A new innovative real-time tracking method for flying insects applicable under natural conditions

Background Sixty percent of all species are insects, yet despite global efforts to monitor animal movement patterns, insects are continuously underrepresented. This striking difference between species richness and the number of species monitored is not due to a lack of interest but rather to the lack of technical solutions. Often the accuracy and speed of established tracking methods is not high enough to record behavior and react to it experimentally in real-time, which applies in particular to small flying animals. Results Our new method of real-time tracking relates to frequencies of solar radiation which are almost completely absorbed by traveling through the atmosphere. For tracking, photoluminescent tags with a peak emission (1400 nm), which lays in such a region of strong absorption through the atmosphere, were attached to the animals. The photoluminescent properties of passivated lead sulphide quantum dots were responsible for the emission of light by the tags and provide a superb signal-to noise ratio. We developed prototype markers with a weight of 12.5 mg and a diameter of 5 mm. Furthermore, we developed a short wave infrared detection system which can record and determine the position of an animal in a heterogeneous environment with a delay smaller than 10 ms. With this method we were able to track tagged bumblebees as well as hawk moths in a flight arena that was placed outside on a natural meadow. Conclusion Our new method eliminates the necessity of a constant or predictable environment for many experimental setups. Furthermore, we postulate that the developed matrix-detector mounted to a multicopter will enable tracking of small flying insects, over medium range distances (>1000m) in the near future because: a) the matrix-detector equipped with an 70 mm interchangeable lens weighs less than 380 g, b) it evaluates the position of an animal in real-time and c) it can directly control and communicate with electronic devices.

Bis(4-methylpiperidine-1-carbodithioato)-lead(II) and Bis(4-benzylpiperidine-1-carbodithioato)-lead(II) as Precursors for Lead Sulphide Nano Photocatalysts for the Degradation of Rhodamine B

Bis(4-methylpiperidine-1-carbodithioato)-lead(II) and bis(4-benzylpiperidine-1-carbodithioato)-lead(II) were prepared and their molecular structures elucidated using single crystal X-ray crystallography and spectroscopic techniques. The compounds were used as precursors for the preparation of lead sulphide nano photocatalysts for the degradation of rhodamine B. The single crystal structures of the lead(II) dithiocarbamate complexes show mononuclear lead(II) compounds in which each lead(II) ion coordinates two dithiocarbamato anions in a distorted tetrahedral geometry. The compounds were thermolyzed at 180 ℃ in hexadecylamine (HDA), octadecylamine (ODA), and trioctylphosphine oxide (TOPO) to prepare HDA, ODA, and TOPO capped lead sulphide (PbS) nanoparticles. Powder X-ray diffraction (pXRD) patterns of the lead sulphide nanoparticles were indexed to the rock cubic salt crystalline phase of lead sulphide. The lead sulphide nanoparticles were used as photocatalysts for the degradation of rhodamine B with ODA-PbS1 achieving photodegradation efficiency of 45.28% after 360 min. The photostability and reusability studies of the as-prepared PbS nanoparticles were studied in four consecutive cycles, showing that the percentage degradation efficiency decreased slightly by about 0.51–1.93%. The results show that the as-prepared PbS nanoparticles are relatively photostable with a slight loss of photodegradation activities as the reusability cycles progress.

Complexation processes in “PbCl2-N2H4CS” aqueous solutions during deposition of lead sulphide films

In this study, we proposed a new approach to assessing the processes of complexation in aqueous solutions using the example of the interaction of lead chloride with thiourea. The goal of this study was the investigation of processes of complexation in “PbCl2-N2H4CS” aqueous solutions and determination of the regions of dominance of thiourea coordination compounds, which are precursors during the deposition of lead sulphide films.Based on the diagrams and cross section lines of equal fractions constructed in three-dimensional space, the regions of dominance of all complex forms existing in the studied solution were found. Such a graphic image is the most informative, since it allows selection of the concentration ranges of the predominance of certain coordination compounds, especially thiourea complexes, which are precursors during the deposition of lead sulphide films. It was shown that an increase in the concentration of N2H4CS led to an increase in the total fraction of thiourea complexes: for a twofold excess of N2H4CS its fraction was 0.25, for a threefold excess it was 0.35, for a fourfold excess it was 0.5, for a fivefold excess it was 0.7.

Towards environmental friendly multi-step processing of efficient mixed-cation mixed halide perovskite solar cells from chemically bath deposited lead sulphide

Organic–inorganic hybrid perovskite is the most promising active layer for new generation of solar cells. Despite of highly efficient perovskite active layer conventionally fabricated by spin coating methods, the need for using toxic solvents like dimethylformamide (DMF) required for dissolving low soluble metal precursors as well as the difficulties for upscaling the process have restricted their practical development. To deal with these shortcomings, in this work, lead sulphide as the lead metal precursor was produced by aqueous chemical bath deposition. Subsequently, PbS films were chemically converted to PbI2 and finally to mixed-cation mixed halide perovskite films. The microstructural, optical and solar cell performance of mixed cation mixed halide perovskite films were examined. Results show that controlling the morphology of PbI2 platelets achieved from PbS precursor films enabled efficient conversion to final perovskite films. Using this processing technique, smooth and pin hole-free perovskite films having columnar grains of about 800 nm and a bandgap of 1.55 eV were produced. The solar cell performance consisting of such perovskite layers gave rise to a notable power conversion efficiency of 11.35% under standard solar conditions. The proposed processing technique is very promising towards an environmentally friendly method for the production of large-scale high efficient perovskite solar cells.

Environmental Friendly Multi-step Processing of Efficient Mixed-cation Mixed Halide Perovskite Solar Cells from Chemically Bath Deposited Lead Sulphide

Organic-inorganic hybrid perovskite is the most promising active layer for new generation of solar cells. Despite of highly efficient perovskite active layer conventionally fabricated by spin coating methods, the need for using toxic solvents like dimethylformamide (DMF) required for dissolving low soluble metal precursors as well as the difficulties for upscaling the process have restricted their practical development. To deal with these shortcomings, in this work, lead sulphide as the lead metal precursor was produced by aqueous chemical bath deposition. PbS films were subsequently chemically converted to PbI2 and finally to mixed-cation mixed halide perovskite films. The microstructural, optical and solar cell performance of mixed cation mixed halide perovskite films were exploited. Results show that controlling the morphology of PbI2 platelets achieved from PbS precursor films enabled efficient conversion to perovskite. Using this processing technique, smooth and pin hole-free perovskite films having columnar grains of about 800 nm and a bandgap of 1.55 eV were produced. The solar cell performance consisting of such perovskite layers gave rise to a notable power conversion efficiency of 11.35% under standard solar conditions. The proposed processing technique is a very promising environmentally friendly method for the production of large-scale high efficient perovskite solar cells.

Characterizations of Galena as Potential Photosensitizer in a Natural Dye-Sensitized Solar Cell

Dye is one of the principal parts for high power conversion efficiency in a Dye-Sensitized Solar Cell. Conspicuous developments have taken place via the work of several researchers in the engineering of novel dye structures so as to enhance the performance of the system. The properties of a natural mineral dye were studied in this work. The structure of the dye was determined and discovered to have contains constituents that could enhance better absorption of solar radiation for use in a Dye-Sensitized Solar Cell (DSSC). The Lead sulphide and iron content of the mineral dye studied as revealed by the X-Ray diffraction analysis done suggest this. The X-Ray Fluorescence (XRF) done revealed that the concentration of Lead and Iron (Fe) is high as compared to other elements present in the material, probably as a result of the fact that it is a geological sample (of the earth) and which may even suggest its colour and hence makes it absorbs solar radiation of visible region at its wavelength (around 380 nm – 800 nm). The functional groups present in the dye as obtained from the Fourier transform infrared spectroscopy are the Amine, Carbonyl, and hydroxyl groups, all of which confirm the suitability of the dye material in photosensitizing a semiconductor in a DSSC. The absorption spectra of the dye within the visible region of electromagnetic radiation show that the material has high, increased, and stable absorption of visible light which is suggesting a more durable natural dye for a DSSC than the easily degraded natural dyes of plants source.

Chemical composition of iron sulphides contained in dust from pyrometallurgical Zn and Pb production

The paper presents results of investigations of the chemical composition of iron sulphides contained in dust from the pyrometallurgical production process of zinc and lead. The main mineral components of these dusts are sphalerite, galena, iron sulphide – pyrite, zincite, anglesite and probably kirchsteinite. The tests performed have demonstrated that the chemical composition of iron sulphide grains was not close to stoichiometric, the grains were non-uniform in terms of phase composition, and they always included admixtures in the form of inclusions of other sulphides, i.e. zinc sulphide and lead sulphide, and accompanying elements (Ca, Mn, Se, As, Ag, Cu, Cd).