High-Performance Poly(3-hexyl thiophene)-Based Organic Photovoltaics with Side-Chain Engineering of Core Units of Small Molecule Acceptors.

In this study, we synthesized a series of four large-band gap small molecule acceptors with side-chain engineering of the dithieno-pyrrolo-fused pentacyclic benzotriazole (BZTTP or Y1 core) or the fused-ring dithienothiophene-pyrrolobenzothiadiazole (TPBT or Y6 core) with difluoro-indene-dione (IO2F) or dichloro-indene-dione (IO2Cl) end groups to form Y1-IO2F, Y1-IO2Cl, Y6-IO2F, and Y6-IO2Cl acceptors, respectively, for blending with poly(3-hexyl thiophene) (P3HT) for bulk heterojunction organic photovoltaics. The complementary UV-vis absorption spectra of these small molecules and P3HT along with their offset energy bands allow broad absorption and effective electron transfer. Through synchrotron wide-angle X-ray scattering (WAXS) analyses and contact angle measurements, we found that the blend of the small molecule Y6-IO2F (having a TPBT core) and P3HT achieves an optimum morphology that balances their crystallinity and miscibility, among those of these four blends, leading to a substantial enhancement in the short-circuit current density and thus power conversion efficiency (PCE) in their devices. For example, the P3HT:Y6-IO2F (w/w: 1/1.2) device exhibited a champion PCE of 10.5% with a short current density (Jsc) value of 15.9 mA/cm2 as compared to the P3HT:Y1-IO2F device having a PCE of 2.2% with a Jsc value of 5.7 mA/cm2 because of the higher Y6-IO2F (with TPBT core) molecular packing that facilitated carrier transport in the devices. The enhanced thermal stability exhibited by the devices incorporating Y6-IO2F and Y6-IO2Cl, as compared to that of Y1-IO2F and Y1-IO2Cl devices, is also due to the more planar TPBT core structure, while the photostability of devices incorporating Y6-IO2Cl and Y1-IO2Cl is better than that of devices incorporating Y6-IO2F and Y1-IO2F, owing to more photostable chemical structures. These results present an outstanding performance for P3HT-based organic solar cells. Moreover, these small molecule blends are processed with an environmentally friendly solvent tetrahydrofuran, demonstrating both the sustainability and commercial viability of these types of organic photovoltaics.

Prospective Application of Tannic Acid in Acetaminophen (APAP)-Induced Acute Liver Failure.

This study investigated the effect of tannic acid (TA), a natural plant-derived polyphenol, on hepatocyte viability and function, focusing on both hepatoprotective and hepatocurative aspects within liver failure models. In an in vitro prevention model, the TA-containing group exhibited 1.5-fold and 59-fold higher relative cell viability and albumin synthesis, respectively, in injured mature hepatocytes (MHs) and 1.14-fold and 1.10-fold higher values in injured small hepatocytes (SHs), compared with the TA-free group. In the in vitro curative model, the TA-containing group exhibited 3.25-fold and 113-fold higher relative cell viability and albumin synthesis, respectively, in injured MHs and 0.36-fold and 3.55-fold higher values in injured SHs, compared with the TA-free group. In the in vivo disease model, the administration of 300 µL of 1 µg/mL TA significantly mitigated acute liver failure damage and post-APAP toxicity in mice. This was evident in serum analysis, where the levels of alanine transaminase, aspartate aminotransferase, and total bilirubin notably decreased, in agreement with histological observations. The study findings reveal that TA can enhance hepatic function at specific additive concentrations. Furthermore, even when injured by APAP, hepatocytes could revert to their preinjury state after additional TA supplementation. Additionally, pretreating hepatocytes with TA can alleviate subsequent damage. Thus, TA holds clinical potential in the treatment of APAP-induced liver failure.

Perylene Diimide-Fused Dithiophenepyrroles with Different End Groups as Acceptors for Organic Photovoltaics.

In this study, we synthesized four new A-DA'D-A acceptors (where A and D represent acceptor and donor chemical units) incorporating perylene diimide units (A') as their core structures and presenting various modes of halogenation and substitution of the functional groups at their end groups (A). In these acceptors, by fusing dithiophenepyrrole (DTP) moieties (D) to the helical perylene diimide dimer (hPDI) to form fused-hPDI (FhPDI) cores, we could increase the D/A' oscillator strength in the cores and, thus, the intensity of intramolecular charge transfer (ICT), thereby enhancing the intensity of the absorption bands. With four different end group units─IC2F, IC2Cl, IO2F, and IO2Cl─tested, each of these acceptor molecules exhibited different optical characteristics. Among all of these systems, the organic photovoltaic device incorporating the polymer PCE10 blended with the acceptor FhPDI-IC2F (1:1.1 wt %) had the highest power conversion efficiency (PCE) of 9.0%; the optimal PCEs of PCE10:FhPDI-IO2F, PCE10:FhPDI-IO2Cl, and PCE10:FhPDI-IC2Cl (1:1.1 wt %) devices were 5.2, 4.7, and 7.7%, respectively. The relatively high PCE of the PCE10:FhPDI-IC2F device resulted primarily from the higher absorption coefficients of the FhPDI-IC2F acceptor, lower energy loss, and more efficient charge transfer; the FhPDI-IC2F system experienced a lower degree of geminate recombination─as a result of improved delocalization of π-electrons along the acceptor unit─relative to that of the other three acceptors systems. Thus, altering the end groups of multichromophoric PDI units can increase the PCEs of devices incorporating PDI-derived materials and might also be a new pathway for the creation of other valuable fused-ring derivatives.

High-Performance Organic Solar Cells Featuring Double Bulk Heterojunction Structures with Vertical-Gradient Selenium Heterocyclic Nonfullerene Acceptor Concentrations.

In this study, we prepared organic photovoltaics (OPVs) featuring an active layer comprising double bulk heterojunction (BHJ) structures, featuring binary blends of a polymer donor and concentration gradients of two small-molecule acceptors. After forming the first BHJ structure by spin-coating, the second BHJ layer was transfer-printed onto the first using polydimethylsiloxane stamps. A specially designed selenium heterocyclic small-molecule acceptor (Y6-Se-4Cl) was employed as the second acceptor in the BHJ. X-ray photoelectron spectroscopy revealed that the two acceptors formed a gradient concentration profile across the active layer, thereby facilitating charge transportation. The best power conversion efficiencies (PCEs) for the double-BHJ-structured devices incorporating PM6:Y6-Se-4Cl/PM6:Y6 and PM6:Y6-Se-4Cl/PM6:IT-4Cl were 16.4 and 15.8%, respectively; these values were higher than those of devices having one-BHJ structures based on PM6:Y6-Se-4Cl (15.0%), PM6:Y6 (15.4%), and PM6:IT-4Cl (11.6%), presumably because of the favorable vertical concentration gradient of the selenium-containing small-molecule Y6-Se-4Cl in the active layer as well as some complementary light absorption. Thus, combining two BHJ structures with a concentration gradient of the two small-molecule acceptors can be an effective approach for enhancing the PCEs of OPVs.

Chlorinated Spiroconjugated Fused Extended Aromatics for Multifunctional Organic Electronics.

The synthesis of a new molecule, SFIC-Cl, is reported, which features enhanced π-electron delocalization by spiroconjugation and narrowed bandgap by chlorination. SFIC-Cl is integrated into a single-crystal transistor (OFET) and organic light-emitting diode (OLED). The material demonstrates remarkable transport abilities across various solution-processed OFETs and retains efficient radiance in a near-infrared OLED emitting light at 700 nm. Furthermore, the intermolecular multi-dimensional connection of SFIC-Cl enables the fabrication of a single-component large-area (2 × 2 cm2 ) near-infrared OLED by spin-coating. The SFIC-Cl-acceptor-based solar cell shows excellent power conversion efficiency of 10.16% resulting from the broadened and strong absorption and well-matched energy levels. The study demonstrates that chlorinated spiroconjugated fused systems offer a novel direction toward the development of high-performance organic semiconductor materials for hybrid organic electronic devices.

High-Performance Organic Photovoltaics Incorporating an Active Layer with a Few Nanometer-Thick Third-Component Layer on a Binary Blend Layer.

In this paper, a universal approach toward constructing a new bilayer device architecture, a few-nanometer-thick third-component layer on a bulk-heterojunction (BHJ) binary blend layer, has been demonstrated in two different state-of-the-art organic photovoltaic (OPV) systems. Through a careful selection of a third component, the power conversion efficiency (PCE) of the device based on PM6/Y6/layered PTQ10 layered third-component structure was 16.8%, being higher than those of corresponding devices incorporating the PM6/Y6/PTQ10 BHJ ternary blend (16.1%) and the PM6/Y6 BHJ binary blend (15.5%). Also, the device featuring PM7/Y1-4F/layered PTQ10 layered third-component structure gave a PCE of 15.2%, which is higher than the PCEs of the devices incorporating the PM7/Y1-4F/PTQ10 BHJ ternary blend and the PM7/Y1-4F BHJ binary blend (14.2 and 14.0%, respectively). These enhancements in PCE based on layered third-component structure can be attributed to improvements in the charge separation and charge collection abilities. This simple concept of the layered third-component structure appears to have great promise for achieving high-performance OPVs.

Incorporating Indium Selenide Nanosheets into a Polymer/Small Molecule Binary Blend Active Layer Enhances the Long-Term Stability and Performance of Its Organic Photovoltaics.

In this report, we demonstrated that the incorporation of 15 wt % two-dimensional transition-metal dichalcogenide materials indium selenide (In2Se3) nanosheets into a polymer (PM6)/small molecule (Y6) active layer not only increased its light absorption but also enhanced the long-term stability of the PM6/Y6/In2Se3 ternary blend organic photovoltaic (OPV) devices. The power conversion efficiency (PCE) of the device was improved from 15.7 to 16.5% for the corresponding PM6/Y6 binary blend device. Moreover, the PM6/Y6/In2Se3 device retained 80% of its initial PCE after thermal treatment at 100 °C for 600 h; in comparison, the binary blend device retained only 62% of its initial value. This relative enhancement of 29% resulted from the In2Se3 nanosheets retarding or facilitating molecule packing in different orientations that stabilizes the morphology of the active layer. We adopted a modified kinetics model to account for the intrinsic degradation of the OPV; the degradation-facilitated energy for the degradation kinetics of the PCE for the ternary blend device was 5.3 kJ/mol, half of that (11.3 kJ/mol) of the binary blend device, indicating a slower degradation rate occurring for the case of incorporating In2Se3 nanosheets. Therefore, the incorporation of transition metal dichalcogenide nanosheets having tunable band gaps and large asymmetric shape appears to be a new way to improve the long-term stability of devices and realize the practical use of OPVs.

Synthesis of IrO2 decorated core-shell PS@PPyNH2 microspheres for bio-interface application.

In this paper, an effective approach is demonstrated for the fabrication of IrO2-decorated polystyrene@functionalized polypyrrole (core@shell; PS@PPyNH2) microspheres. The synthesis begins with the preparation of monodispersive PS microspheres with a diameter of 490 nm, by a process of emulsifier-free emulsion polymerization, followed by a copolymerization process involving pyrrole and PyNH2 monomers in a PS microsphere aqueous suspension, to produce uniform PS@PPyNH2 microspheres with a diameter of 536 nm. The loading of 2 nm IrO2 nanoparticles onto the PS@PPyNH2 microspheres can be easily adjusted by tuning the pH value of the IrO2 colloidal solution and the PS@PPyNH2 suspension. At pH 4, we successfully obtain IrO2-decorated PS@PPyNH2 microspheres via electrostatic attraction and hydrogen bonding simultaneously between the negatively-charged IrO2 nanoparticles and the positively-charged PS@PPyNH2 microspheres. These IrO2-decorated PS@PPyNH2 microspheres exhibit a characteristic cyclic voltammetric profile, similar to that of an IrO2 thin film. The charge storage capacity is 5.19 mA cm-2, a value almost five times greater than that of PS@PPyNH2 microspheres. In addition, these IrO2-decorated PS@PPyNH2 microspheres exhibit excellent cell viability and biocompatibility.

Potassium-Presenting Zinc Oxide Surfaces Induce Vertical Phase Separation in Fullerene-Free Organic Photovoltaics.

Bulk heterojunction (BHJ) structure based organic photovoltaics (OPVs) have recently showed great potential for achieving high power conversion efficiencies (PCEs). An ideal BHJ structure would feature large donor/acceptor interfacial areas for efficient exciton dissociation and gradient distributions with high donor and acceptor concentrations near the anode and cathode, respectively, for efficient charge extraction. However, the random mixing of donors and acceptors in the BHJ often suffers the severe charge recombination in the interface, resulting in poor charge extraction. Herein, we propose a new approach-treating the surface of the zinc oxide (ZnO) as an electron transport layer with potassium hydroxide-to induce vertical phase separation of an active layer incorporating the nonfullerene acceptor IT-4F. Density functional theory calculations suggested that the binding energy difference between IT-4F and the PBDB-T-2Cl, to the potassium (K)-presenting ZnO interface, is twice as strong as that for IT-4F and PBDB-T-2Cl to the untreated ZnO surface, such that it would induce more IT-4F moving toward the K-presenting ZnO interface than the untreated ZnO interface thermodynamically. Benefiting from efficient charge extraction, the best PCEs increased to 12.8% from 11.8% for PBDB-T-2Cl:IT-4F-based devices, to 12.6% from 11.6% for PBDB-T-2Cl:Y1-4F-based devices, to 13.5% from 12.2% for PBDB-T-2Cl:Y6-based devices, and to 15.7% from 15.1% for PM6:Y6-based devices.

Hydrogen plasma-treated MoSe2 nanosheets enhance the efficiency and stability of organic photovoltaics.

In this paper we report the effect on the power conversion efficiency (PCE) and stability of photovoltaic devices after incorporating hydrogenated two-dimensional (2D) MoSe2 nanosheets into the active layer of bulk heterojunction (BHJ) organic photovoltaics (OPV). The surface properties of 2D MoSe2 nanosheets largely affect their dispersion in the active layer blend and, thus, influence the carrier mobility, PCE, and stability of corresponding devices. We treated MoSe2 nanosheets with hydrogen plasma and investigated their influence on the polymer packing and fullerene domain size of the active layer. For the optimized devices incorporating 37.5 wt% of untreated MoSe2, we obtained a champion PCE of 9.82%, compared with the champion reference PCE of approximately 9%. After incorporating the hydrogen plasma-treated MoSe2 nanosheets, we achieved a champion PCE of 10.44%-a relative increase of 16% over that of the reference device prepared without MoSe2 nanosheets. This PCE is the one of the highest ever reported for OPVs incorporating 2D materials. We attribute this large enhancement to the enhanced exciton generation and dissociation at the MoSe2-fullerene interface and, consequently, the balanced charge carrier mobility. The device incorporating the MoSe2 nanosheets maintained 70% of its initial PCE after heat-treatment at 100 °C for 1 h; in contrast, the PCE of the reference device decreased to 60% of its initial value-a relative increase in stability of 17% after incorporating these nanosheets. We also incorporated MoSe2 nanosheets (both with and without treatment) into a polymer donor (PBDTTBO)/small molecule (IT-4F) acceptor system. The champion PCEs reached 7.85 and 8.13% for the devices incorporating the MoSe2 nanosheets with and without plasma treatment, respectively-relative increases of 8 and 12%, respectively, over that of the reference. These results should encourage a push toward the implementation of transition metal dichalcogenides to enhance the performances of BHJ OPVs.

Realizing Efficient Charge/Energy Transfer and Charge Extraction in Fullerene-Free Organic Photovoltaics via a Versatile Third Component.

Solution-processed organic photovoltaics (OPVs) based on bulk-heterojunctions have gained significant attention to alleviate the increasing demend of fossil fuel in the past two decades. OPVs combined of a wide bandgap polymer donor and a narrow bandgap nonfullerene acceptor show potential to achieve high performance. However, there are still two reasons to limit the OPVs performance. One, although this combination can expand from the ultraviolet to the near-infrared region, the overall external quantum efficiency of the device suffers low values. The other one is the low open-circuit voltage (VOC) of devices resulting from the relatively downshifted lowest unoccupied molecular orbital (LUMO) of the narrow bandgap. Herein, the approach to select and incorporate a versatile third component into the active layer is reported. A third component with a bandgap larger than that of the acceptor, and absorption spectra and LUMO levels lying within that of the donor and acceptor, is demonstrated to be effective to conquer these issues. As a result, the power conversion efficiencies (PCEs) are enhanced by the elevated short-circuit current and VOC; the champion PCEs are 11.1% and 13.1% for PTB7-Th:IEICO-4F based and PBDB-T:Y1 based solar cells, respectively.

Two new Aprostocetus species (Hymenoptera: Eulophidae: Tetrastichinae), fortuitous parasitoids of invasive eulophid gall inducers (Tetrastichinae) on Eucalyptus and Erythrina.

Two closely related new species of Aprostocetus Westwood (Hymenoptera: Eulophidae: Tetrastichinae) are described as fortuitous parasitoids of invasive gall inducers in two other genera of Tetrastichinae, Leptocybe Fisher & LaSalle and Quadrastichus Girault. Aprostocetus causalis La Salle & Wu is a parasitoid of Leptocybe invasa Fisher & La Salle on Eucalyptus spp. (Myrtaceae) in China and Thailand, and A. felix La Salle, Yang & Lin is a parasitoid of Quadrastichus erythrinae Kim on Erythrina spp. (Fabaceae) in Taiwan. Epitetrastichus nigriventris Girault, 1913 is removed from synonymy from Aprostocetus gala (Walker), and treated as the valid species A. nigriventris (Girault). 

Cinnamomum cassia essential oil inhibits α-MSH-induced melanin production and oxidative stress in murine B16 melanoma cells.

Essential oils extracted from aromatic plants exhibit important biological activities and have become increasingly important for the development of aromatherapy for complementary and alternative medicine. The essential oil extracted from Cinnamomum cassia Presl (CC-EO) has various functional properties; however, little information is available regarding its anti-tyrosinase and anti-melanogenic activities. In this study, 16 compounds in the CC-EO have been identified; the major components of this oil are cis-2-methoxycinnamic acid (43.06%) and cinnamaldehyde (42.37%). CC-EO and cinnamaldehyde exhibited anti-tyrosinase activities; however, cis-2-methoxycinnamic acid did not demonstrate tyrosinase inhibitory activity. In murine B16 melanoma cells stimulated with α-melanocyte-stimulating hormone (α-MSH), CC-EO and cinnamaldehyde not only reduced the melanin content and tyrosinase activity of the cells but also down-regulated tyrosinase expression without exhibiting cytotoxicity. Moreover, CC-EO and cinnamaldehyde decreased thiobarbituric acid-reactive substance (TBARS) levels and restored glutathione (GSH) and catalase activity in the α-MSH-stimulated B16 cells. These results demonstrate that CC-EO and its major component, cinnamaldehyde, possess potent anti-tyrosinase and anti-melanogenic activities that are coupled with antioxidant properties. Therefore, CC-EO may be a good source of skin-whitening agents and may have potential as an antioxidant in the future development of complementary and alternative medicine-based aromatherapy.