A multicolored LED illumination device is a compact, durable, easy to obtain color-adjustable output illumination source. It is frequently utilized in the domains of room illumination and exterior displays. However, the advancement of multicolor LEDs has been hampered by the rise in price and the fall in luminous efficacy while changing illumination colors. In the present investigation we have prepared intense red emitting Eu3+ 3 + doped CaMoO4 4 phosphor nanopowders via simple solid-state reaction technique. The powder X-ray diffraction (PXRD) studies reveal the crystalline nature of the samples with scheelite-type mono phase tetragonal structure with I41/ 4 1/ a space group. The band gap (Eg) E g ) energy values were estimated and found to range between 4.63-5.32 eV. Scanning electron microscopy (SEM) studies reveled the hexagonal rod-like structures with different Aloe Vera gel concentrations. The particle size was found to be around 40 nm. The vibrational modes of the prepared powders were evaluated by using Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. It was observed from the results that, there were 26 vibrational modes of CaMoO4 4 (Gamma=3Ag Gamma =3A g + 5Au+ u + 5Bg g + 3Bu+ u + 5Eg g + 5Eu) u ) 8 of which (4Auand u and 4Eu) u ) were infrared active and 13 (Ag, g , Bg, g , and Eg) g ) are Raman active. Photoluminescence (PL) emission intensity increases up to 5 mol% of Eu3+ 3 + ions load and subsequently it declines due to the concentration quenching phenomenon and effective energy transfer from Mo-O charge transfer band (CTB) to 5 D 0 levels of Eu3+. 3 + . It was noticed from PL emission spectra that, four intense peaks located at 5 D 0 -> 7 F 1 (590 nm), 5 D 0 -> 7 F 2 (613 nm), 5 D 0 -> 7 F 3 (654 nm), 5 D 0 -> 7 F 4 (702 nm) of Eu3+ 3 + respectively. The Commission International de I'Eclairage (CIE) diagram indicates the red color emission and average correlated color temperature (CCT) value was found to be 2050 K. Further, the external quantum efficiency (QE) and color purity (CP) were calculated to check the phosphor efficiency and found to be 92% and 72% respectively. The present investigation opens up a new avenue in the fabrication of low-cost display devices with high color purity and luminous efficacy.

In the current investigation, pure polyvinylidene fluoride (PVDF) and PVDF-MgO nanocomposite (NC) thin films are fabricated via solvent casting method using PVDF as a polymer matrix with different proportions of magnesium oxide (MgO) (0.5-2 wt%). The structural, morphological and optical properties of the prepared polymer NCs are studied by using XRD, FTIR, SEM, Raman and UV-Vis spectroscopy techniques. The alpha and (3 phases are detected in XRD measurements. MgO powder peaks are in good agreement with the reported literatures. The average crystallite size, lattice strain, and dislocation density of the prepared thin films are estimted by using Williamson-Hall (W-H) plot. SEM micrographs reveals the fluorine-containing carbon chain network that forms the spherulite and fiber-like structure in the PVDF/MgO NCs films. The Raman and FTIR spectra of PVDF/MgO and pure PVDF films are also evaluated. UV-Vis spectroscopy is used to examine the absorbance, transmittance, and reflectance spectra of pure PVDF and PVDF/MgO NCs thin films. The dipole polarization interaction causes the absorption coefficient, direct band gap, indirect band gap, optical activation energy, and skin depth of pure PVDF and PVDF/MgO thin films to decrease, whereas increasing the dielectric constant at high frequency value, refractive index, loss, optical conductivity, and dielectric constant per effective mass of NCs films. Optical dispersion parameters are estimated by the single oscillator model. The obtained results can be employed in the possible applications in supercapacitors. The method used for the preparation of thin films are inexpensive and eco-friendly.

A series of orange-red light emitting Ca2MgSi2O7:Sm3+ nanopowders were fabricated via low-cost eco-friendly green combustion technique using Aloe vera gel as fuel. The phase purity of the samples were confirmed by the powder X-ray diffraction (PXRD) technique. Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks. The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra (DRS) and is found to be in the range of 4.01-5.98 eV. A high resolution scanning electron microscope (SEM) was used to study the morphological behaviour of the samples. Honeycomb-like structures are observed from the SEM results. The particle size was evaluated by transmission electron microscopy (TEM) and is found to be similar to 50 nm. The interplanar distance is found to be 0.53 nm. Photoluminescence properties were systematically studied in detail. The phosphors are successfully excited at 403 nm NUV light, producing reddish-orange characteristic emission. The emission peaks are centered at 558 ((4)G(5/2) -> H-6(5/2)), 607 ((4)G(5/2) -> H-6(7/2)) and 645 nm ((4)G(5/2) -> H-6(9/2)), respectively. Among the observed peaks the red emanation ((4)G(5/2) -> H-6(7/2)) is stronger than the orange emission ((4)G(5/2) -> H-6(5/2)) in the current investigation. The photoluminescent concentration quenching is noticed above 5 mol% Sm3+ ion doping content. The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism. The color features such as Commission Internationale de l'Eclairage (CIE) and correlated color temperature (CCT) were studied in detail. The optimized chromaticity coordinates were estimated to be (0.6363, 0.3632), which fall in the reddish-orange region. The average CCT value obtained is 3362 K. The average color purity is found to be similar to 82%. Sm3+ incorporated Ca2MgSi2O7 samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm3+ ions through host, least possibility for re-absorption of blue-green emission owing to poor direct f-f excitation of Sm3+ ions, and high color purity (reddish-orange emission). The prepared powders exhibit excellent electrochemical redox properties and CPE modified optimized powders show outstanding sensitive response which indicates its use in the potential electrochemical sensor materials for drug sensing studies.

In the present investigation photoluminescent, photocatalytic and advanced forensic applications of hydrothermally prepared BaZrO3:Dy3+ (1-9 mol%) nanopowders were studied in detail. Fresh green Aloe Vera (AV) gel was used as capping agent for the preparation of NPs. The pure cubic phase was observed by powder X-ray diffraction (PXRD) profiles. Fourier transform infrared (FTIR) was utilized to investigate the functional groups present in the prepared NPs. The modification in surface morphology was investigated by using Field emission scanning electron microscope (FESEM) images. The grain size was evaluated by utilizing transmission electron microscope (TEM) images and found to be around 48 nm. Further, with the help of high-resolution TEM (HRTEM) images the interplanar distance was calculated and found to be 0.32 nm. Photoluminescence (PL) studies were carried out in detail using excitation and emission spectra. The maximum intensity was detected for peak 388 nm ascribed to 6H15/2 -> 4I13/2 + 4F7/2 of Dy3+ transition under 574 nm emanation wavelength. The obtained emanation spectra consist of 3 characteristics peaks of Dy3+ ions at 480, 574 and 666 nm attributed to 4F9/2 -> 6H15/2, 4F9/2 -> 6H13/2 and 4F9/2 -> 6H11/2 respectively. The PL intensity increases up to 7 mol% dopant ion weight and afterwards it decreases due to concentration quenching phenomena. The dipole-dipole interaction was responsible for this quenching. The color coordinates results in white emission witnessed from the Commission International de I'Eclairage (CIE) and correlated color temperature (CCT) diagrams. The average CCT value was observed around 4836 K. Further, the color purity (CP) and external quantum efficiency (QE) was estimated and found to be 86 % and 64 % respectively. The photocatalytic degradation activity was also studied for the prepared powders and found that, the optimum degradation was observed till 180 min. The kinetics studies revealed that, the present powders were in agreement with the 0th order with estimated ko = 0.015 with R2 value of 0.98 respectively. The powders were also explored for their latent fingerprint (LFP) visualization on various porous and non-porous surfaces and found that, the powders exhibited all types of fingerprint ridge details including the 3rd type such as sweat pores and scar. The observed all outcomes specify that, the prepared powders can be used as a potential candidate for the fabrication of white LEDs (wLEDs), excellent photocatalyst and fingerprint visualization.

Significant global concerns mainly include removing various environmental organic dye contaminants and detecting the toxic nitrite 〖(NO〗_2^-). Therefore, we have developed a novel composite that combines an inorganic perovskite-based alkaline...

In the present report, a series of intense red light emitting SrZrO3:Eu3+ nanopowders were fabricated via low-cost eco-friendly hydrothermal route using Aloe vera gel as surfactant. Upon utilizing the powder X-ray diffraction (PXRD) method the phase of the prepared nanopowders were evaluated. Pure single-phase tetragonal structure was observed from the PXRD results with no additional impurity peaks. The energy band gap of the fabricated powders was calculated by diffuse reflectance spectra (DRS) and found to be around 3.98 - 4.27 eV. High resolution scanning electron microscope (SEM) was utilized to study the mor-phological behavior of the prepared powders. Honeycomb-like structures were observed from the SEM micrographs. The particle size was evaluated by transmission electron microscopy (TEM) and observed to be -42 nm. The interplanar distance was found to be around 0.32 nm. Photoluminescence proper-ties were systematically studied in detail. The phosphors were successfully excited at 395 nm NUV light, producing intense red characteristics emission. The emission peaks were centered at 585 nm (5D0 -> 7F1), 613 nm (5D0 -> 7F2) and 648 nm (5D0 -> 7F3). The photoluminescent concentration quenching was noticed beyond 5 mol% Eu3+ ion doping content. The dipole-dipole interaction resulting in cross relaxation was found to be the principal cause of concentration quenching mechanism. The color features such as Com-mission International de I'Eclairage (CIE) and correlated color temperature (CCT) were studied in detail. The optimized chromaticity coordinates were estimated to be (0.67, 0.32), which falls in the intense red region. The average CCT value obtained was 4328 K. The color purity was observed around -88%. In ad-dition, the average internal quantum efficiency was calculated, and it was found to be 48%. The prepared powders exhibit excellent luminescence properties, quantum efficiency and high color purity. The ob-tained results indicate the possibility of the present powders in the fabrication of the red-light emitting diode applications.(c) 2023 Elsevier B.V. All rights reserved.

In the present investigation, color tunable samarium ions incorporated SrZrO3 nanopowders fabricated by simple solution combustion technique by using Aloe vera gel as fuel studied. The thorough characterization of the synthesised SrZrO3 nano materials by different analytical techniques has been explored. The powder X-ray diffraction profiles authorizes the orthorhombic phase of SrZrO3. The band gap energies were evaluated by diffuse reflectance spectra profiles and it was found that the values were observed between 4.42-4.81 eV. The dumb-bell shaped morphology was confirmed by the scanning electron microscope images. The size of the particles was estimated by means of Transmission electron microscope and it was found to be around 30 nm. The photoluminescence properties were studied by means of emission spectra at room temperature. The three prominent peaks of Sm ions were observed at 555 ((4)G(5/2)-> 6H(5/2)), 609 ((4)G(5/2)-> H-6(7/2)) and 645 nm ((4)G(5/2)-> H-6(9/2)) respectively under 403 nm (H-6(5/2)-> F-4(7/2)) excitation wavelength. The highest PL emission was observed for 5 mol% of Sm incorporated SrZrO3. The photoluminescence emission decreases beyond 5 mol% of dopant concentrations owing to the well-known concentration quenching mechanism. Commission international de I'Eclairage diagram unveils orange color due to (0.6362, 0.3633) lines and the average color purity of the fabricated powders was found to be similar to 90%. Further, the average internal quantum efficiency was estimated and it was observed to be 36.46%. In addition to this, the optimized powders were utilized to detect the latent fingerprint on non-porous surface. The found results indicated that, the powders can simulate the clear ridge details including the 3 types such as sweat pores without any background hindrance. The achieved results recommend the prepared phosphors can be excellently employed in the production of the white light emitting diode applications as orange-red component and also used for the advanced forensic applications. (C) 2021 Elsevier B.V. All rights reserved.

In this communication, we report the orange-red light emitting Sm3+ ions doped BaZrO3 (BZO) nanopowders (NPs) prepared via green combustion synthesis route by utilizing the local available Aloe vera (AV) gel as the surfactant. For convenient to the readers, we represent BaZrO3:Sm3+ as BZOS. The cubic structure of the BZOS is confirmed by the results of powder X-ray diffraction (PXRD). The energy band gap values are studied by diffuse reflectance spectra (DRS) plots and found to be in the range of 4.71-5.55 eV. The spherical structure of the fabricated nanopowders is analyzed by means of scanning electron microscope (SEM) images. Transmission electron microscope (TEM) image are castoff to evaluate the particle size of the prepared powders. The crystallinity and interplanar distance are analyzed by selected area diffraction (SAED) and high-resolution TEM (HRTEM) images. The luminescence studies are performed at RT. The strong absorption in NUV spectral region is observed. Upon excitation at 403 nm wavelength the emission peaks centered at 565, 607 and 649 nm ascribed to Sm3+ ions 4f-4f characteristics. The explanation for this quenching of focus has been explored in depth. In the pure orange field, the pixel coordinates (0.579, 0.419) for improved BZO: Sm3+ phosphor lie. The CP levels are also calculated and observed to be - 90 percent. The quantum efficiency of the prepared nanopowders is found to be - 88. 62%. The above findings substantiate the ability of BZO: Sm3+ phosphor to be used in photovoltaic applications as a high thermal stability orange-red light producing element.