase in device lifetime at 80 °C.

Nonvolatile rewritable memory effects in graphene oxide functionalized by conjugated polymer containing fluorene and carbazole units.

A new polymer, poly[{9,9-di(triphenylamine)fluorene}(9,9-dihexylfluorene)(4-aminophenylcarbazole)] (PFCz) was synthesized and used in a reaction with graphene oxide (GO) containing surface-bonded acyl chloride moieties to give a soluble GO-based polymer material GO-PFCz. A bistable electrical switching effect was observed in an electronic device in which the GO-PFCz film was sandwiched between indium-tin oxide (ITO) and Al electrodes. This device exhibited two accessible conductivity states, that is, a low-conductivity (OFF) state and a high-conductivity (ON) state, and can be switched to the ON state under a negative electrical sweep; it can also be reset to the initial OFF state by a reverse (positive) electrical sweep. The ON state is nonvolatile and can withstand a constant voltage stress of -1 V for 3 h and 10(8) read cycles at -1 V under ambient conditions. The nonvolatile nature of the ON state and the ability to write, read, and erase the electrical states, fulfill the functionality of a rewritable memory. The mechanism associated with the memory effects was elucidated from molecular simulation results and in-situ photoluminescence spectra of the GO-PFCz film under different electrical biases.

Synthesis and strong optical limiting response of graphite oxide covalently functionalized with gallium phthalocyanine.

A soluble graphite oxide (GO) axially substituted gallium phthalocyanine (PcGa) hybrid material (GO-PcGa) was for the first time synthesized by the reaction of tBu(4)PcGaCl with GO in anhydrous DMSO at 110 °C in the presence of K(2)CO(3). The formation of a Ga-O bond between PcGa and GO has been confirmed by x-ray photoelectron spectroscopy. In contrast to GO, the D and G bands of GO-PcGa in the Raman spectrum are shifted to the lower wavenumbers by Δν = 11 and 18 cm(-1), respectively. At the same level of concentration of 0.1 g l(-1), GO-PcGa exhibit much larger nonlinear optical extinction coefficients and strong optical limiting performance than GO, tBu(4)PcGaCl and C(60) at both 532 and 1064 nm, implying a remarkable accumulation effect as a result of the covalent link between GO and PcGa. GO-PcGa possesses three main mechanisms for the nonlinear optical response-nonlinear light scattering, two-photon absorption and reverse saturable absorption for the 532 nm pulses and nonlinear light scattering for the 1064 nm pulses. tBu(4)PcGaCl does not make any significant contribution to the optical limiting at 1064 nm, while GO-PcGa has a much greater optical limiting response than GO at this wavelength, this suggesting that the PcGa moiety could certainly play an unknown but important role in the GO-PcGa material system.

The complete chloroplast genome of Thalictrum baicalense Turcz. ex Ledeb.

Thalictrum baicalense Turcz. ex Ledeb. is a well-known herbaceous perennid that has been used as a traditional medicine to treat influenza, hepatitis, and detoxfeaction. In this study, we release and detail the complete chloroplast genome sequences of T. baicalense. The whole chloroplast genome was 155,859 bp in length and comprised 130 genes, including 84 protein-coding genes, 37 tRNA genes, eight rRNA genes. The T. baicalense chloroplast genome had a GC content of 38.39%. The phylogenetic relationships inferred that T. baicalense, T. tenue, T. minus and T. petaloideum are closely related to each other within the genus Thalictrum.