Abstract For oxide semiconductors for application in dye-sensitized solar cells (DSSCs), titanium dioxide conjugated with zinc oxide thin films was synthesized and characterized. The UV (ultraviolet) spectrum characterization showed a peak of absorbance at around 355 nm, with a band gap of 3.25 eV and reflectance around 85%. Such characteristics allowed the fabrication of DSSCs with N719 dye, under simulated light of 100 mW/cm2. The highest efficiency of 1.17% was at 5% titanium dioxide and 4 h of dye immersion.

Abstract Semiconductors, such as zinc oxide (ZnO), are used in different scientific fields, including energy. This study applied ZnO thin films on a photovoltaic cell, specifically a dye-sensitized solar cell (DSSC). ZnO was used in solar cells due to its characteristics such as electronic mobility. Electrophoretic deposition (EPD) is an efficient method to deposit thin films since it can be done at room temperature and its parameters can be easily controlled. ZnO thin films were deposited on fluorine-doped tin oxide (FTO) glass, changing the tension parameter, and used in a DSSC, with different dye immersion times, between 7 and 24 h, to observe time effects on cell efficiency. For lower tension, 30 and 40 V, 7 h improved the cell efficiency, and at 50 V, 24 h favored the current density and efficiency. The highest efficiency was for the photoanode EPD deposited at 50 V, for 24 h dye immersion, at about 2.68%, and photocurrent of 13.55 mA/cm2.

Abstract Beauveria bassiana is a promising fungus for the biological control of insect pests. The growing costs of conidia production have raised the need to ascertain the efficiency of some low cost substrates. The aim of this study was to analyze the potential use of different raw substrates without nutritional supplement for B. bassiana conidiogenesis. Growth and sporulation were evaluated using 30 g of substrate and 0.3 μL of a conidia suspension (1 x 106 conidia/mL). After 10 days of incubation (70 ± 10% humidity and temperature (T) = 29 ± 1 °C), rice (2.00 x 106 conidia/g substrate), algaroba (2.36 x 106 conidia/g), malt A (1.22 x 106 conidia/g) and malt B (1.75 x 106 conidia/g) showed the highest levels of conidia production. The resulting conidia showed insecticidal activity higher than 80% on coconut termites. These new raw substrates may represent viable alternatives for the production of entomopathogenic fungi for use in the biological control of various insect pests.

Resumo Beauveria bassiana é um fungo promissor no controle biológico de insetos-praga. As crescentes despesas na produção de conídios levantam a necessidade de averiguar a eficiência de alguns substratos de baixo custo. O objetivo deste trabalho foi analisar o potencial de utilização de diferentes substratos brutos para a conidiogênese de B. bassiana. O crescimento e esporulação foram realizados utilizando 30 g do substrato e 0,3 µL da suspensão de conídios (1 x 106 conídios/mL). Após 10 dias de incubação (umidade 70 ± 10% e temperatura T = 29 ± 1° C), o arroz (2,00 x 106 conídios/g de substrato), algaroba (2,36 x 106 conídios/g), malte A (1,22 x 106 conídios/g) e B (1,75 x 106 conídios/g), apresentaram maior produção de conídios. Os conídios produzidos mostraram atividade inseticida sobre o cupim do coqueiro acima de 80% de mortalidade. Estes novos substratos brutos podem representar uma alternativa viável para produção de fungos entomopatogênicos para uso no controle biológico de vários insetos praga.