Lamp Industry Research Articles

Novel low temperature synthesis of Y2-x 03 :Eux 3+ nanophosphor prepared by combustion with Thioglycerol as fuel for near UV light emitting diodes (n-UVLEDs).

Luminescent materials used in flat panel displays (FPD), compact fluorescent lamps (CFL), and light-emitting diodes (LEDs) require high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology to ensure long-term stability. Y2 O3 :Eu3+ is a widely studied red phosphor known for its characteristic photoluminescence emission at 613 nm with near-UV excitation at 392 nm. Many synthesis methods have been explored to achieve Y2 O3 :Eu3+ nanoparticles with exceptional purity, consistent phases, and uniform particle sizes. The goal is to obtain particles with pristine surfaces, spherical shape, and compact morphology. This study focuses on the low-temperature synthesis and photoluminescence investigation of Y2-x O3 :Eux 3+ nanophosphors prepared using combustion with thioglycerol as a fuel. The results are compared with Y2-x O3 :Eux 3+ red nanophosphors synthesized using wet chemical and nitrate combustion methods. The photoluminescence characteristics of the Y2-x O3 :Eux 3+ nanophosphors were analyzed using PL emission spectroscopy, XRD, and scanning electron microscopy (SEM). These findings highlight the advantageous properties of the synthesized nanophosphors, such as their suitability for solid-state lighting applications in the lamp industry as highly efficient red phosphors. The combination of high purity, uniform particle size, clean surfaces, spherical shape, and dense morphology contributes to their potential for long-term stability and reliable performance in lighting devices.

Structural, morphological, and photoluminescence study of Europium doped spinel ZnAl2O4 phosphors

Nanocrystalline Eu-doped Zinc aluminate spinel was produced by a combustion method. Different methods, including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and photoluminescence spectroscopy, were used to examine the prepared spinel type ZnAl2O4 ceramic material and characterize its structural, morphological, and photoluminescent properties. The formation of a pure phase with a spinel structure and the space groupfd3 ̅m is confirmed by the zinc aluminate material's X-ray diffraction pattern. Scan and transmission electron microscopy were used to further establish the average surface structure and crystalline size. The PL spectra show the strongest emission at 616 nm corresponds to the 5D0 → 7F2 transition of Eu3+. Photometric parameters like CIE coordinates and CCT values show that prepared phosphor that gives off a bright red light is used in the display and lamp industries.

Electric Pioneers: Nationalist Lobbying, Technology Transfer, and the Origins of the Chinese Electric Lamp Industry, 1921–1937

This article uses the case of Oppel Electric Manufacturing Co. Ltd.—the most important Chinese manufacturer of light bulbs before 1937—to explore the early development of the Chinese electrical lamp industry. The article first explores the Chinese market for electrical lamps before the 1920s and shows how the market was dominated by imports and lamps locally manufactured by foreign firms. It then traces how Oppel was established in the 1920s and subsequently grew into a successful manufacturing business able to compete with foreign products. The article explores how the fact that government institutions were major purchasers of light bulbs allowed Oppel to engage in nationalist lobbying and thereby win government contracts. The article shows how the absence of Western-style intellectual property rights allowed Oppel to transfer technology cheaply, efficiently, and without needing to enter into Sino–foreign joint ventures. These discussions of nationalist lobbying and China’s intellectual property environment contribute to our understanding of China’s early industrialization, both in terms of the rapid industrial growth early twentieth century China saw and the leading role that Chinese firms played in this growth.

Insight into the mechanisms involved in the removal of toxic, rare earth, and platinum elements from complex mixtures by Ulva sp.

Hazardous leachate/effluent from fluorescent lamps contains potentially toxic elements such as Hg and Pb, and critical raw materials such as rare earth elements (REEs). This work evaluated the ability of the live macroalgae Ulva sp. to remediate a simulated lamp industry wastewater consisting of a complex mixture of elements (Y, Eu, La, Ce, Tb, Gd, Hg, Pb, Zn, Cu, Co, Cd, and Pt), with particular emphasis on the investigation of the sorption mechanisms. Experiments were performed with 3.0 g/L (fresh weight) of Ulva sp., salinity 25, and an initial concentration of 100 µg/L for each element. Hierarchical cluster analysis highlighted two main groups according to removal: Pt and Cd as the less removed, and all others with removals > 76 %, underlining Hg and Ce with the fastest kinetics (up to 92 %). Apart from Co, Zn and Cd, all mathematical models described sorption kinetics well, with Akaike Information Criteria identifying the Elovich model as the best for describing REEs sorption. FTIR analysis identified the sulphated polysaccharide Ulvan as intervening in binding elements to Ulva biomass. Extraction with EDTA 0.001 mol/L showed that most elements were mainly localized in the outer fraction (surface), except for Hg, which was entirely in the inner part. SEM analysis supported the EDTA analysis and showed a clean surface after washing. The results are an important contribution to the understanding of sorption mechanisms in macroalgae and demonstrate the feasibility of macroalgae-based biotechnologies with reduced costs and high efficiency for water decontamination, in complex saline mixtures.

Photosensitive Behavior Studies of the Ba3CaSi2O8:Eu3+ and aCeSiO4:Eu3+Luminescence Material Synthesis

Phosphors made from inorganic oxides and activated with rare earth metals are usedin numerous practical contexts. These include cathode ray tubes, high-efficiency luminouslights, x-ray radiography screens, field emission display panels, and many more.Inorganic phosphor compounds come in a wide variety of forms and have a wide variety ofpracticalapplications. Because of their many advantageous characteristics, including highquantumefficiency, long persistence of the phosphorescence, good stability, and the fact thataluminate-based phosphor is an excellent host material for the lamp industry, aluminatephosphors havea promising future in practical applications. Divalent europium ion dopedsynthetic hexagonal alkaline earth aluminate is an effective luminescence material. Plasmadisplays, field emission displays, fluorescence lamps, etc. all make use of phosphors based onaluminates.Nanophosphors based on the silicates Ba3CaSi2O8 and NaCeSiO4 havebeen produced at 900 ℃using the sol-gel process and doped with Eu3+. Fouriertransform infrared analysis (FTIR), X-ray powder diffraction (XRD), and photoluminescence(PL) techniques were used to examine the bonding, crystalline structure, andphotoluminescence properties of the produced nanophosphors. Europium doped bariumcalcium silicate (Ba3CaSi2O8:Eu3+) and sodium cerium silicate (NaCeSiO4:Eu3+) phosphorsemitted a red glow when exposed to ultraviolet (UV) light. The excitation and emission spectrawere analysed to determine the luminescence parameters of the produced phosphor. Based onXRD analyses, we know that the produced minerals Ba3CaSi2O8:Eu3+ and NaCeSiO4:Eu3+have orthorhombic and cubic structures, respectively, and have sizes of 46.36 nm and 28.57nm. The crystallinity of the finished products was uncovered by XRD analysis. Vacuumfluorescent displays, cathode ray tubes (CRT), safety indicators, luminous paints, fabrics, etc.all benefit from the optoelectronic characterisation of produced phosphors.

Evolution of beryllium safety standards over the last 70 years and challenges ahead

Beryllium (Be), its alloys, and ceramics are widely used in high-tech applications such as electronics, space, atomic energy, and other day-to-day items of use. Initially, Be-based phosphors such as ZnBeSiO4 were being used in the lamp industry during the 1930s onward but were soon abandoned due to lung-related diseases and deaths of workers in the phosphor industry which was attributed to the highly toxic nature of Be. Typical effects associated with Be inhalation are chronic and acute Be diseases (CBD and ABD) and the main target organ being affected is the lung although effects on other human body organs are also well documented. Such diseases were observed not only in occupational workers handling Be but also in the members of the public residing in the neighborhood of Be manufacturing and processing facilities, especially in the USA. The CBD in occupational workers may depend on many factors such as individual's sensitivity to Be, amount of Be exposure, nature of Be compound, and types of Be operations and processes being performed. All this led to safety concerns about the toxicity of Be and recommendations regarding Be air concentration in the workplace and public environment were issued by the Department of Energy, USA in 1949 as occupational exposure limit (OEL)/threshold limit values (TLVs) which were 2.0 μg/m3 and 0.01 μg/m3 for occupational Be workers and public environment, respectively. It is worth to mention that these recommendations were adopted by various countries and organizations either as it is or with small changes. Later, different organizations recommended changes in the value of TLV for occupational workplaces, but such changes were never adopted as they were lacking sound epidemiological basis. The OEL/TLV of 2.0 μg/m3 continued for nearly 70 years until Occupational Safety and Health Administration (OSHA) in 2017 reduced the Be air concentration (BeAir-Conc) limit for occupational workers to 0.20 μg/m3 as the value of 2.00 μg/m3 was inadequate to protect occupational workers from CBD. This is a major change in the Be-related safety standards recommended recently and is/being adopted by many countries. The present article provides details about the evolution of Be safety standards over the last 70 years, the notion behind the recent revision of Be permissible exposure limit (PEL) value from 2.0 μg/m3 to 0.20 μg/m3 by OSHA and the associated safety challenges ahead. The information from literature about Be safety and related safety standards adopted in India is also given. The article also provides details about TLVs for BeAir-Conc being followed in various countries in the world and various challenges for the implementation of a revised PEL value of 0.20 μg/m3 as suggested by OSHA i.e., reduction in PEL value by a factor of 10 or recommendation of revised TLV of 0.05 μg/m3 by American Conference of Governmental Industrial Hygienists as compared to the previous value of 2.0 μg/m3. In view of different notations and limits for BeAir-Conc recommended by various agencies and limited information about Be safety-related details, all relevant information regarding Be safety along with the evolution of Be safety standards over the last 70 years is included in the present article. This is an important issue for the safety of individual's at occupational workplaces as well as for environmental safety and its compilation was highly needed for providing comprehensive information on Be safety from the inception of standards to till today.

Synthesis and PL Characterization of Zn4B6O13 : Eu3+ Phosphor

Modified solid state synthesis had been used to synthesize Zn4B6O13:Eu3+ phosphor. Compared to other methods, modified solid-state synthesis has several advantages.. Zn4B6O13:Eu3+ phosphor’s’ photoluminescence properties have been investigated.. The PL excitation spectra shows sharp peak at 393nm due to transition of 4f→5d. The shoulder peak of the PL emission spectra is observed at 614nm due to the 5Do→ 7F2 (red) transition of Eu3+ ion while the other peak is observed at 593nm due to the 5Do→ 7F1 (orange). All of the properties of the developed Zn4B6O13:Eu3+phosphor indicate that it could be beneficial in the lamp industry and solid state lighting.

Optical characteristics of europium and terbium doped strontium orthogermanate phosphors

In this work, europium and terbium activated Sr2GeO4 phosphors were successfully developed by traditional solid state method. Powders XRD, FESEM, EDS, FTIR, DRS and PL techniques have been used to probe the as prepared phosphors. Powder XRD patterns of the phosphors are indexed. The elemental composition of phosphors was obtained from their EDS. FTIR spectra are employed to detect different vibrational groups in phosphor compositions. The DRS profiles of both pristine and Eu3+ (Tb3+) substituted samples exhibit broad and strong band in the 230–370 ​nm region. The photoluminescence studies of europium and terbium doped phosphors exhibited optimistic red emission at 617 ​nm (5D0 → 7F2 of Eu3+ ions) and intense green emission at 543 ​nm (5D4 → 7F5 of Tb3+ ions) upon ultraviolet (UV) excitations respectively. The CIE chromaticity co-ordinates are produced in deep red and green regions. Therefore, these materials may become potential alternatives for red and green phosphors in the display devices and in lamp industry.

Synthesis and luminescence properties of Ce3+ doped (Sr, Ba)2GeO4 phosphors

Cerium (Ce3+) doped strontium, barium orthogermanate samples are prepared by conventional solid state mixing method. In this process, X-ray powder diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDAX) and Photoluminescence (PL) measurements are carried out for the synthesized phosphors. The orthorhombic structure is confirmed by X-ray diffraction of the phosphors. EDAX is confirmed that all the elements are present in the compound such as Sr, Ba, Ge, O and Ce. Photoluminescence studies of Sr2GeO4: Ce3+ and Ba2GeO4: Ce3+ phosphors show intense blue emissions at 438 and 429 nm under ultraviolet excitation respectively. These phosphors are ascribed due to the 5d → 2F5/2,2F7/2 electronic transitions of cerium ions. Therefore, these phosphors may be applicable in the display devices and lamp industry as blue emitting phosphors.

Photoluminescence studies and synthesis of KSrPO4:Ce3+, Eu3+ blue and orange-red emitting phosphor

The growing need for leftover fuels and the ecological effects of their use was intended to give life to the traditionally extended global superpower infrastructure. Conventional, reliable fluorescent and incandescent lamps emit energy in the form of either heat or gas discharge. Both principles are strongly owing to the greater energy fluctuations that arise related to higher temperatures with the greater shifts of Stokes concerned. Within this work, we recorded sulphate-based blue & Orange-red emitting phosphors for lamp industry applications prepared using updated wet chemical synthesis methods, because the production of superb materials with high and stable fluorescent and luminescent properties is necessary to achieve high emission and fine clarity in the innovation of display systems. Morphological and structural tests and validation of phase and quality were conducted using XRD and SEM. The photoluminescent emission spectra of KSrPO4:Ce3+, Eu3+ phosphors show a blue emission band centered at 440 nm and a orange-red emission band centered at 593 nm and 618 nm. Typically, the structure of the Ce3+ ion in the ground state is split into two levels such as 2F5/2 and 2F7/2, while the5d1 excited configuration is divided by the crystal playing field into 2 and 5 elements.

Synthesis and characterization of luminescence of (Li-Ca-Eu)P for blue phosphor

From last few decades, phosphate dependent phosphorus and other compositional materials have gained further research interest in solid state lighting applications. Phosphate based phosphors with high photo luminescent compounds (Li,Ca, and Eu) has been synthesised using the sol gel process. Eu+2 ions play a essential character in blue emitting phosphors that are stimulated at near-UV LEDs, due to the 5d to 4f Eu2 + transformation, the Li (Ca1−x Eux)PO4 has been shown to be an effective host in the lamp industry.

Effect of Calcination Temperature on Photoluminescence Intensity of Sol-Gel prepared Sr2CeO4: Eu3+ Nano Phosphor

The photoluminescence (PL) studies of Europium doped Sr2CeO4 Nano Phosphors which are synthesized indigenously exhibit beautiful luminescence and they are of use in lamp industry.

Organic and Inorganic Mercury in Biological Samples of Flouresecent Lamp Industries Workers and Health Risks

ObjectiveThe present study aims to investigate the concentrations of Hg and its aspects methyl mercury (Me-Hg) and inorganic mercury (I-Hg) in the biological samples (BSs) of fluorescent lamp industries workers (FLIWs). MethodologyDifferent BSs including red blood cells (RBCs), plasma, urine, hair and nails were collected from the workers exposed to Hg and unexposed persons were selected as control group to measure both the T-Hg concentration as well as its species in different biological samples through quantitative analysis. Health data was collected through questionnaire survey. ResultsThe mean concentrations of T-Hg (31.9 μg/L), Me-Hg (27.7 μg/L), and I-Hg (5.36 μg/L) in RBCs were found significantly (P < 0.001) higher among the workers (n = 40) as compared to the control group (n = 40). Similarly the mean Hg concentrations in plasma, urine, hair and nails were also significantly higher among the workers than the control group. The statistical relation between Hg concentration and demographic characteristics observed that workers experience and fish consumption has increased the Hg concentration while age, weight and smoking found no significant effect on Hg concentration in the BSs. ConclusionThe study observed that the workers were highly exposed to high concentration of Hg and they are at a high health risk.

Synthesis and Luminescence Properties of La2O2S:RE3+ (RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) Submicron Size Phosphors for Lamp Industry

RE3+(RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) doped La2O2S phosphors was synthesized by solid state flux fusion method and their down conversion spectral properties were studied as a function different RE3+ concentrations and reported in this paper. The solid state flux fusion results in well crystallized hexagonal shaped phosphor particles. The samples were characterized by XRD, SEM, FT-IR photoluminescence (PL) and CIE colour co-ordinates techniques. The lanthanum oxysulphide (La2O2S) phosphor doped with Ce3+ shows broad band emission with peak at 390 nm and 415 nm when excited at 340 nm excitation. La2O2S:Dy3+ shows efficient blue and yellow band emissions at 480 nm and 572 nm. La2O2S:Eu3+ phosphor shows an orange and red emission at 590 nm and 615 nm. Whereas La2O2S:Tb3+ phosphor shows weak blue emission at 488 nm and strong green 545 nm. The excitation spectra used for the La2O2S:RE3+ (where RE3+ = Ce3+, Dy3+, Eu3+ and Tb3+) phosphors is in the near UV region extending from 350 to 400 nm, which is characteristics of near UV excited LED. The effect of the RE3+ (RE3+= Ce3+, Dy3+, Eu3+ and Tb3+) concentration on the luminescence properties of La2O2S:RE3+ phosphors were also studied. The investigated prepared La2O2S phosphors may be suitable for a near UV excited W-LED. Keywords: Oxysulphide, SEM, FT-IR, PL, SSL, CIE.

Characterization of luminescence of samarium with phosphate compounds

Over the years, luminescence has been profoundly used for lighting purposes in lamp industries. The massive production of luminescence in Lamp industries is highly enhanced by use of LED phosphorus. Cathode rays, such as televisions, PC monitors, test equipment as well as fluorescent lighting profoundly make use of LED phosphorus for both white and colored luminescence.Luminescence in lamp industries can also be achieved through exposing Samarium, a rare earth element, to a phosphate compound. Usually, this is achieved by synthesizing Samarium (Sm3+) doped Ca6BaP4017 phosphorus through a conventional solid-state reaction method.The reaction leads to an emission of a spectrum consisting of three different peaks characterized by different intensity levels.

Characterization Of Luminescence Of Holmium With Phosphate Compounds

Holmium is a luminescence producing rare earth element. For the lamp industry, luminescence is produced through a chemical reaction between holmium and a phosphate compound. The reaction does not need special heating but can take place under room temperature (About 230 degrees ). When carrying out the experiment, the two reactants are added in a test-tube, and the reaction takes place in a specific period of time. The observations are thus recorded. However, under different phosphate ions, holmium produces different luminescence intensity.

Isopropyl Alcohol Total Oxidation Over Platinum Supported on Alumina and Mullite

Total catalytic oxidation of isopropyl alcohol (IPA), used in fragrance lamp industry, remains one of the most popular techniques to remove indoor environmental pollutants (Volatile Organic compounds VOC). Many catalysts were already used in such technique. In our study, catalytic oxidation of isopropyl alcohol was investigated on catalysts based on platinum. The influence of two parameters on the catalytic activity was studied: the active phase content and the effect of methyl cellulose on Pt particles dispersion. In this study, mullite (Al6Si2O13) known for its excellent thermal stability and thermal shock resistance, and alumina (α-Al2O3) were used as supports. Pt/α-Al2O3 and Pt/Al6Si2O13 catalysts were prepared using the impregnation method. Platinum supported on mullite was synthetized in two different ways, with and without methyl cellulose (MC) in order to study the influence of adding methyl cellulose on the platinum particles dispersion over mullite. Furthermore, the resulting materials were characterized by BET, X-Ray diffraction (XRD), transmission electron microscopy (TEM) and H2-chemisorption to determine the dispersion of platinum particles. All the catalysts were tested in total catalytic oxidation of isopropyl alcohol. This study showed that Pt/Al6Si2O13 synthesized with MC exhibited better activity performance than the one prepared without MC. This can be explained by the fact that the addition of MC enhanced the Pt dispersion over mullite leading to an improvement in the catalytic activity and the selectivity into carbon dioxide. At the end, this study presents scientific findings and many attracted research interest concerning the use of hydrogel based methyl cellulose as a dispersing agent in the synthesis of catalysts.

Green-light emission through energy transfer from Ce3+ to Tb3+ ions in the Li2 SO4 -Al2 (SO4 )3 system.

An energy transfer process from Ce3+ to Tb3+ ions was successfully achieved in a Li2 SO4 -Al2 (SO4 )3 mixed-sulphate system. A wet-chemical synthesis was employed to prepare the Li2 SO4 -Al2 (SO4 )3 system by doping Ce3+ and Tb3+ ions individually as well as collectively. The phases were identified using X-ray diffraction studies. The as-prepared samples were characterized by FT-IR and photoluminescence measurements. Green-light emission was exhibited by Ce3+ , Tb3+ co-doped Li2 SO4 -Al2 (SO4 )3 system, thus, indicating its potential as a material for display devices or in the lamp industry.

Spectroscopic investigations of Dy3+ activated MCaP2O7 (M = Sr/Ba) pyrophosphate phosphors

The dysprosium activated SrCaP2O7 and BaCaP2O7 phosphors were synthesized by solid-state diffusion technique and studied for their phase uniformity by X-ray diffraction pattern (XRD). Besides, photoluminescence (PL) properties under ultraviolet (UV) ray excitation have been investigated. Photoluminescence (PL) excitation spectrum measurement shows these phosphors can be efficiently excited by near-ultraviolet (UV) light from 300 to 400 nm and presents dominant luminescence band centered at around 470–490 nm (blue) and 575 nm (yellow). A scanning electron microscope (SEM) shows an average crystallite size in sub-micrometer range. The room temperature FTIR spectrum was investigated to study the nature of the chemical bonds and their molecular environment. CIE chromaticity coordinates values are estimated from emission spectra of SrCaP2O7:Dy3+ and BaCaP207: Dy3+ for the prepared samples. The obtained results indicate that these phosphors have possible applications in the lamp industry especially for solid state lighting and n-UV LED. The investigations on quantum efficiency, quantum yield and the energy band gap will be carried out in near future for the present phosphors.

戦後日本における輸出電球工業の展開と輸出規制 : 1950～60年代のクリスマス電球工業を中心として

戦後日本における輸出電球工業の展開と輸出規制 : 1950～60年代のクリスマス電球工業を中心として