Intense Emission Peak Research Articles

Feasibility of a Low-Power, Low-Resolution Laser-Induced Breakdown Spectroscopy Instrument for Analysis of Nickel Alloys: Quantification of the Major Alloying Elements and Classification.

A simple cost-effective laser-induced breakdown spectroscopy (LIBS) instrument was used for quantification of major elements in several nickel alloys and also sorting them. A compact low-power diode-pumped solid-state laser and a miniature low-resolution spectrometer were assembled for the LIBS instrument. Material properties of the nickel alloys depend mainly on the composition of the major elements, Ni, Cr, and Fe, ranging from a few to ∼60 wt%. The emission peaks at 547.7 nm, 520.4 nm, and 438.1 nm for Ni, Cr, and Fe, respectively, were chosen for this analysis. The analytical performance was found to be enough for the quantification of Ni, Cr, and Fe in the nickel alloys. Limits of detection and accuracy were estimated to be a few weight percent (wt%) and measurement precisions were less than 10% in terms of relative standard deviation. The calibration performance of this intensity-based method was compared with that of the "ratio method" which is used in conventional optical emission spectroscopy analyses. The comparison indicates that the intensity-based method is more appropriate with the low-performance LIBS instrument that detects emission peaks of only a few major elements. Also, multivariate modeling of the six different nickel alloy samples based on the emission peak intensities of Ni, Cr, and Fe was performed using k-nearest neighbors (KNN) and linear discriminant analysis (LDA). The KNN and ordinary LDA models showed 95.0% and 98.3% classification correctness for the separate test data set, respectively. To improve classification performance further, the two-step LDA model was trained. In this approach, the two closest sample classes responsible for the decrease in the classification correctness were separately modeled in the second step to exploit their difference effectively. The two-step LDA model showed 100% correctness in classifying the test objects. Our results indicate that such a low-performance LIBS instrument can be effectively utilized for quantitative analysis of the major elements in the nickel alloys and their rapid identification or sorting in combination with an appropriate multivariate modeling algorithm.

Integrating Highly Luminescent Lanthanides with Strongly Coupled Dye J-Aggregates on Nanotubes for Efficient Cascade Energy Transfer

Photoluminescent one-dimensional hybrid nanostructured materials having outstanding inorganic–organic advantages are gaining significant attention on account of their intriguing applications in nanoscale optoelectronic devices, (bio)sensors, and energy harvesting and conversion technologies. Here, we first report on the development of highly photoluminescent lanthanide organic hybrid nanotubular assemblies through in situ incorporation of a trivalent lanthanide ion, terbium (Tb3+), along with organic photosensitizers 2,3-dihydroxynaphthalene (DHN) or 1,10-phenanthroline (Phen) into the self-assembled nanotubes of sodium lithocholate (NaLC). Both the photosensitizers (DHN/Phen) are effective in sensitizing intense narrow emission peaks of Tb3+ on the nanotubes. Next, we utilize these luminescent lanthanides containing hybrid nanotubular assemblies as templates for spontaneous integration of strongly coupled pseudoisocyanine (PIC) dye J-aggregates with a sharp J-band absorption at 555 nm and strong fluorescence emission at 570 nm. The presence of the significant spectral overlap between the luminescence peak of Tb3+ at 545 nm and the J-aggregate absorption band results in efficient cascade energy transfer from photosensitizers to Tb3+ to the coherently coupled PIC dye J-aggregates. These NaLC nanotube-templated photosensitizer-Tb3+-J-aggregate hybrid systems have great potential for sensing and optoelectronic applications.

Gadolinium-based Sm3+ activated GdSr2AlO5 nanophosphor: synthesis, crystallographic and opto-electronic analysis for warm wLEDs.

A material's luminosity characteristics, which in turn dictate its applicability, are critically influenced by its structure. Therefore, it is essential for design and fabrication of optical nanocrystalline materials to comprehend the relationship between structural and luminescence properties. The gel-combustion approach was used to produce a sequence of orange-red light emanating GdSr2AlO5:Sm3+ (GSA:Sm3+) nanophosphors which are used for warm white-light-emitting diodes (w-LEDs). Comprehensive investigation of the structural and optical characteristics of GdSr2AlO5:Sm3+ nanophosphors has been done in a detailed manner. The synthesized powdered nanophosphors are crystallized in a tetragonal phase with I4/mcm (140) space group, affirmed through Rietveld refining method. The nano size with an aggregated, spherical form of the particles in the powdered nanocrystalline material was revealed by TEM analysis. These orange-red emitting phosphors Gd1-x Sr2AlO5:xSm3+ (x = 1-7 mol%) were shown to possess photoluminosity (PL) properties that demonstrated the presence of most intense emission peaks at 603 nm that were caused by 4G5/2 → 6H7/2 transitions of the Sm3+ ion under 273 nm excitation. Considering its long decay lifespan and PL emission, it can be concluded that the GdSr2AlO5:Sm3+ phosphor is a potential single element for the fabrication of warm white light-emitting devices.

SrLaNaTeO6:Eu3+ red-emitting phosphors with high luminescence efficiency and high thermal stability for high CRI white LEDs

A novel single-phase trivalent europium activated red-emitting SrLaNaTeO6 phosphor was first synthesized in a process of traditional high-temperature solid-state. The phase purity, morphology, and spectroscopy of the prepared phosphor were analyzed. Under 395 nm excitation, the photoluminescence (PL) spectra of the SrLaNaTeO6:Eu3+ products mainly contained five dominant sharp peaks. The intense red emission peak at 615 nm was the typical 5D0→7F2 electric dipole transition of Eu3+. The optimum product of high quenching concentration was the SrLaNaTeO6:0.90Eu3+, which reached a high internal quantum efficiency (IQE) of 90.6%. The SrLaNaTeO6:0.90Eu3+ was estimated to have Rc of 6.57 Å and possessed high color purity of 100.0%. The phosphors exhibited excellent thermal stability and high activation energy (Ea = 0.29 eV). The prepared white light-emitting diode (WLED) had a high color rendering index (CRI) Ra of 92 and a low correlated color temperature (CCT) of 5008 K. In conclusion, the phosphors have potential as red components for WLEDs.

Decoupling Individual Optical Nanosensor Responses Using a Spin-Coated Hydrogel Platform.

Significant advances have been made in fields such as nanotechnology and biomedicine using the unique properties of single-walled carbon nanotubes (SWCNTs). Specifically, SWCNTs are used as near-infrared fluorescence sensors in the solution phase to detect a wide array of biologically relevant analytes. However, solution-based sensing has several limitations, including limited sensitivity and poor spatial resolution. We have therefore devised a new spin-coated poly(ethylene glycol) diacrylate (PEG-DA) hydrogel platform to examine individual DNA-functionalized SWCNTs (DNA-SWCNTs) in their native aqueous state and have subsequently used this platform to investigate the temporal modulations of each SWCNT in response to a model analyte. A strong surfactant, sodium deoxycholate (SDC), was chosen as the model analyte as it rapidly exchanges with DNA oligonucleotides on the SWCNT surface, modulating several optical properties of the SWCNTs and demonstrating multiparameter analyte detection. Upon addition of SDC, we observed time-dependent spectral modulations in the emission center wavelengths and peak intensities of the individual SWCNTs, indicative of a DNA-to-surfactant exchange process. Interestingly, we found that the modulations in the peak intensities, as determined by kinetic data, were significantly delayed when compared to their center wavelength counterparts, suggesting a potential decoupling of the response of these two spectral features. We used a 1-D diffusion model to relate the local SDC concentration to the spectral response of each SWCNT and created dose-response curves. The peak intensity shifts at a higher SDC concentration than the center wavelength, indicating a potential change in the conformation of the surfactant molecules adsorbed to the SWCNT sidewall after the initial exchange process. This platform allows for a unique single-molecule analysis technique that is significantly more sensitive and modifiable than utilizing SWCNTs in the solution phase.

Enhanced photocatalytic degradation of Rhodamine B and Methylene blue by novel TiO2/SnSe-SnO2 hybrid nanocomposites under sunlight irradiation: Correlation of photoluminescence property with photocatalytic activity

Semiconducting nanocomposites (NCs) has proved their dominance in various energy applications. The facile chemical synthesis of semiconducting hybrid NCs of TiO2 nanoparticles with SnSe/SnO2 (SS) nanostructures has been carried out. Structural, morphological, compositions, optical and photo-catalytic (PC) properties of the synthesized materials were then studied by various characterization techniques. The hybrid NC of TiO2 nanoparticles grown with addition of 0.5 g of SS nanostructures has been observed to exhibit the best PC activity among the other samples. The fitted photoluminescence (PL) spectra of pristine TiO2 when compared with the other two TiO2 -SS hybrid NCs showed that the oxygen vacancy (OV) defects play a major role in enhancing the PC property. The samples with superior PC activities have higher intensity of PL emission peak from OVs, efficient charge separation owing to longer lifetime of free charge carriers deduced from time-resolved PL studies and higher surface area.

Opto-structural and magnetic properties of fluorine doped CuO nanoparticles: An experimental study

Pristine and p-block element, Fluorine (F) doped CuO nanoparticles (NPs) were synthesized by implementing the modified sol-gel method. The structural, elemental, and phase characteristics of the nanoparticles were examined using XRD and XPS analysis. Structural analysis revealed the lowering of crystallinity and crystallite size due to F doping owing to induced lattice distortion. Reduction of phase stability of CuO giving rise to the emergence of Cu2O phase was also observed. Fused irregularly shaped particles and gradual reduction of particle size for doping were detected from the morphological analysis. Emission peak intensity in photoluminescence study sheds light on the impact of F doping on the concentration of defects like oxygen vacancy. DRS spectra attained from UV–visible spectroscopy utilized for measuring the optical band gaps suggested a decrease in optical band gap with doping which attributes to the generated intra-band defect states. Room temperature ferromagnetism (RTFM) with slight paramagnetic (PM) contribution was evident in both pure and F-doped CuO NPs. The experimental magnetization value and the BMP model were perfectly compatible, indicating that FM emerged from polaron interactions. The intriguing opto-structural and magnetic properties of F-doped CuO NPs make them a promising contender for use in solar cells, magnetic storage devices, magnetic sensors, photocatalytic, photonics, spintronics, etc. applications.

Eye-Resolvable Surface-Plasmon-Enhanced Fluorescence Temperature Sensor.

Temperature sensors are widely used in important fields such as daily home, medical care, and aerospace as a commonly used device for measuring temperature. Traditional temperature sensors such as thermocouples, thermal resistances, and infrared sensors are technically mature; however, they have limitations in the application environment, temperature measurement range, and temperature measurement accuracy. An eye-resolvable surface plasmon-enhanced fluorescence temperature sensor based on dual-emission Ag@SiO2@CdS/ZnS composite nanoparticle film with multiple-parameter detectable signals and high response sensitivity was proposed in this work. The temperature sensor's x-chromaticity coordinate varied from 0.299 to 0.358 in the range of 77-297 K, while the y-chromaticity coordinate varied from 0.288 to 0.440, displaying eye-resolvable surface plasmon-enhanced fluorescence. The ratiometric response of two isolated photoluminescence (PL) peak-integrated areas located around 446 and 592 nm was found to be significantly temperature dependent, with a thermal sensitivity of 1.4% K-1, which can be used as an additional parameter to measure the precise temperature. Furthermore, the surface state emission peak intensity was linearly related to temperature, with a correlation index Adj. R-Square of 99.8%. Multiple independent temperature estimates can help with self-calibration and improve the measurement accuracy. Our findings show that the designed sensors can detect low temperatures while maintaining stability and reproducibility.

Coprecipitation synthesis, structural, optical properties, and thermometry application of Tm3+/Yb3+ co-doped YPO4 phosphor

Coprecipitation synthesis and characterization of upconverting YPO4: Tm3+, Yb3+ phosphor is reported in the present work. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM) were used to examine the structure and morphology of the synthesized phosphor. Tm3+ and Yb3+ co-doped YPO4 material have the tetragonal xenotime crystal structure of space group I41/amd. Upconversion luminescence properties of prepared phosphor are studied under the near-infrared (NIR) 980 nm laser excitation. The intense emission peaks are observed at ∼473 nm and ∼796 nm due to electronic transitions (1G4→3H6) and (3H4→3H6), respectively, and relatively weak emission peaks are observed at 654 nm and 700 nm which are attributed to (1G4→3F4) and (3F2,3→3H6) transitions of Tm3+, respectively. Tm3+ (0.3 mol%)/Yb3+(10 mol%) is the optimized concentration that gives intense and sharp emission in NIR (∼796 nm) region. Power dependence studies have been done to understand the upconversion emission mechanism. The fluorescence intensity ratio of (3F2,3→3H6)/(3H4→3H6) transitions of Tm3+ in the temperature range 323 K–598 K is analyzed. Relative and absolute temperature sensitivity are also calculated. Maximum relative sensitivity is 1.86% K−1 at 323 K and absolute sensitivity increases with rising temperature. Excellent sensitivity, avoidable spectral overlap, and intense upconversion emission, in the first biological window under NIR excitation, show that the prepared material is multifunctional and may have potential applications in temperature sensing and optical heaters for bio-molecules.

Influence of particle size of flame-synthesized carbon nanoparticles on band gap and photoluminescence properties.

Band gap and photoluminescence (PL) properties were investigated for flame-synthesized carbon nanoparticles (CNPs) of four different particle size distributions. The particles were collected by varying the flow rates of fuel and oxidizer in a controllable co-flow diffusion flame. The results indicated the possibility of both direct and indirect band gaps in the synthesized CNPs. The band gaps were found to increase with a decrease in the particle size, thereby exhibiting the quantum confinement effect. The PL properties observed with the pure powdered sample showed strong emission in the green region. However, for samples dispersed in isopropyl alcohol, the emission wavelength shifts towards the blue region, showing strong solvent dependence. The particle size of CNPs, however, only affects the emission peak intensities.

A novel intelligently integrated MOF-based ratio fluorescence sensor for ultra-sensitive monitoring of TC in water and food samples

In this work, a high-precision visual and point-of-care testing (POCT) ratiometric fluorescent nanosensor for TC was constructed by embedding fluorescein (FL) into l-histidine modified ZIF-8 (LZIF-8) and chelating with rare earth citrate complex. Upon exposure to TC, the coordination and energy transfer between Eu3+ and TC make Eu3+ sensitized emission characteristic red fluorescence, while without prejudice to the emission peak intensity of FL. This ratiometric fluorescent probe with stable reference signal had the characteristics of high sensitivity (ultralow LOD = 5.99 nM) and selectivity and fast response kinetics (within 20 s). The high-bright fluorescence emission was beneficial to human eye recognition and it can realize semi-quantitative detection of TC in eggs, meeting the requirements of household use. In addition, the color can be read and analyzed quickly with the help of smart phone color analysis APP, and the semi-quantitative concentration of TC can be determined more conveniently.

Probing Local Emission Properties in InGaN/GaN Quantum Wells by Scanning Tunneling Luminescence Microscopy

Scanning tunneling electroluminescence (STL) microscopy is performed on a 3 nm‐thick InGaN/GaN quantum well (QW) with [In] = 0.23 such that the main light emission occurs in the green. The technique is used to map the radiative recombination properties at a scale of a few nanometers and correlate the local electroluminescence map with the surface topography simultaneously imaged by scanning tunneling microscopy. While the expected green emission is observed all over the sample, measurements performed on a 500 nm × 500 nm area around a 150 nm‐large and 2.5 nm‐deep hexagonal defect reveal intense emission peaks at higher energies close to the defect edges, features which are not visible in the macrophotoluminescence spectrum of the sample. Via a fitting of the local tunneling electroluminescence spectra, quantitative information on the fluctuations of the intensity, peak energy, width, and phonon replica intensity of the different spectral contributions is obtained, which provides information on carrier localization in the QW. This procedure also indicates that the carrier diffusion length on the probed area of the QW is shorter than 50 nm.

Thermally stable red luminescence from Eu3+ -activated telluro zinc phosphate glass under near-ultraviolet light excitation for photonic applications.

Telluro zinc phosphate (TZP) glasses doped with different concentrations of Eu3+ ions were prepared and their physical, structural, and luminescence properties were studied in detail to reveal the utility of the as-prepared glass for white light-emitting diode (w-LED) applications. The broad hump in the diffraction pattern specified the amorphous behaviour of the TZP glass. The various vibrational shoulder linkages were characterized using the Fourier transform infrared (FT-IR) spectroscopy. The optical absorption spectrum was measured in the ultraviolet (UV)-visible (Vis) light region for the Eu3+ -doped TZP (TZPE) glass and the optical band gap was found to be 3.12 eV. Eu3+ -doped TZP glasses showed several emission peaks in the visible region including an intense red emission peak due to the 5 D0 →7 F2 transition under an excitation wavelength of λex = 393 nm, which was matched with the emitting wavelength of the near-UV LED chip. Commission Internationale de I'Eclairage (CIE)chromaticity coordinates were situated in the red region and nearly matched with the coordinates of the commercial red phosphor (Y2 O3 S:Eu3+ ). The decay profile of the TZPE50 glass exhibited a single exponential fit with a decay time ( of 1.76 ms. Temperature-dependent photoluminescence (TDPL) studies demonstratethat the as-prepared glass consist of excellent thermal stability. The detailed analysis and results confirmed that the red-emitting TZPE glasses were potential candidates for white-LED and other photonic applications.

Synthesis, structure and luminescence properties of bifunctional KCaF3 phosphor influenced by incorporating Eu3+ ions for solid state lighting and TL dosimetry applications

Europium doped KCaF3 phosphors (KCaF3:Eu3+) were prepared using various concentrations of Eu3+ by conventional solid-state reaction process. The X-ray diffraction (XRD) studies confirmed the formation of orthorhombic structured KCaF3:Eu3+ phosphors. Scanning Electron Microscopy (SEM) image of the synthesized phosphor exhibits agglomerated particles with irregular shapes. The composition of the synthesized sample was determined by Energy Dispersive Spectroscopy (EDS) spectrum and elemental mapping showed the homogeneous dispersion of Eu3+ ions into the synthesized KCaF3:Eu3+ phosphor. The emission peak intensity at 594 nm from photoluminescence (PL) spectra was found to increase with the increase of Eu3+ concentrations from 0.02 mol% to 0.06 mol% and decreased with the further increase of Eu3+ concentration up to 0.1 mol%. CIE1931 chromaticity diagram coordinates (x, y) of KCaF3:(0.06 mol%) Eu3+ phosphors were positioned in the reddish-orange region (x = 0.5736, y = 0.4224). Photoluminescence property confirms the suitability of KCaF3:Eu3+ phosphors for Solid state lighting application. X-ray induced luminescence (radioluminescence, RL) is recorded for KCaF3:Eu3+ phosphors showing the characteristic emission of Eu2+ and Eu3+. ESR study on KCaF3:Eu3+ phosphors confirm the presence of Eu2+ ions. Beta irradiated thermoluminescence (TL) glow curve of Eu3+ doped KCaF3 phosphors is measured and deconvoluted using Gaussian fitting. TL kinetic parameters like activation energy (Ea) and frequency factor (s) are calculated for all the deconvoluted peaks using peak shape method which shows the synthesized KCaF3:Eu3+ phosphors is suitable for dosimetry application.

Investigation of intense mid-infrared emission in Ho3+/Yb3+/Er3+ triple-doped tellurite glass

Rare earth ion doping is considered to be a feasible way to improve the optical properties of glass in recent years. We investigate the luminescence characteristics of Ho3 + -Er3 + -Yb3 + triple-doped tellurite glass (TeO2-ZnO-WO3-La2O3) at 2.0 μm. A series of characterization analyses on the prepared samples, such as x-ray diffractometer (XRD) pattern, Raman spectrum, differential scanning calorimetry (DSC) curve analyses, absorption spectrum, emission spectrum, and fluorescence decay curve, were performed. XRD pattern and DSC curve analyses indicate that the glass sample exhibits a typical amorphous structure with excellent thermodynamic stability. Through the absorption spectrum, the position and intensity of the absorption peak of the glass sample can be detected. Under an excitation of 980 nm laser, the 2.0-μm emission peak intensity of the glass sample increases by about 1500%, which is attributed to the energy level transition among Ho3 + , Er3 + , and Yb3 + . By analyzing the energy level transition of Ho3 + , Yb3 + , and Er3 + ions, the energy transfer mechanism and fluorescence lifetime can be obtained, and then the fluorescence enhancement phenomenon of Ho3 + -Er3 + -Yb3 + triple-doped tellurite glass at 2.0 μm can be explained. It is demonstrated that the as-prepared Ho3 + -Er3 + -Yb3 + triple-doped tellurite glass has potential for the application of fiber lasers and fiber amplifiers.

Phase transition correlated grain growth in CdSe thin films: Annealing evolution to cadmium chloride activation

In order to explore a potential absorber layer, an impact of post-deposition CdCl2 activation on thermally evaporated CdSe thin films is undertaken where physical characteristics of CdSe thin films are performed at 200 °C, 300 °C and 400 °C temperatures. The crystallographic characteristics reveal that all CdSe films show polycrystalline behavior and having mixture of hexagonal and cubic phases where (111)C phase is changed into (103)H phase at temperature of 400 °C. The crystallite size and resistivity are altered from 27 to 44 nm and from 1.60 × 102 to 1.89 × 102 Ωcm with CdCl2 activation, respectively. The absorbance and intensity of PL emission peaks are enhanced with CdCl2 activation. AFM images show hill like topography where roughness and average grain size are increased from 75.83 nm to 143.8 nm and from 36 nm to 53 nm, respectively. FESEM images demonstrated explicit grain growth with activation. The integration of Cl and successful growth of CdSe films are confirmed by EDS patterns.

Development of novel Eu2+ and Li+ Co-doped cyan-emitting aluminosilicate phosphors

The cyan emission band contains blue and green light regions, which can simplify the fabrication process of white light-emitting diodes and help promote the development of solid-state lighting. In this paper, a series of Eu2+ singly doped and Eu2+ and Li+ co-doped cyan light-emitting KAlSiO4:x Eu2+, y Li + materials were synthesized using the high temperature solid-state method. It was found that the incorporation of 10% Li + could increase the emission intensity of the KAlSiO4:0.02Eu2+ sample by up to a factor of ∼3. This also shifted the emission color of the sample from blue-cyan (472 nm) to cyan (485 nm), and the quantum yield was increased from 71.5% to 93.3%. When the temperature is increased to 150 °C, the peak emission intensity was increased from 75.9% to 92.7% of that at room temperature. DFT calculations were used to demonstrate that the KAlSiO4 phosphor host possesses a wide bandgap of 4.86 eV and the experimentally-determined optical bandgap of the phosphor was 5.6 eV. The phosphor was combined with a commercial red phosphor, and these together were used as the emitting components in a white LED package. The characteristics of the white LED when using two representative samples of the phosphor (KAlSiO4: 0.02Eu2+ and KAlSiO4: 0.02Eu2+, 0.1Li+) were examined; these white LEDs had color rendering indices of 82 and 95, and color temperatures of 5656 K and 4126 K respectively. This work demonstrates the significant potential that KAlSiO4:0.02 Eu2+, 0.1 Li+ phosphors have in the field of LED lighting.

Growth, SHG, Z-scan, optical limiting and quantum chemical investigation of hexamethylenetetraminium hydrogen DL-malate – An organic crystal for optoelectronic applications

Single crystals of hexamethylenetetraminium hydrogen dl-malate (HMTM) have been successfully synthesized by slow evaporation method and structurally analyzed by single crystal X-ray diffraction, powder X-ray diffraction, FTIR, FT-Raman, 1H and 13C NMR spectroscopic techniques. These investigations confirm the formation of HMTM crystal which crystallize in the non-centrosymmetric space group Cc with monoclinic crystal system. The N–H⋯O and O–H⋯O intermolecular hydrogen bonding interactions have been investigated by Hirshfeld surface analysis. The optical absorption cut-off wavelength of the grown crystal is observed at 353 nm in the UV–visible spectrum. From the photoluminescence spectrum, two intense emission peaks are identified at 312 nm and 415 nm. Dielectric study reveals low values of dielectric constant and dielectric loss. The positive photoconducting nature of HMTM is identified from the photoconductivity analysis. Second harmonic generation efficiency of the powdered HMTM is found to be 1.25 times greater than that of powdered KDP. The Z-scan and optical limiting results indicate that HMTM exhibits self-defocusing nature and optical limiting response, respectively. In addition, charge transfer interactions, first- and second-order hyperpolarizability values are computed by density functional theory calculations and are discussed in detail.

Crystal configuration, spectroscopic and optical characteristics of Er3+ doped YAlO3 perovskites for advanced photonic appliances

Perovskite structural based Er (III) doped YAlO3 nanophosphors have been synthesized via cost-effective and simplistic urea assisted solution combustion (SC) synthetic route. The resulting products are well characterized by various structural and spectroscopic studies in detailed. Crystal structure has been elucidated by X-ray diffraction (XRD) and Rietveld refinement method. Prepared powdered samples are crystallized in orthorhombic crystal system having space group Pbnm (62). Energy dispersive X-ray (EDX) spectroscopic analysis is performed to evaluate the atomic (%) and weight (%) of constitute elements and their relative distribution through mapping profile. The most intense excitation peak centred at 378 nm is well harmonized with the distinctive wavelength of commercialized NUV based LED chips. Photoluminescence (PL) studies depicted green emissions of doped nanophosphors upon excitation at 378 nm wavelength. The most intense emission peak at 549 nm is accredited to 4S3/2 →4I15/2 electronic transition of the Er3+ ion. Moreover, PL data is exploited to obtain photometric parameters viz. color coordinates (x and y), color purity (%) and correlated color temperature (CCT), which robustly recommended for their usage as NUV based solid-state advance photonic appliances.

Green Up-Conversion Luminescence in Yb/Er Co-Doped AlN Thin Film by RF Magnetron Sputtering

In this research study, aluminum Nitride (AlN) thin film co-doped with erbium and ytterbium has been deposited on Si (100) substrate by RF magnetron Sputtering. After deposition, the film was annealed at 1100 °C in ambient conditions. It’s structural properties were investigated X-ray diffraction (XRD). Thin films morphology is studied using SEM, and EDX provides the chemical composition information. The photoluminescence property of deposited film was investigated by FS5 spectrofluorometer. XRD result revealed that the film has grown along the c-axis oriented in hexagonal wurtzite structure. SEM Result shows that the average size of the particle is 100 nm. The up-conversion luminescence showed intense green and red emission peaks at 530 nm, 552 nm, and 665 nm due to the transition of Er (2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2) with excitation of 984 nm. The excitation wavelength with 483 nm photons produces visible luminescence in the green and red region with 557 and 660 nm due to Erbium.