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Phosphor

From Wikipedia, the free encyclopedia
For the chemical element, seephosphorus.
Example of phosphorescence
Monochrome monitor
Aperture grilleCRT phosphors

Aphosphoris a substance that exhibits thephenomenonofluminescence;it emits light when exposed to some type ofradiant energy.The term is used both forfluorescentorphosphorescentsubstances which glow on exposure toultravioletor visible light, andcathodoluminescentsubstances which glow when struck by anelectron beam(cathode rays) in acathode-ray tube.

When a phosphor is exposed to radiation, the orbitalelectronsin itsmoleculesare excited to a higherenergy level;when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories:fluorescentsubstances which emit the energy immediately and stop glowing when the exciting radiation is turned off, andphosphorescentsubstances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days.

Fluorescent materials are used in applications in which the phosphor is excited continuously:cathode-ray tubes(CRT) and plasma video display screens,fluoroscope screens,fluorescent lights,scintillation sensors,whiteLEDs,andluminous paintsforblack lightart. Phosphorescent materials are used where a persistent light is needed, such as glow-in-the-dark watch faces and aircraft instruments, and inradar screensto allow the target 'blips' to remain visible as the radar beam rotates. CRT phosphors were standardized beginning aroundWorld War IIand designated by the letter "P" followed by a number.

Phosphorus,the light-emitting chemical element for which phosphors are named, emits light due tochemiluminescence,not phosphorescence.[1]

Light-emission process[edit]

Jablonski diagramshows the energy levels in a fluorescing atom in a phosphor. An electron in the phosphor absorbs a high-energyphotonfrom the applied radiation, exciting it to a higher energy level. After losing some energy in non-radiative transitions, it eventually transitions back to its ground state energy level by fluorescence, emitting a photon of lower energy in the visible light region.

The scintillation process in inorganic materials is due to theelectronic band structurefound in thecrystals.An incoming particle can excite an electron from thevalence bandto either theconduction bandor theexcitonband (located just below the conduction band and separated from the valence band by anenergy gap). This leaves an associatedholebehind, in the valence band. Impurities create electronic levels in theforbidden gap.

The excitons are loosely boundelectron–hole pairsthat wander through thecrystal latticeuntil they are captured as a whole by impurity centers. They then rapidly de-excite by emitting scintillation light (fast component).

In the conduction band, electrons are independent of their associated holes. Those electrons and holes are captured successively by impurity centers exciting certainmetastable statesnot accessible to the excitons. The delayed de-excitation of those metastable impurity states, slowed by reliance on the low-probabilityforbidden mechanism,again results in light emission (slow component). In the case of inorganicscintillators,the activator impurities are typically chosen so that the emitted light is in the visible range ornear-UV,wherephotomultipliersare effective.

Phosphors are oftentransition-metalcompounds orrare-earthcompounds of various types. In inorganic phosphors, these inhomogeneities in the crystal structure are created usually by addition of a trace amount ofdopants,impurities calledactivators.(In rare casesdislocationsor othercrystal defectscan play the role of the impurity.) The wavelength emitted by the emission center is dependent on the atom itself and on the surrounding crystal structure.

Materials[edit]

Phosphors are usually made from a suitable host material with an addedactivator.The best known type is a copper-activatedzinc sulfide (ZnS)and thesilver-activated zinc sulfide (zinc sulfidesilver).

The host materials are typicallyoxides,nitridesand oxynitrides,[2]sulfides,selenides,halidesorsilicatesofzinc,cadmium,manganese,aluminium,silicon,or variousrare-earth metals.The activators prolong the emission time (afterglow). In turn, other materials (such asnickel) can be used to quench the afterglow and shorten the decay part of the phosphor emission characteristics.

Many phosphor powders are produced in low-temperature processes, such assol-gel,and usually require post-annealing at temperatures of ~1000 °C, which is undesirable for many applications. However, proper optimization of the growth process allows manufacturers to avoid the annealing.[3]

Phosphors used forfluorescent lampsrequire a multi-step production process, with details that vary depending on the particular phosphor. Bulk material must be milled to obtain a desired particle size range, since large particles produce a poor-quality lamp coating, and small particles produce less light and degrade more quickly. During thefiringof the phosphor, process conditions must be controlled to prevent oxidation of the phosphor activators orcontaminationfrom the process vessels. After milling, the phosphor may be washed to remove minor excess of activator elements. Volatile elements must not be allowed to escape during processing. Lamp manufacturers have changed compositions of phosphors to eliminate some toxic elements formerly used, such asberyllium,cadmium,orthallium.[4]

The commonly quoted parameters for phosphors are thewavelengthof emission maximum (in nanometers, or alternativelycolor temperatureinkelvinsfor white blends), the peak width (innanometersat 50% of intensity), and decay time (inseconds).

Examples:

  • Calcium sulfidewithstrontium sulfidewithbismuthas activator,(Ca,Sr)S:Bi,yields blue light with glow times up to 12 hours, red and orange are modifications of the zinc sulfide formula. Red color can be obtained from strontium sulfide.
  • Zinc sulfidewith about 5 ppm of acopperactivator is the most common phosphor for the glow-in-the-dark toys and items. It is also calledGSphosphor.
  • Mix of zinc sulfide andcadmium sulfideemit color depending on their ratio; increasing of the CdS content shifts the output color towards longer wavelengths; its persistence ranges between 1–10 hours.
  • Strontium aluminateactivated byeuropium,SrAl2O4:Eu(II):Dy(III), is a material developed in 1993 by Nemoto & Co. engineer Yasumitsu Aoki with higher brightness and significantly longer glow persistence; it produces green and aqua hues, where green gives the highest brightness and aqua the longest glow time.[5][6]SrAl2O4:Eu:Dy is about 10 times brighter, 10 times longer glowing, and 10 times more expensive than ZnS:Cu.[5]The excitationwavelengthsfor strontium aluminate range from 200 to 450 nm. The wavelength for its green formulation is 520 nm, its blue-green version emits at 505 nm, and the blue one emits at 490 nm. Colors with longerwavelengthscan be obtained from the strontium aluminate as well, though for the price of some loss of brightness.

Phosphor degradation[edit]

Many phosphors tend to lose efficiency gradually by several mechanisms. The activators can undergo change ofvalence(usuallyoxidation), thecrystal latticedegrades, atoms – often the activators – diffuse through the material, the surface undergoes chemical reactions with the environment with consequent loss of efficiency or buildup of a layer absorbing the exciting and/or radiated energy, etc.

The degradation of electroluminescent devices depends on frequency of driving current, the luminance level, and temperature; moisture impairs phosphor lifetime very noticeably as well.

Harder, high-melting, water-insoluble materials display lower tendency to lose luminescence under operation.[7]

Examples:

  • BaMgAl10O17:Eu2+(BAM), aplasma-displayphosphor, undergoes oxidation of the dopant during baking. Three mechanisms are involved; absorption of oxygen atoms into oxygen vacancies on the crystal surface,diffusionof Eu(II) along the conductive layer, andelectron transferfrom Eu(II) to absorbed oxygen atoms, leading to formation of Eu(III) with corresponding loss of emissivity.[8]Thin coating ofaluminium phosphateorlanthanum(III) phosphateis effective in creating abarrier layerblocking access of oxygen to the BAM phosphor, for the cost of reduction of phosphor efficiency.[9]Addition ofhydrogen,acting as areducing agent,toargonin the plasma displays significantly extends the lifetime of BAM:Eu2+phosphor, by reducing the Eu(III) atoms back to Eu(II).[10]
  • Y2O3:Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, whereelectron–hole pairsrecombinenonradiatively via surface states.[11]
  • ZnS:Mn, used in AC thin-film electroluminescent (ACTFEL) devices degrades mainly due to formation ofdeep-level traps,by reaction of water molecules with the dopant; the traps act as centers for nonradiative recombination. The traps also damage thecrystal lattice.Phosphor aging leads to decreased brightness and elevated threshold voltage.[12]
  • ZnS-based phosphors inCRTsandFEDsdegrade by surface excitation, coulombic damage, build-up of electric charge, and thermal quenching. Electron-stimulated reactions of the surface are directly correlated to loss of brightness. The electrons dissociate impurities in the environment, thereactive oxygen speciesthen attack the surface and formcarbon monoxideandcarbon dioxidewith traces ofcarbon,and nonradiativezinc oxideandzinc sulfateon the surface; the reactivehydrogenremovessulfurfrom the surface ashydrogen sulfide,forming nonradiative layer of metalliczinc.Sulfur can be also removed assulfur oxides.[13]
  • ZnS and CdS phosphors degrade by reduction of the metal ions by captured electrons. The M2+ions are reduced to M+;two M+then exchange an electron and become one M2+and one neutral M atom. The reduced metal can be observed as a visible darkening of the phosphor layer. The darkening (and the brightness loss) is proportional to the phosphor's exposure to electrons and can be observed on some CRT screens that displayed the same image (e.g. a terminal login screen) for prolonged periods.[14]
  • Europium(II)-doped alkaline earth aluminates degrade by formation ofcolor centers.[7]
  • Y
    2    SiO
    5    :Ce3+degrades by loss of luminescent Ce3+ions.[7]
  • Zn
    2    SiO
    4    :Mn (P1) degrades by desorption of oxygen under electron bombardment.[7]
  • Oxide phosphors can degrade rapidly in presence offluorideions, remaining from incomplete removal of flux from phosphor synthesis.[7]
  • Loosely packed phosphors, e.g. when an excess of silica gel (formed from the potassium silicate binder) is present, have tendency to locally overheat due to poor thermal conductivity. E.g.InBO
    3    :Tb3+is subject to accelerated degradation at higher temperatures.[7]

Applications[edit]

Lighting[edit]

Phosphor layers provide most of the light produced byfluorescent lamps,and are also used to improve the balance of light produced bymetal halide lamps.Variousneon signsuse phosphor layers to produce different colors of light.Electroluminescent displaysfound, for example, in aircraft instrument panels, use a phosphor layer to produce glare-free illumination or as numeric and graphic display devices. WhiteLEDlamps consist of a blue or ultra-violet emitter with a phosphor coating that emits at longer wavelengths, giving a full spectrum of visible light. Unfocused and undeflectedcathode-ray tubeshave been used asstroboscope lampssince 1958.[15]

Phosphor thermometry[edit]

Main article:Phosphor thermometry

Phosphor thermometryis a temperature measurement approach that uses the temperature dependence of certain phosphors. For this, a phosphor coating is applied to a surface of interest and, usually, the decay time is the emission parameter that indicates temperature. Because the illumination and detection optics can be situated remotely, the method may be used for moving surfaces such as high speed motor surfaces. Also, phosphor may be applied to the end of an optical fiber as an optical analog of a thermocouple.[citation needed]

Glow-in-the-dark toys[edit]

Main article:Phosphorescence

In these applications, the phosphor is directly added to theplasticused to mold the toys, or mixed with a binder for use as paints.

ZnS:Cu phosphor is used in glow-in-the-dark cosmetic creams frequently used forHalloweenmake-ups. Generally, the persistence of the phosphor increases as the wavelength increases. See alsolightstickforchemiluminescence-based glowing items.

Oxygen sensing[edit]

Quenching of the triplet state by O2(which has a triplet ground state) as a result ofDexter energy transferis well known in solutions of phosphorescent heavy-metal complexes and doped polymers.[16]In recent years, phosphorescence porous materials(such asMetal–organic frameworksandCovalent organic frameworks) have shown promising oxygen sensing capabilities, for their non-linear gas-adsorption in ultra-low partial pressures of oxygen.[17][18]

Postage stamps[edit]

Phosphor banded stampsfirst appeared in 1959 as guides for machines to sort mail.[19]Around the world many varieties exist with different amounts of banding.[20]Postage stampsare sometimes collected by whether or not they are"tagged"with phosphor (or printed onluminescentpaper).

Radioluminescence[edit]

Main article:Radioluminescence

Zinc sulfide phosphors are used withradioactivematerials, where the phosphor was excited by the alpha- and beta-decaying isotopes, to create luminescent paint for dials ofwatchesand instruments (radium dials). Between 1913 and 1950 radium-228 and radium-226 were used to activate a phosphor made ofsilverdopedzinc sulfide (ZnS:Ag), which gave a greenish glow. The phosphor is not suitable to be used in layers thicker than 25 mg/cm2,as the self-absorption of the light then becomes a problem. Furthermore, zinc sulfide undergoes degradation of its crystal lattice structure, leading to gradual loss of brightness significantly faster than the depletion of radium. ZnS:Ag coatedspinthariscopescreens were used byErnest Rutherfordin his experiments discoveringatomic nucleus.

Copperdoped zinc sulfide (ZnS:Cu) is the most common phosphor used and yields blue-green light. Copper andmagnesiumdoped zinc sulfide(ZnS:Cu,Mg)yields yellow-orange light.

Tritiumis also used as a source of radiation in various products utilizingtritium illumination.

Electroluminescence[edit]

Main article:Electroluminescence

Electroluminescencecan be exploited in light sources. Such sources typically emit from a large area, which makes them suitable for backlights of LCD displays. The excitation of the phosphor is usually achieved by application of high-intensityelectric field,usually with suitable frequency. Current electroluminescent light sources tend to degrade with use, resulting in their relatively short operation lifetimes.

ZnS:Cu was the first formulation successfully displaying electroluminescence, tested at 1936 byGeorges Destriauin Madame Marie Curie laboratories in Paris.

Powder or AC electroluminescence is found in a variety of backlight and night light applications. Several groups offer branded EL offerings (e.g.IndiGloused in some Timex watches) or "Lighttape", another trade name of an electroluminescent material, used in electroluminescentlight strips.The Apollo space program is often credited with being the first significant use of EL for backlights and lighting.[21]

White LEDs[edit]

Whitelight-emitting diodesare usually blueInGaNLEDs with a coating of a suitable material.Cerium(III)-dopedYAG(YAG:Ce3+,orY3Al5O12:Ce3+) is often used; it absorbs the light from the blue LED and emits in a broad range from greenish to reddish, with most of its output in yellow. This yellow emission combined with the remaining blue emission gives the "white" light, which can be adjusted to color temperature as warm (yellowish) or cold (bluish) white. The pale yellow emission of the Ce3+:YAG can be tuned by substituting the cerium with other rare-earth elements such asterbiumandgadoliniumand can even be further adjusted by substituting some or all of the aluminium in the YAG with gallium. However, this process is not one of phosphorescence. The yellow light is produced by a process known asscintillation,the complete absence of an afterglow being one of the characteristics of the process.

Somerare-earth-dopedSialonsarephotoluminescentand can serve as phosphors.Europium(II)-doped β-SiAlON absorbs inultravioletandvisible lightspectrum and emits intense broadband visible emission. Its luminance and color does not change significantly with temperature, due to the temperature-stable crystal structure. It has a great potential as a green down-conversion phosphor for whiteLEDs;a yellow variant also exists (α-SiAlON[22]). For white LEDs, a blue LED is used with a yellow phosphor, or with a green and yellow SiAlON phosphor and a red CaAlSiN3-based (CASN) phosphor.[23][24][25]

White LEDs can also be made by coating near-ultraviolet-emitting LEDs with a mixture of high-efficiency europium-based red- and blue-emitting phosphors plus green-emitting copper- and aluminium-doped zinc sulfide(ZnS:Cu,Al).This is a method analogous to the wayfluorescent lampswork.

Some newer white LEDs use a yellow and blue emitter in series, to approximate white; this technology is used in some Motorola phones such as the Blackberry as well as LED lighting and the original-version stacked emitters by using GaN on SiC on InGaP but was later found to fracture at higher drive currents.

Many white LEDs used in general lighting systems can be used for data transfer, as, for example, in systems that modulate the LED to act as abeacon.[26]

It is also common for white LEDs to use phosphors other than Ce:YAG, or to use two or three phosphors to achieve a higher CRI, often at the cost of efficiency. Examples of additional phosphors are R9, which produces a saturated red, nitrides which produce red, and aluminates such as lutetium aluminum garnet that produce green. Silicate phosphors are brighter but fade more quickly, and are used in LCD LED backlights in mobile devices. LED phosphors can be placed directly over the die or made into a dome and placed above the LED: this approach is known as a remote phosphor.[27]Some colored LEDs, instead of using a colored LED, use a blue LED with a colored phosphor because such an arrangement is more efficient than a colored LED. Oxynitride phosphors can also be used in LEDs. The precursors used to make the phosphors may degrade when exposed to air.[28]

Cathode-ray tubes[edit]

Spectra of constituent blue, green and red phosphors in a common cathode-ray tube

Cathode-ray tubesproduce signal-generated light patterns in a (typically) round or rectangular format. Bulky CRTs were used in the black-and-white household television (TV) sets that became popular in the 1950s, as well as first-generation, tube-based color TVs, and most earlier computer monitors. CRTs have also been widely used in scientific and engineering instrumentation, such asoscilloscopes,usually with a single phosphor color, typically green. Phosphors for such applications may have long afterglow, for increased image persistence.

The phosphors can be deposited as eitherthin film,or as discrete particles, a powder bound to the surface. Thin films have better lifetime and better resolution, but provide less bright and less efficient image than powder ones. This is caused by multiple internal reflections in the thin film, scattering the emitted light.

White(in black-and-white): The mix of zinc cadmium sulfide and zinc sulfide silver, theZnS:Ag + (Zn,Cd)S:Agis the whiteP4phosphor used in black and white television CRTs. Mixes of yellow and blue phosphors are usual. Mixes of red, green and blue, or a single white phosphor, can also be encountered.

Red:Yttriumoxide-sulfideactivated with europium is used as the red phosphor in color CRTs. The development of color TV took a long time due to the search for a red phosphor. The first red emitting rare-earth phosphor, YVO4:Eu3+,was introduced by Levine and Palilla as a primary color in television in 1964.[29]In single crystal form, it was used as an excellent polarizer and laser material.[30]

Yellow:When mixed withcadmium sulfide,the resultingzinc cadmium sulfide(Zn,Cd)S:Ag,provides strong yellow light.

Green:Combination of zinc sulfide withcopper,theP31phosphor orZnS:Cu,provides green light peaking at 531 nm, with long glow.

Blue:Combination of zinc sulfide with few ppm ofsilver,the ZnS:Ag, when excited by electrons, provides strong blue glow with maximum at 450 nm, with short afterglow with 200 nanosecond duration. It is known as theP22Bphosphor. This material,zinc sulfide silver,is still one of the most efficient phosphors in cathode-ray tubes. It is used as a blue phosphor in color CRTs.

The phosphors are usually poor electrical conductors. This may lead to deposition of residual charge on the screen, effectively decreasing the energy of the impacting electrons due to electrostatic repulsion (an effect known as "sticking" ). To eliminate this, a thin layer of aluminium (about 100 nm) is deposited over the phosphors, usually by vacuum evaporation, and connected to the conductive layer inside the tube. This layer also reflects the phosphor light to the desired direction, and protects the phosphor from ion bombardment resulting from an imperfect vacuum.

To reduce the image degradation by reflection of ambient light,contrastcan be increased by several methods. In addition to black masking of unused areas of screen, the phosphor particles in color screens are coated with pigments of matching color. For example, the red phosphors are coated withferric oxide(replacing earlier Cd(S,Se) due to cadmium toxicity), blue phosphors can be coated with marine blue (CoO·nAl
2O
3) orultramarine(Na
8Al
6Si
6O
24S
2). Green phosphors based on ZnS:Cu do not have to be coated due to their own yellowish color.[7]

Black-and-white television CRTs[edit]

The black-and-white television screens require an emission color close to white. Usually, a combination of phosphors is employed.

The most common combination isZnS:Ag + (Zn,Cd)S:Cu,Al(blue + yellow). Other ones areZnS:Ag + (Zn,Cd)S:Ag(blue + yellow), andZnS:Ag + ZnS:Cu,Al + Y2O2S:Eu3+(blue + green + red – does not contain cadmium and has poor efficiency). The color tone can be adjusted by the ratios of the components.

As the compositions contain discrete grains of different phosphors, they produce image that may not be entirely smooth. A single, white-emitting phosphor,(Zn,Cd)S:Ag,Au,Alovercomes this obstacle. Due to its low efficiency, it is used only on very small screens.

The screens are typically covered with phosphor using sedimentation coating, where particlessuspendedin a solution are let to settle on the surface.[31]

Reduced-palette color CRTs[edit]

For displaying of a limited palette of colors, there are a few options.

Inbeam penetration tubes,different color phosphors are layered and separated with dielectric material. The acceleration voltage is used to determine the energy of the electrons; lower-energy ones are absorbed in the top layer of the phosphor, while some of the higher-energy ones shoot through and are absorbed in the lower layer. So either the first color or a mixture of the first and second color is shown. With a display with red outer layer and green inner layer, the manipulation of accelerating voltage can produce a continuum of colors from red through orange and yellow to green.

Another method is using a mixture of two phosphors with different characteristics. The brightness of one is linearly dependent on electron flux, while the other one's brightness saturates at higher fluxes—the phosphor does not emit any more light regardless of how many more electrons impact it. At low electron flux, both phosphors emit together; at higher fluxes, the luminous contribution of the nonsaturating phosphor prevails, changing the combined color.[31]

Such displays can have high resolution, due to absence of two-dimensional structuring of RGB CRT phosphors. Their color palette is, however, very limited. They were used e.g. in some older military radar displays.

Color television CRTs[edit]

The phosphors in color CRTs need higher contrast and resolution than the black-and-white ones. The energy density of the electron beam is about 100 times greater than in black-and-white CRTs; the electron spot is focused to about 0.2 mm diameter instead of about 0.6 mm diameter of the black-and-white CRTs. Effects related to electron irradiation degradation are therefore more pronounced.

Color CRTs require three different phosphors, emitting in red, green and blue, patterned on the screen. Three separate electron guns are used for color production (except for displays that usebeam-index tubetechnology, which is rare). The red phosphor has always been a problem, being the dimmest of the three necessitating the brighter green and blue electron beam currents be adjusted down to make them equal the red phosphor's lower brightness. This made early color TVs only usable indoors as bright light made it impossible to see the dim picture, while portable black-and-white TVs viewable in outdoor sunlight were already common.

The composition of the phosphors changed over time, as better phosphors were developed and as environmental concerns led to lowering the content of cadmium and later abandoning it entirely. The(Zn,Cd)S:Ag,Clwas replaced with(Zn,Cd)S:Cu,Alwith lower cadmium/zinc ratio, and then with cadmium-freeZnS:Cu,Al.

The blue phosphor stayed generally unchanged, a silver-doped zinc sulfide. The green phosphor initially used manganese-doped zinc silicate, then evolved through silver-activated cadmium-zinc sulfide, to lower-cadmium copper-aluminium activated formula, and then to cadmium-free version of the same. The red phosphor saw the most changes; it was originally manganese-activated zinc phosphate, then a silver-activated cadmium-zinc sulfide, then the europium(III) activated phosphors appeared; first in anyttrium vanadatematrix, then inyttrium oxideand currently inyttrium oxysulfide.The evolution of the phosphors was therefore (ordered by B-G-R):

  • ZnS:Ag–Zn2SiO4:Mn–Zn3(PO4)2:Mn
  • ZnS:Ag–(Zn,Cd)S:Ag–(Zn,Cd)S:Ag
  • ZnS:Ag–(Zn,Cd)S:Ag–YVO4:Eu3+(1964–?)
  • ZnS:Ag–(Zn,Cd)S:Cu,Al–Y2O2S:Eu3+orY2O3:Eu3+
  • ZnS:Ag–ZnS:Cu,AlorZnS:Au,Cu,Al–Y2O2S:Eu3+[31]

Projection televisions[edit]

Forprojection televisions,where the beam power density can be two orders of magnitude higher than in conventional CRTs, some different phosphors have to be used.

For blue color,ZnS:Ag,Clis employed. However, it saturates.(La,Gd)OBr:Ce,Tb3+can be used as an alternative that is more linear at high energy densities.

For green, aterbium-activatedGd2O2Tb3+;its color purity and brightness at low excitation densities is worse than the zinc sulfide alternative, but it behaves linear at high excitation energy densities, while zinc sulfide saturates. However, it also saturates, soY3Al5O12:Tb3+orY2SiO5:Tb3+can be substituted.LaOBr:Tb3+is bright but water-sensitive, degradation-prone, and the plate-like morphology of its crystals hampers its use; these problems are solved now, so it is gaining use due to its higher linearity.

Y2O2S:Eu3+is used for red emission.[31]

Standard phosphor types[edit]

Standard phosphor types[32][33]
Phosphor Composition Color Wavelength Peak width Persistence Usage Notes
P1, GJ Zn2SiO4:Mn (Willemite) Green 525 nm 40 nm[34] 1-100ms CRT, Lamp Oscilloscopes andmonochrome monitors
P2 ZnS:Cu(Ag)(B*) Blue-Green 543 nm – Long CRT Oscilloscopes
P3 Zn8:BeSi5O19:Mn Yellow 602 nm – Medium/13 ms CRT Ambermonochrome monitors
P4 ZnS:Ag+(Zn,Cd)S:Ag White 565,540 nm – Short CRT Black and white TV CRTs and display tubes.
P4 (Cd-free) ZnS:Ag+ZnS:Cu+Y2O2S:Eu White – – Short CRT Black and white TV CRTs and display tubes, Cd free.
P5 CaWO4:W Blue 430 nm – Very Short CRT Film
P6 ZnS:Ag+ZnS:CdS:Ag White 565,460 nm – Short CRT
P7 (Zn,Cd)S:Cu Blue with Yellow persistence 558,440 nm – Long CRT RadarPPI,old EKG monitors, early oscilloscopes
P10 KCl Green-absorbingscotophor – – Long Dark-trace CRTs Radar screens; turns from translucent white to dark magenta, stays changed until erased by heating or infrared light
P11, BE ZnS:Ag,Cl or ZnS:Zn Blue 460 nm – 0.01-1 ms CRT, VFD Display tubes andVFDs;Oscilloscopes (for fast photographic recording)[35]
P12 Zn(Mg)F2:Mn Orange 590 nm – Medium/long CRT Radar
P13 MgSi2O6:Mn Reddish-Orange 640 nm – Medium CRT Flying spot scanning systems and photographic applications
P14 ZnS:Ag on ZnS:CdS:Cu Blue with Orange persistence – – Medium/long CRT RadarPPI,old EKG monitors
P15 ZnO:Zn Blue-Green 504,391 nm – Extremely Short CRT Television pickup byflying-spot scanning
P16 CaMgSi2O6:Ce Blue-Purple 380 nm – Very Short CRT Flying spot scanning systems and photographic applications
P17 ZnO,ZnCdS:Cu Blue-Yellow 504,391 nm – Blue-Short, Yellow-Long CRT
P18 CaMgSi2O6:Ti, BeSi2O6:Mn White 545,405 nm – Medium to Short CRT
P19, LF (KF,MgF2):Mn Orange-Yellow 590 nm – Long CRT Radar screens
P20, KA (Zn,Cd)S:Ag or (Zn,Cd)S:Cu Yellow-Green 555 nm – 1–100 ms CRT Display tubes
P21 MgF2:Mn2+ Reddish 605 nm – – CRT, Radar Registered by Allen B DuMont Laboratories
P22R Y2O2S:Eu+Fe2O3 Red 611 nm – Short CRT Red phosphor for TV screens
P22G (Zn,Cd)S:Cu,Al Green 530 nm – Short CRT Green phosphor for TV screens
P22B ZnS:Ag+Co-on-Al2O3 Blue – – Short CRT Blue phosphor forTVscreens
P23 ZnS:Ag+(Zn,Cd)S:Ag White 575,460 nm – Short CRT, Direct viewing television Registered by United States Radium Corporation.
P24, GE ZnO:Zn Green 505 nm – 1–10 μs VFD most common phosphor invacuum fluorescent displays.[36]
P25 CaSi2O6:Pb:Mn Orange 610 nm – Medium CRT Military Displays - 7UP25 CRT
P26, LC (KF,MgF2):Mn Orange 595 nm – Long CRT Radar screens
P27 ZnPO4:Mn Reddish Orange 635 nm – Medium CRT Color TV monitor service
P28, KE (Zn,Cd)S:Cu,Cl Yellow – – Medium CRT Display tubes
P29 Alternating P2 and P25 stripes Blue-Green/Orange stripes – – Medium CRT Radar screens
P31, GH ZnS:Cu or ZnS:Cu,Ag Yellowish-green – – 0.01-1 ms CRT Oscilloscopes and monochrome monitors
P33, LD MgF2:Mn Orange 590 nm – > 1sec CRT Radar screens
P34 – Bluish Green-Yellow Green – – Very Long CRT –
P35 ZnS,ZnSe:Ag Blue-White 455 nm – Medium Short CRT Photographic registration on orthochromatic film materials
P38, LK (Zn,Mg)F2:Mn Orange-Yellow 590 nm – Long CRT Radar screens
P39, GR Zn2SiO4:Mn,As Green 525 nm – Long CRT Display tubes
P40, GA ZnS:Ag+(Zn,Cd)S:Cu White – – Long CRT Display tubes
P43, GY Gd2O2S:Tb Yellow-Green 545 nm – Medium CRT Display tubes, Electronic Portal Imaging Devices (EPIDs) used in radiation therapy linear accelerators for cancer treatment
P45, WB Y2O2S:Tb White 545 nm – Short CRT Viewfinders
P46, KG Y3Al5O12:Ce Green 530 nm – Very short (70ns) CRT Beam-index tube
P47, BH Y2SiO5:Ce Blue 400 nm – Very short CRT Beam-index tube
P53, KJ Y3Al5O12:Tb Yellow-Green 544 nm – Short CRT Projection tubes
P55, BM ZnS:Ag,Al Blue 450 nm – Short CRT Projection tubes
ZnS:Ag Blue 450 nm – – CRT –
ZnS:Cu,Al or ZnS:Cu,Au,Al Green 530 nm – – CRT –
(Zn,Cd)S:Cu,Cl+(Zn,Cd)S:Ag,Cl White – – – CRT –
Y2SiO5:Tb Green 545 nm – – CRT Projection tubes
Y2OS:Tb Green 545 nm – – CRT Display tubes
Y3(Al,Ga)5O12:Ce Green 520 nm – Short CRT Beam-index tube
Y3(Al,Ga)5O12:Tb Yellow-Green 544 nm – Short CRT Projection tubes
InBO3:Tb Yellow-Green 550 nm – – CRT –
InBO3:Eu Yellow 588 nm – – CRT –
InBO3:Tb+InBO3:Eu amber – – – CRT Computer displays
InBO3:Tb+InBO3:Eu+ZnS:Ag White – – – CRT –
(Ba,Eu)Mg2Al16O27 Blue – – – Lamp Trichromatic fluorescent lamps
(Ce,Tb)MgAl11O19 Green 546 nm 9 nm – Lamp Trichromatic fluorescent lamps[34]
BAM BaMgAl10O17:Eu,Mn Blue 450 nm – – Lamp, displays Trichromatic fluorescent lamps
BaMg2Al16O27:Eu(II) Blue 450 nm 52 nm – Lamp Trichromatic fluorescent lamps[34]
BAM BaMgAl10O17:Eu,Mn Blue-Green 456 nm,514 nm – – Lamp –
BaMg2Al16O27:Eu(II),Mn(II) Blue-Green 456 nm, 514 nm 50 nm 50%[34] – Lamp
Ce0.67Tb0.33MgAl11O19:Ce,Tb Green 543 nm – – Lamp Trichromatic fluorescent lamps
Zn2SiO4:Mn,Sb2O3 Green 528 nm – – Lamp –
CaSiO3:Pb,Mn Orange-Pink 615 nm 83 nm[34] – Lamp
CaWO4(Scheelite) Blue 417 nm – – Lamp –
CaWO4:Pb Blue 433 nm/466 nm 111 nm – Lamp Wide bandwidth[34]
MgWO4 Pale Blue 473 nm 118 nm – Lamp Wide bandwidth, deluxe blend component[34]
(Sr,Eu,Ba,Ca)5(PO4)3Cl Blue – – – Lamp Trichromatic fluorescent lamps
Sr5Cl(PO4)3:Eu(II) Blue 447 nm 32 nm[34] – Lamp –
(Ca,Sr,Ba)3(PO4)2Cl2:Eu Blue 452 nm – – Lamp –
(Sr,Ca,Ba)10(PO4)6Cl2:Eu Blue 453 nm – – Lamp Trichromatic fluorescent lamps
Sr2P2O7:Sn(II) Blue 460 nm 98 nm – Lamp Wide bandwidth, deluxe blend component[34]
Sr6P5BO20:Eu Blue-Green 480 nm 82 nm[34] – Lamp –
Ca5F(PO4)3:Sb Blue 482 nm 117 nm – Lamp Wide bandwidth[34]
(Ba,Ti)2P2O7:Ti Blue-Green 494 nm 143 nm – Lamp Wide bandwidth, deluxe blend component[34]
3Sr3(PO4)2.SrF2:Sb,Mn Blue 502 nm – – Lamp –
Sr5F(PO4)3:Sb,Mn Blue-Green 509 nm 127 nm – Lamp Wide bandwidth[34]
Sr5F(PO4)3:Sb,Mn Blue-Green 509 nm 127 nm – Lamp Wide bandwidth[34]
LaPO4:Ce,Tb Green 544 nm – – Lamp Trichromatic fluorescent lamps
(La,Ce,Tb)PO4 Green – – – Lamp Trichromatic fluorescent lamps
(La,Ce,Tb)PO4:Ce,Tb Green 546 nm 6 nm – Lamp Trichromatic fluorescent lamps[34]
Ca3(PO4)2.CaF2:Ce,Mn Yellow 568 nm – – Lamp –
(Ca,Zn,Mg)3(PO4)2:Sn Orange-Pink 610 nm 146 nm – Lamp Wide bandwidth, blend component[34]
(Zn,Sr)3(PO4)2:Mn Orange-Red 625 nm – – Lamp –
(Sr,Mg)3(PO4)2:Sn Light Orange-Pink 626 nm 120 nm – Fluorescent lamps Wide bandwidth, deluxe blend component[34]
(Sr,Mg)3(PO4)2:Sn(II) Orange-red 630 nm – – Fluorescent lamps –
Ca5F(PO4)3:Sb,Mn 3800K – – – Fluorescent lamps Lite-white blend[34]
Ca5(F,Cl)(PO4)3:Sb,Mn White-Cold/Warm – – – Fluorescent lamps 2600 to 9900 K, for very high output lamps[34]
(Y,Eu)2O3 Red – – – Lamp Trichromatic fluorescent lamps
Y2O3:Eu(III) Red 611 nm 4 nm – Lamp Trichromatic fluorescent lamps[34]
Mg4(F)GeO6:Mn Red 658 nm 17 nm – High-pressure mercury lamps [34]
Mg4(F)(Ge,Sn)O6:Mn Red 658 nm – – Lamp –
Y(P,V)O4:Eu Orange-Red 619 nm – – Lamp –
YVO4:Eu Orange-Red 619 nm – – High Pressure Mercury and Metal Halide Lamps –
Y2O2S:Eu Red 626 nm – – Lamp –
3.5MgO· 0.5 MgF2· GeO2:Mn Red 655 nm – – Lamp 3.5MgO· 0.5MgF2·GeO2:Mn
Mg5As2O11:Mn Red 660 nm – – High-pressure mercury lamps, 1960s –
SrAl2O7:Pb Ultraviolet 313 nm – – Special fluorescent lamps for medical use Ultraviolet
CAM LaMgAl11O19:Ce Ultraviolet 340 nm 52 nm – Black-light fluorescent lamps Ultraviolet
LAP LaPO4:Ce Ultraviolet 320 nm 38 nm – Medical and scientific UV lamps Ultraviolet
SAC SrAl12O19:Ce Ultraviolet 295 nm 34 nm – Lamp Ultraviolet
SrAl11Si0.75O19:Ce0.15Mn0.15 Green 515 nm 22 nm – Lamp Monochromatic lamps for copiers[37]
BSP BaSi2O5:Pb Ultraviolet 350 nm 40 nm – Lamp Ultraviolet
SrFB2O3:Eu(II) Ultraviolet 366 nm – – Lamp Ultraviolet
SBE SrB4O7:Eu Ultraviolet 368 nm 15 nm – Lamp Ultraviolet
SMS Sr2MgSi2O7:Pb Ultraviolet 365 nm 68 nm – Lamp Ultraviolet
MgGa2O4:Mn(II) Blue-Green – – – Lamp Black light displays

Various[edit]

Some other phosphors commercially available, for use asX-rayscreens,neutron detectors,alpha particlescintillators,etc., are:

Phosphor Composition Color Wavelength Decay Afterglow X-ray absorption Usage
Gd2O2S:Eu Red 627 nm 850 μs Yes High X-ray, neutrons and gamma
Gd2O2S:Pr Green 513 nm 4 μs No High X-ray, neutrons and gamma
Gd2O2S:Pr,Ce,F Green 513 nm 7 μs No High X-ray, neutrons and gamma
Y2O2S:Pr White 513 nm 7 μs No Low-energy X-ray
HS Zn
0.5Cd
0.4S:Ag 		Green 560 nm 80 μs Yes Efficient but low-res X-ray
HSr Zn
0.4Cd
0.6S:Ag 		Red 630 nm 80 μs Yes Efficient but low-res X-ray
CdWO4 Blue 475 nm 28 μs No Intensifying phosphor for X-ray and gamma
CaWO4 Blue 410 nm 20 μs No Intensifying phosphor for X-ray and gamma
MgWO4 White 500 nm 80 μs No Intensifying phosphor
YAP YAlO3:Ce Blue 370 nm 25 ns No For electrons, suitable for photomultipliers
YAG Y3Al5O12:Ce Green 550 nm 70 ns No For electrons, suitable for photomultipliers
YGG Y3(Al,Ga)5O12:Ce Green 530 nm 250 ns Low For electrons, suitable for photomultipliers
CdS:In Green 525 nm <1 ns No Ultrafast, for electrons
ZnO:Ga Blue 390 nm <5 ns No Ultrafast, for electrons
Anthracene Blue 447 nm 32 ns No For alpha particles and electrons
plastic (EJ-212) Blue 400 nm 2.4 ns No For alpha particles and electrons
P1 Zn2SiO4:Mn Green 530 nm 11 ns Low For electrons
GS ZnS:Cu Green 520 nm Minutes Long For X-rays
NaI:Tl For X-ray, alpha, and electrons
CsI:Tl Green 545 nm 5 μs Yes For X-ray, alpha, and electrons
ND 6LiF/ZnS:Ag Blue 455 nm 80 μs Forthermal neutrons
NDg 6LiF/ZnS:Cu,Al,Au Green 565 nm 35 μs For neutrons
Cerium doped YAG phosphor Yellow

See also[edit]

References[edit]

  1. ^Emsley, John (2000).The Shocking History of Phosphorus.London: Macmillan.ISBN978-0-330-39005-7.
  2. ^Xie, Rong-Jun; Hirosaki, Naoto (2007)."Silicon-based oxynitride and nitride phosphors for white LEDs—A review".Sci. Technol. Adv. Mater.8(7–8): 588.Bibcode:2007STAdM...8..588X.doi:10.1016/j.stam.2007.08.005.Open access icon
  3. ^Li, Hui-Li; Hirosaki, Naoto; Xie, Rong-Jun; Suehiro, Takayuki; Mitomo, Mamoru (2007)."Fine yellow α-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method".Sci. Technol. Adv. Mater.8(7–8): 601.Bibcode:2007STAdM...8..601L.doi:10.1016/j.stam.2007.09.003.Open access icon
  4. ^Kane, Raymond and Sell, Heinz (2001)Revolution in lamps: a chronicle of 50 years of progress,2nd ed. The Fairmont Press.ISBN0-88173-378-4.Chapter 5 extensively discusses history, application and manufacturing of phosphors for lamps.
  5. ^abMatsuzawa, T.; Aoki, Y.; Takeuchi, N.; Murayama, Y. (1996-08-01)."A New Long Phosphorescent Phosphor with High Brightness, SrAl2O4:Eu2+,Dy3+".Journal of the Electrochemical Society.143(8): 2670–2673.Bibcode:1996JElS..143.2670M.doi:10.1149/1.1837067.ISSN0013-4651.
  6. ^US5424006A,"Phosphorescent phosphor", issued 1994-02-25
  7. ^abcdefgPeter W. Hawkes (1 October 1990).Advances in electronics and electron physics.Academic Press. pp. 350–.ISBN978-0-12-014679-6.Retrieved9 January2012.
  8. ^Bizarri, G; Moine, B (2005). "On phosphor degradation mechanism: thermal treatment effects".Journal of Luminescence.113(3–4): 199.Bibcode:2005JLum..113..199B.doi:10.1016/j.jlumin.2004.09.119.
  9. ^Lakshmanan, p. 171.
  10. ^Tanno, Hiroaki; Fukasawa, Takayuki; Zhang, Shuxiu; Shinoda, Tsutae; Kajiyama, Hiroshi (2009). "Lifetime Improvement of BaMgAl10O17:Eu2+Phosphor by Hydrogen Plasma Treatment ".Japanese Journal of Applied Physics.48(9): 092303.Bibcode:2009JaJAP..48i2303T.doi:10.1143/JJAP.48.092303.S2CID94464554.
  11. ^Ntwaeaborwa, O. M.; Hillie, K. T.; Swart, H. C. (2004). "Degradation of Y2O3:Eu phosphor powders ".Physica Status Solidi C.1(9): 2366.Bibcode:2004PSSCR...1.2366N.doi:10.1002/pssc.200404813.
  12. ^Wang, Ching-Wu; Sheu, Tong-Ji; Su, Yan-Kuin; Yokoyama, Meiso (1997). "Deep Traps and Mechanism of Brightness Degradation in Mn-doped ZnS Thin-Film Electroluminescent Devices Grown by Metal-Organic Chemical Vapor Deposition".Japanese Journal of Applied Physics.36(5A): 2728.Bibcode:1997JaJAP..36.2728W.doi:10.1143/JJAP.36.2728.S2CID98131548.
  13. ^Lakshmanan, pp. 51, 76
  14. ^"PPT presentation in Polish (Link to achieved version; Original site isn't available)".Tubedevices.com. Archived from the original on 2013-12-28.Retrieved2016-12-15.{{cite web}}:CS1 maint: bot: original URL status unknown (link)
  15. ^"Vacuum light sources — High speed stroboscopic light sourcesdata sheet "(PDF).Ferranti,Ltd. August 1958.Archived(PDF)from the original on 20 September 2016.Retrieved7 May2017.
  16. ^Lehner, P.; Staudinger, C.; Borisov, S. M.; Klimant, l. (2014)."Ultra-sensitive optical oxygen sensors for characterization of nearly anoxic systems".Nature Communications.5:4460.Bibcode:2014NatCo...5.4460L.doi:10.1038/ncomms5460.PMC4109599.PMID25042041.
  17. ^Hamzehpoor, E; Ruchlin, C.; Tao, Y.; Liu, C. H.; Titi, H. M.; Perepichka, D. F. (2022). "Efficient room-temperature phosphorescence of covalent organic frameworks through covalent halogen doping".Nature Chemistry.15(1): 83–90.doi:10.1038/s41557-022-01070-4.PMID36302870.S2CID253183290.
  18. ^Xie, Z.; Ma, L.; deKrafft, K. E.; Jin, A.; Lin, W. (2010). "Porous phosphorescent coordination polymers for oxygen sensing".J. Am. Chem. Soc.132(3): 922–923.doi:10.1021/ja909629f.PMID20041656.
  19. ^SEEING PHOSPHOR BANDS on U.K. STAMPSArchived2015-10-19 at theWayback Machine.
  20. ^Phosphor BandsArchived2017-03-17 at theWayback Machine.
  21. ^"Archived copy"(PDF).Archived(PDF)from the original on 2016-12-21.Retrieved2017-02-12.{{cite web}}:CS1 maint: archived copy as title (link)
  22. ^XTECH, NIKKEI."Sharp to Employ White LED Using Sialon".NIKKEI XTECH.Retrieved2019-01-10.
  23. ^Youn-Gon Park; et al."Luminescence and temperature dependency of β-SiAlON phosphor".Samsung Electro Mechanics Co.Archived fromthe originalon 2010-04-12.Retrieved2009-09-24.
  24. ^Hideyoshi Kume, Nikkei Electronics (Sep 15, 2009)."Sharp to Employ White LED Using Sialon".Archivedfrom the original on 2012-02-23.
  25. ^Naoto, Hirosaki; et al. (2005)."New sialon phosphors and white LEDs".Oyo Butsuri.74(11): 1449. Archived fromthe originalon 2010-04-04.
  26. ^Fudin, M.S.; et al. (2014)."Frequency characteristics of modern LED phosphor materials".Scientific and Technical Journal of Information Technologies, Mechanics and Optics.14(6): 71.Archivedfrom the original on 2015-06-26.
  27. ^Bush, Steve (March 14, 2014)."Discussing LED lighting phosphors".
  28. ^Setlur, Anant A. (1 December 2009)."Phosphors for LED-based Solid-State Lighting"(PDF).The Electrochemical Society Interface.18(4): 32–36.doi:10.1149/2.F04094IF.Retrieved5 December2022.
  29. ^Levine, Albert K.; Palilla, Frank C. (1964). "A new, highly efficient red-emitting cathodoluminescent phosphor (YVO4:Eu) for color television ".Applied Physics Letters.5(6): 118.Bibcode:1964ApPhL...5..118L.doi:10.1063/1.1723611.
  30. ^Fields, R. A.; Birnbaum, M.; Fincher, C. L. (1987)."Highly efficient Nd:YVO4diode-laser end-pumped laser ".Applied Physics Letters.51(23): 1885.Bibcode:1987ApPhL..51.1885F.doi:10.1063/1.98500.
  31. ^abcdLakshmanan, p. 54.
  32. ^Shionoya, Shigeo (1999)."VI: Phosphors for cathode ray tubes".Phosphor handbook.Boca Raton, Fla.: CRC Press.ISBN978-0-8493-7560-6.
  33. ^Jankowiak, Patrick."Cathode Ray Tube Phosphors"(PDF).bunkerofdoom.com.Archived(PDF)from the original on 19 January 2013.Retrieved1 May2012.[unreliable source?]
  34. ^abcdefghijklmnopqrstu"Osram Sylvania fluorescent lamps".Archived fromthe originalon July 24, 2011.Retrieved2009-06-06.
  35. ^Keller, Peter (1991).The Cathode-Ray Tube: Technology, History, and Applications.Palisades Press. p. 17.ISBN0963155903.
  36. ^"VFD｜Futaba Corporation".27 February 2021.
  37. ^Lagos C (1974) "Strontium aluminate phosphor activated by cerium and manganese"U.S. patent 3,836,477

Bibliography[edit]

External links[edit]

Look upphosphorin Wiktionary, the free dictionary.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Phosphor&oldid=1228605124"