Influence of reaction time and synthesis temperature on the physical properties of ZnO nanoparticles synthesized by the hydrothermal method

Influence of synthesis temperature and reaction time on the structural and optical properties of ZnO nanoparticles synthesized by the hydrothermal method was investigated using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray, Fourier transform infra-red spectroscopy, and UV–visible and fluorescence spectroscopy. The XRD pattern and HR-TEM images confirmed the presence of crystalline hexagonal wurtzite ZnO nanoparticles with average crystallite size in the range 30–40 nm. Their energy gap determined by fluorescence was found to depend on the synthesis temperature and reaction time with values in the range 2.90–3.78 eV. Thermal analysis, thermogravimetric and the differential scanning calorimetry were used to study the thermal reactions and weight loss with heat of the prepared ZnO nanoparticles

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Not AvailableIn tropical regions of India, a number of diseases and insect pests cause substantial economic damage to the grape crop and timely pesticide applications are required for crop protection. At times, this results in detection of pesticide residue above the specified maximum residue levels (MRL) at harvest affecting international trade. Use of Bacillus species to enhance the degradation of the pesticide residues on grape berries is an emerging option. In this study, the bio-efficacy of a WP formulation of Bacillus subtilis DR-39 in enhancing the dissipation rate of eight pesticides was evaluated during 2016–2017 and 2017–2018 on Thompson Seedless grapes. The pesticides were applied twice as foliar spray at their recommended doses followed by application of B. subtilis DR-39 at 1.0, 2.5 and 5.0 g/l after 4 days of the second pesticide application. In 2017–2018, B. subtilis DR-39 was applied at 2.5 g/l, twice at 4 day intervals. The pesticide residues were analysed on LC–MS/MS by ethyl acetate based extraction method on a time frame and degradation kinetics were calculated. The average enhancement in dissipation by B. subtilis DR-39 was 13.7% @ 1.0 g/l, 19.0% @ 2.5 g/l and 22.7% @ 5.0 g/l. Application of B. subtilis DR-39 @ 2.5 g/l reduced the calculated half-life of the pesticides by 1–3 days, except by 5 and 6.5 days for buprofezin and hexaconazole respectively during 2016–2017, and by 6 days for hexaconazole during 2017–2018. Studies show that B. subtilis DR-39 applications in vineyards can be utilized for faster degradation of multi-class pesticide residues.Not Availabl

Perovskite photonic sources

The field of solution-processed semiconductors has made great strides; however, it has yet to enable electrically driven lasers. To achieve this goal, improved materials are required that combine efficient (>50% quantum yield) radiative recombination under high injection, large and balanced charge-carrier mobilities in excess of 10 cm2 V–1 s–1, free-carrier densities greater than 1017 cm–3 and gain coefficients exceeding 104 cm–1. Solid-state perovskites are — in addition to galvanizing the field of solar electricity — showing great promise in photonic sources, and may be the answer to realizing solution-cast laser diodes. Here, we discuss the properties of perovskites that benefit light emission, review recent progress in perovskite electroluminescent diodes and optically pumped lasers, and examine the remaining challenges in achieving continuous-wave and electrically driven lasing