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Ca9Y(VO4)7 phosphor activated with Er3+ ions have been developed by the urea-aided solution combustion technique. XRD profiles assisted with Rietveld refinement executed over-developed Er3+-activated Ca9Y(VO4)7 powder, revealed a trigonal phase with the R3c space group. The electron microscope techniques namely TEM and SEM characterize the size and surface-linked qualities of the developed nanopowder, respectively. The uniform distribution of various elements in the nanocrystalline sample is authenticated by an energy-dispersive spectroscopy (EDS) system. The Eg (band gap) value of 3.64 eV for Ca9Y0.9Er0.1(VO4)7 and 3.74 eV for Ca9Y(VO4)7 has been estimated. Upon 382 nm excitation, Er3+: Ca9Y(VO4)7 phosphor gives rise to the bright green emission owing to the 4S3/2 → 4I15/2 transition. The concentration quenching after 10 mol% composition of trivalent erbium ions is attributed to dipole-dipole interlinkages in accordance with Dexter's theory. The radiative lifetime (1.1083 ms), non-radiative rates (0.2079 ms− 1), quantum efficiency (79%), along with colorimetric parameters i.e. CIE x (= 0.2577), y (= 0.4566), and CCT quantities offer Ca9Y0.9Er0.1(VO4)7 as a proficient green radiating nanomaterial for RGB phosphors in solid-state applications. [ABSTRACT FROM AUTHOR]

In the present system, Sm3+ activated Ba2BiV3O11 nanomaterial series radiating orange-red light was developed via an efficient approach of solution combustion method. The structural examinations using XRD analysis indicate that the sample is crystallized into the monoclinic phase with the P21/a (14) space group. The elemental composition and morphological conduct were studied via energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. Also, the formation of nanoparticles was confirmed by transmission electron microscopy (TEM). Photoluminescent (PL) examinations reveal the orange-red emission from the developed nanocrystals via documenting the emission spectra, which reveals the peak at 606 nm due to the 4G5/2 → 6H7/2 transition. Further, the decay time, non-radiative rates, quantum efficiency, and band gap of the optimal sample were computed as 1.3263 ms, 219.5 s− 1, 70.88%, and 3.41 eV respectively. Finally, the chromatic parameters including color - coordinates (0.5565, 0.4426), 1975 K color correlated temperature (CCT), and color purity (85.58%) reflected their excellent luminous performance. The above-mentioned outcomes endorsed the relevancy of the developed nanomaterials as a propitious agent in the engineering of advanced illuminating optoelectronic appliances. [ABSTRACT FROM AUTHOR]

Strong green-emission is observed in the new Tb3+ activated Sr6Y2Al4O15 nanocrystalline material series fabricated via solution combustion methodology. A monoclinic crystal framework with space group I4/mcm (140) having irregularly shaped grains with an average size of 49 nm is formed. Morphological aspects are examined via scanning and transmission electron microscopy (SEM and TEM). On near-UV excitation, the photoluminescence spectrum presents a fair green-light production at 18382 cm-1 wavenumbers reliable with the 5D4→7F5 electronic transition. The energy transfer phenomena are also discussed. The highest luminous intensity is observed for 5.0 mol% of Tb3+ composition with 282 nm excitation wavelength. d-d exchanges authorized the presence of the concentration quenching phenomenon. Diffuse reflectance spectroscopy was taken into use to explore the energy band gap which lies in the semiconductor domain. The CIE coordinates lay in the greenish zone of the chromaticity scheme, thus confirming their latent contention in pc-WLED fabrication and other advanced photonic applications. Strong green-emission is observed in the new Tb3+ activated Sr6Y2Al4O15 nanocrystalline material series fabricated via solution combustion methodology. A monoclinic crystal framework with space group I4/mcm (140) having irregularly shaped grains with an average size of 49 nm is formed. On near-UV excitation, the photoluminescence spectrum presents a fair green-light production at 18382 cm-1 wavenumbers reliable with the 5D4→7F5 electronic transition. The CIE coordinates lay in the greenish zone of the chromaticity scheme, thus confirming their latent contention in pc-WLED fabrication and other advanced photonic applications. [ABSTRACT FROM AUTHOR]

Strong green emission is observed in the new Tb3+ activated Ba2La4Zn2O10 nanocrystalline material series fabricated via solution combustion methodology. A tetragonal crystal framework with space group I4/mcm (140) having irregularly shaped grains with sizes between 37 and 56 nm is formed. Morphological aspects are examined via scanning and transmission electron microscopy. On near-ultra-violet excitation, the photoluminescence spectrum presents a fair green emission at 18,348 cm−1 wavenumbers consistent with the electronic transition 5D4 → 7F5. The energy transfer phenomena are also discussed. The highest luminous intensity is observed for 5.0 mol% of Tb3+ composition with 283 nm excitation wavelength. d–d exchanges authorized the presence of the concentration quenching phenomenon. Diffuse reflectance spectroscopy was taken into use to explore the energy band gap which lies in the semiconductor domain. The commission international de l’Eclairage coordinates lay in the greenish zone of the chromaticity plot, thus confirming their latent contention in phosphor-converted white light emitting diodes and advanced solid-state lighting applications. [ABSTRACT FROM AUTHOR]

A deep reddish-orange-emitting Sm3+-activated vanadate-based nanocrystalline material series is developed via the solution combustion procedure. A trigonal crystal framework is formed with space group R3c (161) having unevenly designed particles with extents between 33 nm and 62 nm. Morphological aspects are examined via scanning and transmission electron microscopy (SEM and TEM). The elemental investigation is confirmed through energy-dispersive x-ray analysis (EDAX). On near-UV excitation, the luminescence spectrum presents a fair reddish-orange emission at 606-nm wavelength consistent with the electronic transition 4G5/2 → 6H7/2. The energy band gap is inspected via diffuse reflectance measurements. Radiative lifetime, quantum efficacy, and rates of radiation-less transformations were also examined and found to have values as 1.4914 ms, 82.84%, and 115.1 ms−1 for the optimized nanosample, respectively. The CIE coordinates, and hence CCT values, lay in the reddish-orange zone of the chromaticity plot, thus finalizing their potential application in WLEDs, solid-state lighting (SSL), and other advanced optoelectronic applications. [ABSTRACT FROM AUTHOR]

Eu3+ activated Ca9Y(VO4)7 nanomaterials radiating bright-red light were generated via a rapid, efficient, and ecological solution combustion technique. Rietveld refinement of XRD patterns confirmed the trigonal structure including R3c (161) space group of generated crystalline nanophosphors. Energy dispersive X-ray (EDAX) analysis determined the composition of elements present in the targeted samples and electron microscopy (SEM and TEM) determined the non-uniform agglomerated particles lie in nano-domain (1–100 nm). Tauc’s hypothesis was utilized to calculate the band gap. The presence of an intense band at 330 nm in the excitation spectrum, has certified the energy transfer between VO43− → Eu3+ ions. A detailed examination of PL (Photoluminescence) emanation spectra was accomplished to calculate the Judd–Ofelt (J–O) parameters. The bright-red light in the targeted nanophosphors is observed from the 5D0 → 7F2 radiative transition. Dexter’s theory and the Inokuti-Hirayama (I-H) model were applied to confirm the dipole–dipole (d–d) type of interlinkages as a real phenomenon for concentration quenching. Moreover, the optical characteristics of Ca9Y0.6Eu0.4(VO4)7 nanophosphor including high quantum efficiency (65.70%), CIE coordinates (0.4137, 0.3985), and color temperature (3383 K) showed their applications in wLEDs, visible color emitting photonic devices, advanced lasers, sensors, aircraft-components, and in other display devices. [ABSTRACT FROM AUTHOR]

A series of Ca9Gd(VO4)7: Dy3+ (x = 0.01–0.20) nanophosphor crystals emitting a cool white light were synthesized by solution combustion methodology. The X-ray diffraction patterns were analyzed and processed using Rietveld refinement. The fabricated nanophosphor was found to crystallize in a trigonal crystal lattice with space group R3c(161). The morphological behavior of the prepared nanophosphor was investigated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The photoluminescence properties of the nanophosphor correspond to cool white emission upon near-ultraviolet (NUV) excitation at 327 nm due to 4F9/2 → 6H15/2 (bluish) and 4F9/2 → 6H13/2 (yellowish) radiative relaxations at 487 nm and 576 nm respectively. Also, there is a strong occurrence of double charge transfer from O2− ions to Dy3+ and V5+ ions with the latter being stronger due to the high positive charge of V5+ ions. Color coordinates (x = 0.2878, y = 0.3259) are consistent with white emission. Auzel's model was implemented to examine the non-radiative relaxation (113.5 ms−1), radiative lifetime (1.4856 ms), and quantum efficiency (83.13%) values. The crystalline and optical behavior of the synthesized cool white emitting nanophosphor facilitates its use in near-UV-based WLEDs and other advanced solid-state lighting. [ABSTRACT FROM AUTHOR]