We report, synthesis of orange red light emitting Sm3+ activated BiOCl phosphors at relatively low temperature (400 °C) and shorter duration of 1 h. Rietveld refined results confirmed that all the ...compounds crystallized in the tetragonal structure with space group P4/nmm (No. 129). Functional group analysis were carried out by Fourier transform infrared (FT-IR) and Raman spectroscopy. The Photo-luminescent (PL) experiment results reveal that, an intense PL transition at 598 nm (4G5/2 → 6H7/2) corresponds to orange red emission at λex = 408 nm. The maximum emission intensity was observed for BiOCl: Sm3+ (3 mol%) phosphor, above this concentration quenching takes place due to charge exchange with neighboring Sm3+ ions. Time resolved fluorescence spectroscopic result reveals that, the decay curve is bi-exponential in nature and having long lifetime (τ = 0.58 ms). The obtained CIE and CCT values suggest that these phosphors having excellent color purity (∼90%) and low correlated color temperature. These results suggest that, Sm3+ activated BiOCl can be a potential red phosphor materials for WLEDs and other optoelectronics applications.
•Series of Sm3+ ions activated BiOCl phosphors were synthesised by the solid state method.•Concentration dependent PL and quenching effects of Bi1-xSmxOCl phosphors were determined.•CIE, CCT, color purity, quantum efficiency and other spectroscopic properties have been evaluated.•These orange red phosphors can act as a promising candidate for opto-electronic and WLEDs applications.
Cladosporium spp. have been reported for their great diversity of secondary metabolites which represent as a prominent base material for verifying the biological activities. Several bioactive ...compounds which have antimicrobial, cytotoxic, quorum sensing inhibitory and phytotoxic activities have been isolated from Cladosporium species. Most of them are still needed to be explored for their anticancer properties. Therefore, the present study is focused on screening and identifying the bioactive compounds of Cladosporium spp. for their anticancer activity via the integrated approaches of Molecular Docking (MD), Molecular Dynamics Simulation (MDS) and Density Functional Theory (DFT) studies. A total of 123 bioactive compounds of Cladosporium spp. were explored for their binding affinity with the selected breast cancer drug target receptor such as estrogen receptor alpha (PDB:6CBZ). The Molecular Docking studies revealed that amongst the bioactive compounds screened, Altertoxin X and Cladosporol H showed a good binding affinity of - 10.5 kcal/mol and - 10.3 kcal/mol, respectively, with the estrogen receptor alpha when compared to the reference compound (17Formula: see text-Estradiol: - 10.2 kcal/mol). The MDS study indicated the stable binding patterns and conformation of the estrogen receptor alpha-Altertoxin X complex in a stimulating environment. In addition, in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) study suggested that Altertoxin X has a good oral bioavailability with a high LDFormula: see text value of 2.375 mol/kg and did not cause any hepatotoxicity and skin sensitization. In summary, the integrated approaches revealed that Altertoxin X possesses a promising anticancer activity and could serve as a new therapeutic drug for breast cancer treatment.
A series of scheelite-type Eu
3+
-activated CaMoO
4
phosphors were synthesized by the nitrate–citrate gel combustion method. All the compounds crystallized in the tetragonal structure with space ...group
I4
1
/a
(No. 88). FESEM results reveal the spherical-like morphology. The CaMoO
4
phosphor exhibited broad emission centered at 500 nm under the excitation of 298 nm wavelength, while Eu
3+
-activated CaMoO
4
shows an intense characteristic red emission peak at 615 nm at different excitation wavelengths, due to
5
D
0
→
7
F
2
transition of Eu
3+
ions. The intensities of transitions between different
J
levels depend on the symmetry of the local environment of Eu
3+
ions and were estimated using the Judd–Ofelt analysis. The high asymmetric ratio revealed that Eu
3+
occupies sites with a low symmetry and without an inversion center. The CIE chromaticity co-ordinates (
x
,
y
) were calculated from emission spectra, and the values were close to the NTSC standard. Therefore, the present phosphor is highly useful for LEDs applications.
Graphene–nanocrystalline metal sulphide composites were prepared by a one-pot reaction. A dispersion of graphite oxide layers in an aqueous solution of metal ions (Cd
2+/Zn
2+) was reacted with H
2S ...gas, which acts as a sulphide source as well as a reducing agent, resulting in the formation of metal sulphide nanoparticles and simultaneous reduction of graphite oxide sheets to graphene sheets. The surface defect related emissions shown by free metal sulphide particles are quenched in the composites due to the interaction of the surface of the nanoparticles with graphene sheets.
► ZnO:Cu nano particles are prepared via solution combustion technique with ODH fuel at low temperature. ► Analysis of X-ray line broadening and micro strain in nanoparticles are evaluated using W-H ...plots. ► PXRD results confirm that the nanopowders exhibit hexagonal wurtzite structure. ► Decrease in the green emission and enhancement of UV emission in Cu doped ZnO due to the decrease in defects. ► EPR spectrum exhibits a broad resonance signal at
g
∼
2.049 and two narrow resonances one at
g
∼
1.990 and other at
g
∼
1.950.
Cu (0.1
mol%) doped ZnO nanopowders have been successfully synthesized by a wet chemical method at a relatively low temperature (300
°C). Powder X-ray diffraction (PXRD) analysis, scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, UV–Visible spectroscopy, Photoluminescence (PL) and Electron Paramagnetic Resonance (EPR) measurements were used for characterization. PXRD results confirm that the nanopowders exhibit hexagonal wurtzite structure of ZnO without any secondary phase. The particle size of as-formed product has been calculated by Williamson–Hall (W–H) plots and Scherrer's formula is found to be in the range of ∼40
nm. TEM image confirms the nano size crystalline nature of Cu doped ZnO. SEM micrographs of undoped and Cu doped ZnO show highly porous with large voids. UV–Vis spectrum showed a red shift in the absorption edge in Cu doped ZnO. PL spectra show prominent peaks corresponding to near band edge UV emission and defect related green emission in the visible region at room temperature and their possible mechanisms have been discussed. The EPR spectrum exhibits a broad resonance signal at
g
∼
2.049, and two narrow resonances one at
g
∼
1.990 and other at
g
∼
1.950. The broad resonance signal at
g
∼
2.049 is a characteristic of Cu
2+ ion whereas the signal at
g
∼
1.990 and
g
∼
1.950 can be attributed to ionized oxygen vacancies and shallow donors respectively. The spin concentration (
N) and paramagnetic susceptibility (
χ) have been evaluated and discussed.
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•BaMoO4: Eu3+ phosphors were synthesized using nitrate–citrate gel combustion method.•Host BaMoO4 phosphor revealed white emission upon excitation at 370nm.•Eu3+-activated BaMoO4 ...exhibited red luminescence which was confirmed by CIE chromaticity diagram.•Judd–Ofelt parameters and other radiative properties of Eu3+-activated BaMoO4 have been determined.•These phosphors can be used in red lasers and optical display devices.
Eu3+-activated BaMoO4 phosphors were synthesized by the nitrate–citrate gel combustion method. The Rietveld refinement analysis confirmed that all the compounds were crystallized in the scheelite-type tetragonal structure with I41/a (No. 88) space group. Photoluminescence (PL) spectra of BaMoO4 phosphor reveals broad emission peaks at 465 and 605nm, whereas the Eu3+-activated BaMoO4 phosphors show intense 615nm (5D0→7F2) emission peak. Judd–Ofelt theory was applied to evaluate the intensity parameters (Ω2, Ω4) of Eu3+-activated BaMoO4 phosphors. The transition probabilities (AT), radiative lifetime (τrad), branching ratio (β), stimulated emission cross-section (σe), gain bandwidth (σe×Δλeff) and optical gain (σe×τrad) were investigated by using the intensity parameters. CIE color coordinates confirmed that the BaMoO4 and Eu3+-activated BaMoO4 phosphors exhibit white and red luminescence, respectively. The obtained results revealed that the present phosphors can be a potential candidate for red lasers and white LEDs applications.
La2CuO4, a layered perovskites oxide was synthesized using solution combustion method at different calcination temperatures. XRD characterization and Rietveld refinement analysis confirms the pure ...phase of the synthesized material. The effect of calcination causes shrinking in the lattice parameters affirm the change in the oxygen stoichiometry. Four Probe (Van der Pauw’s) and CP-AFM analysis were carried out to understand the influences of calcination temperature on electrical conductivity. Electrochemical investigations on La2CuO4 were performed at various negative potential ranges using cyclic voltammetry (CV) to identify the redox active centre. Thermodynamic calculations are further carried out to validate the electrochemical results in different mediums. Selective electrocatalytic conversion of CO2 to C2-hydrocarbon (C2H4) with FE% of 40.3% which is 10 times higher than CH4 (FE% = 4.1%) emphasized the in-situ formation of Cu2O from the redox active centre present in La2CuO4. Hydrocarbons are generated at a very low overvoltage (−0.4 V RHE) in comparison to literature. XPS analysis indeed confirms the presence of Cu+ species i.e., in-situ generated Cu2O, on La2CuO4 after CV and CO2 electrocatalysis.
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•In the present study, we have explored the electrochemical behavior of redox active centre ‘Cu2+’ in a highly crystalline layered La2CuO4 perovskite.•During electrochemical reduction, La2CuO4 breaks into La2O3 and Cu2O. This Cu2O further undergo reduction and forms Cu metal which is a reversible reaction.•Thermodynamic calculations aided in understanding the electrochemical in-situ formation of Cu2O.•Selective electrocatalytic reduction of CO2 to C2H4 (10 times higher than CH4), at −0.4 V RHE, very low overpotential, emphasis the typical behaviour of Cu2O.•XPS analysis confirms the presence of Cu+ species (i.e., Cu2O) after electrochemical treatment of La2CuO4 and retained after selective CO2 electrocatalysis.
In the present study synthesis of BaTi1–x Cr x O3 nanocatalysts (x = 0.0 ≤ x ≤ 0.05) by conventional oxalate and microwave assisted hydrothermal synthesis methods was carried out to investigate the ...effect of synthesis methods on the physicochemical and catalytic properties of nanocatalysts. These catalysts were thoroughly characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 physisortion, and total acidity by pyridine adsorption method. Their catalytic performance was evaluated for the reduction of nitrobenzene using hydrazine hydrate as the hydrogen source. Structural parameters refined by Rietveld analysis using XRD powder data indicate that BaTi1–x Cr x O3 conventional catalysts were crystallized in the tetragonal BaTiO3 structure with space group P4mm, and microwave catalysts crystallized in pure cubic BaTiO3 structure with space group Pm3̅m. TEM analysis of the catalysts reveal spherical morphology of the particles, and these are uniformly dispersed in microwave catalysts whereas agglomeration of the particles was observed in conventional catalysts. Particle size of the microwave catalysts is found to be 20–35 nm compared to conventional catalysts (30–48 nm). XPS studies reveal that Cr is present in the 3+ and 6+ mixed valence state in all the catalysts. Microwave synthesized catalysts showed a 4–10-fold increase in surface area and pore volume compared to conventional catalysts. Acidity of the BaTiO3 catalysts improved with Cr dopant in the catalysts, and this could be due to an increase in the number of Lewis acid sites with an increase in Cr content of all the catalysts. Catalytic reduction of nitrobenzene to aniline studies reveals that BaTiO3 synthesized by microwave is very active and showed 99.3% nitrobenzene conversion with 98.2% aniline yield. The presence of Cr in the catalysts facilitates a faster reduction reaction in all the catalysts, and its effect is particularly notable in conventional synthesized catalysts.
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