Chromaticity study of Curcumin Dye Extracted from Curcuma longa L. using for UV light down conversion for white light emitting diode

Turmeric phosphor dye extracted from Curcuma Longa L. through simple technique using silica gel. The phosphor was used light down-conversion of UV light for white light emitting diode (WLED).Two types of UV (380nm and 395nm )wavelengths have been used.The characteristics of the white light chromaticity was controlled by changing the current and the concentration of the phosphor.The concentration has a critical effect on the conversion efficiency. The CIE coordinates and correlated colortemperature were measured for various phosphorweight and current. An optimum color renderingindex (CRI) value of 78.5 is obtained .The white phosphor has a (CIE) value of (0 .336,0.355) and the color temperature (CCT)5350K

The Effect of the Wavelength of the LED used to Pump Phosphor Produced from Curcuminoids Dye Extracted from Turmeric (Curcuma longa L.) to Produce White Light

Previous studies have investigated the use of curcuminoids dye extracted from turmeric (Curcuma longa L.) for light down-conversion of UV light (390 nm) for application as white light emitting diode (WLED) as well as the three methods used to extract curcuminoids dye (the normal method, use of Soxhlet apparatus and by combining the normal method with the Soxhlet extraction). This paper goes a step further to analyze the effect of the wavelengths of LED sources (365, 390 and 445nm) used to pump phosphor in the conversion of white light. The chromaticity coordinates (CIE), color rendering index (CRI) and color temperature (CCT) were measured for different applied currents (20, 60 and 100mA) and weights of curcuminoids (5, 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55mg). With optimum CRI, CIE and CCT values of 73.9, 0.3304;0.3501, and 5579K, respectively, the samples pumped with LED source of 365 nm wavelength produced better white light compared to 390 and 445 nm, in terms of the amount of phosphor used. Thus, the wavelength of the LED source used to pump phosphor is inversely related to the amount of yellow light produced into the blue light when the concentration of phosphor is constant. The stress test showed that the degradation time of the dye could be improved by reducing the wavelength used to pump the sample or selecting a weak thermal conductivity material

Hydrothermal Synthesis and Structural Properties of V205 Nanoflowers at Low Temperatures

Vanadium pentoxide nanoflowers were synthesized through a simple hydrothermal method at low temperatures. The structure was fabricated using NH4V03 and oxalic acid as precursors with 0.1 M concentration. The morphology and structure of the nanoflowers were characterized by FESEM, XRD, Raman, and UV-Visible spectroscopy. The results reveal an orthorhombic structure with preferred orientation along (001) plane of the prepared V205 nanoflowers. Characteristic Raman peaks also expressed the same structural features. Microstructure analysis by FESEM showed the nanoflower structure of V205 with diameters in the range of 60-80 nm and length in 600-800 nm. A red-shift is observed in the characteristic absorption peak of V205, with the annealing, which attributed to the decrease of the bandgap of the samples

Hydrothermal Synthesis and Structural Properties of V2O5 Nanoflowers at Low Temperatures

Vanadium pentoxide nanoflowers were synthesized through a simple hydrothermal method at low temperatures. The structure was fabricated by using NH4VO3 and oxalic acid as precursors with 0.1 M solution concentration. The morphology and structural properties of the nanoflowers were characterized using FESEM, XRD, Raman, and UV-Visible spectroscopy. The results reveal an orthorhombic structure with preferred orientation along (001) plane of the prepared V2O5 nanoflowers. Raman peaks also expressed the same structural features. FESEM images showed the V2O5 nanoflower with diameters in the range of 60-80 nm and length in 600-800 nm. A red-shift was observed in the characteristic absorption peak of V2O5 nanoflowers, which are attributed to the decrease of the bandgap of the samples

Chromaticity Properties Of Curcuminoids Dye Nanofibers Prepared By Electrospinning For White Light Downconversion

In this study, the chromaticity properties of curcuminoids dye were studied when it be in nanometer scale, where curcuminoids were loaded in nanofibers using the electrospinning technique. Poly(methyl methacrylate) PMMA was used in three types of viscosity (5, 10 and 15wt%) which were mixed with (curcuma longa L.) powder to produce curcuminoids solution by using the centrifuge to separate the curcuminoids solution from the impurities. Different amounts of polymer solution mixed with curcuminoids (1 to 5 ml) were spun by electrospinning to study its properties. The effect of annealing on samples was studied. The chromatic study of the samples and the effect of the amount and viscosity of the solution were studied by pumping the samples in three different LED wavelengths (365, 390 and 445 nm). The white light chromaticity coordinates (CIE), color temperature (CCT) and color rendering index (CRI) were measured. The optimum CIE, CRI and CCT values of (X = 0.3051; Y = 0.3370), 64 and 6809K, respectively were obtained. By using field emission scanning electron microscope (FESEM) device, the curcuminoids nanofibers diameter was measured, where the values obtained ranged between 191 to 234 nm. After the annealing process, 15 nm nanoparticles were obtained

Effect of Annealing Temperature on Growth Particles of YAG: Ce +3 Phosphor and White Light Chromaticity Values

In the present work white-emitting Y3A15O12:xCe3 (x = 0.04) nanophosphor in the form Of powder were synthesized by a microwave-induced combustion synthesis method (MW) Using metal nitrates as precursors and urea as fuel. By covering blue light-emitting diodes (blue-LED, 445 nm) white light emission (WLED)was generated. The sintering temperature with fixed time (5 hours) for phosphor powder was optimized and found to be 1050 °C. The crystallinity structure, luminescent properties and chromaticity were characterized by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), electroluminescence (EL) and standard CIE 1931 Chromaticity diagram. The results show that the obtained YAG:Ce+3 phosphor sintered at 1050°C has good crystallinity with pure phase, low agglomeration particles and strong yellow emission that offering daylight white LED with tuneable correlated color temperature (CCT) and a good colour rendering index (CRI) compared to those sintered at 950 °C, 850°C and non-sintered phosphor powders

Impacts of Sol-Gel Auto-Combustion and Ultrasonication Approaches on Structural, Magnetic, and Optical Properties of Sm-Tm Co-Substituted Sr0.5Ba0.5Fe12O19 Nanohexaferrites : Comparative Study

In this paper, we introduced a comparative study of Sm-Tm-substituted Sr-Ba nanohexaferrites (NHFs), Sr0.5Ba0.5TmxSmxFe12-2xO19 with x = 0.00-0.05, manufactured via both citrate sol-gel auto-combustion and ultrasonication approaches. The phase formation of M-type hexaferrite (HF) for both compositions was confirmed by X-ray diffraction (XRD) powder pattern, Fourier-transform infrared (FT-IR) spectra, scanning and transmission electron microscopy (SEM and TEM) micrographs, energy dispersive X-ray (EDX) spectra, and elemental mappings. The magnetic properties at room temperature (RT) and low temperature (T = 10 K) were also investigated. M-H loops revealed ferrimagnetic nature for various prepared nanohexaferrites via sol-gel and ultrasonication routes. The M-s (saturation magnetization) and M-r (remanence) values increased with increasing Tm-Sm substituting contents. M-s and M-r reached their maximum values at x = 0.04 in the case of samples prepared using the sol-gel technique and at x = 0.03 for those prepared via ultrasonication route. M-H loops were very broad in samples prepared via ultrasonication route in comparison to those produced by means of the sol-gel approach, implying that the products synthesized via ultrasonication route have greater values of coercivity (H-c). The variations in H-c values with respect to Tm-Sm substitutions were governed by the evolutions in the magneto-crystalline anisotropy. Diffuse reflectance spectra (DRS) were employed to estimate the direct band gap of pristine and co-substituted Sr0.5Ba0.5Fe12O19 hexaferrites. Optical energy band gaps (E-g) of pristine samples were significantly tuned by co-substitution of Tm3+ and Sm3+ ions. E-g values of the Sr0.5Ba0.5Fe12O19 sample, which was synthesized using the sol-gel method, decreased almost linearly from 1.75 to 1.45 eV by increasing co-doped ion content. However, we observed a sharp drop from 1.85 eV to an average of 1.50 eV for the samples, which were synthesized using the ultrasonication approach

Optical and structural properties of curcuminoids extracted from Curcuma longa L. for hybrid white light diode

In this study, curcuminoids were extracted from turmeric (Curcuma longa L.) by means of three methods, comprising the normal method, use of Soxhlet apparatus and by combining the normal method with the Soxhlet extraction approach. The limitation of stickiness in the use of curcuminoids was resolved by mixing it with silica gel. The curcuminoids used light down-conversion of UV light (390 nm) for the white light-emitting diode (WLED). The characteristics of the white light chromaticity were controlled by changing the current and concentration of the curcuminoids. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for different applied currents (20, 60 and 100 mA) and weights (25, 35 and 50 mg) of curcuminoids. It was observed from the concentration of phosphor that the combination of the normal and Soxhlet apparatus methods is most effective extraction approach. The results showed that increasing the concentration of phosphor significantly and remarkably increased the value of CCT when different values of current were applied. The stress test showed that the prolongation of dye degradation can be improved using air gap and glass slid, with air gap being more effective. An optimum color rendering index (CRI) value of 61.2 is obtained. The white phosphor exhibited CIE values of 0.333, 0.3151 and color temperature (CCT) of 5405 K

Investigation of Structural and Magnetic Properties on Mg1-xZnxFe2-xAlxO4 (0.0 <= x <= 0.8) Nanoparticles

A mixed spinel ferrite nanoparticle, Mg1−xZnxFe2−xAlxO4 NPs (0.0 ≤ x ≤ 0.8), were synthesized effectively by co-precipitation method and sintered at 600 °C for 10 h. The structural and magnetic properties of the products were studied through X-ray powder diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer. The cubic spinel phase was confirmed by XRDs with particle size between 24.5 and 40.2 nm. The lattice parameters for the products are increased with increasing the Zn2+ and Al3+ ratio due to the successfully integrated into the cubic system without changing the original structure. Although it was observed from the cation distributions, that the cubic phase is was an inverse spinel, wherein which the Fe3+ and Mg2+ ions occupied both the tetrahedral A and octahedral B- sites, the Zn2+ ions preferred to occupy the A- sites and Al3+ occupy preferred the B -sites. The morphology of the nanoparticles NPs detailed was using TEM, HR-TEM, and SAED in selected area confirmed the particle size and crystalline spinel structure. Magnetization results at room temperature presents a narrow hysteresis loop for all ratios, which is specific of the soft magnetic materials. Also, we noticed that the increase in the magnetization with increasing the ratio of Zn2+ and Al3+ consistent with the enhancement of crystallinity. Moreover, we found that the saturation magnetization, coercively and remanent for Mg1−xZnxFe2−xAlxO4 where x = 0.6 sample is the highest, indicating the potential of Zn and Al substitution in enhancing the magnetic properties of magnesium ferrite. According to AC magnetic susceptibility measurements, the nanoparticles exhibit superparamagnetic/spin glassy behaviour with a very strong inter-nanoparticles interaction. Additionally, AC susceptibility measurements indicated a relative sensitivity of samples to the variation of applied frequency, which is an important result for the applications in hyperthermia based therapy. This is the first study in which both Zn2+ and Al3+ ions with varying concentration were tried to substitute into MgFe2O4 simultaneously and their effects on magnetic properties of MgFe2O4 was investigated