Suitable Excitation Wavelength Research Articles

Luminescent properties of ZSM-5 zeolite phosphor and its application to aquatic plant lighting and white LEDs

In order to explore ideal materials with suitable excitation wavelengths, high thermal stability and good emission characteristics for phosphor-converted white light emitting diodes (pc-WLEDs), in this work, a blueish-white phosphor (λex = 390 nm) was realized by a new strategy of carbocations formation in ZSM-5 zeolite, which maintains the luminescence intensity at 473 K is 103% of that at room temperature. Following immersion in ethanol, water, 40 wt% sodium hydroxide solution (NaOH), and concentrated hydrochloric acid (HCl) for 120 h, the luminescence intensity was maintained at 92%, 87%, 80%, and 82% of the normal state, respectively. By packaging the sample on a near-ultraviolet (NUV) chip (390 nm), a blueish-white pc-LED was fabricated, which has a promising commercial prospect in the field of aquatic plant lighting. Meanwhile, a pc-WLED device was fabricated by combining a 390 nm NUV chip and ZSM-5 zeolite and red phosphor K2MgGeO4:Eu3+. It has an excellent property with the correlated color temperature (CCT) = 4600 K and color rendering index (CRI) = 91.5, indicating that ZSM-5 zeolite has good application prospects in the pc-WLEDs field.

High-Efficiency Red-Emitting Phosphor of Li0.5La0.5SrMgWO6: Mn4+, Pr3+

The 400–500 nm blue light and 630–750 nm red light play crucial roles in plant cultivation. In this work, a high efficiency red-emitting phosphor, Li0.5La0.5SrMgWO6:Mn4+, Pr3+, was synthesized through the solid-state reaction technique. The absorption and excitation spectra were measured, indicating that 467 nm was an suitable excitation wavelength for this material. Upon excitation with a 467 nm LED, the fluorescence characteristics were evaluated, revealing dual-band red emission peaks located at 621–654 nm and 695–710 nm. The quantum efficiency and pumping slope efficiency were measured to be 63% and 35%, respectively. Based on energy level theory and Tanabe-Sugano theory, the dual-band fluorescence mechanism was analyzed, revealing that cross relaxation phenomenon contributed to the high quantum efficiency. The temperature sensing property was also demonstrated. The relative sensitivity (Sr) exhibited a significant change from 0.05% K−1 to 0.85% K−1 with different temperatures. The phosphor’s high efficiency and exceptional temperature property confer it with extensive potential applications in the fields of plant cultivation and display technology.

Synthesis and Greenish‐Yellow Luminescence Properties of Li6AlGd(BO3)4: Tb3+ Phosphors for Solid State Lighting

The Li6AlGd(1−x)(BO3)4:xTb3+ (0 ≤ x ≤ 4.0 mol%) phosphors are fabricated via solid‐state reaction process. The structural investigations are carried out through powder X‐ray diffraction and Fourier transform infrared techniques. The morphology is examined using high‐resolution scanning electron microscope and transmission electron microscope. The temperature‐dependent luminescence properties are completed at 378 nm excitation. The photoluminescence excitation analysis is carried out by controlling the emission at 545 nm corresponding to Tb3+:5D4 → 7F5 transition. The suitable excitation wavelength is selected as 378 nm for efficient emission by studying the emission spectra at several excitation wavelengths. The emission spectra show two groups of emission bands through Tb3+:5D3 → 7FJ and Tb3+:5D4 → 7FJ transitions. The concentration‐dependent investigations reveal the optimum Tb3+ions concentration as 2.0 mol% for intense luminescence. Upon 378 nm excitation, they produce greenish‐yellow luminescence of color purity 60% with CIE color coordinates (0.286, 0.572) close to the standard European Broadcasting Union Green Illuminant and they found suitability in the design of solid‐state lighting devices.

Dual-functional lanthanide-MOF probe nanocomposite based on hydroxyapatite nanowires as fluorescent sensor for ascorbic acid.

Adual-functional lanthanide-MOF nanocomposite probewas designed and constructed for the detection of ascorbic acid (AA). The magnetically functionalized hydroxyapatite nanowires are selected as the carriers and simultaneously loaded with ciprofloxacin (CIP) and terbium metal organic framework to form the internal reference fluorescence probe nanocomposite (Fe3O4-HAPNWs-Tb/MOF-CIP). This dual-functional lanthanide-MOF probe not only combines the respectively unique fluorescence properties of lanthanide MOFs and CIP, but also takes full advantage of the rapid separation properties of the magnetic component. Structural and spectroscopic characterization results have demonstrated the successful synthesis of probe material and the fluorescence mechanism. At a suitable excitation wavelength (295nm), the probe can simultaneously emit characteristic fluorescence of CIP (445nm) and Tb3+ (543nm). In the presence of AA, the ratio of I543/I445 decreases rapidly with increasing of AA concentration. The linear range of determinationis 0.3-40μM with a detection limit of 20.4nM. Thecontents of AA in vitamin C tablets and four fruit juice samples were detected by the composite probe. The spiked recoveries ranged from 82.6 to 104.2% with relative standard deviations (RSD) less than 2.1%, revealing the practical application value of the developed sensor in healthcare and food fields. A novel internal reference fluorescence sensor (Fe O -HAPNWs-Tb/MOF-CIP) was constructed for detecting ascorbic acid by solvothermal and self-assembly techniques, showing excellent selectivity and sensitivity based on the different responses of Tb/MOF and CIP to the target.

In situ analysis of volatile oil in Angelica sinensis roots by fluorescence imaging combined with mass spectrometry imaging

In this study, the spatial distribution and accumulation dynamics of volatile oil in Angelica sinensis roots was realized by fluorescence imaging combined with mass spectrometry imaging. The laser scanning confocal microscopy was used to determine the optimal excitation wavelength and the fluorescent stability of volatile oil in the sections of Angelica sinensis roots. The results demonstrated that 488 nm was the most suitable excitation wavelength for the identification and quantitative analysis of volatile oil. It was observed that volatile oil accumulated in the oil chamber of the phelloderm and secondary phloem, and the oil canal of the secondary xylem. The results also indicated that there were differences in content during different periods. Furthermore, the MALDI-TOF-MSI technology was used to study the spatial distribution and compare the chemical compositions of different parts of Angelica sinensis roots during the harvest period. A total of 55, 49, 50 and 30 compounds were identified from the head, body, tail of the root and root bark, respectively. The spatial distribution of phthalides, organic acids and other compounds were revealed in Angelica sinensis roots. The method developed in this study could be used for the in situ analysis of volatile oil in Angelica sinensis roots.

Thermal stable cyan-emitting Ba9(Lu1.5Ga0.5)Si6O24:Ce3+ for high color-rendering white LEDs

Cyan-emitting phosphors are key color converters for achieving a high color-rendering index (CRI) in white light-emitting diodes (LEDs). However, cyan phosphors that have a suitable excitation wavelength and high thermal stability are still challenges. In this work, the Ba9Lu1.5Ga0.5Si6O24:Ce3+ (BLGSO:Ce3+) cyan phosphor is studied. The excitation band has a peak at 395 nm, which is close to the emission light from the near-ultraviolet (NUV) LEDs (395-405 nm). BLGSO:Ce3+ manifests an emissive peak at 488 nm and a full-width at half maximum (FWHM) of 125 nm. Its internal quantum efficiency (IQE) reaches 90.7% at room temperature. At 150°C, the cyan emission intensity decreases to 97.2% of the initial value at room temperature, indicating excellent thermal stability. Combining with CaAlSiN3:Eu2+ and the 395 nm chip, a white LED with a high CRI of 91.9 is achieved.

Optical properties of Sr3Gd(PO4)3: Eu3+ phosphors for white LED sources

The SGPEux phosphors of composition Sr3Gd(1–x)(PO4)3:xEu3+ were synthesized by modified citrate-gel combustion method for white LED sources. The optimum conditions of synthesis were obtained from thermogravimetric and differential scanning calorimetry. The synthesized phosphors were crystallized into BCC structure with JCPDS No. 29–1301. The presence of various bonds due to stretching and bending vibrations of different functional groups were studied through Fourier transform infrared spectroscopy. The morphology was examined using high-resolution scanning electron microscopy. The luminescence analysis was carried out through photoluminescence excitation and emission studies. The charge transfer band and f-f transitions of Gd3+ and Eu3+ ions cause a transfer of energy from Gd3+ to Eu3+. A suitable excitation wavelength for efficient luminescence was selected as 273 nm by studying the emission properties at different excitations. The quenching in luminescence noticed beyond 2.0 mol% was assigned to non-radiative transitions at higher Eu3+ concentrations. The analysis of colour perception and colour temperature of emitted luminescence was studied using chromaticity coordinates evaluated from the emission spectra. The observed results suggest that the 2.0 mol% of Eu3+ doped SGPEu phosphor has more proficiency to design new class of w-LED sources.

Unusual temperature-range-tunable fluorescence characteristic of C6-unsubstituted tetrahydro-pyrimidines: Influence factors, sensitivity evaluation and application in different temperature ranges

Fluorescence thermometers have attracted wide interesting owing to their advantages of ultra-high sensitivity, fast response speed, high spatial resolution, safe and non-invasive detection signal etc. However, conventional fluorescence thermometers are sensitive only in a certain range. In 2016, we found that one of C6-unsubstituted tetrahydro-pyrimidines (THPs) that synthesized by an efficient five-multicomponent reaction (5CR) shows unusual temperature-range-tunable (TRT) fluorescence characteristic: showing sensitive fluorescence-color/-on-off changes in different temperature ranges by only changing excitation wavelength. Here, the influences of molecular structures, packing modes and chirality on the TRT fluorescence characteristic of THPs were investigated in detail. In addition, the crucial parameter evaluating the TRT characteristics and the selection of the suitable excitation wavelengths in different T-ranges are explored. The obtained experimental results indicate that: (a) the TRT characteristics of THPs mainly depends on molecular structures rather than their R- and S-enantiomer molecular packing modes; (b) although the pure enantiomeric alignments of THPs significantly decrease their fluorescence quantum yields, they favor the TRT characteristics; (c) the response (Sλrex) of red-edge excitation wavelength (λrex) to temperature is a crucial parameter for evaluating TRT characteristic; (d) the suitable excitation wavelengths for fluorescence measurement in different temperature ranges can be simply identified by the good linear relationship between λrex and temperature; (e) Racemic THP 5c is the most sensitive thermometer in different T-ranges. From 10–430 K (−263 °C−157 °C), 5c could show sensitive fluorescence-on-off change in any narrow T-range (<40 K), such as 10–30 K, 30–60 K … 300–330 K, 400–430 K, by selecting suitable λrex values (the thermo-response sensitivities ranges from 0.83 to 4.20% K−1). The work reported here is expected to promote the development and application of different kinds of fluorescence thermometers with TRT characteristics.

Dendronized Arm Snowflake Polymer as a Highly Branched Scaffold for Cellular Imaging and Delivery.

Incorporation of branched structures is a major pathway to build macromolecules with desired three-dimensional (3D) structures, which are of high importance in the rational design of functional polymeric scaffolds. Dendrimers and hyperbranched polymers have been extensively studied for this purpose, but proper gain-of-function for these structures usually requires large enough molecular weights and a highly branched interior so that a spherical 3D core-shell architecture can be obtained, yet it is generally challenging to achieve precise control over the structure, high molecular weight, and high degree of branching (DoB) simultaneously. In this article, we present a set of snowflake-shaped star polymers with functional cores and dendronized arms, which ensure a high DoB and an overall globular conformation, thus facilitating the introduction of functional moieties onto the easily achieved scaffold without the need for high-generation dendrons. Using a polyglycerol dendron (PGD) as a proof of concept, we propose that this dendronized arm snowflake polymer (DASP) structure can serve as a better performing alternative to high-generation PGDs. DASPs with molecular weights of 750, 1220, 2120, and 3740 kDa were prepared with >85% yields in all cases, and we show that these DASPs have high encapsulating efficiency of Nile Red due to their high DoB and high biocompatibility due to their hydroxyl-rich nature after ketal removal, as well as high cell permeability that is molecular-weight-dependent. Introduced fluorophores such as fluorescein and difluoroboron 1,3-diphenylaminophenyl β-diketonate with suitable excitation wavelengths may turn the DASPs into stable, endosome-staining fluorophores with ultra-large Stokes shifts, narrowed emission bands, and suitability for long-term cellular tracing. Moreover, the scaffold can encapsulate antibiotic molecules and deliver them into phagolysosomes for efficient elimination of intracellular Staphylococcus aureus, which is insensitive toward many antibiotics but is a key target for the clinical success of methicillin-resistant Staphylococcus aureus infection treatment. Elimination of Staphylococcus aureus could be improved to >99.9% for chloramphenicol at 32 μg/mL with 450 μg/mL DASP.

Effective energy transfer from Dy3+ to Tb3+ ions in thermally stable KZABS glasses for intense green emitting device applications

Potassium Zinc Alumino Borosilicate (KZABS) glasses co-doped with Dy3+/Tb3+ ions have been synthesized by employing a sudden melt quenching technique. To check the luminescence behavior, the as prepared glasses were characterized by employing spectroscopic tools like photoluminescence (PL) excitation and emission, temperature dependent PL and PL decay to see the energy transfer between Dy3+ and Tb3+ ions and optimum green emission suitable for photonic applications. The XRD spectra reveals the amorphous nature of the as prepared KZABS glasses. PL spectral features show optimum green emission and confirms energy transfer from Dy3+ to Tb3+ ions. With the help of temperature dependent PL, glasses were found to be thermally stable. The decay profiles recorded show bi-exponential nature and demonstrates the energy transfer that took place from Dy3+ to Tb3+ ions. The Inokuti- Hirayama (I–H) model confirms the interaction involved in energy transfer process as dipole-dipole in nature. The CIE coordinates are found to be shifting gradually towards intense green region with increase in activator concentration (Tb3+) under the optimized sensitizer (Dy3+) concentration. It is also observed that, the CIE coordinates shifting towards intense green region when the as prepared KZABS glasses are excited with suitable excitation wavelengths of both sensitizer and activator. All the studies finally reveal the superiority of Dy3+/Tb3+ co-doped KZABS glasses for their usage in green emitting photonic device applications such as w-LEDs and display devices.

Rare-earth-free Sr2YSb1-xO6:xMn4+: Synthesis, structure, luminescence behavior, thermal stability, and applications

We report the rare-earth-free Sr2YSbO6 (SYS):Mn4+ phosphors with excellent photoluminescence performance for indoor illuminations. The phase structure, elemental composition, luminescence behavior, thermal stability, lifetime, color purity, and quantum yield (QY) were analyzed in detail. The resultant sample showed a broadband excitation wavelength in the range of 250–450 nm, and the optimal doping concentration was 0.5 mol%. Under the suitable excitation wavelength of 307 nm, the SYS:0.005Mn4+ phosphor emitted a deep-red emission with the Commission Internationale de I'Eclairage chromaticity coordinate of (0.708, 0.290) and a high color purity of 93.34%. The emission intensity was found to be about 59.45% at 423 K while the activation energy was 0.28 eV. Moreover, the lifetime and QY of the optimal sample were measured to be 641.58 µs and 38.37%, respectively. Eventually, the white lighting-emitting didoes (LEDs) exhibited a strong white light with good color-rendering index (CRI) and correlated color temperature (CCT) values. Besides that, the novel LED structure based on the SYS:0.005Mn4+-polydimethylsiloxane film could also emit a warm white region while the CRI and CCT values were measured to be about 81.39 and 3091 K.

Iridium(III)porphyrin arrays with tuneable photophysical properties.

The photophysical properties of iridium(III) porphyrins complexes with two different axial ligands (Cl(CO) and bipyridine (bpy)) in solution and in cellulose acetate polymer matrix were investigated. The axial ligands substitution was made aiming to evaluate the photophysical properties and the solubility in different solvents. Therefore, dissimilar from the free porphyrin, non-polar solvents (as toluene) favours the quantum yield of iridium(III)porphyrins and ligands with a more extended π-conjugated compound as bpy results in higher yields. Moreover, despite all the porphyrins reveals a negative solvatochromism, the substitution of Cl(CO) ligand by bpy ligand exhibits similar solubility either on non-polar or polar solvents. The observed photoluminescence (PL) at room temperature appears at NIR region in contrast to the previously reported iridium(III) porphyrins. Comparing with free porphyrin H2TTP, the red/NIR PL spectra of the iridium(III)porphyrins (either in solution and in the polymer matrix) reveals remarkable changes. Particularly, a more significative decrease of the red/NIR intensity ratio was detected for [Ir(ttp)(bpy)2] 2 where the maxima of the NIR emission can be adjusted under suitable excitation wavelength.

Tunable emission and energy-transfer mechanism of single-phase Na3Y(PO4)2:Ce3+, Mn2+phosphors for white LEDs

A series of color-tunable single-phase Na3Y(PO4)2:Ce3+, Mn2+ (NYPO:Ce,Mn) phosphors were synthesized by means of solid-state reaction method for white light-emitting diodes. First, the concentration of Ce (x = 0.07) in the NYPO phosphors was optimized according to the photoluminescence (PL) properties, and then the optimized NYPO:0.07Ce phosphor was selected to study the single-phase phosphor with various concentrations of the Mn (y = 0.01, 0.03, 0.05, 0.07) co-dopant. The physicochemical characterization of both the doped and co-doped samples was performed via X-ray powder diffraction, infrared spectroscopy, and X-ray photoelectron spectroscopy. Further, for the investigation of the PL properties, emission spectra of both doped and codoped samples were recorded upon 375 nm excitation, and spectra of NYPO:Ce exhibited two distinct peaks around 424 nm (blue emission) and 527 nm (green emission) due to the 5d1 to 4f transitions of Ce3+ ions, while the co-doped NYPO:Ce, Mn phosphors exhibited three peaks, two of them are at 414 and 515 nm (blue and green emission, respectively) due to the 5d1–2f7/2,5/2 transitions of Ce3+ ions and third peak is closer to the red range (620 nm) due to the 4T1(4G)- 6A1(6S) transitions of Mn2+ in the visible spectrum. NYPO:0.07Ce, 0.05Mn emits the combination of the three emission peaks (blue, green, and red) resulted in bright white light with CIE chromaticity coordinates of (0.322, 0.317), CCT (6036 K), and CRI (93), at a suitable excitation wavelength of 375 nm. The emission due to the addition of rare-earth Ce3+ ions and metal activator Mn2+ ions to the NYPO proves that it may be potential phosphor for obtaining white-light emission and tunable luminescence.

Fiber-Enhanced Raman Sensing of Cefuroxime in Human Urine.

Fiber-enhanced Raman spectroscopy was developed for the chemically selective and sensitive quantification of the important antibiotic cefuroxime in human urine. A novel optical sensor fiber was drawn and precisely prepared. In this fiber structure, light is strongly confined in the selectively filled liquid core, and the Raman scattered signal is collected with unprecedented efficiency over an extended interaction length. The filling, emptying, and robustness are highly improved due to the large core size (>30 μm). Broadband step-index guidance allows the free choice of the most suitable excitation wavelength in complex body fluids. The limit of detection of cefuroxime in human urine was improved by 2 orders of magnitude (to μM level). The quantification of cefuroxime was achieved in urine after oral administration. This method has great potential for the point-of-care monitoring of antibiotics concentrations and is an important step forward to enable clinicians to rapidly adjust doses.

Excitation wavelength selection for quantitative analysis of carotenoids in tomatoes using Raman spectroscopy

The difference in Raman spectra for different excitation wavelengths (532 nm, 785 nm, and 1064 nm) was investigated to identify an appropriate wavelength for the quantitative analysis of carotenoids in tomatoes. For the 532 nm-excited Raman spectra, the intensity of the peak assigned to the carotenoid has no correlation with carotenoid concentration, and the peak shift reflects carotenoid composition changing from lycopene to β-carotene and lutein. Thus, 532 nm-excited Raman spectra are useful for the qualitative analysis of carotenoids. For the 785 nm- and 1064 nm-excited Raman spectra, the peak intensity of the carotenoid showed good correlation with carotenoid concentration; thus, regression models for carotenoid concentration were developed using these Raman spectra and partial least squares regression. A regression model designed using the 785 nm-excited Raman spectra showed a better result than the 532 nm- and 1064 nm-excited Raman spectra. Therefore, it can be concluded that 785 nm is the most suitable excitation wavelength for the quantitative analysis of carotenoid concentration in tomatoes.

Fluorescence analysis of natural dyes from Plumeria rubra (red and white) flowers

Eco-friendly aqueous dye is extracted from the flowers of Plumeria rubra (red and white). Absorption, luminescence and fluorescence spectroscopic properties of the extracted dyes are analyzed by respective spectroscopic techniques. Fluorescence quantum yields, Stoke’s shift, fluorescence life time, radiative and non-radiative rate constants are discussed with various excitation wavelengths in the range of 200–420 nm. Hence, a suitable excitation wavelength of the extracted dye is found to be in the range of 300–370 nm and the dye shows strong fluorescence in this range. Radiative and non-radiative rate constants and fluorescence life time results elucidate the effective fluorescence properties of the extracted dyes. It can be used as a potentially durable natural dye for fluorescence related applications.

Niobium-oxygen octahedra and oxygen interstitial defect emissions in calcium niobate matrix and its color manipulation via doping Pr3+

The luminescent properties of Ca2Nb2O7 matrix and Ca2Nb2O7: Pr3+ were studied in this work. In addition to the emission band from NbO6 octahedra, the orange-red emission aroused by oxygen interstitial defects was observed in Ca2Nb2O7. When Pr3+ was introduced, both of the matrix emission and the characteristic Pr3+ luminescence could appear simultaneously under suitable excitation wavelength. By further adjusting the doping concentration, color manipulation from blue-green to pink and red could be realized in Ca2Nb2O7: Pr3+. In particular, a warm white light could be achieved when doping 0.1% Pr3+. Based on the luminescent results, the underlying mechanisms were discussed and proposed. The color manipulation results suggest that Ca2Nb2O7: Pr3+ is promising for various fields related to lighting, displaying, and imaging.

Lanthanide functionalized hybrid materials of polyoxometallate based metal–organic frameworks for multi-color luminescence

Lanthanide functionalized hybrids of polyoxometallate based MOF Ln3+⊂COK-15 are prepared and display multi-color light, together with a white luminescence (x = 0.3845, y = 0.303) by tuning an appropriate amount of Eu3+ and a suitable excitation wavelength.

Optical methodology for process monitoring of chalcopyrite photovoltaic technologies: Application to low cost Cu(In,Ga)(S,Se)2 electrodeposition based processes

Non-destructive characterization of both single layers and completed devices are important issues for the development of efficient and low cost Cu(In,Ga)(S,Se)2 (CIGS) modules at high yields. This implies for the need of methodologies suitable for the assessment of optical, electrical, and physico-chemical parameters that are relevant for the final device efficiency and that can be used for quality control and process monitoring at different process steps. In these applications, detection of in-homogeneities in the different layers from large area modules is especially relevant, being the presence of these inhomogeneities responsible for the existing gap between the efficiencies achieved in these technologies at cell and module levels. In this context, this work reviews the different optical methodologies that have been developed in the framework of the SCALENANO European project for the advanced assessment of the different layers in high efficiency electrodeposited – based CIGS devices. This has includes different strategies as those based on Raman scattering, Photoluminescence/Electroluminescence (PL/EL) based techniques and new photoelectrochemical based tools and firstly Raman spectroscopy is very sensitive to both composition and crystal quality parameters that are determining for device efficiency. Use of resonant Raman excitation strategies allows achieving a high sensitivity of the Raman spectra to the analysed features in the different regions of the device. This involves selection of the suitable excitation wavelength (in the broad spectral region from UV to IR) for the resonant Raman excitation of the required layer in the device. The strong increase in the intensity of the Raman peaks related to the use of resonant excitation conditions allows also decreasing the measuring time to times compatible with the implementation of these techniques at online process monitoring level. Analysed parameters include the electrical conductivity of the Al-doped ZnO window layer, the thickness of the CdS buffer layer and the chemical composition (S/(S+Se) relative content) and presence of relevant secondary phases as Cu-poor ordered vacancy compounds in the surface region of the absorbers. In addition PL/EL imaging are powerful techniques that provide direct access to the optoelectronic properties of the materials and devices. Whereas EL is performed using complete devices by injecting current in analogy to the operation of a light emitting diode, PL allows the characterization of bare absorber materials without the need for any functional or contacting layers. Moreover, semiconductor photo-electrochemistry (PEC) is a versatile technique that enables many opto-electronic properties of semiconductors to be determined. Essentially, a semiconductor on a conducting substrate placed in a solution containing redox species forms a Schottky barrier junction. The formation of such a diode enables basic semiconductor properties to be measured such as doping type, doping density, band gap and the flat band position versus the vacuum energy scale. In all these cases, quality control indicators suitable for the advanced assessment of these processes have been identified and validated for the electrodeposition-based processes developed at Nexcis Company.

Excitation wavelength dependent luminescence properties for Eu3+-activated Ba2Gd2Si4O13 phosphor

The tunable spectroscopy properties of Eu3+-activated Ba2Gd2Si4O13 phosphors under different wavelengths from vacuum ultraviolet (VUV) to ultraviolet region have been demonstrated. From the emission spectra, a broad band centered at 410 nm can be observed by choosing the suitable excitation wavelength, which is determined to be the defects produced under high temperature. Based on the result, the phosphor shows a tunable emission depending on the excitation source and the concentration of Eu3+. In addition, the VUV photoluminescence property of a series of Ba2Gd2Si4O13:Eu3+ indicates that the optimal sample is Ba2Gd1.9Si4O13:5 %Eu3+ whose emitting color and decay time is beneficial for the application compared to the value for the commercial red-emitting phosphor.