A Novel 1D Organic Lead Halide Hybrid for Blue and White Dual Emission

In recent years, photoelectric performances of many low-dimensional metal halide hybrid materials have been researched and utilized in the domain of phosphors, light emitting diodes (LEDs) and photoelectric detection etc. Nevertheless, unlike two-dimensional (2D) ones, one-dimensional (1D) hybrids received less attention to study their structures and optical properties. Herein, we deal with luminous performance and photoluminescence mechanism for an original 1D organic-inorganic lead chloride hybrid C5H14N3PbCl3 which is abbreviated as TMGPbCl3 (TMG+ = 1, 1, 3, 3-tetramethyguanidine cation). According to photoluminescence spectra, its broadband white-light luminescence are dual emissions from organic component TMG+ peaked at 429 nm and self-trapped excitons (STEs) of inorganic metal halide octahedra peaked at 510 nm, respectively and this property make it to be a promising white-light phosphor.

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.

Influence of different anionic charges in lead compounds in the remediation of lead by Eleusine indica (Gaertn)

The study was carried out to investigate the remediative capacity of Eleusine indica in lead-polluted soil. Soil samples were collected near student hostel (hall 5) in the University of Benin. The soil samples were sun dried to constant weight and was pulverized with wooden roller and sieved with a hand sieve of 2 mm mesh size. The sieved soil was spiked with 0.625 g lead nitrate (PbNO3), lead sulphate (PbSO4), lead carbonate (PbCO3), lead acetetrahydrate (PbC2H6) and lead chloride (PbCl2) separately in three replicate using aqueous standard solutions. Tillers of Eleusine Indica were placed in the metal polluted soil immediately and the experiment was allowed to stay for 15 weeks. The result showed that the uptake efficiency for Eleusine indica in both shoots and roots for lead nitrate was 0.016% and 0.8%, lead sulphate 0.016 % and 0.352 %, lead carbonate 0.064% and 0.496 %, lead acetetrahydrate 0.032 % and 0.688 %, and lead chloride 0.08 % and 0.72 % respectively, indicating that the plant might have sequestered the metal in the soil rather than accumulating it in the leaves. This was evident in the presentation of the metal sequestration factor of over 70 % irrespective of the nature of the metal. Microbial count of soil before and after contamination with lead nitrate was 19000 and 4000 cfu/g indicating a reduction. The study therefore revealed that Eleusine indica is a high efficient plant in sequestering lead in polluted soil.

Highly efficient blue light-emitting diodes with tunable wavelength using vertically graded bandgap quasi-2D perovskite films

Metal halide perovskite materials have emerged as a unique class of solution process compatible semiconductors and alluring candidates for high-performance optoelectronic applications1,2,3, especially light-emitting diodes (LEDs), owing to high quantum efficiency, facile color tunability, narrow emission line widths, as well as cost-effectiveness4,5,6. Despite of the great successes on green and red perovskite LEDs (PeLEDs), the advancement of external quantum efficiency (EQE) of blue PeLEDs still lags far behind those of green and red PeLEDs7,8. Here, we demonstrate color-tunable blue PeLEDs devices with high EQE of 16.1% and 10% for emission wavelengths of 472 nm and 461 nm, respectively. The efficient tunable wavelength electroluminescence (EL) and high (EQE) originate from the optimization of the recombination zone position to reach the charge injection balance in the vertically graded bandgap quasi-2D perovskite materials. Under the synergetic effect of lead chloride (PbCl2) doping and propane-1,3-diammonium (PDABr2) incorporation, the vertically graded bandgap perovskite materials can be prepared by the self-regulation of the reduced-dimensional perovskite during the annealing process. Our work here has significantly elevated the performance of the current blue PeLEDs. It opens up a novel avenue to fabricate high-performance blue PeLEDs that can match up the performance of the green and red PeLEDs for future lighting and display applications.