Orange-red Light Research Articles

Influence of Rare Earth Ions (REIs) on the Visible Emission of Magnesium Sodium Borate Glasses

Borate glass systems have been extensively studied for practical applications in optical display devices by virtue of their peculiar luminescence efficiency. However, the attainment of high emission from borate glass materials via apposite control of rare earth ions (REIs) contents remains a topical issue in Material Physics. In this paper, we report the influence of REIs (Dy3+, Eu3+, and Sm3+) on multiple-colour emission of magnesium sodium borate (MSB) glasses fabricated by using the conventional melt-quenching method. These glasses were optically characterized via X-ray Diffraction (XRD), UV-VIS-NIR and Photoluminescence techniques. The XRD pattern confirms the amorphous nature of the as-prepared glasses. The absorption spectra disclosed several absorption bands at 347 nm (6H15/2 → 6P7/2) for Dy3+, 393 nm (7F0 →5L6) for Eu3+ and 403 nm (6H5/2 →6P5/2) assigned for Sm3+ respectively. Also, the emission spectra radiate at 463 nm (4F9/2 → 6F11/2 + 6H9/2), 612 nm (5D0 → 7FJ) and 599 nm (4G5/2 → 6H7/2) for Dy3+, Eu3+, and Sm3+ correspondingly, wherein Dy3+ emits blue, yellow, and red light, Eu3+ emits red light and Sm3+ emits reddish-orange light. Finally, 1.0 mol% content of Dy3+, Eu3+, and Sm3+ in MSB glasses was found to be optimal and hence considered the best optical host for colour display devices.

Intense photoluminescence in CaTiO3:Sm3+ phosphors, effect of co-doping singly, doubly and triply ionized elements and their applications in LEDs.

In this work, Sm3+-doped and Sm3+/Li+/K+/Mg2+/Ba2+/Gd3+/Bi3+ co-doped CaTiO3 phosphors were synthesized by a solid-state reaction method at 1473 K. The phase of phosphors was identified to be orthorhombic with space group Pnma (62) by XRD measurements. The morphological properties of the prepared samples were studied by SEM measurements. The average crystallite and particle sizes were found to increase in the presence of modifiers and they follow the trend Li+ > Mg2+ > Gd3+ > K+ > Bi3+ > Ba2+. EDX measurements were used to verify the presence of Ca, Ti, O, Sm, K, Mg, Ba, Gd and Bi atoms in the prepared phosphor samples. The Sm3+ ion shows emission peaks at 564, 599 and 646 nm due to 4G5/2 → 6H5/2, 6H7/2 and 6H9/2 transitions upon 407 nm excitation, among which the peak situated at 599 nm has maximum emission intensity. Concentration quenching was observed above 2 mol% of Sm3+ ions in this host. However, the emission intensity of Sm3+ peaks can be enhanced using different modifier (Li+/K+/Mg2+/Ba2+/Gd3+/Bi3+) ions. It was found that the size (ionic radii) and charge compensation of the ion together play a dominant role. The enhancement is more after co-doping with smaller radius ions (Li+, Mg2+ and Gd3+), among which Li+ shows the largest enhancement. This is because ions of smaller size will be able to go closer to the activator ion and the charge imbalance causes a larger field. The CIE color coordinates, correlated color temperature (CCT) and color purity of the phosphors were calculated and show orange-red color emissions with a maximum color purity of ∼93% in the case of CaTiO3:2Sm3+/1.0Li+ phosphor. The lifetime value is increased in the presence of these ions. It is again maximum for the Li+ co-doped CaTiO3:2Sm3+ phosphor sample. Thus, the prepared phosphor samples are suitable sources for orange-red light.

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.

Copolymers of 4-Trimethylsilyl Diphenyl Acetylene and 1-Trimethylsilyl-1-Propyne: Polymer Synthesis and Luminescent Property Adjustment

Poly(4-trimethylsilyl diphenyl acetylene) (PTMSDPA) has strong fluorescence emission, but its application is limited by the effect of aggregation-caused quenching (ACQ). Copolymerization is a commonly used method to adjust the properties of polymers. Through the copolymerization of 4-trimethylsilyl diphenyl acetylene and 1-trimethylsilyl-1-propyne (TMSP), we successfully realized the conversion of PTMSDPA from ACQ to aggregation-induced emission (AIE) and aggregation-induced emission enhancement (AEE). By controlling the monomer feeding ratio and with the increase of the content of TMSDPA inserted into the copolymer, the emission peak was red-shifted, and a series of copolymers of poly(TMSDPA-co-TMSP) that emit blue-purple to orange-red light was obtained, and the feasibility of the application in explosive detection was verified. With picric acid (PA) as a model explosive, a super-quenching process has been observed, and the quenching constant (KSV) calculated from the Stern-Volmer equation is 24,000 M-1, which means that the polymer is potentially used for explosive detection.

Structural and luminescent characteristics of orthorhombic GdAlO3:Sm3+ nanocrystalline materials for solid state lighting

In the current article, an eco-friendly, efficient and less energy consuming gel-combustion process has been used to develop a series of perovskite based Gd1-xAlO3:xSm3+ (x = 0.01, 0.03, 0.05, 0.07 and 0.09 mol) nanomaterials which produce reddish orange light. According to crystallographic investigation, the synthesized nanocrystalline materials belong to orthorhombic crystal symmetry having space group Pnma (62). The non-uniform agglomerated particles in nano range (35–45 nm) were examined via TEM analysis, which supports the results obtained from XRD analysis. The PL spectra involve 4f-transitions of trivalent samarium ions, such as 4G5/2→ 6H5/2 (565 nm), 4G5/2→ 6H7/2 (601 nm) and 4G5/2 → 6H9/2 (647 nm). The energy transferal mechanism between neighbouring trivalent samarium ions is dipole–dipole (DD) interaction, which is answerable for the quenching of luminous intensity. Additionally, colorimetric characteristics like color coordinates, color-purity and correlated-color temperature were obtained using PL data. These photometric parameters were strongly recommends these synthesized nanophosphors samples for solid state lighting applications.

Preparation and luminescence properties of Ba3P4O13:Sm3+ orange-red phosphors with high thermal stability

In this work, a series of Ba3P4O13:Sm3+ phosphors are prepared via calcining the precursor synthesized by a chemical co-precipitation method, meanwhile, the phase and fluorescence properties are characterized as required. The results demonstrate that the phosphors emit orange-red light with several emission peaks centering at 564 nm, 600 nm and 648 nm under ultraviolet (UV) excitation, which originate from the transition of 4G5/2 to 6H5/2 (or 6H7/2,6H9/2) energy level in Sm3+. Among them, Ba2.98P4O13:0.02Sm3+ phosphor exhibit the strongest emission intensity, and then concentration quenching occurs due to the d-d interaction once the concentration of Sm3+ ions exceeded 0.02. Even so, the color coordinates of all BaP4O13:Sm3+ samples are calculated to be close to (0.58, 0.41), implying a high color purity. Significantly, the charge compensation of alkali metal ions, especially for K+ ion, enhances the emission intensity, thermal stability and fluorescence lifetime of the phosphors remarkably, even zero thermal quenching is observed in the range of 25–250 °C.

Synthesis, photoluminescent properties, and an insight into the Judd-Ofelt analysis of the NaPbBi(2-x)(PO4)3: xEu3+ orthophosphate phosphors for light applications

A set of novel reddish orange light emitting NaPbBi2(PO4)3: xEu3+ (hereafter referred to as NPbBP) phosphate phosphors were synthesized by the conventional solid state reaction route. The phase formation, particle morphology, elemental composition and the optical properties of the prepared phosphors were studied in detail from the powder XRD data, SEM images, EDS analysis, and the diffuse reflectance spectroscopy measurements respectively. The photoluminescence properties were systematically studied by recording the excitation and emission spectra of the prepared phosphors. The NPbBP: xEu3+ phosphors, excited at the near ultraviolet light, exhibited the reddish orange light emission in the visible region due to the dominance of magnetic dipole transition of the Eu3+ ions in the host. The details of the radiative properties were analyzed through the Judd- Ofelt intensity parameters, which were found to follow the trend of Ω2< Ω4. The thermal stability and the life time of the phosphors were investigated. The calculated photometric parameters of the NPbBP: 0.09Eu3+ phosphor suggested that the emission was found in the reddish-orange region with a high color purity and high quantum yield of 99.53% and 79.7% respectively. These results showed that the NPbBP: Eu3+ phosphor could serve as a good phosphor for use in various optoelectronic devices such as phosphor converted WLEDs, solar cells, and display panels.

Preparation and photoluminescence performance of BaMoO4:Sm3+ orange–red phosphor

In the present paper, orange–red BaMoO4:Sm3+ phosphor was synthesized by high-temperature solid-phase method. The morphology, elemental composition, crystal structure, photoluminescence performance, and charge compensation mechanism of BaMoO4:Sm3+ were investigated. Results indicated that the BaMoO4:Sm3+ phosphor particles were spherical-like in shape with approximate particle size of 2 μm and contained Ba, Mo, O, and Sm elements. The Rietveld-refinement of X-ray diffraction profile of BaMoO4:Sm3+ was consistent with a tetragonal lattice. Under 404 nm excitation of light, BaMoO4:Sm3+ phosphor showed the strongest emission peak at 649 nm and emitted an orange–red light. When the orange–red phosphor was packaged with a 395 nm UV chip and tested, the color coordinates were (0.3109, 0.3626) under a current of 60 mA, the color rendering index Ra = 81.5, and the color temperature was 6385 K. These results indicated that BaMoO4:Sm3+ red phosphor is suitable as a red light component in WLEDs and has potential practical applications.

Synthesis, adjustable-color emission and energy transfer of Ba2MgSi2O7:Sm3+, Bi3+ phosphors

Ba2MgSi2O7:M (M = Bi3+, Sm3+, Sm3+/Bi3+) phosphors are synthesized in air by the high-temperature solid-state reaction method. All samples are confirmed to be a pure phase. With a 316 nm excitation wavelength, Ba2MgSi2O7:Bi3+ shows blue-white emission including a broad emission band in the range of 340 - 750 nm, and Ba2MgSi2O7:Sm3+, Bi3+ emits a adjustable-color light with the change of the ratio of Sm3+ to Bi3+ ions. Under excited at 402 nm, Ba2MgSi2O7:Sm3+ and Ba2MgSi2O7:Sm3+, Bi3+ emit orange-red light with emission spectrum region from 545 nm to 750 nm, which contain four emission bands peaking at ∼560, 598, 646 and 704 nm due to the 4G5/2 → 6H5/2, 6H7/2, 6H9/2, and 6H11/2 transitions of Sm3+ ion, respectively. Ba2MgSi2O7:Sm3+, Bi3+ under excitation at 316 nm can show a white-color emission by changing the ratio between Sm3+ and Bi3+ ions. Lifetimes of samples decrease with increasing doped ion (Sm3+ or Bi3+) concentration. We explain the luminous mechanism of samples by the schematic energy level diagrams of Bi3+ and Sm3+ ions in Ba2MgSi2O7:Sm3+, Bi3+.

Effects of Light Conversion Film on the Growth of Leafy Vegetables in Facilities under Haze Weather

The light intensity is low in haze weather, and the facility is in a weak light environment for a long time. As a functional film, light conversion film (LCF) can improve the light conversion performance and is conducive to regulating the environment in the facility to promote crop growth. It can be seen from the test that the light transmittance of LCF under visible light conditions (400–780 nm) is 8.67% higher than that of ordinary film (OF), with stronger light transmittance. In the red–orange light band (600–700 nm), the LCF is 1.3% higher than that of the OF. Through the detection of irradiance, it was found that the irradiance was outdoor environment &gt; LCF &gt; OF in any weather. A two-year greenhouse experiment was conducted to study the effect of LCF on the whole growth process of facility agriculture (environment-soil-crop) under weak light. It is found that LCF reduces the air humidity by 0.47~2.83%; it has an obvious warming effect on the surface soil of greenhouse, and it is linearly correlated with temperature. In terms of crop growth, LCF significantly (p &lt; 0.05) increased the photosynthetic rate at heading stage, and finally increased the yield, total soluble sugar and reduction-type Vitamin C by 8.97–39.53%, 9.22–30.14%, and 1.41–21.09%, respectively. In addition, considering the frequent haze weather in North China, the use of LCF can improve air temperature, CO2 concentration, photosynthetically active radiation (PAR), and soil temperature, and it can effectively deal with the challenge of weak light. In conclusion, LCF can improve the facility environment and improve crop yield and quality, indicating that the implementation of LCF has potential benefits in solving crop yield reduction and quality decline in haze weather. In addition, as the main component of LCF, rare earth materials are a new type of clean energy, which can effectively promote the sustainable development of the agricultural ecosystem.

Structural and luminescence characterization of thermally stable orange-red emitting LiSrP3O9:Sm3+ phosphor to fill the amber gap in WLEDs

Orange-red light emitting LiSr(1-x)P3O9:xSm3+ phosphors were successfully prepared by the Solution combustion method. The Powder X-ray Diffraction analysis confirmed a single phase for the samples with a crystallite size ranging from 66 ± 0.9 nm to 72 ± 0.5 nm. The photoluminescence (PL) spectra revealed that at 398 nm excitation, the LiSrP3O9:Sm3+ phosphors could be easily excited and displayed a bright orange-red emission which attributes to 4G5/2 → 6H7/2 transition of dopant (Sm3+) ion. At 398 nm excitation, the optimum PL intensity was obtained for the 2 mol% Sm3+ ion-doped sample. The lifetime decay measurements showed that the lifespan decreased steadily from 3.48311 to 2.98869 ms with an increase in the Sm3+ ion concentration. Commission International de l'Eclairage coordinates (0.58, 0.42), which correspond to a strong orange red emission situated in the amber gap, colour purity (97.73%), and colour correlated temperature (1666 K) demonstrated excellent luminescent performance. To assess the thermal stability of the phosphor, the thermal quenching behavior of its PL emission was investigated. These results indicate that the LiSrP3O9:Sm3+ phosphor might be a viable option for filling the amber gap in light-emitting diodes.

Abnormal thermal quenching and optical performance of new niobate perovskite Sr3LaNb3O12:Sm3+ phosphors for w-LEDs

Novel orange-red Sr3LaNb3O12 (SLNO):xSm3+ (0.01 ≤ x ≤ 0.03) phosphors are successfully prepared using the traditional solid-state method. The feasibility that the SLNO compounds can act as an appropriate host has been effectively demonstrated by unit cell structure and bandgap structure. The phase purity, particle size distribution, and elemental composition of SLNO:Sm3+ phosphors are studied. The luminescence properties, concentration-quenching mechanism, color purity, thermostability, CIE chromaticity coordinates, and correlated color temperature (CCT) of the obtained SLNO:Sm3+ products are also discussed. Under 408 nm excitation, SLNO:0.10Sm3+ sample emits a bright orange-red light at 598 nm owing to the 4G5/2 to 6H7/2 transition of Sm3+. The concentration-quenching mechanism is found to be dipole-dipole interaction by the calculated Rc value (17.12 Å) and Dexter's theory. Impressively, the color purity of the phosphors is high and stable (all reach 99.9%), which is rarely affected by the Sm3+ doping concentration. It is worth noting that the obtained phosphors exhibit an abnormal thermal quenching (ATQ) behavior, increasing by 16.12% from 300 to 380 K (SLNO:0.10Sm3+). The CIE x and y chromaticity coordinates vary slightly with the change of temperature, indicating a good thermostability. The mechanism of ATQ has been studied as the lattice defects, and the thermal activation energy is calculated to be 0.51 eV. Ultimately, a white-light-emitting diode (w-LED) with a high color rendering index (Ra) of 88 and a CIE chromaticity coordinate of (0.333, 0.333) has been prepared. The results above reveal the potential of SLNO:Sm3+ to be widely used in w-LEDs.

Photoluminescence and Judd-Ofelt analysis of Eu3+ doped akermanite silicate phosphors for solid state lighting

After aluminates, alkaline-earth silicates are the most researched category of luminescent inorganic phosphors. Eu3+ doped Ca2MgSi2O7 and Sr2MgSi2O7 phosphors synthesized by the combustion process. For the as-prepared phosphors, XRD and Rietveld refinement revealed a single phase with akermanite type structure belonging to tetragonal crystallography. UV–Vis spectroscopy was used to calculate the optical bandgap. Ca2MgSi2O7:x%Eu and Sr2MgSi2O7:x%Eu (x = 0.5 - 2.5) phosphors produced orange-red light with emission peaks at 590 nm, 614 nm, and 702 nm, which corresponded to the Eu3+ transitions 5D0 → 7F1, 5D0 → 7F2, and 5D0 → 7F4, respectively. Using a modified Judd-Ofelt technique based on the emission spectrum, the key spectroscopic properties (transition probabilities, radiative lifetimes, and branching ratios) associated with the 5D0 orange-red emitting level were found. Ω2 < Ω4 reveals that Eu3+ ions occupy high symmetry locations in the generated sample under the doping level studied in this work. There has also been a decrease in the Ω4 parameter. It implies that the 5D0 → 7F2 transition is more efficient than the 5D0 → 7F4. This indicates that the red color emission has been improved. The estimated CIE coordinates corroborated the PL emission in the orange-red region.

Neodymium europium oxynitridosilicates of β-K2SO4 type: Structural, magnetic and red luminescence properties

Rare earth activated nitridosilicates have important applications as phosphor components in white light emitting diodes. (Oxy)nitridosilicates with β-K2SO4 structure doped with Eu2+ are luminescent materials with emission wavelengths ranging from green to red under excitation with blue-UV light. Here we report the synthesis of isostructural NdEuSiO3N and the new oxynitridosilicate NdSrSiO3N by solid state reaction between Nd2O3, NdN, Eu2O3 or SrO and Si3N4 under N2/H2 gas at temperatures of 1300 ​°C and 1500 ​°C respectively. These compounds are the limiting compositions of the solid solution NdSr1-xEuxO3N crystallizing in the space group Pmnb with cell parameters a ​= ​5.62293(1), b ​= ​7.02285(1), c ​= ​9.64784(2) Å for NdEuSiO3N, and a ​= ​5.63074(9), b ​= ​7.01658(10), c ​= ​9.65765(15) Å for NdSrSiO3N. The Nd3+and Eu2+ cations in NdEuSiO3N or Nd3+ and Sr2+ in NdSrSiO3N show partial order in the two available crystallographic sites of coordination numbers 10 (M1) and 9 (M2), with strongly preferred occupancy of the larger divalent cations Eu2+ (77%) and Sr2+ (78%) for the M1 site, whereas the M2 site is preferred by Nd3+. Magnetic susceptibility measurements down to 2 ​K show that NdEuSiO3N is ferromagnetic with Tc ​= ​3 ​K, in contrast to NdSrSiO3N that shows antiferromagnetic interactions at low temperatures. The band gaps of NdEuSiO3N and NdSrSiO3N determined from diffuse reflection spectroscopy are 2.37 and 3.72 ​eV respectively. NdEuSiO3N and the members of the solid solution NdSr0.98Eu0.02SiO3N and NdSr0.5Eu0.5SiO3N are orange-red light emitting luminescent materials, showing a broad emission band centered between 605 and 639 ​nm under excitation at 405 ​nm. These compounds are new phosphor materials with emission wavelengths shifted to the red with respect to the isostructural oxysilicates, which is induced by the introduction of nitride.

Tunable photoluminescence of LiNbO3: RE3+ (RE3+ = Dy3+, Sm3+, Dy3+/Sm3+) single-phase phosphors for warm white LEDs

LiNbO3 single-phase phosphors with varying single-doping and co-doping contents of Dy3+ and Sm3+ ions were fabricated via the solid phase reaction. All the X-ray diffractions of these samples revealed that they belonged to the single-phase trigonal structure of LiNbO3. LiNbO3: Dy3+ phosphors could have a neutral white light at 392 nm excitation owing to two strong emission bands (at 488 and 585 nm). Upon the excitation of 412 nm, LiNbO3: Sm3+ phosphors produced orange-red light which attributed to the biggest emission of Sm3+ at 613 nm. The most appropriate doping content of Dy3+ and Sm3+ and the concentration quenching mechanism were also examined. The PL spectra of Dy3+ matched well with the PLE spectra of Sm3+, implying that the energy might be delivered from Dy3+ to Sm3+. At 392 nm excitation, Dy3+ and Sm3+ co-doping LiNbO3 phosphors showed tunable photoluminescence from ordinary to warm white light when doped with more Sm3+ ions. The process of Dy3+ passing on the energy to Sm3+ was validated through the PL spectra of LiNbO3: Dy3+/Sm3+ phosphors. The decay lifetimes also affirmed the energy transfer process. Moreover, Li0.97NbO3: 0.02Dy3+/0.01Sm3+ phosphors exhibited admirable thermal property with the activation energy 0.15 eV. Hence, the results strongly suggested that LiNbO3: Dy3+/Sm3+ phosphors could be applied to fabricate warm white LEDs.

Li6AlGd(BO3)4: Sm3+ phosphors for orange-red light sources

A new class of Li6AlGd(BO3)4: Sm3+ phosphors were prepared via solid-state-reaction method and analyzed for orange-red light sources. The structure, morphology, distribution of particles, presence of various bonds responsible for optical properties, energy-transfer among the excited Sm3+ ions and decay properties were broadly studied. Most of the intense and sharp excitation transitions of Sm3+ in LAGBSmx phosphors appear in n-UV region and the emission spectra reveal 4G5/2 → 6H5/2, 7/2, 9/2, 11/2 transitions upon 408 nm n-UV wavelength excitation. The concentration was optimized to be 1.0 mol% for efficient orange-red emission. The CIE colour coordinates were obtained as (0.611, 0.388) for LAGBSmx phosphors with a negligible change with variation in concentration of Sm3+ ions. The decay profiles were well fitted to double-exponential function showing the occupation of Sm3+ in two different sites. The transfer of energy among the excited Sm3+ ions was possible through exchange interaction at higher concentrations. The emission of orange-red light shows its proficiency for solid-state lighting devices as well as red light source replacement in the design of white-LEDs.

Green fluorescent protein-like pigments optimise the internal light environment in symbiotic reef-building corals.

Pigments homologous to the green fluorescent protein (GFP) have been proposed to fine-tune the internal light microclimate of corals, facilitating photoacclimation of photosynthetic coral symbionts (Symbiodiniaceae) to life in different reef habitats and environmental conditions. However, direct measurements of the in vivo light conditions inside the coral tissue supporting this conclusion are lacking. Here, we quantified the intra-tissue spectral light environment of corals expressing GFP-like proteins from widely different light regimes. We focus on: (1) photoconvertible red fluorescent proteins (pcRFPs), thought to enhance photosynthesis in mesophotic habitats via wavelength conversion, and (2) chromoproteins (CPs), which provide photoprotection to the symbionts in shallow water via light absorption. Optical microsensor measurements indicated that both pigment groups strongly alter the coral intra-tissue light environment. Estimates derived from light spectra measured in pcRFP-containing corals showed that fluorescence emission can contribute to >50% of orange-red light available to the photosynthetic symbionts at mesophotic depths. We further show that upregulation of pink CPs in shallow-water corals during bleaching leads to a reduction of orange light by 10-20% compared to low-CP tissue. Thus, screening by CPs has an important role in mitigating the light-enhancing effect of coral tissue scattering and skeletal reflection during bleaching. Our results provide the first experimental quantification of the importance of GFP-like proteins in fine-tuning the light microclimate of corals during photoacclimation.

Investigation of spectroscopic properties of Sm3+ doped phosphate glasses for reddish orange light applications

Samples of phosphate glasses with composition of (40-x) P2O5-40Na2O-20ZnO-xSm2O3, with Sm3+ ion concentration varying from 0.1 to 2.5%, were synthesized using melt quenching technique and characterized by X-Rays Diffraction, UV–Vis and luminescence spectroscopies. Using Judd-Ofelt analysis, the parameters Ω2, Ω4 and Ω6 of Sm3+ (4f7) were determined. Three transitions of Sm3+: 4G5/2→ 6H5/2, 6H7/2, 6H9/2 were observed from the luminescence spectra. The radiative (τr) and the measured (τmea) lifetimes for 4G5/2 level, were discussed and compared with other works. The quantum efficiency (η) is found to be higher for × = 0.5 mol % of Sm2O3. The CIE chromaticity coordinates were calculated, and it was found that PSm glasses can be suitable for the development of visible lasers in the orange red spectral region.

Spectrum Acquisition System Using Photoelectric Detection and Its Data Mining Simulation of Spectral Texture Features

Weak spectral signal detection technology is a new subject in the measurement engineering field. It obtains the characteristic information of the measured object based on the characteristics of light diffraction, interference, polarization and so on. Regarding light source entropy, the artificial light source of mercury argon lamp with a spectrum of 250 nm~918 nm is selected as the first research object. The grating monochromator with built-in grating scale lines (1200 g/mm, 600 g/mm) is selected as the light splitting device. Due to the weak spectral signal, the output signal is vulnerable to noise interference after a certain amount of photoelectric conversion. AD202 variable voltage coupling filtering technology is adopted. It means that in the signal isolation and amplification process, the AD202 variable voltage coupled filter amplifier chip is employed to design the current/voltage conversion circuit and the same direction proportional operation amplifier circuit. Meanwhile, a second-order low-pass filter circuit is designed based on the characteristics of the OP07 operational amplifier. For the data mining of multispectral image texture features, Contourlet transform is used, that is, the multispectral image texture features are fuzzy preprocessed to remove the adjacent range correlation knowledge. On this basis, the texture features of multispectral images are analyzed. In the experiment, Contourlet transform is adopted to transform multispectral images from spatial domain to frequency domain, which has the advantages of short extraction time, low cost, and high mining accuracy. A spectrum acquisition system based on photoelectric detection is designed. With chlorophyll as the research object, the sample solution to be tested has high photoelectric absorbance in the range of blue-violet light (400 nm~500 nm) and red-orange light (600 nm~700 nm).

Synthesis and characterization of Sm3+ doped BaO-ZnO-LiF-B2O3 glass system for reddish-orange light generation with high color purity

Sm3+ containing BaO-ZnO-LiF-B2O3 glass system by a melt-quenching procedure was synthesized and the structural, thermal, dielectric, optical, and radiative properties were studied. The creation of Non-Bridging Oxygens (NBOs) with Sm3+ doping was manifested from Fourier Transform Infrared (FTIR) spectroscopy by the decrement of the relative area of component peaks associated with the [BO4] units and simultaneous increment of the relative area linked with the [BO3] units. The glass transition temperature was identified by Differential Scanning Calorimetry (DSC). The dielectric properties were analyzed with varying frequency and temperature through dielectric constant, loss tangent, conductivity, and capacitance. The optical transition properties were studied in the framework of Judd-Ofelt (JO) theory. JO parameters were confirmed, and furthermore, the optical transition rates and fluorescence branching ratios were also derived. With 401 nm excitation, the emission spectra of the glass system exhibited emissions of the Sm3+ ion corresponding to transitions 4G5/2→6H5/2, 6H7/2,6H9/2,6H11/2 at 563, 601, 647, and 708 nm, respectively. The higher emission rate, branching ratio, stimulated emission cross-section, gain linewidth, and figure of merit for the transition 4G5/2→6H7/2 calculated by Fuchtbauer-Ladenburg theory indicated potential of the titled glass system for reddish-orange solid-state lasers. The investigated glass system also exhibited high quantum efficiency and color purity (99%) for emission device application.