A New Strategy for Organic Optoelectronic Devices

Energy Conversion & StorageMy MS research has focused on alternative organic optoelectronic devices as promising technology that may be environmentally friendly renewable energy resources and the next generation flat-panel display platform. During my research, first, high-performance organic optoelectronic devices enhanced by surface plasmon resonance have been demonstrated containing interfacial metal nanoparticles such as copper, gold, and copper-gold alloy between indium tin oxide (ITO) and poly(3,4-ethylenedioxylenethiophene):polystyrene sulfonic acid (PEDOT:PSS) via a polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) copolymer template. In the organic solar cells (OPVs), the improved optical absorption is attributed to the increased electric field in the photoactive layer caused by excited localized surface plasmon from the nanoparticles. Moreover, enhanced luminance intensity and improved luminous efficiency in organic light emitting diodes (OLEDs) are achieved due to the acceleration of the radiative processes at the surface plasmon frequency. A significant effect of the SPR is attained in organic optoelectronic devices, which show up to 20% enhanced performance as compared with reference devices. Second, a rod-coil block copolymer consisting of poly(3-hexylthiophene) (P3HT) and poly(N-vinylcarbazole) (PVK) (P3HT-b-PVK) in a single molecular architecture is prepared as the first example for white light emitting diodes(WOLEDs). By obtaining the phase separated domains in thin film of the resulting block copolymer, it is possible to suppress energy transfer from PVK as wide bandgap units to P3HT as low bandgap blocks, yielding dual emissions for white electroluminescence with CIE coordination of (0.34, 0.33).ope

Highly controllable transparent and conducting thin films using layer-by-layer assembly of oppositely charged reduced graphene oxides

A new approach for the fabrication of reduced graphene oxide (rGO) multilayers which can be used for transparent and conducting thin films was developed. This was achieved by using layer-by-layer (LbL) assembly of positively and negatively charged rGO sheets, which could provide highly controllable thin films in terms of thickness, transmittance, and sheet resistance. In particular, the thickness of the multilayer thin films of rGO was able to be controlled precisely in the subnanometre scale by similar to 0.46 nm via simply varying the number of stacking layers. Therefore, this method enabled an excellent control of the rGO multilayers over the optical and electrical properties, which are related to the thickness. Furthermore, we demonstrated the application of the rGO multilayers for an OLED device.close585

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Structural Characteristics of Amphiphilic Cyclic and Linear Block Copolymer Micelles in Aqueous Solutions

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Structural Characteristics of Amphiphilic Cyclic and Linear Block Copolymer Micelles in Aqueous Solutions

The structural characteristics of aqueous micelles composed of amphiphilic cyclic poly(n-butyl acrylate-b-ethylene oxide) (cyclic PBA-b-PEO) or a linear analogue (i.e., linear poly(n-butyl acrylate-b-ethylene oxide-b-n-butyl acrylate) (linear PBA-b-PEO-b-PBA)) were examined for the first time using synchrotron X-ray scattering techniques and quantitative data analysis. The scattering data were analyzed using a variety of methodologies in a comprehensive complementary manner. These analyses provided details of the structural information about the micelles. Both micelles were found to consist of a core and a fuzzy shell; however, the cyclic block copolymer had a strong tendency to form micelles with core and shell parts that were more compact and dense than the corresponding parts of the linear block copolymer micelles. The PBA block of the cyclic copolymer was found to form a hydrophobic core with a density that exceeded the density of the homopolymer in the bulk state. The structural differences originated primarily from the topological difference between the cyclic and linear block copolymers. The elimination of the chain end groups (which introduced entropy and increased the excess excluded volume) from the amphiphilic block copolymer yielded more stable dense micelles in solution.X113125sciescopu

Novel 4,7-Dithien-2-yl-2,1,3-benzothiadiazole-based Conjugated Copolymers with Cyano Group in Vinylene Unit for Photovoltaic Applications

Two novel conjugated copolymers utilizing 4,7-dithien-2-yl-2,1,3-benzothiadiazole (DTBT) coupled with cyano (-CN) substituted vinylene, as the electron deficient moeity, have been synthesized and evaluated in bulk heterojunction solar cell. The electron deficient moeity was coupled with carbazole and fluorene unit by Knoevenagel condition to provide poly(bis-2,7-((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl-ethenyl)-alt-9-(1-octylnonyl)-9H-carbazol-2-yl-2-butenenitrile) (PCVCNDTBT) and poly(bis-2,7((Z)-1-cyano-2-(5-(7-(2-thienyl)-2,1,3-benzothiadiazol-4-yl)-2-thienyl)ethenyl)-alt-9,9-dihexyl-9H-fluoren-2-yl) (PFVCNDTBT). The optical band gaps of PCVCNDTBT (1.74 eV) and PFVCNDTBT (1.80 eV) are lower than those of PCDTBT (1.88 eV) and PFVDTBT (2.13 eV), which is advantageous to provide better coverage of the solar spectrum in the longer wavelength region. The high V-oc value of the PSC of PCVCNDTBT (similar to 0.91 V) is attributed to its lower HOMO energy level (-5.6 eV) as compared to PCDTBT (-5.5 eV). Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-C-61-butyric acid methyl ester (PC61BM) gave power conversion efficiencies of 0.76% for PCVCNDTBT under AM 1.5, 100 mW/cm(2).close

Investigation of Marine-Derived Fungal Diversity and Their Exploitable Biological Activities

Marine fungi are potential producers of bioactive compounds that may have pharmacological and medicinal applications. Fungi were cultured from marine brown algae and identified using multiple target genes to confirm phylogenetic placement. These target genes included the internal transcribed spacer (ITS), the nuclear large subunit (LSU), and the β-tubulin region. Various biological activities of marine-derived fungi were evaluated, including their antifungal, antioxidant and cellulolytic enzyme activities. As a result, a total of 50 fungi was isolated from the brown algae Sargassum sp. Among the 50 isolated fungi, Corollospora angusta was the dominant species in this study. The genus Arthrinium showed a relatively strong antifungal activity to all of the target plant pathogenic fungi. In particular, Arthrinium saccharicola KUC21221 showed high radical scavenging activity and the highest activities in terms of filter paper units (0.39 U/mL), endoglucanase activity (0.38 U/mL), and β-glucosidase activity (1.04 U/mL)

Semen quality and sperm DNA fragmentation in cancer patients undergoing sperm cryopreservation

Purpose: We compared semen quality and sperm DNA fragmentation in cancer patients who underwent sperm banking and controls who underwent sperm cryopreservation for assisted reproductive technology (ART). Materials and Methods: A total of 132 men, 65 cancer patients and 67 controls, were prospectively enrolled and performed sperm cryopreservation for fertility preservation from May 2019 to February 2021. Sperm quality was determined by measuring semen volume, sperm concentration, sperm motility, and sperm DNA fragmentation index (DFI). Sperm quality and sperm DFI were compared in cancer patients and controls. Results: The major cancers of the 65 cancer patients were leukemia (26.2%), testicular cancer (23.1%), and lymphoma (20.0%). Sperm concentration, sperm total motility, and sperm progressive motility were significantly lower in cancer patients than in controls. Sperm DFI was significantly higher in cancer patients than in controls (24.32%±15.69% vs. 19.11%±11.63%; p=0.033). After excluding 8 cancer patients who received chemotherapy before sperm banking, sperm concentration, sperm total motility, and sperm progressive motility were significantly lower in cancer patients than in controls, but there was no significant difference in sperm DFI for cancer patients and controls (23.14%±12.79% vs. 19.11%±11.63%; p=0.069). Conclusions: Sperm quality was lower in cancer patients than in controls. There was no difference in the sperm DFI of cancer patients prior to chemotherapy and men presenting for sperm cryopreservation for ART. We recommend that all men who are planning cancer therapy should be offered sperm banking prior to gonadotoxic chemotherapy as a standard of fertility preservation

Structural Characteristics of Amphiphilic Cyclic and Linear Block Copolymer Micelles in Aqueous Solutions

The structural characteristics of aqueous micelles composed of amphiphilic cyclic poly­(<i>n</i>-butyl acrylate-<i>b</i>-ethylene oxide) (cyclic PBA-<i>b</i>-PEO) or a linear analogue (i.e., linear poly­(<i>n</i>-butyl acrylate-<i>b</i>-ethylene oxide-<i>b</i>-<i>n</i>-butyl acrylate) (linear PBA-<i>b</i>-PEO-<i>b</i>-PBA)) were examined for the first time using synchrotron X-ray scattering techniques and quantitative data analysis. The scattering data were analyzed using a variety of methodologies in a comprehensive complementary manner. These analyses provided details of the structural information about the micelles. Both micelles were found to consist of a core and a fuzzy shell; however, the cyclic block copolymer had a strong tendency to form micelles with core and shell parts that were more compact and dense than the corresponding parts of the linear block copolymer micelles. The PBA block of the cyclic copolymer was found to form a hydrophobic core with a density that exceeded the density of the homopolymer in the bulk state. The structural differences originated primarily from the topological difference between the cyclic and linear block copolymers. The elimination of the chain end groups (which introduced entropy and increased the excess excluded volume) from the amphiphilic block copolymer yielded more stable dense micelles in solution